WORLDCOM INC /GA/
S-4/A, 1997-06-27
TELEPHONE COMMUNICATIONS (NO RADIOTELEPHONE)
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<PAGE>
 
     
  AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JUNE 27, 1997     
 
                                                     REGISTRATION NO. 333-27345
- -------------------------------------------------------------------------------
- -------------------------------------------------------------------------------
 
                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549
 
                               ----------------
                                
                             AMENDMENT NO. 2     
                                      TO
                                   FORM S-4
                            REGISTRATION STATEMENT
                                     UNDER
                          THE SECURITIES ACT OF 1933
 
                               ----------------
 
                                WORLDCOM, INC.
            (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)
 
         GEORGIA                     4813                    58-1521612
     (STATE OR OTHER     (PRIMARY STANDARD INDUSTRIAL     (I.R.S. EMPLOYER
      JURISDICTION        CLASSIFICATION CODE NUMBER)  IDENTIFICATION NUMBER)
   OF INCORPORATION OR
      ORGANIZATION)
 
                             515 EAST AMITE STREET
                        JACKSON, MISSISSIPPI 39201-2702
                                (601) 360-8600
  (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE, OF
                   REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)
 
                               ----------------
 
                               BERNARD J. EBBERS
                     PRESIDENT AND CHIEF EXECUTIVE OFFICER
                                WORLDCOM, INC.
                             515 EAST AMITE STREET
                        JACKSON, MISSISSIPPI 39201-2702
                                (601) 360-8600
(NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                             OF AGENT FOR SERVICE)
 
                               ----------------

<TABLE> 
<CAPTION> 
 
                                  COPIES TO:
<S>                                    <C>                         <C>  
  P. BRUCE BORGHARDT, ESQ.             R. RANDALL WANG, ESQ.       ALLAN G. SPERLING, ESQ.
      GENERAL COUNSEL--                NICK H. VARSAM, ESQ.        CLEARY, GOTTLIEB, STEEN
    CORPORATE DEVELOPMENT                 BRYAN CAVE LLP                      &
       WORLDCOM, INC.                   211 NORTH BROADWAY                HAMILTON
10777 SUNSET OFFICE DRIVE, SUITE 330         SUITE 3600                ONE LIBERTY PLAZA
     ST. LOUIS, MO 63127                ST. LOUIS, MO 63102          NEW YORK, NY 10006
       (314) 909-4100                     (314) 259-2000               (212) 225-2260
 
</TABLE> 
                               ----------------
 
  APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: As soon as
practicable after this Registration Statement is declared effective.
 
  If the securities being registered on this form are being offered in
connection with the formation of a holding company and there is compliance
with General Instruction G, check the following box. [_]
 
  THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT
SHALL FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS
REGISTRATION STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH
SECTION 8(a) OF THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT
SHALL BECOME EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID
SECTION 8(a), MAY DETERMINE.
 
- -------------------------------------------------------------------------------
- -------------------------------------------------------------------------------
<PAGE>
 
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+INFORMATION CONTAINED HEREIN IS SUBJECT TO COMPLETION OR AMENDMENT. A         +
+REGISTRATION STATEMENT RELATING TO THESE SECURITIES HAS BEEN FILED WITH THE   +
+SECURITIES AND EXCHANGE COMMISSION. THESE SECURITIES MAY NOT BE SOLD NOR MAY  +
+OFFERS TO BUY BE ACCEPTED PRIOR TO THE TIME THE REGISTRATION STATEMENT        +
+BECOMES EFFECTIVE. THIS PROSPECTUS SHALL NOT CONSTITUTE AN OFFER TO SELL OR   +
+THE SOLICITATION OF AN OFFER TO BUY NOR SHALL THERE BE ANY SALE OF THESE      +
+SECURITIES IN ANY STATE IN WHICH SUCH OFFER, SOLICITATION OR SALE WOULD BE    +
+UNLAWFUL PRIOR TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES LAWS OF  +
+SUCH STATE.                                                                   +
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                   
                SUBJECT TO COMPLETION, DATED JUNE 27, 1997     
 
PROSPECTUS AND CONSENT SOLICITATION
 
WORLDCOM, INC.
                       [LOGO OF WORLDCOM APPEARS HERE]
OFFERS TO EXCHANGE
   
$686,398,000 9 3/8% SENIOR NOTES OF WORLDCOM, INC. DUE JANUARY 15, 2004 FOR ANY
AND ALL OUTSTANDING     
9 3/8% SENIOR DISCOUNT NOTES OF MFS COMMUNICATIONS COMPANY, INC. DUE JANUARY
15, 2004
   
$671,850,000 8 7/8% SENIOR NOTES OF WORLDCOM, INC. DUE JANUARY 15, 2006 FOR ANY
AND ALL OUTSTANDING     
8 7/8% SENIOR DISCOUNT NOTES OF MFS COMMUNICATIONS COMPANY, INC. DUE JANUARY
15, 2006
 
AND
 
CONSENT SOLICITATIONS
   
WorldCom, Inc. ("WorldCom" or the "Company") hereby offers, upon the terms and
subject to the conditions set forth in this Prospectus and Consent Solicitation
(together, the "Prospectus") and the accompanying Letters of Transmittal and
Consent (each a "Letter of Transmittal"), to exchange (i) $871.597 principal
amount of its 9 3/8% Senior Notes due January 15, 2004 ("WorldCom 2004 Notes")
for each $1,000 principal amount at stated maturity of outstanding 9 3/8%
Senior Discount Notes due January 15, 2004 ("MFS 2004 Notes") of MFS
Communications Company, Inc., a wholly owned subsidiary of WorldCom ("MFS"),
properly tendered for exchange and accepted and (ii) $737.912 principal amount
of its 8 7/8% Senior Notes due January 15, 2006 ("WorldCom 2006 Notes" and,
together with the WorldCom 2004 Notes, the "WorldCom Notes") for each $1,000
principal amount at stated maturity of outstanding 8 7/8% Senior Discount Notes
due January 15, 2006 ("MFS 2006 Notes" and, together with the MFS 2004 Notes,
the "MFS Notes") of MFS properly tendered for exchange and accepted (each such
offer, an "Exchange Offer," and collectively, the "Exchange Offers"). Interest
on the WorldCom Notes will accrue from July 15, 1997 (the "Interest Accrual
Date") at the stated rate thereon. The principal amount of WorldCom Notes
offered in exchange for the applicable series of MFS Notes is equal to the
Accreted Value (as defined herein) of such MFS Notes as of the Interest Accrual
Date. The Accreted Value, as of the Interest Accrual Date, per $1,000 principal
amount at stated maturity, of the MFS 2004 Notes and the MFS 2006 Notes is
$871.597 and $737.912, respectively.     
   
Concurrently with the Exchange Offers, WorldCom is soliciting consents
("Consents") from each registered holder of the MFS 2004 Notes and the MFS 2006
Notes (each such holder, a "Holder," and collectively, the "Holders") to
certain amendments (the "Proposed Amendments") to the Indenture dated as of
January 15, 1994 (as supplemented by a First Supplemental Indenture thereto
dated as of March 31, 1995, the "1994 Indenture") and the Indenture dated as of
January 15, 1996 (as supplemented by a First Supplemental Indenture thereto
dated as of January 15, 1996, the "1996 Indenture" and, together with the 1994
Indenture, the "MFS Indentures"), under which the MFS Notes were issued (each
such solicitation, a "Consent Solicitation," and collectively, the "Consent
Solicitations"). No record date has been or will be set for purposes of giving
Consents.     
 
(cover page continues)
 
 EACH EXCHANGE OFFER WILL EXPIRE AT 11:59 P.M., NEW YORK CITY TIME, ON , 1997,
 UNLESS EXTENDED (SUCH TIME AND DATE, AS EXTENDED, THE "EXPIRATION DATE" WITH
 RESPECT TO SUCH EXCHANGE OFFER). TENDERS OF MFS NOTES MAY NOT BE WITHDRAWN (AND
 THE RELATED CONSENTS THEREBY REVOKED) AT ANY TIME AFTER 11:59 P.M., NEW YORK
 CITY TIME, ON      , 1997, UNLESS THE APPLICABLE EXCHANGE OFFER IS EXTENDED AND
 CONTAINS NEW TERMS MATERIALLY ADVERSE TO THE TENDERING HOLDERS THEREOF.
 
SEE "RISK FACTORS" COMMENCING ON PAGE 17 FOR CERTAIN INFORMATION THAT SHOULD BE
CONSIDERED IN EVALUATING THE EXCHANGE OFFERS AND CONSENT SOLICITATIONS.
 
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE SECURITIES
AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION PASSED UPON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS
A CRIMINAL OFFENSE.
   
None of WorldCom, MFS or the Dealer Managers makes any recommendation as to
whether or not Holders should exchange their MFS Notes pursuant to the Exchange
Offers and provide Consents to the Proposed Amendments.     
 
  THE JOINT DEALER MANAGERS FOR THE EXCHANGE OFFERS AND CONSENT SOLICITATIONS
                                      ARE:
 
SALOMON BROTHERS INC                                        GOLDMAN, SACHS & CO.
 
For assistance in connection with the Exchange Offers, please contact the
appropriate party listed on the back cover hereof.
 
The date of this Prospectus and Consent Solicitation is      , 1997.
<PAGE>
 
(cover page continued)
   
The Company hereby offers, upon the terms and subject to the conditions set
forth in this Prospectus and in the Letters of Transmittal, to pay each Holder
who gives a valid Consent on or prior to the Expiration Date a cash fee in an
amount equal to (i) with respect to such Holder's MFS 2004 Notes, 0. % of the
Accreted Value, as of the Interest Accrual Date, of such MFS 2004 Notes and
(ii) with respect to such Holder's MFS 2006 Notes, 0.  % of the Accreted
Value, as of the Interest Accrual Date, of such MFS 2006 Notes, in either
case, with respect to which such Consent has been given (each such cash
payment, a "Consent Payment"). HOLDERS OF MFS NOTES OF EITHER SERIES MAY GIVE
THEIR CONSENT TO THE PROPOSED AMENDMENTS APPLICABLE TO THAT SERIES ONLY BY
TENDERING SUCH MFS NOTES IN THE APPLICABLE EXCHANGE OFFER AND WILL BE DEEMED
TO HAVE GIVEN SUCH CONSENT BY SO TENDERING. Consents from Holders of a
majority in aggregate principal amount Outstanding (as defined herein) of MFS
Notes of a series (the "Requisite Consent") must be received in order to amend
the MFS Indenture governing that series as described herein, except with
respect to the modification of the term "Change of Control," which requires
Consents from Holders of not less than 75% of the aggregate principal amount
Outstanding (as defined herein) of MFS Notes of a series (the "Supermajority
Consent"). As used herein, "Accreted Value" shall have the meaning given such
term in the applicable MFS Indenture. The Accreted Value of a series of MFS
Notes as of the Interest Accrual Date is the sum of (i) the initial issue
price of such MFS Notes plus (ii) the portion of the original issue discount
applicable to such MFS Notes accreted from and including the original issue
date thereof and to but excluding the Interest Accrual Date. See "The Proposed
Amendments--Certain Definitions."     
   
The obligation of the Company, with respect to either series of MFS Notes, to
consummate the applicable Exchange Offer and to make the Consent Payments is
conditional upon, among other things, the receipt of the Requisite Consent to
the Proposed Amendments with respect to both series of MFS Notes. See "The
Exchange Offers--Conditions to the Exchange Offers" and "The Consent
Solicitations--Consent Payments." The Company will not consummate the Exchange
Offer with respect to the MFS 2004 Notes if less than $343.2 million of
principal amount of WorldCom 2004 Notes would be issued in such Exchange Offer
and will not consummate the Exchange Offer with respect to the MFS 2006 Notes
if less than $336.0 million of principal amount of WorldCom 2006 Notes would
be issued in such Exchange Offer.     
   
WorldCom Notes will be issued only in denominations of $1,000 and integral
multiples thereof. If the aggregate principal amount of WorldCom Notes that
otherwise would be issued in exchange for the MFS Notes of a series tendered
by a Holder and accepted by the Company pursuant to an Exchange Offer is not
an integral multiple of $1,000, such principal amount will be reduced to the
nearest such multiple and the Company will pay to such Holder an amount in
cash equal to the reduction of such principal amount. WorldCom Notes to be
exchanged for MFS Notes pursuant to the Exchange Offers will be delivered and
Consent Payments and other cash payments, if any, will be made on the third
business day following the Expiration Date, or as soon as possible thereafter
(the "Exchange Date").     
   
The WorldCom Notes will be senior, unsecured obligations of the Company, will
rank pari passu in right of payment with all other existing and future senior,
unsecured indebtedness of the Company and will rank senior in right of payment
to any future subordinated obligations of the Company. The WorldCom Notes will
be effectively subordinated to any secured indebtedness of the Company to the
extent of the value of the assets securing such indebtedness. As of March 31,
1997, after giving effect to the issuance and sale by the Company of the April
WorldCom Notes (as defined herein), the aggregate amount of indebtedness of
the Company to which the WorldCom Notes would have ranked pari passu was
approximately $3.18 billion and the aggregate amount of secured indebtedness
of the Company was approximately $53 million. The WorldCom Notes will be
structurally subordinated to all obligations of the Company's subsidiaries,
including any MFS Notes not exchanged for WorldCom Notes in the Exchange
Offers, to the extent of the assets of such subsidiaries. As of March 31,
1997, the aggregate amount of outstanding obligations of the Company's
subsidiaries to which the holders of the WorldCom Notes would have been
structurally subordinated (including trade payables but excluding intercompany
indebtedness) was approximately $2.66 billion (of which $1.38 billion
represented the carrying value of the MFS Notes). See "Risk Factors--Certain
Considerations Relating to Holders Tendering in the Exchange Offers--
Structural Subordination of the WorldCom Notes" and "Description of the
WorldCom Notes--Ranking."     
   
The financial terms of the WorldCom 2004 Notes and the WorldCom 2006 Notes
will be substantially identical in all material respects to the financial
terms of the MFS 2004 Notes and the MFS 2006 Notes, respectively, except that:
(i) the MFS Notes are the sole obligations of MFS, while the WorldCom Notes
will be the sole obligations of WorldCom; (ii) the MFS 2004 Notes and MFS 2006
Notes were originally issued at a discount and, except as described below, the
principal amount thereof accretes in value until January 15, 1999 and January
15, 2001, respectively, while the WorldCom Notes will have a fixed principal
amount; (iii) except as described below, no cash interest accrues on the MFS
2004 Notes and the MFS 2006 Notes until January 15, 1999 and January 15, 2001,
respectively, while interest will begin to accrue on the WorldCom Notes on the
Interest Accrual Date and will be payable in cash semi-annually in arrears on
each January 15 and July 15, commencing July 15, 1997; and (iv) overdue
principal and premium, if any, and interest on the overdue principal and any
overdue premium of the MFS 2004 Notes and the MFS 2006 Notes bear interest at
the rate of 10 3/8% and 9 7/8% per annum, respectively, while overdue
principal and premium, if any, and interest on the overdue principal and any
overdue premium of the WorldCom 2004 Notes and the WorldCom 2006 Notes will
bear interest at 9 3/8% and 8 7/8% per annum, respectively. The WorldCom
Indenture (as defined herein) will contain covenants that are substantially
less restrictive than those that are currently in the MFS Indentures, and the
WorldCom Notes will carry significantly reduced protections than now afforded
to the MFS Notes. Pursuant to the MFS Indentures, MFS may elect, prior to July
15, 1997 (or a future Interest Payment Date, as such term is defined herein
(see "The Proposed Amendments--Certain Definitions"), to commence the accrual
of cash interest on either series of MFS Notes beginning on such date, at
which time the outstanding principal amount of each of such MFS Notes at their
respective stated maturities will equal the Accreted Value of such MFS Notes
as of such date, and cash interest will be payable on January 15, 1998 (or the
next succeeding Interest Payment Date, as the case may be) and on each
Interest Payment Date thereafter. In the event any such election is made prior
to the Expiration Date, MFS intends to issue a press release and file with the
Securities and Exchange Commission a Current Report on Form 8-K publicly
announcing the commencement of the accrual of cash interest on the MFS Notes
beginning on July 15, 1997 (or a future Interest Payment Date, as the case may
be). See "The Exchange Offers--Description of Differences Between the MFS
Notes and the WorldCom Notes."     
 
The Company does not intend to list the WorldCom Notes on any national
securities exchange. The Dealer Managers currently plan to make a market in
the WorldCom Notes. However, there can be no assurance that the Dealer
Managers will make such a market or that any active market in the WorldCom
Notes will develop or be maintained.
   
The receipt of WorldCom Notes, Consent Payments and other cash, if any,
pursuant to the Exchange Offers and Consent Solicitations will be a taxable
transaction for United States federal income tax purposes. See "Certain U.S.
Federal Income Tax Consequences."     
<PAGE>
 
  NO DEALER, SALESPERSON OR OTHER PERSON HAS BEEN AUTHORIZED TO GIVE ANY
INFORMATION OR TO MAKE ANY REPRESENTATIONS OTHER THAN THOSE CONTAINED OR
INCORPORATED BY REFERENCE IN THIS PROSPECTUS AND, IF GIVEN OR MADE, SUCH
INFORMATION OR REPRESENTATIONS MUST NOT BE RELIED UPON AS HAVING BEEN
AUTHORIZED BY THE COMPANY, OR ANY UNDERWRITER, AGENT OR DEALER. NEITHER THE
DELIVERY OF THIS PROSPECTUS NOR ANY SALE MADE HEREUNDER SHALL, UNDER ANY
CIRCUMSTANCE, CREATE AN IMPLICATION THAT THERE HAS BEEN NO CHANGE IN THE
AFFAIRS OF THE COMPANY SINCE THE DATE HEREOF. THIS PROSPECTUS DOES NOT
CONSTITUTE AN OFFER TO SELL OR A SOLICITATION OF AN OFFER TO BUY ANY OF THE
SECURITIES OFFERED HEREBY IN ANY JURISDICTION TO ANY PERSON TO WHOM IT IS
UNLAWFUL TO MAKE SUCH OFFER OR SOLICITATION IN SUCH JURISDICTION.
 
                             AVAILABLE INFORMATION
 
  Each of WorldCom and MFS is subject to the informational requirements of the
Securities Exchange Act of 1934, as amended (the "Exchange Act"), and in
accordance therewith files reports, proxy statements and other information
with the Securities and Exchange Commission (the "Commission"). Such reports,
proxy statements and other information filed by each of WorldCom and MFS may
be inspected and copied at the public reference facilities maintained by the
Commission at Room 1024, Judiciary Plaza, 450 Fifth Street, N.W., Washington,
D.C. 20549 and at the Commission's regional offices located at Northeast
Regional Office, Seven World Trade Center, Suite 1300, New York, New York
10048 and Midwest Regional Office, Citicorp Center, 500 West Madison Street,
Suite 1400, Chicago, Illinois 60661-2511. Copies of such materials can also be
obtained by mail from the Public Reference Section of the Commission,
Judiciary Plaza, 450 Fifth Street, N.W., Washington, D.C. 20549, at prescribed
rates. The Commission maintains a Web site that contains reports, proxy and
information statements and other materials that are filed through the
Commission's Electronic Data Gathering, Analysis and Retrieval (EDGAR) system.
This Web site can be accessed at http://www.sec.gov. Shares of the Company's
Common Stock are listed on the Nasdaq National Market and the reports, proxy
statements and other information filed by WorldCom also can be inspected at
the offices of the National Association of Securities Dealers, Inc. (the
"NASD"), at 1735 K Street, N.W., Washington, D.C. 20006. Upon completion of
the Exchange Offers, application (on Form 15) to the Commission promptly will
be made to deregister the common stock of MFS under the Exchange Act. As a
result of such deregistration and the effectiveness of the Proposed
Amendments, MFS no longer will be obligated to file periodic reports with the
Commission. See "The Proposed Amendments."
 
  This Prospectus constitutes a part of a registration statement on Form S-4
(together with all amendments and exhibits thereto, the "Registration
Statement") filed by WorldCom with the Commission under the Securities Act of
1933, as amended (the "Securities Act"), with respect to the WorldCom Notes
offered hereby. This Prospectus does not contain all of the information set
forth in the Registration Statement, certain parts of which are omitted in
accordance with the rules and regulations of the Commission. Reference is made
to such Registration Statement and to the exhibits relating thereto for
further information with respect to WorldCom, the WorldCom Notes, MFS and the
MFS Notes. Any statements contained herein concerning the provisions of
certain documents are not necessarily complete, and in each instance,
reference is made to the copy of such document filed as an exhibit to the
Registration Statement or otherwise filed with the Commission for a more
complete description of the matter involved. Each such statement is qualified
in its entirety by such reference.
 
                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE
 
  The following documents filed with the Commission by WorldCom (formerly
Resurgens Communications Group, Inc.) under File No. 0-11258 (formerly File
No. 1-10415) and by MFS under File No. 33-72594 (formerly File No. 0-21594)
pursuant to the Exchange Act are incorporated herein by reference:
 
    (a)(1) WorldCom's Annual Report on Form 10-K for the fiscal year ended
  December 31, 1996 (the "WorldCom 1996 Form 10-K");
 
    (2) WorldCom's Quarterly Report on Form 10-Q for the quarter ended March
  31, 1997; and
 
                                       3
<PAGE>
 
     
    (3) WorldCom's Current Reports on Form 8-K dated August 25, 1996 (filed
  August 26, 1996 and as amended on Forms 8-K/A filed November 4, 1996 and
  November 20, 1996), December 31, 1996 (filed January 15, 1997), March 18,
  1997 (filed March 24, 1997), March 26, 1997 (filed April 2, 1997) and May
  22, 1997 (filed June 6, 1997).     
 
    (b)(1) MFS' Annual Report on Form 10-K for the year ended December 31,
  1996;
 
    (2) MFS' Quarterly Report on Form 10-Q for the quarter ended March 31,
  1997;
 
    (3) MFS' Current Report on Form 8-K dated January 20, 1997 (filed January
  24, 1997); and
 
    (4) MFS' Form 10 dated May 16, 1997 (filed May 16, 1997).
 
  All documents filed by WorldCom and MFS with the Commission pursuant to
Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act subsequent to the date
hereof and prior to the termination of the offering of any securities offered
hereby shall be deemed to be incorporated by reference into this Prospectus
and to be a part hereof from the date of filing of such documents. See
"Available Information." Any statement contained herein, or in a document
incorporated or deemed to be incorporated herein by reference, shall be deemed
to be modified or superseded for purposes of this Prospectus to the extent
that a statement contained herein or in any other subsequently filed document
incorporated or deemed to be incorporated herein by reference, which statement
is also incorporated herein by reference, modifies or supersedes such
statement. Any such statement so modified or superseded shall not be deemed,
except as so modified or superseded, to constitute a part of this Prospectus.
 
  THIS PROSPECTUS INCORPORATES DOCUMENTS BY REFERENCE WHICH ARE NOT PRESENTED
HEREIN OR DELIVERED HEREWITH. COPIES OF THESE DOCUMENTS (EXCLUDING EXHIBITS
UNLESS SUCH EXHIBITS ARE SPECIFICALLY INCORPORATED BY REFERENCE INTO THE
INFORMATION INCORPORATED HEREIN) WILL BE PROVIDED BY FIRST CLASS MAIL WITHOUT
CHARGE TO EACH PERSON TO WHOM THIS PROSPECTUS IS DELIVERED UPON WRITTEN OR
ORAL REQUEST BY SUCH PERSON TO WORLDCOM, INC., 515 EAST AMITE STREET, JACKSON,
MISSISSIPPI 39201-2702, ATTENTION: STEPHANIE Q. SCOTT, DIRECTOR OF FINANCIAL
REPORTING (TELEPHONE: (601) 360-8600). IN ORDER TO ENSURE TIMELY DELIVERY OF
THE DOCUMENTS, ANY REQUEST SHOULD BE MADE BY      , 1997.
 
                               TABLE OF CONTENTS
<TABLE>   
<S>                                                                          <C>
AVAILABLE INFORMATION.......................................................   3
INCORPORATION OF CERTAIN DOCUMENTS
 BY REFERENCE...............................................................   3
PROSPECTUS SUMMARY..........................................................   5
CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS...................  17
RISK FACTORS................................................................  17
THE EXCHANGE OFFERS.........................................................  27
 Purpose of the Exchange Offers.............................................  27
 Terms of the Exchange Offers...............................................  27
 Conditions of the Exchange Offers and
  the Consent Solicitations.................................................  28
 Certain Consequences to Holders Not
  Tendering in the Exchange Offers..........................................  29
 Expiration Date; Extensions; Amendments....................................  30
 Effect of Tender...........................................................  30
 Acceptance of MFS Notes for Exchange;
  Delivery of WorldCom Notes................................................  30
 Procedures for Tendering...................................................  31
 Proper Execution and Delivery of Letters of Transmittal....................  33
 Withdrawal of Tenders and Revocation of Consents...........................  34
 Exchange Agent.............................................................  35
 Information Agent..........................................................  36
 Dealer Managers............................................................  36
</TABLE>    
<TABLE>   
<S>                                                                         <C>
 Other Fees and Expenses; Transfer Taxes...................................  36
 Description of Differences Between the
  MFS Notes and the WorldCom Notes.........................................  37
THE CONSENT SOLICITATIONS..................................................  55
 Required Consents.........................................................  55
 Consent Payments..........................................................  56
THE PROPOSED AMENDMENTS....................................................  57
 Provisions to be Deleted..................................................  57
 Provisions to be Revised..................................................  60
 Definition to be Revised Upon Receipt of Supermajority Consent from
  Holders of Each
  Series of MFS Notes......................................................  62
 Certain Definitions.......................................................  63
DESCRIPTION OF THE WORLDCOM NOTES..........................................  72
CERTAIN U.S. FEDERAL INCOME TAX CONSEQUENCES...............................  84
 United States Holders.....................................................  84
 Non-U.S. Holders..........................................................  86
INFORMATION REGARDING WORLDCOM.............................................  87
INFORMATION REGARDING MFS..................................................  87
CERTAIN RELATED TRANSACTIONS...............................................  87
ACCOUNTING TREATMENT OF EXCHANGE OFFERS....................................  87
LEGAL MATTERS..............................................................  87
EXPERTS....................................................................  87
</TABLE>    
 
                                       4
<PAGE>
 
                               PROSPECTUS SUMMARY
 
  The following summary does not purport to be complete and is qualified in its
entirety by, and should be read in conjunction with, the more detailed
financial information and Consolidated Financial Statements (including the
notes thereto) incorporated by reference in this Prospectus. In particular,
prospective purchasers should carefully consider the information set forth
under "Cautionary Statement Regarding Forward-Looking Statements" and "Risk
Factors."
 
                                    WORLDCOM
 
  WorldCom is one of the four largest long distance telecommunications
companies in the United States. The Company provides telecommunications
services to business, government, telecommunications companies and consumer
customers, through its network of fiber optic cables, digital microwave, and
fixed and transportable satellite earth stations.
 
  WorldCom is one of the first major facilities-based telecommunications
companies with the capability to provide businesses with high quality local,
long distance, Internet, data and international communications services over
its global networks. With service to points throughout the nation and the
world, WorldCom provides telecommunications products and services including:
switched and dedicated long distance and local products, 800 services, calling
cards, domestic and international private lines, broadband data services, debit
cards, conference calling, advanced billing systems, enhanced fax and data
connections, high speed data communications, facilities management, local
access to long distance companies, local access to ATM-based backbone service
and interconnection via Network Access Points to Internet service providers.
 
  WorldCom's principal executive offices are located at 515 East Amite Street,
Jackson, Mississippi 39201-2702, and its telephone number is (601) 360-8600.
 
                                      MFS
 
  MFS provides communications services domestically and internationally in the
form of: (i) dedicated special access and private line circuits, local switched
service and high speed data communications to large business customers; (ii)
single source integrated local and long distance switched services, high speed
data communications services and facilities management to medium and small
businesses; (iii) local access to long distance companies; (iv) local access,
ATM-based backbone service and interconnection via Network Access Points to
Internet service providers; and (v) a comprehensive range of Internet-based
services. MFS provides communications services by utilizing its international
network platform, which consists of MFS-owned transmission and switching
facilities and network capacity leased from the other carriers primarily in the
United States and Western Europe.
 
  On August 12, 1996, MFS acquired UUNET Technologies, Inc. ("UUNET") through a
merger of a subsidiary of MFS with and into UUNET. UUNET is a leading worldwide
provider of a comprehensive range of Internet access options, applications, and
consulting services tailored to meet the needs of businesses and professionals.
UUNET makes available to customers a variety of products and services,
including dedicated and dial-up Internet access, Web server hosting and content
development services, client software and security products and training, all
of which can be integrated by UUNET through its network integration and
consulting services. UUNET enables Internet users to purchase access,
applications and services, including integration services, through a single
source. UUNET's products and services are supported by a technical staff that
is highly experienced in Internet
 
                                       5
<PAGE>
 
operations and services. UUNET's network operations center monitors traffic
across UUNET's network 24 hours per day, seven days per week.
 
  MFS provides network systems integration services primarily through MFS
Network Technologies, Inc. ("MFS Network Technologies"). Initially created to
design and build MFS' networks in a high quality and cost-effective manner, MFS
Network Technologies provides network systems integration services for MFS and
third parties which desire to deploy sophisticated networks, including
intelligent transportation systems, voice and data networks, interactive
distance learning networks, security systems and combined cable television-
telephone networks.
 
  The principal executive offices of MFS are located at 11808 Miracle Hills
Drive, Omaha, Nebraska 68154, a telephone number is (402) 231-3000.
 
                              WORLDCOM/MFS MERGER
 
  On December 31, 1996, WorldCom, through a wholly owned subsidiary, merged
with MFS (the "MFS Merger"). As a result of the MFS Merger, each share of MFS
common stock was converted into the right to receive 2.1 shares of WorldCom
common stock (the "Common Stock") or approximately 471.0 million shares of
Common Stock in the aggregate. Each share of MFS Series A 8% Cumulative
Convertible Preferred Stock ("MFS Series A Preferred Stock") was converted into
the right to receive one share of Series A 8% Cumulative Convertible Preferred
Stock of WorldCom ("WorldCom Series A Preferred Stock") or 94,992 shares of
WorldCom Series A Preferred Stock in the aggregate. Each share of MFS Series B
Convertible Preferred Stock was converted into the right to receive one share
of Series B Convertible Preferred Stock of WorldCom ("WorldCom Series B
Preferred Stock") or approximately 12.7 million shares of WorldCom Series B
Preferred Stock in the aggregate. In addition, each depositary share
representing 1/100th of a share of MFS Series A Preferred Stock was exchanged
for a depositary share representing 1/100th of a share of WorldCom Series A
Preferred Stock. Upon effectiveness of the MFS Merger, the then outstanding and
unexercised options and warrants exercisable for shares of MFS common stock
were converted into options and warrants, respectively, exercisable for shares
of Common Stock having substantially the same terms and conditions as the MFS
options and warrants, except that (i) the exercise price and the number of
shares issuable upon exercise were divided and multiplied, respectively, by 2.1
and (ii) the holders of each then outstanding and unexercised MFS "Shareworks
Plus Award" granted under the MFS 1993 Stock Plan instead received the cash
value of such award in accordance with the terms of such plan.
   
  As a result of the MFS Merger, MFS became a wholly-owned subsidiary of
WorldCom. Operationally and financially, WorldCom has been integrating MFS into
the WorldCom organization. The Exchange Offers are an element of such
integration efforts. Subsequent to the MFS Merger, WorldCom filed a shelf
registration statement with the Commission (the "Shelf Registration Statement")
in order to register and issue debt securities having an aggregate initial
offering price of up to $3.0 billion. Pursuant to the WorldCom Indenture and
the Shelf Registration Statement, WorldCom issued and sold senior notes having
an aggregate principal amount of $2.0 billion (the "April WorldCom Notes") on
April 1, 1997. The April WorldCom Notes contain covenants that are
substantially identical to the WorldCom Notes offered hereby.     
 
                                       6
<PAGE>
 
                              THE EXCHANGE OFFERS

TERMS OF THE EXCHANGE       
OFFERS......................  The Company hereby offers, upon the terms and
                              subject to the conditions set forth in this
                              Prospectus and in the Letters of Transmittal, to:
                                 
                              (i) exchange $871.597 principal amount of
                              WorldCom 2004 Notes for each $1,000 principal
                              amount at stated maturity of outstanding MFS 2004
                              Notes properly tendered for exchange and
                              accepted; and     
                                 
                              (ii) exchange $737.912 principal amount of
                              WorldCom 2006 Notes for each $1,000 principal
                              amount at stated maturity of outstanding MFS 2006
                              Notes properly tendered for exchange and
                              accepted.     
                                 
                              The principal amount of WorldCom Notes offered in
                              each Exchange Offer for the applicable series of
                              MFS Notes is equal to the Accreted Value of such
                              MFS Notes as of the Interest Accrual Date, and
                              interest on such WorldCom Notes will accrue from
                              the Interest Accrual Date at the stated interest
                              rate on such WorldCom Notes.     
                                 
                              As of the Interest Accrual Date, the Accreted
                              Value of the MFS 2004 Notes is $871.597 per
                              $1,000 principal amount at stated maturity and
                              the Accreted Value of the MFS 2006 Notes is
                              $737.912 per $1,000 principal amount at stated
                              maturity.     
                                 
                              WorldCom Notes will be issued only in
                              denominations of $1,000 and integral multiples
                              thereof. If the aggregate principal amount of
                              WorldCom Notes that otherwise would be issued in
                              exchange for the MFS Notes of a series tendered
                              by a Holder and accepted by the Company pursuant
                              to the Exchange Offers is not an integral
                              multiple of $1,000, such principal amount will be
                              reduced to the nearest such multiple and the
                              Company will pay to such Holder an amount in cash
                              equal to the reduction of such principal amount.
                              See "The Exchange Offers."     
   
CONSENT SOLICITATIONS;           
CONSENT PAYMENTS.......       Concurrently with the Exchange Offers, WorldCom
                              is soliciting Consents to the Proposed Amendments
                              to the 1994 Indenture and the 1996 Indenture from
                              each Holder of the MFS 2004 Notes and the MFS
                              2006 Notes, respectively. HOLDERS OF MFS NOTES OF
                              EITHER SERIES MAY GIVE THEIR CONSENT TO THE
                              PROPOSED AMENDMENTS APPLICABLE TO THAT SERIES
                              ONLY BY TENDERING SUCH MFS NOTES IN THE
                              APPLICABLE EXCHANGE OFFER AND WILL BE DEEMED TO
                              HAVE GIVEN SUCH CONSENT BY SO TENDERING. Consents
                              from Holders of a majority in aggregate principal
                              amount Outstanding of MFS Notes of a series (the
                              "Requisite Consent") must be received in order to
                              amend the MFS Indenture governing that series as
                              described herein, except with respect to the
                              modification of the term "Change of Control"
                              which requires Consents from Holders of not less
                              than 75% of the aggregate principal amount
                              Outstanding of MFS Notes of a series (the
                              "Supermajority Consent"). See "The Consent
                              Solicitations" and "The Proposed Amendments."    

                                       7
<PAGE>
 
                                 
                              The Company hereby offers, upon the terms and
                              subject to the conditions set forth in this
                              Prospectus and in the Letters of Transmittal, to
                              pay each Holder who gives a valid Consent on or
                              prior to the Expiration Date a cash fee in an
                              amount equal to (i) with respect to such Holder's
                              MFS 2004 Notes, 0.   % of the Accreted Value, as
                              of the Interest Accrual Date, of such MFS 2004
                              Notes and (ii) with respect to such Holder's 2006
                              Notes, 0.   % of the Accreted Value, as of the
                              Interest Accrual Date, of such MFS 2006 Notes, in
                              either case, with respect to which such Consent
                              has been given. See "The Consent Solicitations--
                              Consent Payments."     
     
CONDITIONS TO THE EXCHANGE
OFFERS AND CONSENT              
SOLICITATIONS...............  The obligation of the Company, with respect to
                              either series of MFS Notes, to consummate the
                              Exchange Offer and to make the Consent Payments
                              is conditioned upon, among other things, the
                              receipt of the Requisite Consent with respect to
                              both series of MFS Notes. See "The Exchange
                              Offers--Conditions to the Exchange Offers" and
                              "The Consent Solicitations."     
 
                              The Company will not consummate the Exchange
                              Offer with respect to the MFS 2004 Notes if less
                              than $    of principal amount of WorldCom 2004
                              Notes would be issued in such Exchange Offer and
                              will not consummate the Exchange Offer with
                              respect to the MFS 2006 Notes if less than $
                              of principal amount of WorldCom 2006 Notes would
                              be issued in such Exchange Offer.
                            
BACKGROUND AND REASONS FOR  
THE EXCHANGE OFFERS AND THE   
CONSENT SOLICITATIONS.......  Since the MFS Merger, WorldCom has been
                              operationally and financially integrating MFS
                              into the WorldCom organization, which integration
                              includes creating a single, more efficient,
                              consolidated credit entity. The Exchange Offers
                              are an element of this integration effort, and
                              the Proposed Amendments are expected to provide
                              greater financial and operating flexibility to
                              the fully integrated organization. The Company
                              believes that the failure to consummate the
                              Exchange Offers and Consent Solicitations will
                              not have a material adverse effect on the
                              Company. See "The Exchange Offers--Purpose of the
                              Exchange Offers" and "The Proposed Amendments."
                                                              
                            
CERTAIN CONSEQUENCES TO     
HOLDERS TENDERING IN THE      
EXCHANGE OFFERS.............  Holders whose MFS Notes are properly tendered and
                              accepted in the Exchange Offers will receive
                              WorldCom Notes. The WorldCom Notes will be
                              senior, unsecured obligations of WorldCom and
                              rank pari passu with all existing and future
                              senior, unsecured indebtedness of WorldCom. In
                              addition, the financial terms of the WorldCom
                              Notes and the MFS Notes will be substantially
                              identical in all material respects except that:
                              (i) the MFS Notes are the sole obligations of
                              MFS, while the WorldCom Notes will be the sole
                              obligations of WorldCom; (ii) the MFS 2004 Notes
                              and MFS     
 
                                       8
<PAGE>
 
                                 
                              2006 Notes were originally issued at a discount
                              and, except as described below, the principal
                              amount thereof accretes in value until January
                              15, 1999 and January 15, 2001, respectively,
                              while the WorldCom Notes will have a fixed
                              principal amount; (iii) except as described
                              below, no cash interest accrues on the MFS 2004
                              Notes and the MFS 2006 Notes until January 15,
                              1999 and January 15, 2001, respectively, while
                              interest will begin to accrue on the WorldCom
                              Notes on the Interest Accrual Date and will be
                              payable in cash semi-annually in arrears on each
                              January 15 and July 15, commencing July 15, 1997;
                              and (iv) overdue principal and premium, if any,
                              and interest on the overdue principal and any
                              overdue premium of the MFS 2004 Notes and the MFS
                              2006 Notes bear interest at the rate of 10 3/8%
                              and 9 7/8% per annum, respectively, while overdue
                              principal and premium, if any, and interest on
                              the overdue principal and any overdue premium of
                              the WorldCom 2004 Notes and the WorldCom 2006
                              Notes will bear interest at 9 3/8% and 8 7/8% per
                              annum, respectively. The WorldCom Indenture will
                              contain covenants that are substantially less
                              restrictive than those currently contained in the
                              MFS Indentures, and the WorldCom Notes will carry
                              significantly reduced protections than now
                              afforded to the MFS Notes. Pursuant to the MFS
                              Indentures, MFS may elect, prior to July 15, 1997
                              (or a future Interest Payment Date), to commence
                              the accrual of cash interest on either series of
                              MFS Notes beginning on such date, at which time
                              the outstanding principal amount of each of such
                              MFS Notes at their respective stated maturities
                              will equal the Accreted Value of such MFS Notes
                              as of such date, and cash interest will be
                              payable on January 15, 1998 (or the next
                              succeeding Interest Payment Date, as the case may
                              be) and on each Interest Payment Date thereafter.
                              In the event any such election is made prior to
                              the Expiration Date, MFS intends to issue a press
                              release and file with the Commission a Current
                              Report on Form 8-K publicly announcing the
                              commencement of the accrual of cash interest on
                              the MFS Notes beginning on July 15, 1997 (or a
                              future Interest Payment Date, as the case may
                              be). See "Risk Factors--Certain Considerations
                              Relating to Holders Tendering in the Exchange
                              Offers" and "The Exchange Offers--Description of
                              Differences Between the MFS Notes and the
                              WorldCom Notes."     
 
CERTAIN CONSEQUENCES TO
HOLDERS NOT TENDERING IN
THE EXCHANGE OFFERS.........
                                 
                              Consummation of the Exchange Offers and the
                              adoption of the Proposed Amendments will have
                              certain consequences to Holders of the MFS Notes
                              who elect not to tender in the Exchange Offers,
                              including, without limitation, that the covenants
                              and certain other terms set forth in the MFS
                              Indentures, as proposed to be amended, with
                              respect to the MFS Notes will be substantially
                              less restrictive, and afford less protection to
                              such Holders, than those that are currently in
                              the MFS Indentures. The Proposed Amendments
                              would, among other things, eliminate (i) the
                              covenants in each of the MFS     

                                       9
<PAGE>
 
                                 
                              Indentures that (a) restrict the ability of MFS
                              and its restricted subsidiaries to incur debt,
                              incur liens, enter into sale and leaseback
                              transactions, make restricted payments (including
                              payment of dividends) or enter into transactions
                              with affiliates and (b) restrict the ability of
                              restricted subsidiaries of MFS to issue equity
                              securities, to encumber their ability to pay
                              dividends or to make certain loans or transfers
                              of property to MFS or another restricted
                              subsidiary of MFS and (ii) the separate financial
                              reporting requirements contained in the MFS
                              Indentures. If a Supermajority Consent with
                              respect to a series of MFS Notes is received, the
                              Proposed Amendments would also limit the
                              circumstances in which a Change of Control will
                              be deemed to occur and consequently limit the
                              circumstances in which MFS would be required, as
                              a result of a Change of Control or certain asset
                              sales, to offer to repurchase such series of MFS
                              Notes. See "The Proposed Amendments." In
                              addition, the trading market for unexchanged MFS
                              Notes could become more limited due to the
                              reduction in the amount of the MFS Notes
                              outstanding after the Exchange Offers, which may
                              adversely affect the liquidity, market price and
                              price volatility of such MFS Notes. See "Risk
                              Factors--Certain Considerations Relating to
                              Holders Not Tendering in the Exchange Offers." 
    
    
CERTAIN U.S. FEDERAL INCOME      
TAX CONSIDERATIONS..........  The receipt of WorldCom Notes, Consent Payments
                              and other cash, if any, pursuant to the Exchange
                              Offers and Consent Solicitations will be a
                              taxable transaction for United States federal
                              income tax purposes. See "Certain U.S. Federal
                              Income Tax Consequences."     
 
EXPIRATION DATE.............  The Exchange Offers will expire at 11:59 p.m.,
                              New York City time, on    , 1997, unless the
                              Exchange Offers (or either of them) are extended
                              by the Company in its sole discretion, in which
                              case the term "Expiration Date," with respect to
                              an Exchange Offer, will mean the latest date and
                              time to which such Exchange Offer is extended.
                              See "The Exchange Offers--Expiration Date;
                              Extensions; Amendments."
                             
EXCHANGE DATE...............  WorldCom Notes to be exchanged for MFS Notes
                              pursuant to the Exchange Offers will be delivered
                              and the related Consent Payments and other cash
                              payments, if any, will be made on the third
                              business day following the Expiration Date, or as
                              soon as possible thereafter.     
                              
RECORD DATE.................  No record date has been or will be set for
                              purposes of giving Consents in either of the
                              Consent Solicitations.     
 
SPECIAL CONSIDERATIONS FOR
BENEFICIAL OWNERS...........  Any beneficial owner whose MFS Notes are held by
                              a broker, dealer, commercial bank, trust company
                              or other nominee and who wishes to tender such
                              MFS Notes in the Exchange Offers should contact
                              such nominee promptly and instruct such nominee
                              to tender on such beneficial owner's behalf. See
                              "The Exchange Offers--Procedures for Tendering."
 
                                       10
<PAGE>
                            
                            
PROCEDURES FOR TENDERING    
MFS NOTES AND GIVING THE   
RELATED CONSENT.............  Each Holder of MFS Notes wishing to accept either
                              of the Exchange Offers must complete, sign and
                              date the appropriate Letter of Transmittal, or a
                              facsimile thereof, in accordance with the
                              instructions contained herein and therein, and
                              mail or otherwise deliver such Letter of
                              Transmittal, or such facsimile, together with
                              such MFS Notes and any other required
                              documentation to Harris Trust and Savings Bank,
                              as exchange agent, at its address set forth
                              therein on or prior to the Expiration Date. By
                              executing a Letter of Transmittal, the Holder
                              will represent to and agree with the Company
                              that, among other things, the MFS Notes tendered
                              therewith are held by such Holder free and clear
                              of all security interests, liens, restrictions,
                              charges, encumbrances, conditional sale
                              agreements or other obligations relating to their
                              sale or transfer, and are not subject to any
                              adverse claim when the same are accepted by the
                              Company. See "The Exchange Offers--Procedures for
                              Tendering." 
                              The proper completion, execution and delivery of
                              a Letter of Transmittal with respect to MFS Notes
                              of a series will constitute the giving of a
                              Consent to the Proposed Amendments for such
                              series.
                              The WorldCom Notes issued in exchange for
                              properly tendered and accepted MFS Notes will be
                              delivered only in book-entry form through The
                              Depository Trust Company ("DTC"). Accordingly,
                              Holders who anticipate tendering and whose MFS
                              Notes are not held custodially through DTC are
                              urged to contact promptly a bank, broker or other
                              intermediary that has the capability to hold
                              securities custodially through DTC, to arrange
                              for receipt of any WorldCom Notes to be delivered
                              pursuant to the Exchange Offers and to obtain the
                              information necessary to provide the required DTC
                              participant and account information in the
                              relevant Letter of Transmittal. See "The Exchange
                              Offers--Procedures for Tendering--Book-Entry
                              Delivery Procedures."      
                           
GUARANTEED DELIVERY         
PROCEDURES..................  Holders of MFS Notes who wish to tender their MFS
                              Notes and whose MFS Notes are not immediately
                              available or who cannot deliver their MFS Notes,
                              the Letter of Transmittal or any other
                              documentation required by the Letter of
                              Transmittal to the Exchange Agent on or prior to
                              the Expiration Date may, nonetheless, tender
                              their MFS Notes according to the guaranteed
                              delivery procedures set forth under "The Exchange
                              Offers--Guaranteed Delivery Procedures."     
                      
ACCEPTANCE OF THE MFS NOTES; 
RETURN OF MFS NOTES.........  Subject to the satisfaction or waiver of the
                              conditions to each Exchange Offer, the Company
                              will accept for exchange any and all MFS Notes
                              that are properly tendered in such Exchange Offer
                              on or prior to the Expiration Date. Any MFS Notes
                              not accepted for exchange for any reason will be
                              returned to the tendering Holder as promptly as
                              practicable after the expiration or termination
                              of the applicable Exchange     
 
                                       11
<PAGE>
 
                                 
                              Offer. See "The Exchange Offers--Terms of the
                              Exchange Offers."     
    
WITHDRAWAL AND REVOCATION
RIGHTS......................  Tenders of MFS Notes in an Exchange Offer may not
                              be withdrawn at any time after 11:59 p.m., New    
                              York City time, on    , 1997, unless such         
                              Exchange Offer is extended and contains new terms 
                              materially adverse to the tendering Holders       
                              thereof. Valid withdrawal of a tendered MFS Note  
                              will constitute the revocation of the related     
                              Consent. Holders may not revoke a Consent without 
                              validly withdrawing the related MFS Note. See     
                              "The Exchange Offers--Withdrawal of Tenders" and  
                              "The Consent Solicitations."                      
                                                                                
NO DISSENTERS' RIGHTS.......  Holders of MFS Notes do not have any appraisal or
                              dissenters' rights under the Delaware General
                              Corporation Law or the applicable MFS Indenture
                              in connection with the Exchange Offers.
 
NO PROCEEDS TO COMPANY......  The Company will not receive any proceeds from
                              the issuance of the WorldCom Notes offered hereby
                              and has agreed to pay certain expenses of the
                              Exchange Offers. See "The Exchange Offers--
                              Exchange Agent," "--Information Agent," "--Dealer
                              Managers" and "--Other Fees and Expenses;
                              Transfer Taxes." WorldCom will cause the MFS
                              Notes surrendered in exchange for the WorldCom
                              Notes to be retired and cancelled. Issuance of
                              the WorldCom Notes will not result in any
                              increase in the outstanding debt of the Company,
                              on a consolidated basis.
                            
EXCHANGE AGENT..............  Harris Trust and Savings Bank (the "Exchange
                              Agent"). The address and telephone numbers of the
                              Exchange Agent are set forth on the back cover
                              page of this Prospectus.      
                            
INFORMATION AGENT...........  MacKenzie Partners, Inc. (the "Information
                              Agent"). Questions concerning tender procedures
                              and requests for additional copies of this
                              Prospectus, the Letters of Transmittal or Notices
                              of Guaranteed Delivery should be directed to the
                              Information Agent. The address and telephone
                              numbers of the Information Agent are set forth on
                              the back cover page of this Prospectus.      
                       
DEALER MANAGERS.............  Salomon Brothers Inc and Goldman, Sachs & Co.
                              (the "Dealer Managers"). Questions concerning the
                              terms of the Exchange Offers should be directed
                              to the Dealer Managers. The addresses and
                              telephone numbers of the Dealer Managers are set
                              forth on the back cover page of this Prospectus.
                                              
                                                                            
DEALER MANAGER MARKET         
ACTIVITY...................   The Dealer Managers currently plan to make a
                              market in the WorldCom Notes following the
                              completion of the Exchange Offers and may buy and
                              sell WorldCom Notes on a "when and if issued"
                              basis prior to the completion of the Exchange
                              Offers. However, there can be no assurance that
                              the Dealer Managers will engage in such
                              activities or that any active market in the
                              WorldCom Notes will develop or be maintained. See
                              "Risk Factors--Certain Considerations Relating to
                              Holders Tendering in the Exchange Offers."     
 
                                       12
<PAGE>
 
                               THE WORLDCOM NOTES
   
  The financial terms of the WorldCom 2004 Notes and the WorldCom 2006 Notes
will be substantially identical in all material respects to the financial terms
of the MFS 2004 Notes and the MFS 2006 Notes, respectively, except that: (i)
the MFS Notes are the sole obligations of MFS, while the WorldCom Notes will be
the sole obligations of WorldCom (ii) the MFS 2004 Notes and the MFS 2006 Notes
were originally issued at a discount and, except as described below, the
principal amount thereof accretes in value until January 15, 1999, and January
15, 2001, respectively, while the WorldCom Notes will have a fixed principal
amount; (iii) except as described below, no cash interest accrues on the MFS
2004 Notes and the MFS 2006 Notes until January 15, 1999 and January 15, 2001,
respectively, while interest will begin to accrue on the WorldCom Notes on the
Interest Accrual Date and will be payable in cash semi-annually in arrears on
each January 15 and July 15, commencing July 15, 1997; and (iv) overdue
principal and premium, if any, and interest on the overdue principal and any
overdue premium of the MFS 2004 Notes and the MFS 2006 Notes bear interest at
the rate of 10 3/8% and 9 7/8% per annum, respectively, while overdue principal
and premium, if any, and interest on the overdue principal and any overdue
premium of the WorldCom 2004 Notes and the WorldCom 2006 Notes will bear
interest at 9 3/8% and 8 7/8% per annum, respectively. The WorldCom Indenture
will contain covenants that are substantially less restrictive than those that
are currently in the MFS Indentures, and the WorldCom Notes will carry
significantly reduced protections than those now afforded to the MFS Notes.
Pursuant to the MFS Indentures, MFS may elect, prior to July 15, 1997 (or a
future Interest Payment Date), to commence the accrual of cash interest on the
MFS Notes beginning on such date, at which time the outstanding principal
amount of either series of MFS Notes at their respective stated maturities will
equal the Accreted Value of such MFS Notes as of such date, and cash interest
will be payable on January 15, 1998 (or the next succeeding Interest Payment
Date, as the case may be) and on each Interest Payment Date thereafter. In the
event any such election is made prior to the Expiration Date, MFS intends to
issue a press release and file with the Commission a Current Report on Form 8-K
publicly announcing the commencement of the accrual of cash interest on the MFS
Notes beginning on July 15, 1997 (or a future Interest Payment Date, as the
case may be). See "The Exchange Offers--Description of Differences Between the
MFS Notes and the WorldCom Notes." The following is a summary of certain terms
of the WorldCom Notes:     
 
<TABLE>
<CAPTION>
                      MATURITY DATE   INTEREST RATE    INTEREST PAYMENT DATE
                     ---------------- ------------- ---------------------------
 <C>                 <C>              <C>           <S>
 WorldCom 2004 Notes January 15, 2004     9 3/8%    Payable semi-annually on
                                                    January 15 and July 15 each
                                                    year, commencing July 15,
                                                    1997.
 WorldCom 2006 Notes January 15, 2006     8 7/8%    Payable semi-annually on
                                                    January 15 and July 15 each
                                                    year, commencing July 15,
                                                    1997.
</TABLE>
 
ISSUER......................  WorldCom, Inc.
 
RANKING.....................     
                              The WorldCom Notes will be senior, unsecured
                              obligations of the Company, will rank pari passu
                              in right of payment with all other existing and
                              future senior, unsecured indebtedness of the
                              Company and will rank senior in right of payment
                              to any future subordinated obligations of the
                              Company. The WorldCom Notes will be effectively
                              subordinated to any secured indebtedness of the
                              Company to the extent of the value of the assets
                              securing such indebtedness. As of March 31, 1997,
                              after giving effect to the issuance and sale by
                              the    

                                       13
<PAGE>
 
                                 
                              Company of the April WorldCom Notes, the
                              aggregate amount of indebtedness of the Company
                              to which the WorldCom Notes would have ranked
                              pari passu was approximately $3.18 billion and
                              the aggregate amount of secured indebtedness of
                              the Company was approximately $53 million. The
                              WorldCom Notes will be structurally subordinated
                              to all obligations of the Company's subsidiaries,
                              including any MFS Notes not exchanged for
                              WorldCom Notes in the Exchange Offers to the
                              extent of the assets of such subsidiaries. As of
                              March 31, 1997, the aggregate amount of
                              outstanding obligations of the Company's
                              subsidiaries to which the holders of WorldCom
                              Notes would have been structurally subordinated
                              (including trade payables but excluding
                              intercompany indebtedness) was approximately
                              $2.66 billion (of which $1.38 billion represented
                              the carrying value of the MFS Notes). See "Risk
                              Factors" and "Description of the WorldCom Notes--
                              Ranking."     
 
OPTIONAL REDEMPTION.........  The WorldCom 2004 Notes and the WorldCom 2006
                              Notes will be redeemable at the option of the
                              Company, on or after January 15, 1999 and January
                              15, 2001, respectively, in whole at any time or
                              in part from time to time, at the prices set
                              forth herein, plus accrued and unpaid interest,
                              if any, to the date of redemption. See
                              "Description of the WorldCom Notes--Optional
                              Redemption."
 
CERTAIN COVENANTS...........  The WorldCom 2004 Notes and the WorldCom 2006
                              Notes will be entitled to the benefits of and
                              governed by the Senior Indenture dated as of
                              March 1, 1997 between WorldCom and Mellon Bank,
                              N.A., as Trustee (as supplemented and described
                              herein, the "WorldCom Indenture"). The WorldCom
                              Indenture contains certain covenants which,
                              subject to certain exceptions and qualifications,
                              restrict the ability of the Company and its
                              Restricted Subsidiaries to create liens, to enter
                              into sale and leaseback transactions and to sell
                              assets or merge with or into another company. See
                              "Description of the WorldCom Notes--Limitation on
                              Liens," "--Consolidation, Merger, Conveyance,
                              Sale or Lease" and "--Certain Definitions."
 
FORM........................  The WorldCom Notes will be available only in
                              book-entry form through DTC.
   
  For additional information regarding the WorldCom Notes, please see
"Description of the WorldCom Notes" and "Certain U.S. Federal Income Tax
Consequences."     
 
                                  RISK FACTORS
 
  Prospective investors should carefully consider certain factors relating to
an investment in the WorldCom Notes. See "Cautionary Statement Regarding
Forward-Looking Statements" and "Risk Factors" beginning on page 17.
 
                                       14
<PAGE>
 
                       SELECTED HISTORICAL FINANCIAL DATA
 
  The following table presents selected historical financial data of WorldCom,
MFS and UUNET. The historical data for each of the years in the five-year
period ended December 31, 1996 are based on the audited historical financial
statements of the respective companies, excluding UUNET for 1996 (see note 8 to
the table below). The selected financial data for each of WorldCom, MFS and
UUNET for the three month periods ended March 31, 1997 and 1996 have been
obtained from unaudited financial statements and, in the opinion of the
respective managements of WorldCom, MFS and UUNET, include all adjustments (of
a normal and recurring nature) which are necessary to present fairly the data
for such periods. This data should be read in conjunction with and is qualified
in its entirety by the consolidated financial statements of each of WorldCom,
MFS and UUNET and the related notes thereto, incorporated by reference herein.
See "Available Information" and "Incorporation of Certain Documents by
Reference."
 
                       SELECTED HISTORICAL FINANCIAL DATA
                (IN THOUSANDS, EXCEPT PER SHARE DATA AND RATIOS)
 
<TABLE>
<CAPTION>
                                                                                                  THREE MONTHS ENDED
                                         YEAR ENDED DECEMBER 31,                                       MARCH 31,
                          -------------------------------------------------------------------    ----------------------
                           1996(1)          1995          1994           1993         1992          1997        1996
                          ----------     ----------    ----------     ----------    ---------    ----------  ----------
<S>                       <C>            <C>           <C>            <C>           <C>          <C>         <C>
WORLDCOM
Revenues................  $4,485,130     $3,696,345    $2,245,663     $1,474,257    $ 948,060    $1,677,239  $1,034,060
Net income (loss) from
 continuing operations
 (after preferred
 dividend requirement):
 Total..................  (2,189,804)(2)    233,080(3)   (151,779)(4)    112,638(4)     6,232(4)     43,054      85,802
 Per common share:
 Primary................       (5.50)          0.64         (0.48)          0.41         0.03          0.05        0.22
 Fully diluted..........       (5.50)          0.64         (0.48)          0.40         0.03          0.05        0.21
Dividends per common
 share..................         --             --            --             --           --            --          --
Total assets............  19,861,977      6,656,629     3,441,474      3,236,718    1,241,278    19,595,269   6,816,942
Long-term debt..........   4,803,581      3,391,598(5)    794,001        730,023      448,496     4,617,431   2,194,357
Shareholders'
 investment.............  12,959,976      2,187,681     1,827,410      1,911,800      478,823    13,021,153   2,295,295
Ratio of earnings to
 fixed charges(6).......         N/A         2.59:1        0.15:1         5.10:1       1.47:1        1.94:1      3.15:1
Deficiency of earnings
 to fixed charges.......   2,066,991            --         52,597            --           --            --          --
<CAPTION>
                                                                                                  THREE MONTHS ENDED
                                         YEAR ENDED DECEMBER 31,                                       MARCH 31,
                          -------------------------------------------------------------------    ----------------------
                             1996           1995          1994           1993         1992          1997        1996
                          ----------     ----------    ----------     ----------    ---------    ----------  ----------
<S>                       <C>            <C>           <C>            <C>           <C>          <C>         <C>
MFS
Revenues................  $1,115,006     $  583,194    $  286,747     $  141,111    $ 108,707    $  425,935  $  186,316
Income (loss) from
 continuing operations
 (after preferred
 dividend requirement):
 Total..................  (1,867,459)(7)   (282,962)     (151,201)       (15,769)     (13,129)      (82,192)    (93,296)
 Per common share:
 Primary................      (11.22)         (2.21)        (1.21)         (0.15)       (0.15)                    (0.75)
 Fully diluted..........      (11.22)         (2.21)        (1.21)         (0.15)       (0.15)                    (0.75)
Dividends per common
 share..................         --             --            --             --           --            --          --
Total assets............  12,550,329      1,867,134     1,584,546        906,937      363,299    12,334,647   2,347,211
Long-term debt..........   1,477,670        723,471       548,333            143          169     1,412,843   1,286,354
Shareholders' equity....  10,287,586        830,332       770,103        811,105      298,516    10,190,119     754,582
</TABLE>
 
                                       15
<PAGE>
 
<TABLE>   
<CAPTION>
                                                                        THREE MONTHS ENDED
                                   YEAR ENDED DECEMBER 31,                  MARCH 31,
                          --------------------------------------------- ---------------------
                          1996(8)     1995     1994     1993     1992   1997(8)     1996
                          --------  --------  -------  -------  ------- ---------------------
<S>                       <C>       <C>       <C>      <C>      <C>     <C>       <C>
UUNET
Revenues................  $129,047  $ 94,461  $33,138  $24,019  $20,396           $    43,013
Income (loss) from
 continuing operations
 (after preferred
 dividend requirement):
 Total..................   (14,373)  (18,257)  (7,988)  (2,026)   1,074                   233
 Per common share (pro
  forma):
 Primary................     (0.44)    (0.63)   (0.35)     --       --
 Fully diluted..........     (0.44)    (0.63)   (0.35)     --       --                   0.01
Dividends per common
 share..................       --        --      0.01      --      0.08                  0.01
Total assets............             137,610   29,625   10,585    8,285               156,278
Long-term debt..........              13,686   15,269    3,310      974                18,045
Shareholders' equity....              80,667      279      425    2,567                82,084
</TABLE>    
- --------
 
(1) On December 31, 1996, WorldCom completed the MFS Merger. The MFS Merger is
    being accounted for as a purchase; accordingly, the operating results for
    MFS are reflected from the date of acquisition.
(2) WorldCom's results for 1996 include a $2.14 billion charge for in-process
    research and development related to the MFS Merger. The charge is based
    upon a valuation analysis of the technologies of MFS' worldwide information
    system, the Internet network expansion system of UUNET, and certain other
    identified research and development projects purchased in the MFS Merger.
    The expense includes $1.6 billion associated with UUNET and $0.54 billion
    related to MFS. Additionally, 1996 results include other after-tax charges
    of $121.0 million for employee severance, employee compensation charges,
    alignment charges, and costs to exit unfavorable telecommunications
    contracts and $343.5 million after-tax write-down of operating assets
    within the Company's non-core businesses. On a pre-tax basis, these charges
    totaled $600.1 million.
(3) In 1995, Metromedia Company ("Metromedia") converted its Series 1 Preferred
    Stock into Common Stock, exercised warrants to acquire Common Stock and
    immediately sold its position of 61,699,096 shares of Common Stock in a
    public offering. In connection with the preferred stock conversion,
    WorldCom made a non-recurring payment of $15.0 million to Metromedia,
    representing a discount to the minimum nominal dividends that would have
    been payable on the Series 1 Preferred Stock prior to the September 15,
    1996 optional call date of approximately $26.6 million (which amount
    includes an annual dividend requirement of $24.5 million plus accrued
    dividends to such call date).
(4) As a result of the acquisitions of IDB Communications Group, Inc. ("IDB")
    in 1994 (the "IDB Merger") and of Advanced Telecommunications Corporation
    in 1992 (the "ATC Merger"), the Company initiated plans to reorganize and
    restructure its management and operational organization and facilities to
    eliminate duplicate personnel, physical facilities and service capacity, to
    abandon certain products and marketing activities, and to take further
    advantage of the synergies available to the combined entities. Also, during
    the fourth quarter of 1993, plans were approved to reduce IDB's cost
    structure and to improve productivity. Accordingly, in 1994, 1993 and 1992,
    the Company charged to operations the estimated costs of such
    reorganization and restructuring activities, including employee severance,
    physical facility abandonment and duplicate service capacity. These costs
    totaled $43.7 million in 1994, $5.9 million in 1993 and $79.8 million in
    1992. Also, during 1994 and 1992, the Company incurred direct merger costs
    of $15.0 million and $7.3 million, respectively, related to the IDB Merger
    (in 1994) and the ATC Merger (in 1992). These costs include professional
    fees, proxy solicitation costs, travel and related expenses and certain
    other direct costs attributable to these mergers.
(5) Long-term debt as of December 31, 1995 includes $1.1 billion related to the
    Company's previous credit facilities which were classified as a current
    maturity on the December 31, 1995 balance sheet. In June 1996, WorldCom
    replaced its then existing $3.41 billion credit facilities with a new $3.75
    billion revolving credit facility with no reduction of principal for five
    years.
(6) For the purpose of computing the ratio of earnings to fixed charges,
    earnings consist of income (loss) from continuing operations, and fixed
    charges consist of pre-tax interest (including capitalized interest) on all
    indebtedness, amortization of debt discount and expense and that portion of
    rental expense which the Company believes to be representative of interest.
    For the historical years ended December 31, 1994 and 1996, earnings were
    inadequate to cover fixed charges by the amounts shown.
(7) MFS' results for 1996 include a $1.4 billion charge for in-process research
    and development related to its acquisition of UUNET. The charge is based on
    a valuation analysis of the technologies of the Internet network expansion
    system of UUNET and certain other identified research and development
    projects purchased in the acquisition.
(8) MFS' acquisition of UUNET closed on August 12, 1996 and was accounted for
    as a purchase. Therefore, the year ended December 31, 1996 under the
    caption "UUNET" above represents UUNET's results of operations for the
    period from January 1, 1996 through August 12, 1996 and includes one-time
    merger related costs of $15.7 million. Subsequent to August 12, 1996, the
    operating results of UUNET are consolidated with MFS and are included under
    the caption "MFS" above in the balance sheet and results of operations of
    MFS.
 
                                       16
<PAGE>
 
           CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS
 
  Certain statements contained in "Risk Factors" and certain statements
incorporated by reference from documents filed with the Commission by WorldCom
and MFS, including any statements contained herein or incorporated by
reference herein regarding the development of WorldCom's and MFS' businesses,
the markets for WorldCom's and MFS' services and products, anticipated capital
expenditures, regulatory reform and the effects of the MFS Merger, and other
statements, including any forecasts, projections and synergies, contained or
incorporated by reference herein regarding matters that are not historical
facts, are or may constitute forward-looking statements (as such term is
defined in the Private Securities Litigation Reform Act of 1995). Such
statements are subject to risks and uncertainties and, therefore, actual
results could differ materially from those expressed or implied by such
statements. Factors that could cause actual results to differ materially (the
"Cautionary Statements") include, but are not limited to, those discussed
under "Risk Factors." All subsequent written and oral forward-looking
statements attributable to the Company, or persons acting on its behalf, are
expressly qualified in their entirety by the Cautionary Statements.
 
                                 RISK FACTORS
   
  In addition to the other information included in or incorporated by
reference into this Prospectus, Holders of the MFS Notes should carefully
consider the following risk factors before deciding to surrender MFS Notes in
exchange for WorldCom Notes pursuant to the Exchange Offers. The
considerations listed below are not intended to represent a complete list of
the general or specific risks that may affect Holders who tender or fail to
tender in the Exchange Offers or that relate to the Company or MFS. It should
be recognized that other risks may be significant, now or in the future, and
the risks set forth below may affect tendering or non-tendering Holders to a
greater extent than indicated.     
 
CERTAIN CONSIDERATIONS RELATING TO HOLDERS TENDERING IN THE EXCHANGE OFFERS
 
 Liquidity of WorldCom Notes; No Prior Public Market for WorldCom Notes
   
   Upon consummation of the Exchange Offers and depending on the amount of the
WorldCom Notes outstanding after the Exchange Offers (which will be no less
than $343.2 million principal amount of WorldCom 2004 Notes and $336.0 million
principal amount of WorldCom 2006 Notes), the trading market for the WorldCom
Notes may be more limited than the trading market for the MFS Notes prior to
the Exchange Offers, which might adversely affect the liquidity and market
price of such WorldCom Notes. The Company does not plan to list the WorldCom
Notes on any national securities exchange or interdealer quotation system
sponsored by a national securities association. Although the MFS Notes are not
so listed, there is currently a limited trading market for the MFS Notes. The
WorldCom Notes are new securities for which there is currently no market.
While the Dealer Managers intend to make a market for the WorldCom Notes, they
are not obligated to do so and any market making may be discontinued at any
time. There can be no assurance that an active trading market for the WorldCom
Notes will develop or, if such market develops, as to the liquidity or
sustainability of any such market.     
 
 Structural Subordination of the WorldCom Notes
   
  WorldCom conducts a portion of its business through its subsidiaries. The
Company is therefore dependent to some extent upon dividends and other
payments from its subsidiaries to generate a portion of the funds necessary to
meet its obligations, including the payment of principal and interest on the
WorldCom Notes. As a result, the WorldCom Notes will be structurally
subordinated to all obligations of the Company's subsidiaries, including any
MFS Notes that are not exchanged in the Exchange Offers, to the extent of the
assets of such subsidiaries. As of March 31, 1997, the aggregate     
 
                                      17
<PAGE>
 
   
amount of outstanding obligationsof the Company's subsidiaries to which the
holders of the WorldCom Notes would have been structurally subordinated
(including trade payables but excluding intercompany indebtedness) was
approximately $2.66 billion (of which $1.38 billion represented the carrying
value of the MFS Notes). WorldCom expects that substantially all of its
business will ultimately be conducted through its subsidiaries as a result of
the transfer of operating assets to such subsidiaries. Thus, the Company
expects that the amount of obligations of its subsidiaries will increase and
that the Company will become increasingly dependent upon dividends and other
payments from its subsidiaries.     
 
 Recognition of Income to Holders Accepting Exchange Offers
   
  The receipt of WorldCom Notes, Consent Payments and other cash, if any,
pursuant to the Exchange Offers and Consent Solicitations will be a taxable
transaction for United States federal income tax purposes. See "Certain U.S.
Federal Income Tax Consequences."     
 
CERTAIN CONSIDERATIONS RELATING TO HOLDERS NOT TENDERING IN THE EXCHANGE
OFFERS
 
 Proposed Amendments to the MFS Indentures
   
  In the event that the Proposed Amendments are adopted with respect to a
series of the MFS Notes, the covenants and certain other terms with respect to
such series of MFS Notes will be substantially less restrictive, and will
afford less protection to Holders, than those currently set forth in the MFS
Indentures. The Proposed Amendments contemplated by the Consent Solicitations
would, among other things, eliminate the covenants in each of the MFS
Indentures that (a) restrict the ability of MFS and its restricted
subsidiaries to incur debt, incur liens, enter into sale and leaseback
transactions, make restricted payments (including payment of dividends) or
enter into transactions with affiliates and (b) restrict the ability of
restricted subsidiaries of MFS to issue equity securities, to encumber their
ability to pay dividends or to make certain loans or transfers of property to
MFS or another restricted subsidiary of MFS. In addition, the Proposed
Amendments would eliminate the separate financial reporting requirements
currently contained in the MFS Indentures and, upon receipt of a Supermajority
Consent with respect to a series of MFS Notes, would redefine the term "Change
of Control" as to such series. See "The Proposed Amendments."     
   
  In the event the Proposed Amendments are adopted with respect to a series of
MFS Notes, each non-exchanging Holder of such series of MFS Notes will be
bound by the Proposed Amendments even if such Holder did not consent to the
Proposed Amendments. The elimination or modification of the covenants
contemplated in the Proposed Amendments would, among other things, permit
WorldCom and MFS and their subsidiaries to take actions that could increase
the credit risk with respect to MFS, and might adversely affect the liquidity,
market price and price volatility of the MFS Notes or otherwise be adverse to
the interests of the holders of the MFS Notes. See "The Proposed Amendments."
    
 Reduced Liquidity of MFS Notes
   
  Although the Company believes there is currently a limited trading market
for the MFS Notes, no generally reliable public pricing information for the
MFS Notes is available. The trading market for unexchanged MFS Notes could
become even more limited or nonexistent due to the reduction in the amount of
MFS Notes outstanding upon consummation of the Exchange Offers, which might
adversely affect the liquidity, market price and price volatility of such MFS
Notes. If a market for unexchanged MFS Notes exists or develops, such MFS
Notes may trade at a discount to the price at which such MFS Notes would trade
if the amount outstanding were not reduced, depending on prevailing interest
rates, the market for similar securities and other factors. However, there can
be no assurance that an active market in the unexchanged MFS Notes will exist,
develop or be maintained and no assurance as to the prices at which the
unexchanged MFS Notes may be traded.     
 
                                      18
<PAGE>
 
CERTAIN CONSIDERATIONS REGARDING THE BUSINESS AND OPERATIONS OF WORLDCOM
          
  Prospective investors should carefully consider the following risk factors
in evaluating the Company and its business before deciding to surrender MFS
Notes in exchange for WorldCom Notes pursuant to the Exchange Offers.     
   
  Risks of Increased Financial Leverage; Debt Service, Interest Rate
Fluctuations, Possible Reduction in Liquidity, Dividend Restrictions and Other
Restrictive Covenants     
   
  At March 31, 1997, the Company had $4.62 billion of long-term debt
(including capital leases and excluding current maturities) and a long-term
debt to equity ratio of 0.35 to 1.0. The Company currently has a $3.75 billion
five-year revolving credit facility (the "Credit Facility"). The Credit
Facility has a five-year term and bears interest, payable in varying periods,
depending on the interest period, not to exceed six months, at rates selected
by the Company under the terms of the Credit Facility including a Base Rate or
the LIBOR, plus applicable margin. The applicable margin for a LIBOR rate
borrowing varies from 0.35% to 0.875% based upon a specified financial test.
The Credit Facility is unsecured and requires compliance with certain
financial and other operating covenants which limit, among other things, the
incurrence of additional indebtedness by WorldCom and restricts the payment of
cash dividends to WorldCom's shareholders. The Credit Facility is also subject
to an annual commitment fee not to exceed 0.25% of any unborrowed portion of
the Credit Facility. The Company is currently negotiating an amendment to the
Credit Facility which would, among other things, increase the facility to $5.0
billion. There can be no assurance that WorldCom will be successful in
amending the Credit Facility or that the terms thereof will be favorable to
WorldCom.     
   
  Increases in interest rates, economic downturns and other adverse
developments, including factors beyond the Company's control, could impair its
ability to service its indebtedness under the WorldCom Notes, the MFS Notes,
the April WorldCom Notes or the Credit Facility. In addition, the cash flow
required to service the Company's debt may reduce its ability to fund internal
growth, additional acquisitions and capital improvements. In addition, the
Credit Facility restricts the payment of cash dividends and otherwise limits
the Company's financial flexibility. See Item 7, "Management's Discussion and
Analysis of Financial Condition and Results of Operations," of the WorldCom
1996 Form 10-K.     
   
  The Company has historically utilized cash flow from operations to finance
capital expenditures and a mixture of cash flow, debt and stock to finance
acquisitions. The Company expects to experience increased capital intensity
due to network expansions and believes that funding needs in excess of
internally generated cash flow will be met by utilization of the Credit
Facility.     
   
  Acquisition Integration     
   
  A major portion of the Company's growth in recent years has resulted from
acquisitions, which involve certain operational and financial risks.
Operational risks include the possibility that an acquisition does not
ultimately provide the benefits originally anticipated by management of the
acquiror, while the acquiror continues to incur operating expenses to provide
the services formerly provided by the acquired company. Financial risks
involve the incurrence of indebtedness by the acquiror in order to effect the
acquisition and the consequent need to service that indebtedness. In addition,
the issuance of stock in connection with acquisitions dilutes the voting power
and may dilute certain other interests of existing shareholders. In carrying
out its acquisition strategy, the Company attempts to minimize the risk of
unexpected liabilities and contingencies associated with acquired businesses
through planning, investigation and negotiation, but such unexpected
liabilities may nevertheless accompany acquisitions. There can be no assurance
that the Company will be successful in identifying attractive acquisition
candidates or completing additional acquisitions on favorable terms.     
   
  Additionally, achieving the expected benefits of the MFS Merger will depend
in part upon the integration of the businesses of WorldCom and MFS, together
with UUNET, in an efficient manner, and     
 
                                      19
<PAGE>
 
   
there can be no assurance that this will occur. The transition to a combined
company will require substantial attention from management. The diversion of
management attention and any difficulties encountered in the transition
process could have an adverse effect on the revenues and operating results of
the combined company. In addition, the process of combining the three
organizations could cause the interruption of, or a disruption in, the
activities of any or all of the companies' businesses, which could have a
material adverse effect on their combined operations. There can be no
assurance that the Company will realize any of the anticipated benefits of the
MFS Merger.     
   
  Contingent Liabilities     
   
  WorldCom is subject to a number of legal and regulatory proceedings. While
WorldCom believes that the probable outcome of these matters, or all of them
combined, will not have a material adverse effect on WorldCom's consolidated
results of operations or financial position, no assurance can be given that a
contrary result will not be obtained.     
   
  Risks of International Business     
   
  The Company derives substantial revenues by providing international
communications services to United States commercial and carrier customers.
Such operations are subject to certain risks such as changes in United States
or foreign government regulatory policies, disruption, suspension or
termination of operating agreements, and currency fluctuations. In particular,
the Company's revenues and costs of sales are sensitive to changes in
international settlement rates and international traffic routing patterns. The
rates that the Company can charge its customers for international services may
decrease in the future due to the entry of new carriers with substantial
resources, aggressiveness on the part of new or existing carriers, the
widespread resale of international private lines, the provision of
international services via non-traditional means including the Internet, the
consummation of mergers and joint ventures among large international carriers
that facilitate targeted pricing and cost reductions, and the rapid growth of
international circuit capacity due to the deployment of new undersea fiber
optic cables and new high capacity satellite systems in the Atlantic, Pacific
and Indian Ocean regions.     
   
  Risks of Overseas Business Operations     
   
  The Company derives substantial revenues from providing services to
customers in overseas locations, particularly the United Kingdom and Germany.
Such operations are subject to certain risks such as changes in the legal and
regulatory policies of the foreign jurisdiction, local political and economic
developments, currency fluctuations, exchange controls, royalty and tax
increases, retroactive tax claims, expropriation, and import and export
regulations and other laws and policies of the United States affecting foreign
trade, investment and taxation. In addition, in the event of any dispute
arising from foreign operations, the Company may be subject to the exclusive
jurisdiction of foreign courts and may not be successful in subjecting foreign
persons or entities to the jurisdiction of the courts in the United States.
WorldCom may also be hindered or prevented from enforcing its rights with
respect to foreign governments because of the doctrine of sovereign immunity.
There can be no assurance that the laws, regulations or administrative
practices of foreign countries relating to WorldCom's ability to do business
in that country will not change. Any such change could have a material adverse
effect on the business and financial condition of WorldCom.     
   
  Dependence on Availability of Transmission Facilities     
   
  The future profitability of the Company will be dependent in part on its
ability to utilize transmission facilities leased from others on a cost-
effective basis. The MFS Merger, and the Company's acquisition of the network
services operations of Williams Telecommunications Group, Inc. in January 1995
and     
 
                                      20
<PAGE>
 
   
merger with IDB Communications Group, Inc. in December 1994 have reduced the
leasing risk through the ownership of significant domestic and international
facilities; however, due to the possibility of unforeseen changes in industry
conditions, the continued availability of leased transmission facilities at
historical rates cannot be assured.     
   
  Rapid Technological Change; Dependence upon Product Development     
   
  The telecommunications industry is subject to rapid and significant changes
in technology. While WorldCom does not believe that, for the foreseeable
future, these changes will either materially or adversely affect the continued
use of fiber optic cable or materially hinder its ability to acquire necessary
technologies, the effect of technological changes, including changes relating
to emerging wireline and wireless transmission and switching technologies, on
the businesses of WorldCom cannot be predicted.     
   
  The market for UUNET's Internet-related products and services is
characterized by rapidly changing technology, evolving industry standards,
emerging competition and frequent new product and service introductions. There
can be no assurance that UUNET will successfully identify new product and
service opportunities and develop and bring new products and services to
market in a timely manner. UUNET is also at risk from fundamental changes in
the way Internet access services are marketed and delivered. UUNET's Internet
service strategy assumes that the Transmission Control Protocol/Internet
Protocol, utilizing fiber optic or copper-based telecommunications
infrastructures, will continue to be the primary protocol and transport
infrastructure for Internet-related services. Emerging transport alternatives
include cable modems and satellite delivery of Internet information;
alternative open protocol and proprietary protocol standards have been or are
being developed. UUNET's pursuit of necessary technological advances may
require substantial time and expense, and there can be no assurance that UUNET
will succeed in adapting its Internet services business to alternate access
devices, conduits and protocols.     
   
  Regulation Risks     
   
  The Company is subject to extensive regulation at the federal and state
levels, as well as in various foreign countries in connection with certain
overseas business activities. The regulatory environment varies substantially
by jurisdiction.     
   
  The Company is subject to varying degrees of federal, state, local and
international regulation. In the United States, the Company is most heavily
regulated by the states, especially for the provision of local exchange
services. The Company must be separately certified in each state to offer
local exchange and intrastate long distance services. No state, however,
subjects the Company to price cap or rate of return regulation, nor is the
Company currently required to obtain Federal Communications Commission ("FCC")
authorization for installation or operation of its network facilities used for
domestic services. FCC approval is required, however, for the installation and
operation of its international facilities and services. The Company is subject
to varying degrees of regulation in the foreign jurisdictions in which it
conducts business including authorization for the installation and operation
of its network facilities. Although the trend in federal, state, local and
international regulation appears to favor increased competition, no assurance
can be given that changes in current or future regulations adopted by the FCC,
state or foreign regulators or legislative initiatives in the United States
and abroad would not have a material adverse effect on the Company.     
   
  On February 8, 1996, President Clinton signed the Telecommunications Act of
1996 (the "Telecom Act") which: permits, without limitation, the Bell System
Operating Companies ("BOCs") to provide domestic and international long
distance services to customers located outside of the BOCs' home regions;
permits a petitioning BOC to provide domestic and international long distance
service to customers within its home region upon a finding by the FCC that a
petitioning BOC has satisfied     
 
                                      21
<PAGE>
 
   
certain criteria for opening up its local exchange network to competition and
that its provision of long distance services would further the public
interest; and removes existing barriers to entry into local service markets.
Additionally, there are significant changes in the manner in which carrier-to-
carrier arrangements are regulated at the federal and state levels; procedures
to revise universal service standards; and penalties for unauthorized
switching of customers. The FCC has instituted proceedings addressing the
implementation of this legislation.     
   
  On August 8, 1996, the FCC released its FCC Interconnect Order which
established nationwide rules designed to encourage new entrants to participate
in the local service markets through interconnection with the Incumbent Local
Exchange Carriers ("ILECs"), resale of the ILEC's retail services and
unbundled network elements. These rules set the groundwork for the statutory
criteria governing BOC entry into the long distance market. WorldCom cannot
predict the effect such legislation or the implementing regulations will have
on it or the industry. Motions to stay implementation of the FCC Interconnect
Order were filed with the FCC and federal courts of appeal. Appeals
challeging, among other things, the validity of the FCC Interconnect Order
were filed in several federal courts of appeal and assigned to the Eight
Circuit Court of Appeals for disposition. The Eighth Circuit Court of Appeals
has stayed the pricing provisions of the FCC Interconnect Order. WorldCom
cannot predict either the outcome of these challenges and appeals or the
eventual effect on its business or the industry in general.     
   
  On December 24, 1996, the FCC released a Notice of Proposed Rulemaking (the
"NPRM") seeking to reform the FCC's current access charge policies and
practices to comport with a competitive or potentially competitive local
access service market. On May 7, 1997, the FCC announced that it will issue a
series of orders that reform Universal Service Subsidy allocations, adopt
various reforms to the existing rate structure for interstate access that are
designed to reduce access charges, over time, to more economically efficient
levels and rate structures. In particular, the FCC adopted changes to its rate
structures for Common Line, Local Switching and Local Transport rate elements.
The FCC generally removed from minute-of-use access charges costs that are not
incurred on a per-minute-of-use-basis, with such costs being recovered through
flat rated charges. Additional charges and details of the FCC's actions are to
be addressed when Orders are released within the near future. Access charges
are a principal component of the Company's line cost expense. The Company
cannot predict whether or not results of this proceeding will have a material
impact upon the financial position or results of operations of the Company.
       
  In the NPRM, the FCC tentatively concluded that information services
providers (including among others Internet service providers) should not be
subject to existing interstate access charges. However, the FCC recognized
that these services and recent technological advances may be constrained by
current regulatory practices that have their foundations in traditional
services and technologies. The FCC issued on December 24, 1996, a Notice of
Inquiry to seek comment on whether it should, in addition to access charge
reform, consider actions relating to interstate information services and the
Internet. Changes in the regulatory environment relating to the
telecommunications or Internet-related services industry could have an adverse
effect on the Company's Internet-related services business. The Telecom Act
may permit telecommunications companies, BOCs or others to increase the scope
or reduce the cost of their Internet access services. The Company cannot
predict the effect that the Notice of Inquiry, the Telecom Act or any future
legislation, regulation or regulatory changes may have on its business.     
   
  In December 1996, the FCC adopted a new policy that will make it easier for
United States international carriers to obtain authority to route
international public switched voice traffic to and from the United States
outside of the traditional settlement rate and proportionate return regimes.
In February 1997, the United States entered into a World Trade Organization
Agreement (the "WTO Agreement") that should have the effect of liberalizing
the provision of switched voice telephone and     
 
                                      22
<PAGE>
 
   
other telecommunications services in scores of foreign countries over the next
several years. As a result of the WTO Agreement, WorldCom expects the FCC,
among other things, to reexamine its policies regarding (i) the services that
may be provided by foreign owned United States international common carriers,
including carriers owned or controlled by foreign carriers that have market
power in their home markets, and (ii) the provision of international switched
voice services outside of the traditional settlement rate and proportionate
return regimes. Although the FCC's new flexible settlement rate policy, and
the WTO Agreement and any ensuing FCC policy changes, may result in lower
costs to the Company to terminate international traffic, there is a risk that
the revenues that the Company receives from inbound international traffic may
decrease to an even greater degree. The implementation of the WTO Agreement
may also make it easier for foreign carriers with market power in their home
markets to offer United States and foreign customers end-to-end services to
the disadvantage of WorldCom, which may face substantial obstacles in
obtaining from foreign governments and foreign carriers the authority and
facilities to provide such end-to-end services.     
   
  The Company is or will be subject to the applicable laws and has obtained or
will need to obtain the approval of the regulatory authority of each overseas
country in which it provides or proposes to provide telecommunications
services. The laws and regulatory requirements vary from country to country.
Some countries have substantially deregulated various communications services,
while other countries have maintained strict regulatory regimes. The
application procedure to enter new markets can be time-consuming and costly,
and terms of licenses vary for different countries. There can be no assurance
that the Company will receive all authorizations or licenses necessary for new
communications services or that delays in the licensing process will not
adversely affect its business.     
   
  Competition     
   
  Virtually all markets for telecommunications services are extremely
competitive, and the Company expects that competition will intensify in the
future. In each of the markets in which it offers telecommunications services,
the Company faces significant competition from carriers with greater market
share and financial resources. The Company competes domestically with
incumbent providers, which have historically dominated their local
telecommunications markets, and long distance carriers, for the provision of
long distance services. In certain markets the incumbent provider offers both
local and long distance services. The ILECs presently have numerous advantages
as a result of their historic monopoly control of the local exchange market. A
continuing trend toward business combinations and alliances in the
telecommunications industry may create significant new competitors to the
Company. Many of the Company's existing and potential competitors have
financial, personnel and other resources significantly greater than those of
the Company. The Company also faces competition from one or more competitors
in most markets in which it operates, including Competitive Access Providers
operating fiber optic networks, in some cases in conjunction with the local
cable television operator. Each of AT&T Corp. ("AT&T"), MCI Communications
Corporation ("MCI") and Sprint Corporation has indicated its intention to
offer local telecommunications services in major United States markets using
its own facilities or by resale of the Local Exchange Carriers' or other
providers' services. In addition, the Company competes with equipment vendors
and installers and telecommunications management companies with respect to
certain portions of its business.     
   
  In overseas markets, the Company competes with incumbent providers, many of
which still have special regulatory status and the exclusive rights to provide
certain services, and virtually all of which have historically regulatory
status and the exclusive rights to provide certain services, and virtually all
of which have historically dominated their local, domestic long distance and
international services markets. These incumbent providers have numerous
advantages including existing facilities, customer loyalty, and substantial
financial resources. The Company also competes with other service providers in
overseas markets, many of which are affiliated with incumbent providers in
other countries. Typically, the Company must devote extensive resources to
obtaining regulatory approvals necessary     
 
                                      23
<PAGE>
 
   
to operate in overseas markets, and then to obtaining access to and
interconnection with the incumbent's network on a non-discriminatory basis.
    
          
  The Company may also be subject to additional competition due to the
development of new technologies and increased availability of domestic and
international transmission capacity. For example, even though fiber optic
networks, such as that of the Company, are now widely used for long distance
transmission, it is possible that the desirability of such networks could be
adversely affected by changing technology. The telecommunications industry is
in a period of rapid technological evolution, marked by the introduction of
new product and service offerings and increasing satellite and fiber optic
transmission capacity for services similar to those provided by the Company.
The Company cannot predict which of many possible future product and service
offerings will be important to maintain its competitive position or what
expenditures will be required to develop and provide such products and
services.     
   
  Under the Telecom Act and ensuing federal and state regulatory initiatives,
barriers to local exchange competition are being removed. The introduction of
such competition, however, also establishes the predicate for the BOCs to
provide in-region interexchange long distance services. The BOCs are currently
allowed to offer certain "incidental" long distance service in-region and to
offer out-of-region long distance services. Once the BOCs are allowed to offer
in-region long distance services, they could be in a position to offer single
sources local and long distance service similar to that being offered by the
Company. The Company expects that the increased competition made possible by
regulatory reform will result in certain pricing and margin pressures in the
domestic telecommunications services business.     
   
  The Company, through UUNET, also competes in the market for data
communications services, including Internet access and on-line services. This
market is also extremely competitive. The Company expects that competition
will intensify in the future. The Company believes that its ability to compete
successfully in this market depends on a number of factors, including: market
presence; the ability to execute a rapid expansion strategy; the capacity,
reliability and security of its network infrastructure; ease of access to and
navigation on the Internet; the pricing policies of its competitors and
suppliers, the timing of the introduction of new products and services by the
Company and its competitors; UUNET's ability to support industry standards;
and industry and general economic trends. The success of the Company in this
market will depend heavily upon UUNET's ability to provide high quality
Internet connectivity and value-added Internet services at competitive prices.
       
  The Company expects that all of the major on-line services providers and
telecommunications companies will expand their current services to compete
fully in the Internet access market. The Company believes that new
competitors, including large computer hardware, software, media and other
technology and telecommunications companies will enter the Internet access
market, resulting in even greater competition for UUNET. Certain companies,
including America Online, Inc., AT&T, MCI, BBN Corporation and PSINet, Inc.,
have obtained or expanded their Internet access products and services as a
result of acquisitions and strategic investments. Such acquisitions may permit
UUNET's competitors to devote greater resources to the development and
marketing of new competitive products and services and the marketing of
existing competitive products and services. UUNET expects these acquisitions
and strategic investments to increase, thus creating significant new
competitors to UUNET.     
   
  As UUNET continues to expand Internet operations outside of the United
States, UUNET will be forced to compete with and buy services from government-
owned or subsidized telecommunications providers, some of which may enjoy an
absolute monopoly on telecommunications services essential to its business.
UUNET will also encounter competition from companies whose operating styles
are substantially different from those that it usually experiences. For
example, in the United Kingdom, the Company competes directly with: (1)
telecommunications companies, such as British     
 
                                      24
<PAGE>
 
   
Telecommunications plc, Mercury Communications Limited and others; (2) other
Internet access providers, such as Demon Internet Limited and EUnet GB
Limited; and (3) on-line services providers, such as CompuServe Corporation,
America Online/Bertelsmann AG, Microsoft Corporation and AT&T. These foreign
competitors may also possess a better understanding of their local markets and
may have better working relationships with local telecommunications companies.
There can be no assurance that UUNET can obtain similar levels of local
knowledge, and failure to obtain that knowledge could place UUNET at a serious
competitive disadvantage.     
   
  Potential Liability of On-Line Service Providers     
   
  The law in the United States relating to the liability of on-line service
providers and Internet access providers for information carried on,
disseminated through or hosted on their systems is currently unsettled.
Several private lawsuits seeking to impose such liability are currently
pending. In one case brought against an Internet access provider, Religious
Technology Center v. Netcom On-Line Communication Services, Inc., the United
States District Court for the Northern District of California ruled in a
preliminary phase that under certain circumstances Internet access providers
could be held liable for copyright infringement. The case has been settled by
the parties. The Telecom Act prohibits and imposes criminal penalties and
civil liability for using an interactive computer service for transmitting
certain types of information and content, such as indecent or obscene
communications. On June 12, 1996, however, a panel of three federal judges
granted a preliminary injunction barring enforcement of this portion of the
Telecom Act to the extent that enforcement is based upon allegations other
than obscenity or child pornography as an impermissible restriction on the
First Amendment's right of free speech. In addition, the United States
Congress in consultation with the United States Patent and Trademark Office
and the Administration's National Information Infrastructure Task Force, is
currently considering legislation to address the liability of on-line service
providers and Internet access providers, and numerous states have adopted or
are currently considering similar types of legislation. The imposition upon
Internet access providers of potential liability for materials carried on or
disseminated through their systems could require UUNET to implement measures
to reduce its exposure to such liability, which may require the expenditure of
substantial resources or the discontinuation of certain product or service
offerings. The Company believes that it is currently unsettled whether the
Telecom Act prohibits and imposes liability for any services provided by UUNET
should the content or information transmitted be subject to the statute.     
   
  The law relating to the liability of on-line service providers and Internet
access providers in relation to information carried, disseminated or hosted
also is being discussed by the World Intellectual Property Organization in the
context of ongoing consideration of updating existing, and adopting new,
international copyright treaties. Similar developments are ongoing in the
United Kingdom and other jurisdictions. The scope of authority of various
regulatory bodies in relation to on-line services is at present uncertain. The
Office of Telecommunications in the United Kingdom has recently published a
consultative document setting out a number of issues for discussion, including
the roles of traditional telecommunications and broadcasting regulators with
respect to on-line services. The Securities Investment Board in the United
Kingdom is investigating the status of on-line services and the transmission
of investment information over networks controlled by access providers. Such
transmissions may make an access provider liable for any violation of
securities and other financial services legislation and regulations. Decisions
regarding regulation, enforcement, content liability and the availability of
Internet access in other countries may significantly affect the ability to
offer certain services worldwide and the development and profitability of
companies offering Internet and on-line services in the future. For example,
an Internet access provider that competes with UUNET removed certain content
from its services worldwide in reaction to law enforcement activities in
Germany, and it has been reported that an Internet access provider in Germany
has been advised by prosecutors that it may have liability for disseminating
neo-Nazi writings by providing access to the Internet where these materials
are available.     
 
 
                                      25
<PAGE>
 
   
  The increased attention focused upon liability issues as a result of these
lawsuits, legislation and legislative proposals could affect the growth of
Internet use. Any costs incurred as a result of liability or asserted
liability for information carried on or disseminated through its systems could
have a material adverse effect on the business, financial condition and
results of operations of UUNET.     
   
  Dependence upon Network Infrastructure; Risk of System Failure; Security
Risks     
   
  The success of the Company in marketing its services to business and
government users requires that the Company provide superior reliability,
capacity and security via its network infrastructures. These networks are
subject to physical damage, power loss, capacity limitations, software
defects, breaches of security (by computer virus, break-ins or otherwise) and
other factors, certain of which have caused, and will continue to cause,
interruptions in service or reduced capacity for the customers of such
company. Similarly, UUNET's business relies on the availability of its network
infrastructure for the provision of Internet access services. Interruptions in
service, capacity limitations or security breaches could have a material
adverse effect on the Company's business, financial condition and results of
operations.     
   
  Anti-Takeover Provisions     
   
  The Second Amendment and Restated Articles of Incorporation of WorldCom
contains provisions (a) requiring a 70% vote for approval of certain business
combinations with certain 10% shareholders unless approved by a majority of
the continuing Board of Directors or unless certain minimum price, procedural
and other requirements are met; (b) restricting aggregate beneficial ownership
of the capital stock of WorldCom by foreign shareholders to 20% of the total
outstanding capital stock, and subjecting excess shares to redemption, and (c)
authorizing WorldCom's Board of Directors to issue preferred stock in one or
more classes without any action on the part of shareholders. In addition,
WorldCom has adopted a rights plan (the "WorldCom Rights Plan") and in
connection therewith entered into the Rights Agreement between WorldCom and
The Bank of New York, as Rights Agent, dated as of August 25, 1996, as
amended, which will cause substantial dilution to a person or group that
attempts to acquire WorldCom on terms not approved by WorldCom's Board of
Directors. Further, WorldCom's Bylaws (a) contain requirements regarding
advance notice of nomination of directors by shareholders and (b) restrict the
calling of special meetings by shareholders to those owning shares
representing not less than 40% of the votes to be cast. These provisions,
including the WorldCom Rights Plan, may have an "anti-takeover" effect.     
 
                                      26
<PAGE>
 
                              THE EXCHANGE OFFERS
 
PURPOSE OF THE EXCHANGE OFFERS
   
  Since the MFS Merger, WorldCom has been operationally and financially
integrating MFS into the WorldCom organization, which integration includes
creating a single, more efficient, consolidated credit entity. The Exchange
Offers are an element of this integration effort, and the Proposed Amendments
are expected to provide greater financial and operating flexibility to the
fully integrated organization. The Company believes that the failure to
consummate the Exchange Offers and the Consent Solicitations will not have a
material adverse effect on the Company. See "The Proposed Amendments."     
 
TERMS OF THE EXCHANGE OFFERS
   
  Upon the terms and subject to the conditions set forth in this Prospectus
and in the Letters of Transmittal and in accordance with applicable law, the
Company offers to exchange (i) $871.597 principal amount of its WorldCom 2004
Notes for each $1,000 principal amount at stated maturity of MFS 2004 Notes
validly tendered on or prior to the Expiration Date and not withdrawn as
provided herein and (ii) $737.912 principal amount of its WorldCom 2006 Notes
for each $1,000 principal amount at stated maturity of MFS 2006 Notes validly
tendered on or prior to the Expiration Date and not withdrawn as provided
herein. Interest on the WorldCom Notes will accrue from and including the
Interest Accrual Date at the stated interest rate on such WorldCom Notes. The
principal amount of WorldCom Notes offered in exchange for the applicable
series of MFS Notes is equal to the Accreted Value of such MFS Notes as of the
Interest Accrual Date. As of the Interest Accrual Date, the Accreted Value of
the MFS 2004 Notes is $871.597 per $1,000 principal amount at stated maturity
and the Accreted Value of the MFS 2006 Notes is $737.912 per $1,000 principal
amount at stated maturity. The Accreted Value of a series of MFS Notes, as of
the Interest Accrual Date, is the sum of (i) the initial issue price of such
MFS Notes plus (ii) the portion of the original issue discount applicable to
such MFS Notes accreted from and including the original issue date thereof and
to but excluding the Interest Accrual Date.     
   
  WorldCom Notes will be issued only in denominations of $1,000 and integral
multiples thereof. If the aggregate principal amount of WorldCom Notes that
otherwise would be issued in exchange for the MFS Notes of a series tendered
by a Holder and accepted by the Company pursuant to an Exchange Offer is not
an integral multiple of $1,000, such principal amount will be reduced to the
nearest such multiple and the Company will pay to such Holder an amount in
cash equal to the reduction of such principal amount. WorldCom Notes to be
exchanged for MFS Notes pursuant to the Exchange Offers will be delivered and
Consent Payments and other cash payments, if any, will be made on the Exchange
Date.     
   
  The financial terms of the WorldCom 2004 Notes and WorldCom 2006 Notes are
substantially identical in all material respects to the financial terms of the
MFS 2004 Notes and MFS 2006 Notes, respectively, except that: (i) the MFS
Notes are the sole obligations of MFS, while the WorldCom Notes will be the
sole obligations of WorldCom; (ii) the MFS 2004 Notes and the MFS 2006 Notes
were originally issued at a discount and, except as described below, the
principal amount thereof accretes in value until January 15, 1999 and January
15, 2001, respectively, while the WorldCom Notes will have a fixed principal
amount; (iii) except as described below, no cash interest accrues on the MFS
2004 Notes and the MFS 2006 Notes until January 15, 1999 and January 15, 2001,
respectively, while interest will begin to accrue on the WorldCom Notes on the
Interest Accrual Date and will be payable in cash semi-annually in arrears on
each January 15 and July 15, commencing July 15, 1997; and (iv) overdue
principal and premium, if any, and interest on the overdue principal and any
overdue premium of the MFS 2004 Notes and the MFS 2006 Notes bear interest at
the rate of 10 3/8% and 9 7/8% per annum, respectively, while overdue
principal and premium, if any, and interest on the overdue principal and any
overdue premium of the WorldCom 2004 Notes and the WorldCom 2006 Notes will
bear interest at 9 3/8% and 8 7/8% per annum, respectively. The WorldCom
Indenture will contain covenants that are substantially less restrictive than
those that are currently in the MFS Indentures and the     
 
                                      27
<PAGE>
 
   
WorldCom Notes will carry significantly reduced protections than those now
afforded to the MFS Notes. Pursuant to the MFS Indentures, MFS may elect,
prior to July 15, 1997 (or a future Interest Payment Date), to commence the
accrual of cash interest on either series of MFS Notes beginning on such date,
at which time the outstanding principal amount of each of such MFS Notes at
their respective stated maturities will equal the Accreted Value of such MFS
Notes as of such date, and cash interest will be payable on January 15, 1998
(or the next succeeding Interest Payment Date, as the case may be) and on each
Interest Payment Date thereafter. In the event any such election is made prior
to the Expiration Date, MFS intends to issue a press release and file with the
Commission a Current Report on Form 8-K publicly announcing the commencement
of the accrual of cash interest on the MFS Notes beginning on July 15, 1997
(or a future Interest Payment Date, as the case may be).     
   
  As of the date of this Prospectus, $787,519,000 in aggregate principal
amount at stated maturity of the MFS 2004 Notes and $910,475,000 in aggregate
principal amount at stated maturity of the MFS 2006 Notes were Outstanding.
Only a Holder of the MFS Notes (or such Holder's legal representative or
attorney-in-fact) as reflected on the records of the Trustee under the MFS
Indentures may participate in the Exchange Offers and the Consent
Solicitations. There is and will be no fixed record date for determining
Holders of the MFS Notes entitled to participate in the Exchange Offers.     
 
  The Company reserves the right, in its sole discretion, to purchase or make
offers for any MFS Notes that remain outstanding subsequent to the Expiration
Date and, to the extent permitted by applicable law, purchase MFS Notes in the
open market, in privately negotiated transactions or otherwise. The terms of
any such purchases or offers could differ from the terms of the Exchange
Offers. Any purchase or offer by the Company will not be made except in
accordance with applicable law and will in no event be made prior to the
expiration of ten business days after the Expiration Date.
 
CONDITIONS OF THE EXCHANGE OFFERS AND CONSENT SOLICITATIONS
 
  Notwithstanding any other provisions of an Exchange Offer or Consent
Solicitation, or any extension of such Exchange Offer or Consent Solicitation,
the Company will not be required to issue WorldCom Notes or make any payments
in respect of any properly tendered MFS Notes or properly given Consents, and
may terminate such Exchange Offer or Consent Solicitation or, at its option,
modify, extend or otherwise amend such Exchange Offer or Consent Solicitation
with respect to such MFS Notes, if any of the following conditions has not
been satisfied, prior to or concurrently with the consummation of such
Exchange Offer or Consent Solicitation:
 
    (a) receipt of the Requisite Consents with respect to both series of MFS
  Notes;
 
    (b) there shall not have been any action taken or threatened, or any
  statute, rule, regulation, judgment, order, stay, decree or injunction
  promulgated, enacted, entered, enforced or deemed applicable to the
  Exchange Offers, the exchange of MFS Notes pursuant to the Exchange Offers
  (the "Exchange"), the Consent Solicitations or the Proposed Amendments by
  or before any court or governmental regulatory or administrative agency or
  authority tribunal, domestic or foreign, which (i) challenges the making of
  the Exchange Offers, the Exchange, the Consent Solicitations or the
  Proposed Amendments or might, directly or indirectly, prohibit, prevent,
  restrict or delay consummation of, or might otherwise adversely affect in
  any material manner, the Exchange Offers, the Exchange, the Consent
  Solicitations or the Proposed Amendments or (ii) in the sole judgment of
  the Company, could materially adversely affect the business, condition
  (financial or otherwise), income, operations, properties, assets,
  liabilities or prospects of the Company and its subsidiaries, taken as a
  whole, or materially impair the contemplated benefits of the Exchange
  Offers, the Exchange, the Consent Solicitations or the Proposed Amendments
  to the Company or might be material to holders of MFS Notes in deciding
  whether to accept such Exchange Offers and give such Consents;
 
    (c) there shall not have occurred or be likely to occur any event
  affecting the business or financial affairs of the Company that, in the
  sole judgment of the Company, would or might prohibit, prevent, restrict or
  delay consummation of the Exchange Offers, the Exchange, the
 
                                      28
<PAGE>
 
  Consent Solicitations or the Proposed Amendments or that will, or is
  reasonably likely to, materially impair the contemplated benefits of the
  Exchange Offers, the Exchange, the Consent Solicitations or the Proposed
  Amendments to the Company or might be material to Holders of MFS Notes in
  deciding whether to accept such Exchange Offers and give the related
  Consent;
 
    (d) there shall not have occurred (i) any general suspension of or
  limitation on trading in securities on the NYSE or in the over-the-counter
  market (whether or not mandatory), (ii) any material adverse change in the
  prices of the MFS Notes, (iii) a material impairment in the general trading
  market for debt securities, (iv) a declaration of a banking moratorium or
  any suspension of payments in respect of banks by federal or state
  authorities in the United States (whether or not mandatory), (v) a
  commencement of a war, armed hostilities or other national or international
  crisis directly or indirectly relating to the United States, (vi) any
  limitation (whether or not mandatory) by any governmental authority on, or
  other event having a reasonable likelihood of affecting, the extension of
  credit by banks or other lending institutions in the United States or (vii)
  any material adverse change in United States securities or financial
  markets generally, or in the case of any of the foregoing existing at the
  time of the commencement of the Exchange Offers, a material acceleration or
  worsening thereof; and
     
    (e) the Trustee under the MFS Indentures (the "MFS Trustee") shall have
  executed and delivered the supplemental indentures relating to the Proposed
  Amendments and shall not have objected in any respect to, or taken any
  action that could in the sole judgment of the Company adversely affect the
  consummation of, any of the Exchange Offers, the Exchange, the Consent
  Solicitations or the Company's ability to effect the Proposed Amendments
  nor shall the MFS Trustee have taken any action that challenges the
  validity or effectiveness of the procedures used by the Company in
  soliciting Consents (including the form thereof) or in making the Exchange
  Offers, the Exchange or the Consent Solicitations.     
   
  If any of the foregoing conditions are not satisfied with respect to a
particular series of MFS Notes, the Company may (i) terminate the Exchange
Offer and the Consent Solicitation with respect to such series of MFS Notes
and return all tendered MFS Notes of such series to the Holders thereof; (ii)
extend such Exchange Offer and Consent Solicitation and retain all tendered
MFS Notes and Consents until the Expiration Date, as extended, of such
Exchange Offer and Consent Solicitation, subject, however, to the withdrawal
rights of Holders, see "--Withdrawal of Tenders" and "--Expiration Date;
Extensions; Amendments"; or (iii) waive the unsatisfied conditions with
respect to such Exchange Offer and Consent Solicitation and accept all MFS
Notes tendered and not previously withdrawn.     
 
  The foregoing conditions are for the sole benefit of the Company and may be
waived by the Company, in whole or in part, in its sole discretion. Any
determination made by the Company concerning an event, development or
circumstance described or referred to above shall be conclusive and binding.
   
  Notwithstanding any of the foregoing, the Company will not consummate the
Exchange Offer with respect to the MFS 2004 Notes if less than $343.2 million
of principal amount of WorldCom 2004 Notes would be issued in such Exchange
Offer and will not consummate the Exchange Offer with respect to the MFS 2006
Notes if less than $336.0 million of principal amount of WorldCom 2006 Notes
would be issued in such Exchange Offer.     
   
  Except for the requirements of applicable federal and state securities laws,
there are no federal or state regulatory requirements to be complied with or
approvals to be obtained by the Company or MFS in connection with the Exchange
Offers which, if not complied with, would have a material adverse effect on
the Company.     
 
CERTAIN CONSEQUENCES TO HOLDERS NOT TENDERING IN THE EXCHANGE OFFERS
 
  Consummation of the Exchange Offers and the adoption of the Proposed
Amendments with respect to the MFS Notes will have certain consequences to
Holders of the MFS Notes who elect not
 
                                      29
<PAGE>
 
   
to tender in the Exchange Offers, including, without limitation, that the
covenants and certain other terms set forth in the MFS Indentures, as proposed
to be amended, with respect to the MFS Notes will be substantially less
restrictive, and afford less protection to such Holders, than those that are
currently in the MFS Indentures. See "Risk Factors--Certain Considerations
Relating to Holders Not Tendering in the Exchange Offers."     
 
EXPIRATION DATE; EXTENSIONS; AMENDMENTS
 
  The term "Expiration Date" shall mean 11:59 p.m., New York City time, on
    , 1997, subject to the right of the Company to extend such date and time
for either or both Exchange Offers in its sole discretion, in which case the
term "Expiration Date" shall mean, with respect to any such extended Exchange
Offer, the latest date and time to which such Exchange Offer is extended.
   
  The Company reserves the right, in its sole discretion, (i) to delay
accepting any validly tendered MFS Notes, (ii) to extend the Exchange Offers
or (iii) to terminate or amend the Exchange Offers by giving oral or written
notice of such delay, extension, termination or amendment to the Exchange
Agent. Any such delay in acceptance, extension, termination or amendment will
be followed as promptly as practicable by a public announcement thereof which,
in the case of an extension, will be made no later than 9:00 a.m., New York
City time, on the next business day after the previously scheduled Expiration
Date. If the Exchange Offers are amended in a manner determined by the Company
to constitute a material change, the Company will promptly disclose such
amendment by means of a prospectus supplement that will be distributed to the
Holders, and the Company will extend the Exchange Offers for a period of five
to ten business days, depending upon the significance of the amendment and the
manner of disclosure to the Holders, if the Exchange Offers would otherwise
have expired during such five to ten business day period. Any change in the
consideration offered to Holders of MFS Notes pursuant to either Exchange
Offer shall be paid to all Holders whose MFS Notes have previously been
tendered pursuant to such Exchange Offer.     
 
  Without limiting the manner in which the Company may choose to make a public
announcement of any delay, extension, amendment or termination of the Exchange
Offers, the Company shall have no obligation to publish, advertise, or
otherwise communicate any such public announcement, other than by making a
timely release to an appropriate news agency, including, without limitation,
the Dow Jones News Service.
 
EFFECT OF TENDER
   
  Any tender by a Holder (and subsequent acceptance of such tender by the
Company) that is not withdrawn prior to the Expiration Date will constitute an
agreement between such Holder and the Company in accordance with the terms and
subject to the conditions of the applicable Exchange Offer described herein
and in the applicable Letter of Transmittal. The acceptance of an Exchange
Offer by a tendering Holder of MFS Notes will constitute the agreement by such
Holder to deliver good and marketable title to the tendered MFS Notes free and
clear of all liens, charges, claims encumbrances, interests and restrictions
of any kind.     
   
  Holders of the MFS Notes do not have any appraisal or dissenters' rights
under the Delaware General Corporation Law or the MFS Indentures in connection
with the Exchange Offers. The Company intends to conduct the Exchange Offers
in accordance with the applicable requirements of the Securities Act and the
Exchange Act, and the rules and regulations of the Commission thereunder.     
 
ACCEPTANCE OF MFS NOTES FOR EXCHANGE; DELIVERY OF WORLDCOM NOTES
 
  The Company shall be deemed to have accepted validly tendered MFS Notes and
properly given Consents which have not been withdrawn or revoked as provided
in this Prospectus when, and if, the
 
                                      30
<PAGE>
 
   
Company has given oral or written notice thereof to the Exchange Agent.
Subject to the terms and conditions of the Exchange Offers, delivery of
WorldCom Notes, Consent Payments and other cash payments, if any, for MFS
Notes so accepted will be made by the Exchange Agent on the Exchange Date upon
receipt of such notice. The Exchange Agent will act as agent for tendering
Holders for the purpose of receiving MFS Notes from and transmitting Consent
Payments and WorldCom Notes to such Holders. If any tendered MFS Notes are not
accepted for any reason set forth in the terms and conditions of the Exchange
Offers or if MFS Notes are withdrawn or are submitted for a greater principal
amount than the Holder thereof desires to exchange, such unaccepted, withdrawn
or non-exchanged MFS Notes will be returned without expense to the tendering
Holder thereof as promptly as practicable.     
 
PROCEDURES FOR TENDERING
   
  To tender in the Exchange Offers, a Holder of MFS Notes must complete, sign
and date the applicable Letter of Transmittal, or a facsimile thereof, have
the signatures thereon guaranteed if required by the Letter of Transmittal,
and mail or otherwise deliver such Letter of Transmittal or such facsimile to
the Exchange Agent at the address set forth in the Letter of Transmittal for
receipt on or prior to the Expiration Date. In addition, either (i)
certificates for such MFS Notes along with the applicable Letter of
Transmittal, must be received by the Exchange Agent on or prior to the
Expiration Date (ii) a timely confirmation of a book-entry transfer (a "Book-
Entry Confirmation") of such MFS Notes, if such procedure is available, into
the Exchange Agent's account at DTC pursuant to the procedure for book-entry
transfer described below, must be received by the Exchange Agent prior to the
Expiration Date or (iii) the Holder must comply with the guaranteed delivery
procedures described below.     
   
  THE METHOD OF DELIVERY OF MFS NOTES, THE LETTERS OF TRANSMITTAL AND ALL
OTHER REQUIRED DOCUMENTS TO THE EXCHANGE AGENT IS AT THE ELECTION AND RISK OF
THE HOLDER. INSTEAD OF DELIVERY BY MAIL, IT IS RECOMMENDED THAT HOLDERS USE AN
OVERNIGHT OR HAND DELIVERY SERVICE, PROPERLY INSURED. IN ALL CASES, SUFFICIENT
TIME SHOULD BE ALLOWED TO ASSURE DELIVERY TO AND RECEIPT BY THE EXCHANGE AGENT
ON OR BEFORE THE EXPIRATION DATE. DO NOT SEND THE LETTER OF TRANSMITTAL OR ANY
MFS NOTES TO ANYONE OTHER THAN THE EXCHANGE AGENT.     
          
  Any beneficial owner whose MFS Notes are held by a broker, dealer,
commercial bank, trust company or other nominee and who wishes to tender
should contact such nominee promptly and instruct such nominee to tender on
such beneficial owner's behalf. If such beneficial owner wishes to tender on
such owner's own behalf, such owner must, prior to completing and executing
the applicable Letter of Transmittal and delivering such owner's MFS Notes,
either make appropriate arrangements to register ownership of the MFS Notes in
such owner's name or obtain a properly completed bond power from its nominee.
The transfer of registered ownership may take considerable time and be
difficult to complete prior to the Expiration Date.     
 
  All WorldCom Notes will be delivered only in book-entry form through DTC.
Accordingly, Holders who anticipate tendering other than through DTC are urged
to contact promptly a bank, broker or other intermediary (that has the
capability to hold securities custodially through DTC) to arrange for receipt
of any WorldCom Notes to be delivered pursuant to the Exchange Offers and to
obtain the information necessary to provide the required DTC participant and
account information in the applicable Letter of Transmittal.
   
  The YELLOW Letter of Transmittal must be used to tender MFS 2004 Notes. The
BLUE Letter of Transmittal must be used to tender MFS 2006 Notes. Holders who
wish to tender MFS Notes of both series must complete a separate Letter of
Transmittal in respect of each series of MFS Notes tendered.     
 
                                      31
<PAGE>
 
  Tender of MFS Notes Held in Physical Form.
   
  To tender MFS Notes held in physical form, the Holder thereof must: (i)
complete and sign the applicable Letter of Transmittal in accordance with the
instructions set forth therein; and (ii) deliver the properly completed and
executed Letter of Transmittal and the MFS Notes in physical form to the
Exchange Agent at the address set forth on the back cover page of this
Prospectus on or prior to the Expiration Date. THE PROPER COMPLETION,
EXECUTION AND DELIVERY OF A LETTER OF TRANSMITTAL WITH RESPECT TO PARTICULAR
MFS NOTES WILL CONSTITUTE THE GIVING OF A CONSENT TO THE PROPOSED AMENDMENTS
WITH RESPECT TO SUCH MFS NOTES.     
 
  Book-Entry Delivery Procedures for Holders Tendering MFS Notes held with
DTC.
   
  To tender MFS Notes held by a nominee with DTC, the beneficial owner thereof
must: (i) inform such owner's nominee of such owner's interest in tendering
such owner's MFS Notes pursuant to the Exchange Offers; (ii) instruct such
nominee to effect a book-entry transfer of all MFS Notes to be tendered in the
Exchange Offers by such owner into the Exchange Agent's account at DTC on or
prior to the Exchange Date; (iii) instruct such nominee to complete and sign
the applicable Letter of Transmittal in accordance with the instructions set
forth therein; and (iv) instruct such nominee to deliver the properly
completed and executed Letter of Transmittal (or a facsimile thereof) to the
Exchange Agent on or prior to the Expiration Date. THE PROPER COMPLETION,
EXECUTION AND DELIVERY OF A LETTER OF TRANSMITTAL WITH RESPECT TO PARTICULAR
MFS NOTES WILL CONSTITUTE THE GIVING OF A CONSENT TO THE PROPOSED AMENDMENTS
WITH RESPECT TO SUCH MFS NOTES.     
   
  The Exchange Agent will establish promptly an account with respect to the
MFS Notes at DTC for purposes of the Exchange Offers. The Exchange Agent and
DTC have confirmed that any financial institution that is a participant in
DTC's system may utilize DTC's Automated Tender Offer Program to tender MFS
Notes. Any such financial institution may make a book-entry delivery of MFS
Notes by causing DTC to transfer MFS Notes to the Exchange Agent's account.
However, although delivery of MFS Notes may be effected through book-entry
transfer at DTC, a properly completed and executed Letter of Transmittal,
together with any other documents required by the Letter of Transmittal, must,
in any case, be transmitted to, and received by, the Exchange Agent at its
address set forth in the Letter of Transmittal on or prior to the Expiration
Date, or the guaranteed delivery procedures described below must be complied
with. MFS Notes will not be deemed surrendered until the Letter of Transmittal
and signature guarantees, if any, is received by the Exchange Agent. DELIVERY
OF A LETTER OF TRANSMITTAL TO DTC WILL NOT CONSTITUTE VALID DELIVERY TO THE
EXCHANGE AGENT.     
       
       
  Guaranteed Delivery Procedures.
 
  Holders who wish to tender their MFS Notes and (i) whose MFS Notes are not
immediately available or (ii) who cannot deliver their MFS Notes, the Letter
of Transmittal or any other required documents to the Exchange Agent prior to
the Expiration Date, may effect a tender if:
 
    (a) The tender is made by or through a firm or other entity identified in
  Rule 17Ad-15 under the Exchange Act, including (as such terms are defined
  therein): (i) a bank; (ii) a broker, dealer, municipal securities dealer,
  municipal securities broker, government securities dealer or government
  securities broker; (iii) a credit union; (iv) a national securities
  exchange, registered securities association or clearing agency; or (v) a
  savings institution that is a participant in a Securities Transfer
  Association recognized program (an "Eligible Institution");
     
    (b) On or prior to the Expiration Date, the Exchange Agent receives from
  such Eligible Institution a properly completed and duly executed Notice of
  Guaranteed Delivery (by facsimile transmission, mail or hand delivery)
  substantially in the form provided by the Company setting forth the name
  and address of the Holder, and the principal amount of MFS Notes tendered,
      
                                      32
<PAGE>
 
     
  stating that the tender is being made thereby and guaranteeing that, within
  two New York Stock Exchange trading days after the Expiration Date, the
  Letter of Transmittal (or a facsimile thereof), together with the
  certificate(s) representing the MFS Notes in proper form for transfer or a
  Book-Entry Confirmation, as the case may be, and any other documents
  required by the Letter of Transmittal, will be delivered by the Eligible
  Institution to the Exchange Agent; and     
 
    (c) Such properly executed Letter of Transmittal (or facsimile thereof),
  as well as the certificate(s) representing all tendered MFS Notes in proper
  form for transfer and all other documents required by the Letter of
  Transmittal are received by the Exchange Agent within two New York Stock
  Exchange trading days after the Expiration Date.
 
  Upon request to the Information Agent, a Notice of Guaranteed Delivery will
be sent to Holders who wish to tender their MFS Notes according to the
guaranteed delivery procedures set forth above.
 
PROPER EXECUTION AND DELIVERY OF LETTERS OF TRANSMITTAL
       
  Signatures on a Letter of Transmittal or notice of withdrawal described
below (see "--Withdrawal of Tenders and Revocation of Consents"), as the case
may be, must be guaranteed by an Eligible Institution unless the MFS Notes
tendered pursuant thereto are tendered (i) by a Holder who has not completed
the box entitled "Special Delivery Instructions" or "Special Issuance and
Payment Instructions" on the Letter of Transmittal or (ii) for the account of
an Eligible Institution. In the event that signatures on a Letter of
Transmittal are required to be guaranteed, such guarantee must be made by a
member firm of a registered national securities exchange or of the National
Association of Securities Dealers, Inc., a commercial bank or trust company
having an office or correspondent in the United States or an Eligible
Institution.
 
  The YELLOW Letter of Transmittal must be used to tender MFS 2004 Notes. The
BLUE Letter of Transmittal must be used to tender MFS 2006 Notes. Holders who
wish to tender from both series must complete a separate Letter of Transmittal
in respect of each series of MFS Notes tendered.
 
  If the Letter of Transmittal is signed by the Holder(s) of MFS Notes
tendered thereby, the signature(s) must correspond with the name(s) as written
on the face of the MFS Notes without alteration, enlargement or any change
whatsoever. If any of the MFS Notes tendered thereby are held by two or more
Holders, all such Holders must sign the Letter of Transmittal. If any of the
MFS Notes tendered thereby are registered in different names on different MFS
Notes, it will be necessary to complete, sign and submit as many separate
Letters of Transmittal as there are different registrations of certificates.
 
  If the certificates for WorldCom Notes issued pursuant to the Exchange
Offers are to be registered in the name of, or payments are to be made to, a
person other than the signatory on the Letter of Transmittal, or if MFS Notes
that are not tendered for exchange pursuant to the Exchange Offers are to be
returned to a person other than the Holder thereof, then certificates for such
MFS Notes must be endorsed or accompanied by an appropriate instrument of
transfer, signed exactly as the name of the registered owner appears on the
certificates, with the signatures on the certificates or instruments of
transfer guaranteed by an Eligible Institution.
 
  If the Letter of Transmittal is signed by a person other than the Holder of
any MFS Notes listed therein, such MFS Notes must be properly endorsed or
accompanied by a properly completed bond power, signed by such Holder exactly
as such Holder's name appears on such MFS Notes.
 
                                      33
<PAGE>
 
  If the Letter of Transmittal or any MFS Notes or bond powers are signed by
trustees, executors, administrators, guardians, attorneys-in-fact, officers of
corporations or others acting in a fiduciary or representative capacity, such
persons should so indicate when signing, and, unless waived by the Company,
evidence satisfactory to the Company of their authority to so act must be
submitted with the Letter of Transmittal.
       
  No alternative, conditional, irregular or contingent tenders or consents
will be accepted. By executing the Letter of Transmittal (or facsimile
thereof), the tendering Holders of MFS Notes waive any right to receive any
notice of the acceptance for exchange of their MFS Notes.
   
  Tendering Holders should indicate in the applicable box in the Letter of
Transmittal the name and address to which payments and/or substitute
certificates evidencing MFS Notes for amounts not tendered or not exchanged
are to be issued or sent, if different from the name and address of the person
signing the Letter of Transmittal. If no such instructions are given, such
payments and/or MFS Notes not tendered or not exchanged will be returned to
such tendering Holder.     
   
  All questions as to the validity, form, eligibility (including time of
receipt) and acceptance and withdrawal of tendered MFS Notes will be
determined by the Company in its sole discretion, which determination will be
final and binding. The Company reserves the absolute right to reject any and
all tendered MFS Notes determined by it not to be in proper form or not to be
properly tendered or any tendered MFS Notes the Company's acceptance of which
would, in the opinion of counsel for the Company, be unlawful. The Company
also reserves the right to waive, in its sole discretion, any defects,
irregularities or conditions of tender as to particular MFS Notes, whether or
not waived in the case of other MFS Notes. The Company's interpretation of the
terms and conditions of the Exchange Offers and the Consent Solicitations
(including the instructions in the Letters of Transmittal) will be final and
binding on all parties. Unless waived, any defects or irregularities in
connection with tenders of MFS Notes must be cured within such time as the
Company shall determine. Although the Company intends to notify Holders of
defects or irregularities with respect to tenders of MFS Notes, neither the
Company, the Exchange Agent nor any other person will be under any duty to
give such notification or shall incur any liability for failure to give any
such notification. Tenders of MFS Notes will not be deemed to have been made
until such defects or irregularities have been cured or waived.     
 
  By tendering, each Holder of MFS Notes will represent to and agree with the
Company that, among other things, the MFS Notes tendered are held by such
Holder free and clear of all security interests, liens, restrictions, charges,
encumbrances, conditional sale agreements or other obligations relating to
their sale or transfer, and not subject to any adverse claim when the same are
accepted by the Company.
 
  Any holder whose MFS Notes have been mutilated, lost, stolen or destroyed
will be responsible for obtaining replacement securities or for arranging for
indemnification with the MFS Trustee. Holders may contact the Information
Agent for assistance with such matters.
       
WITHDRAWAL OF TENDERS AND REVOCATION OF CONSENTS
   
  Except as otherwise provided herein, tenders of MFS Notes may be withdrawn
at any time prior to 11:59 p.m., New York City time, on    , 1997. Tenders of
MFS Notes may not be withdrawn at any time after such time unless the
applicable Exchange Offer is extended with changes in the terms of such
Exchange Offer that are materially adverse to the tendering Holder, in which
case tenders of MFS Notes may be withdrawn under the conditions described in
the extension. The withdrawal of tendered MFS Notes will be deemed to be a
revocation of the Consents related to such MFS Notes.     
 
                                      34
<PAGE>
 
  Withdrawal of MFS Notes Held in Physical Form.
 
  To withdraw a tender of MFS Notes in the Exchange Offers, a Holder of MFS
Notes held in physical form must provide a written or facsimile transmission
notice of withdrawal to the Exchange Agent at its address set forth herein
prior to 11:59 p.m., New York City time, on        , 1997, or such later time,
if any, specified in an extension of the applicable Exchange Offer. Any such
notice of withdrawal must (i) specify the name of the person who tendered the
MFS Notes to be withdrawn, (ii) identify the MFS Notes to be withdrawn
(including the certificate number or numbers and aggregate principal amount of
such MFS Notes), (iii) be signed by the Holder in the same manner as the
original signature on the Letter of Transmittal by which such MFS Notes were
tendered (including any required signature guarantees) and (iv) if such MFS
Notes are held by a new beneficial owner, include evidence satisfactory to the
Company that the person withdrawing the tender has succeeded to the beneficial
ownership of the MFS Notes. A purported notice of withdrawal which lacks any
of the required information will not be an effective withdrawal of a tender
previously made.
 
  Withdrawal of MFS Notes Held with DTC.
   
  To withdraw a tender of MFS Notes in the Exchange Offers, a beneficial owner
of MFS Notes held with DTC must: (i) call such owner's nominee and instruct
such nominee to withdraw such tender of MFS Notes by debiting the Exchange
Agent's account at DTC of all MFS Notes to be withdrawn; and (ii) instruct
such nominee to provide a written or facsimile transmission notice of
withdrawal to the Exchange Agent at its address set forth herein prior to
11:59 p.m., New York City time, on        , 1997, or such later time, if any,
specified in an extension of the applicable Exchange Offer. Such notice of
withdrawal must: (A) specify the name of the person who tendered the MFS
Notes; (B) specify the aggregate principal amount of MFS Notes to be
withdrawn; (C) specify the number of the account at DTC to be credited with
the withdrawn MFS Notes; and (D) if such MFS Notes are held by a new
beneficial owner, evidence satisfactory to the Company that the person
withdrawing the tender has succeeded to the beneficial ownership of the MFS
Notes. A purported notice of withdrawal which lacks any of the required
information will not be an effective withdrawal of a tender previously made.
       
  All questions as to the validity, form and eligibility (including time of
receipt) of any such notices of withdrawal will be determined by the Company,
in its sole discretion, whose determination shall be final and binding on all
parties. Unless waived, any defects or irregularities in connection with
withdrawals of tenders of MFS Notes must be cured within such time as the
Company shall determine. Neither the Company, the Exchange Agent nor any other
person will be under any duty to give notification of any such defect or
irregularity or shall incur any liability for failure to give any such
notification. Withdrawals of tenders of MFS Notes will not be deemed to have
been made until such defects or irregularities have been cured or waived. Any
MFS Notes so withdrawn will be deemed not to have been validly tendered for
purposes of the Exchange Offers and the Consents with respect thereto not to
have been validly given, and no WorldCom Notes will be issued with respect
thereto unless the MFS Notes so withdrawn are validly retendered. Properly
withdrawn MFS Notes may be retendered by following one of the procedures
described above under "The Exchange Offers--Procedures for Tendering" at any
time on or prior to the Expiration Date.     
 
EXCHANGE AGENT
   
  Harris Trust and Savings Bank has been appointed Exchange Agent for the
Exchange Offers and Consent Solicitations. Letters of Transmittal, Notices of
Guaranteed Delivery and all correspondence in connection with the Exchange
Offers should be sent or delivered by each Holder or a beneficial owner's
broker, dealer, commercial bank, trust company or other nominee to the
Exchange Agent at the addresses and telephone numbers set forth in the
applicable Letter of Transmittal. The Company will pay the Exchange Agent
reasonable and customary fees for its services and will reimburse it for its
reasonable, out-of-pocket expenses in connection therewith.     
 
                                      35
<PAGE>
 
INFORMATION AGENT
   
  MacKenzie Partners, Inc. has been appointed as Information Agent for the
Exchange Offers and the Consent Solicitations, and will receive customary
compensation for its services. Questions concerning tender procedures and
requests for additional copies of this Prospectus, the Letters of Transmittal
or the Notices of Guaranteed Delivery should be directed to the Information
Agent at the address and telephone numbers set forth on the back cover page of
this Prospectus. Holders of MFS Notes may also contact their broker, dealer,
commercial bank or trust company for assistance concerning the Exchange
Offers.     
 
DEALER MANAGERS
   
  The Company has retained Salomon Brothers Inc and Goldman, Sachs & Co. to
act as Dealer Managers in connection with the Exchange Offers and Consent
Solicitations and will pay a fee to the Dealer Managers for soliciting
acceptances of the Exchange Offers, which fee is based on the Accreted Value,
as of July 15, 1997, of all MFS Notes tendered and not validly revoked. The
obligations of the Dealer Managers to perform such function are subject to
certain conditions. The Company has agreed to indemnify the Dealer Managers
against certain liabilities, including certain liabilities under the federal
securities laws, or to contribute to payments that the Dealer Managers may be
required to make in respect thereof. Any questions regarding the terms of the
Exchange Offers or the Consent Solicitations should be directed to the Dealer
Managers at the addresses and telephone numbers set forth on the back cover
page of this Prospectus.     
 
  The Dealer Managers currently plan to make a market in the WorldCom Notes
following the completion of the Exchange Offers and may buy and sell WorldCom
Notes on a "when and if issued" basis prior to the completion of the Exchange
Offers. However, there can be no assurance that the Dealer Managers will
engage in such activities or that any active market in the WorldCom Notes will
develop or be maintained. See "Risk Factors--Certain Considerations Relating
to Holders Tendering in the Exchange Offers."
   
  The Dealer Managers, from time to time, make markets in the MFS Notes. As of
the date hereof, the Dealer Managers hold approximately   % and   % of the
aggregate principal amount of Outstanding MFS 2004 Notes and MFS 2006 Notes,
respectively.     
 
OTHER FEES AND EXPENSES; TRANSFER TAXES
 
  The expenses of soliciting tenders will be borne by the Company. The
principal solicitation is being made by mail; however, additional solicitation
may be made by telegraph, facsimile transmission, telephone or in person by
the Dealer Managers and the Information Agent, as well as by officers and
regular employees of the Company and its affiliates.
 
  Tendering Holders of MFS Notes will not be required to pay any fee or
commission to the Dealer Managers. However, if a tendering Holder handles the
transaction through its broker, dealer, commercial bank, trust company or
other institution, such Holder may be required to pay brokerage fees or
commissions.
 
  The Company will pay all transfer taxes, if any, applicable to the exchange
of MFS Notes pursuant to the Exchange Offers. If, however, WorldCom Notes
and/or substitute MFS Notes for amounts not tendered or not exchanged are to
be delivered to, or are to be registered in the name of, any person other than
the Holder of MFS Notes tendered, or if tendered MFS Notes are registered in
the name of any person other than the person signing the Letter of
Transmittal, or if a transfer tax is imposed for any reason other than the
exchange of the MFS Notes pursuant to an Exchange Offer, then the amount of
any such transfer taxes (whether imposed on the registered Holder or any other
persons) will be payable by the tendering Holder. If satisfactory evidence of
payment of such taxes or exemption
 
                                      36
<PAGE>
 
therefrom is not submitted with the appropriate Letter of Transmittal, the
amount of such transfer taxes will be billed directly to such tendering Holder
and/or withheld from any payments due with respect to the MFS Notes tendered
by such Holder.
 
DESCRIPTION OF DIFFERENCES BETWEEN THE MFS NOTES AND THE WORLDCOM NOTES
   
  The following is a summary comparison of the material terms of the MFS Notes
and the WorldCom Notes. The description of the MFS Notes reflects the MFS
Notes as currently constituted and does not reflect any changes to the
covenants and other terms of the MFS Notes that may be effected pursuant to
the Consent Solicitations. Such summary does not purport to be complete and is
qualified in its entirety by reference to the WorldCom Indenture and the MFS
Indentures. Capitalized terms appearing below within the descriptions of the
MFS Notes and the WorldCom Notes and which are not otherwise defined herein
have the same meanings as are given to such terms in the MFS Indentures and
the WorldCom Indenture, respectively, copies of which are exhibits to the
Registration Statement of which this Prospectus forms a part. Definitions of
certain capitalized terms relating to the MFS Indentures are set forth under
"The Proposed Amendments--Certain Definitions." Whenever particular sections
or defined terms are referred to, it is intended that such sections or defined
terms shall be incorporated by reference. For additional information regarding
the WorldCom Notes and for definitions of certain capitalized terms used with
respect to the WorldCom Notes but not heretofore defined, see "Description of
the WorldCom Notes" below.     
 
               ----------------------------------------------------------------
                MFS NOTES                         WORLDCOM NOTES
 
- -------------------------------------------------------------------------------
 
ISSUER:         MFS                               WorldCom
 
INTEREST                                          
PAYMENT         Interest on the MFS 2004 Notes    Interest on the WorldCom
DATES:          is payable semi-annually on       Notes will accrue from the
                January 15 and July 15 begin-     Interest Accrual Date. In-
                ning on July 15, 1999, and in-    terest on the WorldCom 2004
                terest on the MFS 2006 Notes      Notes is payable semi-annu-
                is payable semi-annually on       ally on January 15 and July
                January 15 and July 15 begin-     15 beginning on January 15,
                ning on July 15, 2001; provid-    1998, and interest on the
                ed, however, that MFS may         WorldCom 2006 Notes is pay-
                elect, prior to July 15, 1997     able semi-annually on Janu-
                (or a future Interest Payment     ary 15 and July 15 beginning
                Date), to commence the accrual    on January 15, 1998. (Sec-
                of cash interest beginning on     tions 2(a)(iv) and 2(b)(iv)
                such date, at which time the      of WorldCom Indenture) 
                outstanding principal amount
                of each of the MFS Notes at
                their respective stated matu-
                rities will equal the Accreted
                Value of such MFS Notes as of
                such date, and cash interest
                will be payable on January 15,
                1998 (or the next succeeding
                Interest Payment Date, as the
                case may be) and on each In-
                terest Payment Date thereaf-
                ter. (Sections 202 and 301 of
                1994 Indenture, Section
                2(a)(iv) of 1996 Indenture)
                    
- -------------------------------------------------------------------------------
 
                                      37
<PAGE>
 
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes
 
               ----------------------------------------------------------------
                MFS NOTES                         WORLDCOM NOTES
 
- -------------------------------------------------------------------------------
OPTIONAL        The MFS 2004 Notes are not re-    The WorldCom 2004 Notes have
REDEMPTION:     deemable at the option of MFS     the same redemption provi-
                prior to January 15, 1999. On     sions as the MFS 2004 Notes,
                or after January 15, 1999, the    and the WorldCom 2006 Notes
                MFS 2004 Notes are redeemable     have the same redemption
                at the option of MFS, in whole    provisions as the MFS 2006
                at any time or in part from       Notes, except that WorldCom
                time to time, at the following    is the Issuer of the
                prices (expressed as percent-     WorldCom Notes and has the
                ages of the principal amount      optional right to redeem
                at Stated Maturity), if re-       such notes. (Sections
                deemed during the twelve          2(a)(vi) and 2(b)(vi) of the
                months beginning January 15 of    WorldCom Indenture)
                the years indicated below, in
                each case together with inter-
                est accrued to the redemption
                date:
 
<TABLE>
<CAPTION>
           YEAR                   PERCENTAGE
           ----                   ----------
           <S>                    <C>
           1999..................  103.52%
           2000..................  102.34%
           2001..................  101.17%
           2002 and thereafter...  100.00%
</TABLE>
                   
                (Section 203 of 1994 Inden-
                ture)     
 
                The MFS 2006 Notes are not re-
                deemable at the option of MFS
                prior to January 15, 2001. On
                or after January 15, 2001, the
                MFS 2006 Notes will be redeem-
                able at the option of MFS, in
                whole at any time or in part
                from time to time, at the fol-
                lowing prices (expressed as
                percentages of the principal
                amount at Stated Maturity), if
                redeemed during the twelve
                months beginning January 15 of
                the years indicated below, in
                each case together with inter-
                est accrued to the redemption
                date:
 
<TABLE>
<CAPTION>
           YEAR                   PERCENTAGE
           ----                   ----------
           <S>                    <C>
           2001..................  103.32%
           2002..................  102.21%
           2003..................  101.11%
           2004 and thereafter...  100.00%
</TABLE>
                (Section 2(a)(vi) of 1996 In-
                denture)
 
CHANGE OF       Upon the occurrence of a          None
CONTROL:        Change of Control, each Holder
                will have the right
 
- -------------------------------------------------------------------------------
 
                                      38
<PAGE>
 
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes
 
               ----------------------------------------------------------------
                MFS NOTES                         WORLDCOM NOTES
 
- --------------------------------------------------------------------------------
                to require MFS to repurchase
                all or any part of such Hold-
                er's Notes at a purchase price
                in cash equal to 101 percent
                of the Accreted Value thereof
                on any Purchase Date occurring
                prior to January 15, 1999, in
                the case of the MFS 2004
                Notes, and prior to January
                15, 2001, in the case of the
                MFS 2006 Notes, plus any ac-
                crued and unpaid cash interest
                not otherwise included in Ac-
                creted Value to such Purchase
                Date, or 101 percent of the
                principal amount thereof at
                Stated Maturity (subject to
                possible reduction as provided
                in the MFS Indentures) on any
                Purchase Date occurring on or
                after January 15, 1999 and
                January 15, 2001, respective-
                ly, plus accrued and unpaid
                interest, if any, to such Pur-
                chase Date, in accordance with
                the procedures set forth in
                the MFS Indentures. (Section
                1013 of 1994 Indenture; Sec-
                tion 5(r) of 1996 Indenture)
 
LIMITATION OF   MFS will not incur any Debt       None
DEBT:           unless (i) after giving effect
                to such incurrence of Debt and
                the contemporaneous applica-
                tion of the proceeds thereof,
                no Default or Event of Default
                shall have occurred and be
                continuing at the time or
                would occur as a consequence
                of the incurrence of such
                Debt, and (ii) such Debt is
                Permitted Debt. (Section 1008
                of 1994 Indenture; Section
                5(e) of 1996 Indenture)
 
LIMITATION OF   MFS will not permit any of its    None
DEBT AND        Restricted Subsidiaries to in-
PREFERRED       cur any Debt or issue any pre-
STOCK OF        ferred stock, except (a) Sub-
RESTRICTED      sidiary Vendor Debt; (b) Debt
SUBSIDIARIES:   and preferred stock of Re-
                stricted Subsidiaries out-
                standing as of January 26,
                1994; (c) Debt and preferred
                stock of a Restricted Subsidi-
                ary issued to and held by MFS;
                (d) Interest Swap Obligations,
                provided that such obligations
                are related to payment obliga-
                tions on Debt otherwise per-
                mitted by the terms of this
                paragraph, and Currency Hedge
                Obligations;
 
- --------------------------------------------------------------------------------
 
                                       39
<PAGE>
 
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes
 
               ----------------------------------------------------------------
                MFS NOTES                         WORLDCOM NOTES
 
- -------------------------------------------------------------------------------
 
                (e) Debt or preferred stock
                incurred in exchange for, or
                the proceeds of which are used
                to refinance, Restricted Sub-
                sidiary Debt or preferred
                stock referred to in clause
                (a) of this paragraph, subject
                to certain exceptions; (f)
                Debt or preferred stock of MFS
                Telecom, which is convertible
                into Capital Stock of MFS, is-
                sued to a Strategic Equity In-
                vestor; provided, however,
                that the proceeds of such
                incurrence or issuance are
                used as though such proceeds
                were Net Cash Proceeds in ac-
                cordance with the provisions
                of "Limitations on Asset
                Sales" (described below); and
                (g) Guarantees by Restricted
                Subsidiaries of Debt of MFS
                described in clause (a) of the
                definition of Permitted Debt.
                (Section 1009 of 1994 Inden-
                ture; Section 5(f) of 1996 In-
                denture)
 
LIMITATIONS     MFS will not, and will not        Same as MFS Notes, except
ON LIENS:       permit any of its Restricted      that, WorldCom may issue,
                Subsidiaries to enter into,       assume or guarantee indebt-
                create, incur, assume or suf-     edness secured by Liens on
                fer to exist any Liens of any     Property that are not Per-
                kind, other than Permitted        mitted Liens without equally
                Liens, on or with respect to      and ratably securing the
                any of its Property or assets     WorldCom Notes, provided
                now owned or hereafter ac-        that the sum of all such in-
                quired, or any interest           debtedness then being is-
                therein or any income or prof-    sued, assumed or guaranteed
                its therefrom, unless the MFS     together with such indebted-
                Notes are secured equally and     ness theretofore issued, as-
                ratably with (or prior to)        sumed or guaranteed that re-
                such Debt and any and all         mains outstanding does not
                other Debt so secured by such     exceed 15% of the Consoli-
                Property or assets for so long    dated Net Tangible Assets
                as any and all other Debt is      prior to the time such in-
                so secured. (Section 1012 of      debtedness was issued, as-
                1994 Indenture; Section 5(g)      sumed or guaranteed. (Sec-
                of 1996 Indenture)                tion 1004 of WorldCom Inden-
                                                  ture)
 
LIMITATIONS     MFS will not, and will not        Sale and Leaseback Transac-
ON SALE AND     permit any of its Restricted      tions are considered Liens
LEASEBACK       Subsidiaries to enter into,       and are subject to the cove-
TRANSACTIONS:   assume, Guarantee or otherwise    nant restricting the ability
                become liable with respect to     of the Company to incur
                any Sale and Leaseback Trans-     Liens, as described above.
                action, unless (i) the obliga-    (Section 1004 of WorldCom
                tion of MFS or such Restricted    Indenture)
                Subsidiary with respect
                thereto is included as Debt
                and would be permitted under
                other covenants and any Liens
                granted thereby would be per-
                mitted by
 
- -------------------------------------------------------------------------------
 
                                      40
<PAGE>
 
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes
 
               ----------------------------------------------------------------
                MFS NOTES                         WORLDCOM NOTES
 
- --------------------------------------------------------------------------------
 
                other covenants, (ii) the net
                proceeds from such transaction
                are at least equal to the Fair
                Market Value of such Property
                being transferred, and (iii)
                the Net Cash Proceeds from
                such transaction are applied
                in accordance with other cove-
                nants. (Section 1016 of 1994
                Indenture; Section 5(h) of
                1996 Indenture)
 
LIMITATIONS     MFS will not, and will not        None
ON RESTRICTED   permit any of its Restricted
PAYMENTS:       Subsidiaries to make any Re-
                stricted Payment unless, at
                the time of and after giving
                effect to the proposed Re-
                stricted Payment (i) no De-
                fault or Event of Default
                shall have occurred and be
                continuing or shall occur as a
                consequence thereof; (ii) af-
                ter giving effect, on a pro
                forma basis, to such Re-
                stricted Payment and the
                incurrence of any Debt the net
                proceeds of which are used to
                finance such Restricted Pay-
                ment, MFS could incur at least
                $1.00 of additional Debt pur-
                suant to clause (h) or (i) of
                the definition of Permitted
                Debt; and (iii) after giving
                effect to such Restricted Pay-
                ment on a pro forma basis, the
                aggregate amount expended or
                declared for all Restricted
                Payments on or after January
                26, 1994 does not exceed cer-
                tain formula amounts. (Section
                1010 of 1994 Indenture; Sec-
                tion 5(i) of 1996 Indenture)
 
LIMITATIONS     MFS will not, and will not        None
ON DIVIDENDS    permit any Restricted Subsidi-
AND OTHER       ary to cause or suffer to ex-
PAYMENT         ist or become effective or en-
RESTRICTIONS    ter into any encumbrance or
AFFECTING       restriction (other than pursu-
RESTRICTED      ant to law or regulation) on
SUBSIDIARIES:   the ability of any Restricted
                Subsidiary (i) to pay divi-
                dends or make any other dis-
                tributions in respect of its
                Capital Stock or pay any Debt
                or other obligation owed to
                MFS or any other Restricted
                Subsidiary of MFS; (ii) to
                make loans or advances to MFS
                or any Restricted Subsidiary
                of MFS; or (iii) to transfer
                any of its Property or assets
                to MFS or any other Restricted
                Subsidiary
 
- --------------------------------------------------------------------------------
 
                                       41
<PAGE>
 
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes
 
               ----------------------------------------------------------------
                MFS NOTES                         WORLDCOM NOTES
 
- --------------------------------------------------------------------------------
                   
                of MFS, except pursuant to
                certain ordinary course of
                business exceptions. (Section
                1014 of 1994 Indenture; Sec-
                tion 5(j) of 1996 Indenture)
                    
                                                  None
LIMITATIONS     MFS (i) shall not permit any
ON ISSUANCE     Restricted Subsidiary to issue
AND SALE OF     any Capital Stock other than
CAPITAL STOCK   to MFS or a Restricted Subsid-
OF RESTRICTED   iary, other than pursuant to
SUBSIDIARIES:   certain specified agreements
                in existence on January 26,
                1994, unless MFS acquires at
                the same time not less than
                its Proportionate Interest in
                such issuance of Capital Stock
                and (ii) shall not permit any
                Person other than MFS or a Re-
                stricted Subsidiary to own any
                Capital Stock of any Re-
                stricted Subsidiary of MFS
                (other than directors' quali-
                fying shares), except for cer-
                tain specified transactions.
                (Section 1018 of 1994 Inden-
                ture; Section 5(k) of 1996 In-
                denture)     
 
LIMITATIONS     MFS will not, and will not        None
ON ASSET        permit any Restricted Subsidi-
SALES:          ary to, consummate an Asset
                Sale unless (i) MFS or such
                Restricted Subsidiary, as the
                case may be, receives consid-
                eration at the time of such
                Asset Sale at least equal to
                the Fair Market Value (as evi-
                denced by a resolution of the
                Board of Directors of MFS) of
                the Property or assets sold or
                otherwise disposed of, (ii) at
                least 85 percent of the con-
                sideration received by MFS or
                such Restricted Subsidiary for
                such Property or assets con-
                sists of Cash Proceeds (or, if
                less than 85 percent, the re-
                mainder of such consideration
                consists of Telecommunications
                Assets) and (iii) MFS or such
                Restricted Subsidiary, as the
                case may be, uses the Net Cash
                Proceeds in the manner set
                forth in the next paragraph.
 
                Within 360 days, in the case
                of the MFS 2004 Notes, or 300
                days, in the case of the MFS
                2006 Notes, after any Asset
                Sale, MFS or such Restricted
                Subsidi-
                ary, as the case may be, may
                at its op-
 
- --------------------------------------------------------------------------------
 
                                       42
<PAGE>
 
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes
 
               ----------------------------------------------------------------
                MFS NOTES                         WORLDCOM NOTES
 
- --------------------------------------------------------------------------------
 
                tion (a) reinvest an amount
                equal to the Net Cash Proceeds
                (or any portion thereof) from
                such disposition in Replace-
                ment Assets and/or (b) apply
                an amount equal to such Net
                Cash Proceeds (or remaining
                Net Cash Proceeds) to the per-
                manent reduction of any Debt
                of MFS ranking pari passu with
                the MFS Notes (including the
                MFS Notes) or Debt of any Re-
                stricted Subsidiaries of MFS.
                Any Net Cash Proceeds from any
                Asset Sale that are not used
                to reinvest in Replacement As-
                sets and/or repay any pari
                passu Debt of MFS as described
                above constitute "Excess Pro-
                ceeds."
 
                When the aggregate amount of
                Excess Proceeds exceeds $5.0
                million, MFS must offer to
                purchase to the extent of such
                Excess Proceeds on a pro rata
                basis from all Holders of the
                MFS Notes (and any unsecured
                Debt of MFS ranking pari passu
                with the MFS Notes and
                containing similar provisions
                requiring MFS to purchase such
                Debt) the MFS Notes (and such
                other Debt) at a purchase
                price equal to 100 percent of
                the Accreted Value thereof on
                any Purchase Date occurring
                prior to January 15, 1999, in
                the case of the MFS 2004
                Notes, and January 15, 2001,
                in the case of the MFS 2006
                Notes, plus any accrued and
                unpaid interest not otherwise
                included in Accreted Value to
                such Purchase Date, or 100
                percent of the principal
                amount thereof at Stated
                Maturity (subject to possible
                reduction as provided in the
                MFS Indentures) on any
                Purchase Date occurring on or
                after January 15, 1999, in the
                case of the MFS 2004 Notes,
                and January 15, 2001, in the
                case of the MFS 2006 Notes,
                plus accrued and unpaid
                interest, if any, to such
                Purchase Date, in accordance
                with the procedures set forth
                in the MFS Indentures.
                (Section 1015 of 1994
                Indenture; Section 5(l) of
                1996 Indenture)
 
 
- --------------------------------------------------------------------------------
 
                                       43
<PAGE>
 
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes
 
               ----------------------------------------------------------------
                MFS NOTES                         WORLDCOM NOTES
 
- --------------------------------------------------------------------------------
 
 
                                            

LIMITATIONS     MFS will not, and will not        None 
ON              permit any of its Restricted
TRANSACTIONS    Subsidiaries to conduct any
WITH            business or enter into or per-
AFFILIATES:     mit to exist any transaction
                or series of related transac-
                tions with any Affiliate of
                MFS or such Restricted Subsid-
                iary, as the case may be, un-
                less (i) such business, trans-
                action or series of related
                transactions is in the best
                interest of MFS or such Re-
                stricted Subsidiary, (ii) such
                business, transaction or se-
                ries of related transactions
                is on terms no less favorable
                to MFS or such Restricted Sub-
                sidiary than those that could
                be obtained in a comparable
                arm's-length transaction with
                a Person that is not such an
                Affiliate and (iii) (a) with
                respect to such business,
                transaction or series of re-
                lated transactions that has a
                Fair Market Value or involves
                aggregate payments equal to,
                or in excess of, $10.0 million
                but less than $15.0 million,
                MFS delivers to the Trustee an
                Officer's Certificate stating
                that such business, transac-
                tion or series of related
                transactions complies with
                clauses (i) and (ii) above;
                and (b) with respect to such
                business, transaction or se-
                ries of related transactions
                that has a Fair Market Value
                or involves aggregate payments
                equal to, or in excess of,
                $15.0, million such business,
                transaction or series of
                transactions is approved by a
                majority of the Board of Di-
                rectors (including a majority
                of the Disinterested Direc-
                tors), which approval is set
                forth in a Board Resolution
                delivered to the Trustee cer-
                tifying that such business,
                transaction or series of re-
                lated transactions complies
                with clauses (i) and (ii)
                above. (Section 1011 of 1994
                Indenture; Section 5(m) of
                1996 Indenture)     
 
PROVISION OF    Whether or not MFS is subject     None
FINANCIAL       to Section 13(a) or 15(d) of
INFORMATION:    the Exchange Act, or any suc-
                cessor provision thereto, MFS
                shall file with the Commission
                the annual reports, quarterly
                reports and
 
- --------------------------------------------------------------------------------
 
                                       44
<PAGE>
 
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes
 
               ----------------------------------------------------------------
                MFS NOTES                         WORLDCOM NOTES
 
- -------------------------------------------------------------------------------
 
                other documents which MFS
                would have been required to
                file with the Commission pur-
                suant to such Section 13(a) or
                15(d) or any successor provi-
                sion thereto if MFS were sub-
                ject thereto, such documents
                to be filed with the
                Commission on or prior to the
                respective dates (the
                "Required Filing Dates") by
                which MFS would have been
                required to file them. MFS
                shall also in any event within
                15 days of each Required
                Filing Date (i) transmit by
                mail to all Holders, as their
                names and addresses appear in
                the Security Register, without
                cost to such Holders, and (ii)
                file with the Trustee copies
                of the annual reports,
                quarterly reports and other
                documents (without exhibits)
                which MFS would have been
                required to file with the
                Commission pursuant to Section
                13(a) or 15(d) of the Exchange
                Act or any successor
                provisions thereto if MFS were
                subject thereto. (Section 1017
                of 1994 Indenture; Section
                5(n) of 1996 Indenture)
 
                                                  WorldCom may consolidate
CONSOLIDATION,  MFS will not, and will not        with, or sell, lease or
MERGER,         permit any Restricted             convey all or substantially
CONVEYANCE,     Subsidiary to, in any             all of its assets to, or
TRANSFER OR     transaction or series of          merge with or into any other
LEASE:          transactions, consolidate with    corporation, provided that
                or merge into any other Person    (a) either WorldCom shall be
                (other than a merger of a         the continuing corporation,
                Restricted Subsidiary into MFS    or the successor corporation
                in which MFS is the continuing    (if other than WorldCom)
                corporation or the merger of a    formed by or resulting from
                Restricted Subsidiary into or     any such consolidation or
                with a Restricted Subsidiary),    merger or which shall have
                or sell, convey, assign,          received the transfer of
                transfer, lease or otherwise      such assets shall expressly
                dispose of all or                 assume payment of the
                substantially all of the          principal of (and premium,
                Property and assets of MFS and    if any) and interest on all
                the Restricted Subsidiaries       the WorldCom Notes and the
                taken as a whole to any other     performance and observance
                Person, unless:                   of all the covenants and
                (a) either (i) MFS shall be       conditions of the WorldCom
                the continuing corporation or     Indenture; and (b) WorldCom
                (ii) the corporation (if other    or such successor
                than MFS) formed by such          corporation shall not
                consolidation or into which       immediately thereafter be in
                MFS is merged, or the Person      default under the WorldCom
                which acquires, by sale,          Indenture. (Section 801 of
                assignment, conveyance,           WorldCom Indenture)
                transfer, lease or 
                disposition, all or 
                substantially all of the
                Property and assets of MFS 
                and the Restricted
                                
                
                
                
                
                
                
                
 
- -------------------------------------------------------------------------------
 
                                      45
<PAGE>
 
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes
 
               ----------------------------------------------------------------
                MFS NOTES                         WORLDCOM NOTES
 
- -------------------------------------------------------------------------------
 
                Subsidiaries taken as a whole
                (such corporation or Person,
                the "Surviving Entity"), shall
                be a corporation organized and
                validly existing under the
                laws of the
                United States of America, any
                political subdivision thereof
                or any state thereof or the
                District of Columbia, and
                shall expressly assume, by a
                supplemental MFS Indenture,
                the due and punctual payment
                of the principal of (and
                premium, if any) and interest
                on all the Notes and the
                performance of MFS' covenants
                and obligations under the MFS
                Indentures;
 
                (b) immediately before and af-
                ter giving effect to such
                transaction or series of
                transactions on a pro forma
                basis no Event of Default or
                Default shall have occurred
                and be continuing or would re-
                sult therefrom;
 
                (c) immediately after giving
                effect to any such transaction
                or series of transactions on a
                pro forma basis as if such
                transaction or series of
                transactions had occurred on
                the first day of the determi-
                nation period, MFS (or the
                Surviving Entity if MFS is not
                continuing) would be permitted
                to incur $1.00 of additional
                Debt pursuant to paragraphs
                (h) or (i) of the definition
                of "Permitted Debt"; and
 
                (d) immediately after giving
                effect to such transaction or
                series of transactions on a
                pro forma basis, MFS (or the
                Surviving Entity if MFS is not
                continuing) shall have a Con-
                solidated Net Worth equal to
                or greater than the Consoli-
                dated Net Worth of MFS immedi-
                ately prior to such transac-
                tion.
 
                Upon any transaction, or se-      Upon any transaction ef-
                ries of transactions that are     fected in accordance with
                of the type described in, and     the foregoing paragraph and
                are effected in accordance        upon any such assumption by
                with, the foregoing paragraph     the successor corporation,
                the Surviving Entity shall        such successor corporation
                succeed to, and be substituted    shall succeed to and be sub-
                for, and may exercise every       stituted for WorldCom with
                right and power of, MFS under     the same effect as if it had
                the MFS Indentures and the MFS    been named as WorldCom in
                Notes with the same effect as     the
 
- -------------------------------------------------------------------------------
 
                                      46
<PAGE>
 
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes
 
               ----------------------------------------------------------------
                MFS NOTES                         WORLDCOM NOTES
 
- -------------------------------------------------------------------------------
 
                if such Surviving Entity had      WorldCom Indenture, and
                been named as MFS in the MFS      WorldCom, except in the case
                Indentures; and when a Surviv-    of a lease, will be relieved
                ing Person duly assumes           of any further obligations
                all of the obligations and        under the WorldCom Indenture
                covenants of MFS pursuant to      and the WorldCom Notes.    
                the MFS Indentures and the MFS    (Section 802 of WorldCom   
                Notes, except in the case of a    Indenture)                  
                lease, the predecessor Person             
                shall be relieved of all such
                obligations. (Sections 801 and
                802 of 1994 Indenture; Sec-
                tion 7 of 1996 Indenture)
   
EVENTS OF                                         The WorldCom Notes are sub-  
DEFAULT         Each of the following is an       ject to substantially simi-   
                "Event of Default" with re-       lar "Events of Default" as    
                spect to a series of MFS Notes    are described in paragraphs   
                under the applicable MFS In-      (a), (b), (e), (f) and (h)    
                denture:                          under "MFS Notes--Events of   
                                                  Default". In addition under   
                (a) default in the payment of     the WorldCom Indenture, cer-  
                any installment of interest       tain events of default re-    
                upon any MFS Notes of that se-    sulting in the acceleration   
                ries when it becomes due and      of the maturity of indebted-  
                payable, and the continuance      ness aggregating in excess    
                of such default for a period      of $50,000,000 under any      
                of 30 days;                       mortgages, indentures or in-  
                                                  struments under which         
                (b) default in the payment of     WorldCom may have issued, or  
                the principal of (or premium,     by which there may have been  
                if any, on) any MFS Note of       secured or evidenced, any     
                that series at its Maturity,      other indebtedness of         
                whether at Stated Maturity or     WorldCom; but only if such    
                upon repurchase, acceleration,    indebtedness is not dis-      
                optional redemption or other-     charged or such acceleration  
                wise;                             is not rescinded or annulled  
                                                  are also considered "Events   
                (c) default, on the applicable    of Default." (Section 501 of  
                Purchase Date, in the purchase    WorldCom Indenture)           
                of MFS Notes required to be                                     
                purchased by MFS pursuant to    
                an Offer to Purchase as to      
                which an Offer has been mailed  
                to Holders or the failure to    
                make an Offer to Purchase as    
                required in the applicable MFS  
                Indentures;                     
                                                
                (d) MFS fails to comply with    
                any of its covenants or agree-  
                ments related to "Limitation    
                on Debt" or "Limitation on      
                Debt and Preferred Stock of     
                Restricted Subsidiaries" or     
                fails to perform or comply      
                with the provisions of the ap-  
                plicable MFS Indenture related  
                to "Consolidation, Merger,      
                Conveyance, Transfer or         
                Lease";                         

                (e) default in the perfor-      
                mance, or breach, of any cove-  
                nant or warranty of     
 
- -------------------------------------------------------------------------------
 
                                      47
<PAGE>
 
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes
 
               ----------------------------------------------------------------
                MFS NOTES                         WORLDCOM NOTES
 
- --------------------------------------------------------------------------------
                   
                MFS in the applicable MFS In-
                denture (other than a covenant
                or warranty a default in whose
                performance or breach is spe-
                cifically dealt with in (a),
                (b), (c) or (d) above) and
                continuance of such default or
                breach for a period of 60 days
                after specified written notice
                thereof has been given to MFS
                by the Trustee or to MFS and
                the Trustee by the Holders of
                at least 25 percent of the ag-
                gregate principal amount of
                the Outstanding MFS Notes of
                that series; (f) Debt of MFS
                or any Restricted Subsidiary
                is not paid when due within
                the applicable grace period,
                if any, or is accelerated by
                the holders thereof and, in
                either case, the principal
                amount of such unpaid or ac-
                celerated Debt exceeds $10.0
                million; 
                
                (g) the entry by a court of
                competent jurisdiction of one
                or more judgments or orders
                against MFS or any Restricted
                Subsidiary in an uninsured or
                unin- demnified aggregate
                amount in excess of $10.0 mil-
                lion which remains undis-
                charged, unwaived, unstayed,
                unbonded or unsatisfied for a
                period of 60 consecutive days;
                and 
                
                (h) certain events of bank-
                ruptcy, insolvency, liquida-
                tion or reorganization, or
                court appointment of a custo-
                dian, trustee or other similar
                official of MFS or any Signif-
                icant Restricted Subsidiary or
                of all or substantially all of
                its property or property of
                significant restricted subsid-
                iaries. (Section 501 of 1994
                Indenture; Section 4(a) of
                1996 Indenture) 
                
                If any Event of Default (other    If any Event of Default un-
                than an Event of Default spec-    der the WorldCom Indenture
                ified in clause (h) above) oc-    with respect to WorldCom
                curs with respect to a series     Notes of a series at the
                of MFS Notes and is continu-      time outstanding occurs and
                ing, then and in every such       is continuing, then in every
                case the Trustee or the Hold-     such case the Trustee or the
                ers of not less than 25 per-      holders of not less than 25
                cent of the Outstanding aggre-    percent in principal amount
                gate principal amount at          of the outstanding WorldCom
                Stated Maturity (as such prin-    Notes of such series may de-
                cipal amount may be reduced       clare the principal 
                for the     
 
- --------------------------------------------------------------------------------
 
                                       48
<PAGE>
 
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes
 
               ----------------------------------------------------------------
                MFS NOTES                         WORLDCOM NOTES
 
- -------------------------------------------------------------------------------
                                                  
                MFS 2006 Notes pursuant to        amount of all of the       
                Section 2(a)(iv) of the 1996      WorldCom Notes of that se- 
                Indenture) of MFS Notes of        ries to be due and payable 
                such series may declare the       immediately by written no- 
                Default Amount and any accrued    tice thereof to WorldCom   
                and unpaid interest on all MFS    (and to the Trustee if given
                Notes of such series then Out-    by the holders). Under cer- 
                standing to be immediately due    tain circumstances, the     
                and payable, by a notice in       holders of a majority in    
                writing to MFS (and to the        principal amount of out-    
                Trustee if given by Holders),     standing WorldCom Notes of  
                and upon any such declaration,    such series by notice to    
                such Default Amount and any       WorldCom and the Trustee may
                accrued interest will become      rescind and annul an accel- 
                and be immediately due and        eration and its conse-      
                payable. If any Event of De-      quences. The WorldCom Inden-
                fault specified in clause (h)     ture also provides that the 
                above occurs with respect to a    holders of not less than a  
                series of MFS Notes, the Ac-      majority in principal amount
                creted Value and accrued in-      of the outstanding WorldCom 
                terest, if any, on the MFS        Notes of any series issued  
                Notes of such series then Out-    thereunder may waive certain
                standing shall become immedi-     past defaults with respect  
                ately due and payable without     to such series and their    
                any declaration or other act      consequences. (Sections 502 
                on the part of the Trustee or     and 513 of WorldCom         
                any Holder. Until and includ-     Indenture)                  
                ing January 15, 1999, in the
                case of the MFS 2004 Notes, or
                January 15, 2001, in the case
                of the MFS 2006 Notes, the
                "Default Amount" shall equal
                the Accreted Value thereof as
                of such date. On or after Jan-
                uary 15, 1999, in the case of
                the MFS 2004 Notes, or January
                15, 2001, in the case of the
                MFS 2006 Notes, the Default
                Amount shall equal 100 percent
                of the principal amount
                thereof at the Stated Maturity
                (subject to reduction for the
                MFS 2006 Notes as aforesaid)
                thereof. Under certain circum-
                stances, the Holders of a ma-
                jority in principal amount at
                Stated Maturity (subject to
                reduction for the MFS 2006
                Notes as aforesaid) of the
                Outstanding MFS Notes by no-
                tice to MFS and the Trustee
                may rescind and annul an ac-
                celeration and its conse-
                quences. The MFS Indentures
                provide that the Holders of
                not less than a majority in
                principal amount at Stated Ma-
                turity of the Outstanding MFS
                Notes may waive certain past
                defaults and their conse-
                quences. (Sections 502 and 513
                of 1994 Indenture; Sections
                4(b) and 4(c) of 1996 Inden-
                ture)     
 
- -------------------------------------------------------------------------------
 
                                      49
<PAGE>
 
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes
 
               ----------------------------------------------------------------
                MFS NOTES                         WORLDCOM NOTES
 
- --------------------------------------------------------------------------------
                
AMENDMENT AND   MFS and the Trustee may, at       Same as MFS, except that
SUPPLEMENT:     any time and from time to         WorldCom and the Trustee
                time, without notice or con-      may, at any time and from
                sent of any Holder, enter into    time to time, without notice
                one or more indentures supple-    or consent of any Holder,
                mental to either of the MFS       also enter into one or more
                Indentures (1) to evidence the    indentures supplemental to
                succession of another Person      the WorldCom Indenture to
                to MFS and the assumption by      supplement any of the provi-
                such successor of the cove-       sions thereof to such extent
                nants of MFS under such MFS       as shall be necessary to
                Indenture and contained in the    permit or facilitate the de-
                MFS Notes, (2) to add to the      feasance and discharge of
                covenants of MFS, for the ben-    either series of WorldCom
                efit of the Holders, or to        Notes pursuant to the
                surrender any right or power      WorldCom Indenture, provided
                conferred upon MFS by such MFS    that any such action shall
                Indenture, (3) to add any ad-     not adversely affect the in-
                ditional Events of Default,       terests of the Holders of
                (4) to provide for                the WorldCom Notes. (Section
                uncertificated notes in addi-     901 of WorldCom Indenture)
                tion to or in place of certif-        
                icated MFS Notes issued under
                such MFS Indenture, (5) to
                change or eliminate any of the
                provisions of such MFS In-
                denture, provided that any
                such change or elimination
                will become effective only
                when there is not Outstanding
                any MFS Note created prior to
                the execution of such supple-
                mental indenture which is en-
                titled to the benefit of such
                provision, (6) to evidence and
                provide for the acceptance of
                appointment under such MFS In-
                denture by a successor Trust-
                ee, (7) to secure the MFS
                Notes issued under such MFS
                Indenture, (8) to cure any am-
                biguity, to correct or supple-
                ment any provision in such MFS
                Indenture which may be defec-
                tive or inconsistent with any
                other provision therein or to
                add any other provisions with
                respect to matters or ques-
                tions arising under such MFS
                Indenture; provided such ac-
                tions will not adversely af-
                fect the interests of the
                Holders in any material re-
                spect, or (9) to comply with
                the requirements of the Com-
                mission in order to effect or
                maintain the qualification of
                such MFS Indenture under the
                Trust Indenture Act. (Section
                901 of 1994 Indenture; Section
                8(a) of 1996 Indenture)     
                                                      
- --------------------------------------------------------------------------------
 
                                       50
<PAGE>
 
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes
 
               ----------------------------------------------------------------
                MFS NOTES                         WORLDCOM NOTES
 
- --------------------------------------------------------------------------------
                                                  
                With the consent of the Hold-     The WorldCom Indenture also
                ers of not less than a major-     generally requires the con-
                ity in principal amount at        sent of the holders of at
                Stated Maturity (subject to       least a majority in princi-
                reduction for the MFS 2006        pal amount of outstanding
                Notes as aforesaid) of the        WorldCom Notes of a series
                Outstanding MFS Notes of a se-    to supplement or amend the
                ries, MFS and the Trustee may     WorldCom Indenture with re-
                enter into one or more inden-     spect to that series, except
                tures supplemental to the MFS     as described above and ex-
                Indenture under which such se-    cept that the consent of the
                ries was issued for the pur-      Holder of each Outstanding
                pose of adding any provisions     WorldCom Note of each series
                to or changing in any manner      is required to (1) change
                or eliminating any of the pro-    the Stated Maturity of the
                visions of such MFS Indenture     principal of, or any in-
                or the modifying in any manner    stallment of principal of or
                of the rights of such Holders;    interest on, any WorldCom
                provided, however, that no        Note of such series, or re-
                such supplemental indentures      duce the principal amount
                will, without the consent of      thereof, or rate or amount
                the Holder of each Outstanding    of interest thereon that
                MFS Note of that series, (1)      would be due and payable
                change the Stated Maturity of     upon Maturity thereof, or
                the principal of, or any in-      adversely affect any right
                stallment of interest on, any     of repayment at the option
                such MFS Note, or reduce the      of the Holder of any
                principal amount thereof (or      WorldCom Note of such se-
                premium, if any), or the in-      ries, or change any Place of
                terest thereon that would be      Payment where, or the cur-
                due and payable upon Maturity     rency in which, any WorldCom
                thereof, or reduce the Default    Note of such series or the
                Amount that would be due and      interest thereon is payable,
                payable on acceleration of the    or impair the right to in-
                Maturity thereof provided in      stitute suit for the en-
                such MFS Indenture or change      forcement of any such pay-
                the place of payment where, or    ment on or after the Stated
                the coin or currency in which,    Maturity thereof, (2) reduce
                any such MFS Note or any pre-     the percentage in principal
                mium or interest thereon is       amount of such Outstanding
                payable, or impair the right      WorldCom Notes, the consent
                to institute suit for the en-     of whose Holders is required
                forcement of any such payment     for any such supplemental
                on or after the Stated Matu-      indenture, or the consent of
                rity thereof, (2) reduce the      whose Holders is required
                percentage in principal amount    for any waiver with respect
                at Stated Maturity of such        to such notes (or compliance
                Outstanding MFS Notes, the        with certain provisions of
                consent of whose Holders is       the WorldCom Indenture or
                necessary for any such supple-    certain defaults thereunder
                mental indenture or required      and their consequences) pro-
                for any waiver of compliance      vided for in the WorldCom
                with certain provisions of        Indenture, or reduce the re-
                such MFS Indenture or certain     quirements of the WorldCom
                Defaults thereunder, (3) mod-     Indenture with respect to
                ify the obligations of MFS to     such WorldCom Notes for quo-
                make offers to purchase such      rum or voting, or (3) to
                MFS Notes upon a Change of        modify with respect to such
                Control or from the proceeds      WorldCom Notes the provi-
                of Asset Sales, (4) subordi-      sions regarding "Supplemen-
                nate in right of payment, or      tal Indentures with Consent
                otherwise subordinate, such       of Holders" or "Waiver of
                MFS Notes to any other indebt-    Past Defaults", except to
                edness, (5) modify any pro        increase     
                
 
- --------------------------------------------------------------------------------
 
                                       51
<PAGE>
 
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes
 
               ----------------------------------------------------------------
                MFS NOTES                       WORLDCOM NOTES
 
- --------------------------------------------------------------------------------
                    
                visions of such MFS Indenture   any such percentage or to pro-
                relating to the calculation     vide that certain provisions
                of Accreted Value or (6) mod-   of the WorldCom Indenture can-
                ify any of the provisions of    not be modified or waived
                the MFS Indentures providing    without the unanimous consent
                for the execution of supple-    of the Holders of such
                mental indentures requiring     WorldCom Notes. (Section 902
                the consent of Holders,         of WorldCom Indenture)
                waiver of past defaults and
                waiver of certain covenants     The WorldCom Indenture does  
                (except to increase any per-    not have any provisions that 
                centage set forth therein);     require the consent of the   
                provided, further, that the     Holders of not less than 75  
                consent of the Holders of not   percent in principal amount of
                less than 75 percent of the     Outstanding WorldCom Notes.   
                principal amount at Stated
                Maturity (subject to reduc-
                tion as aforesaid) of the
                Outstanding MFS Notes of that
                series is required to make
                any amendment to the covenant
                described under "Change of
                Control." (Section 902 of
                1994 Indenture; Section 8(b)
                of 1996 Indenture) 

SATISFACTION    MFS may terminate its obliga-   Same as MFS (Sections 401 and
AND DISCHARGE   tions under either MFS Inden-   1401-1405 of WorldCom Inden-
OF THE          ture when (i) either (A) all    ture)
INDENTURES;     Outstanding MFS Notes issued
DEFEASANCE      under such MFS Indenture have
AND COVENANT    been delivered to the Trustee
DEFEASANCE:     for cancellation or (B) all
                such MFS Notes not thereto-
                fore delivered to the Trustee
                for cancellation have become
                due and payable, will become
                due and payable within one
                year or are to be called for
                redemption within one
                year under irrevocable
                arrangements satisfactory to 
                the Trustee for the giving 
                of notice of redemption by 
                the Trustee in the name, and 
                at the expense, of MFS, and 
                MFS has irrevocably deposited 
                or caused to be deposited with
                the Trustee funds in an
                amount sufficient to pay and
                discharge the entire indebt-
                edness on such MFS Notes, not
                theretofore delivered to the
                Trustee for cancellation, for
                principal of, premium, if
                any, and interest to the date
                of deposit or Stated Maturity
                or date of redemption; (ii)
                MFS has paid or caused to be
                paid all sums payable by MFS
                under such MFS Indenture; and
                (iii) MFS has delivered an
                Officer's Certificate and an
                    
- --------------------------------------------------------------------------------
 
 
                                       52
<PAGE>
 
   
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes     
 
               ----------------------------------------------------------------
                   
                MFS NOTES                        WORLDCOM NOTES     
 
- --------------------------------------------------------------------------------
 
                Opinion of Counsel relating to
                compliance with the conditions
                set forth in such MFS Inden-
                ture. (Section 401 of 1994 In-
                denture; Section 3(a) of 1996
                Indenture)
                   
                MFS will be deemed to have
                paid and discharged the entire
                Debt on a series of MFS Notes
                and the MFS Indenture under
                which such MFS Notes were is-
                sued shall cease to be of fur-
                ther effect as to all Out-
                standing MFS Notes (except as
                to (i) rights of registration
                of transfer, substitution and
                exchange of such MFS Notes and 
                MFS' right of optional 
                redemption, (ii) rights of 
                Holders to receive payments
                of principal of, premium, if
                any, and interest on such MFS
                Notes (but not the Change of
                Control Repurchase Price of
                such MFS Notes) and any rights
                of the Holders with respect to
                such amounts, (iii) the
                rights, obligations and immu-
                nities of the Trustee under
                such MFS Indenture and (iv)
                certain other specified provi-
                sions in such MFS Indenture
                (the foregoing exceptions (i)
                through (iv) are collectively
                referred to as the "Reserved
                Rights")) after the irrevoca-
                ble deposit by MFS with the
                Trustee, in trust for the ben-
                efit of the Holders, at any
                time prior to the Stated Matu-
                rity of such MFS Notes, of (A)
                money in an amount, (B) U.S.
                Government Obligations which
                through the payment of inter-
                est and principal will pro-
                vide, not later than one day
                before the due date of payment
                in respect of the MFS Notes,
                money in an amount, or (C) a
                combination thereof, suffi-
                cient to pay and discharge the
                principal of and interest on
                such MFS Notes then outstand-
                ing on the dates on which any
                such payments are due in ac-
                cordance with the terms of
                such MFS Indenture and of such
                MFS Notes. Defeasance may only
                be deemed to occur if certain
                conditions are satisfied, in-
                cluding, among other     
 
- --------------------------------------------------------------------------------
 
 
                                       53
<PAGE>
 
   
 Continuation of Description of Differences Between the MFS Notes and the
WorldCom Notes     
 
               ----------------------------------------------------------------
                    
                MFS NOTES                         WORLDCOM NOTES     
 
- --------------------------------------------------------------------------------
 
                things, delivery by MFS to the
                Trustee of an opinion of out-
                side counsel acceptable to the
                Trustee to the effect that,
                among other things, (i) the
                deposit, defeasance and dis-
                charge will not be deemed, or
                result in, a taxable event for
                federal income tax purposes,
                with respect to the Holders
                and (ii) MFS' deposit will not
                result in the Trust or the
                Trustee being subject to regu-
                lation under the Investment
                Company Act of 1940. (Sections
                1201-1206 of 1994 Indenture;
                Section 6 of 1996 Indenture)
 
- --------------------------------------------------------------------------------
 
                                       54
<PAGE>
 
                           THE CONSENT SOLICITATIONS
   
  Concurrently with the Exchange Offers, the Company is soliciting Consents
from the Holders to the Proposed Amendments to the 1994 Indenture (under which
the MFS 2004 Notes were issued) and the 1996 Indenture (under which the MFS
2006 Notes were issued). The proper completion, execution and delivery of a
Letter of Transmittal by a Holder tendering MFS Notes pursuant to an Exchange
Offer will constitute the Consent of such tendering Holder to the Proposed
Amendments with respect to such MFS Notes. Holders may not deliver Consents
without tendering their MFS Notes in the Exchange Offers.     
 
REQUIRED CONSENTS
   
  Consents from Holders of a majority in aggregate principal amount
Outstanding of a series of MFS Notes must be received in order to amend the
MFS Indenture governing that series in the manner contemplated by the Proposed
Amendments as described herein, except with respect to the modification of the
term "Change of Control," which requires Consents from Holders of not less
than 75% of the aggregate principal amount Outstanding of MFS Notes of a
series. Among other things, the Proposed Amendments would eliminate (i) the
covenants in each of the MFS Indentures that (a) restrict the ability of MFS
and its restricted subsidiaries to incur debt, incur liens, enter into sale
and leaseback transactions, make restricted payments (including payment of
dividends) or enter into transactions with affiliates and (b) restrict the
ability of restricted subsidiaries of MFS to issue equity securities to
encumber their ability to pay dividends or to make certain loans or transfers
of property to MFS or another restricted subsidiary of MFS and (ii) the
separate financial reporting requirements contained in the MFS Indentures,
and, subject to receipt of a Supermajority Consent, would redefine the events
constituting a "Change of Control" under the MFS Indentures. See "The Proposed
Amendments." Among other conditions, receipt of the Requisite Consent with
respect to both series of MFS Notes, the execution and delivery by the MFS
Trustee of the supplemental indentures relating to the Proposed Amendments and
the lack of any objection by the MFS Trustee as to MFS' ability to effect the
Proposed Amendments are conditions to consummation of each Exchange Offer and
payment of the Consent Payments by the Company. See "The Exchange Offers--
Conditions to the Exchange Offers."     
 
  If the Requisite Consent or the Supermajority Consent, as the case may be,
is received with respect to a series of MFS Notes and the Exchange Offer with
respect to such series is consummated, then MFS and the MFS Trustee will
execute a supplemental indenture setting forth the Proposed Amendments in
respect of the MFS Notes of such series and the MFS Indenture, as so
supplemented, will become operative on the Exchange Date. Each non-exchanging
Holder of such series of MFS Notes will be bound by such supplemental
indenture even if such Holder did not give its Consent. Each of the MFS
Indentures, without giving effect to the Proposed Amendments, will remain in
effect until the Proposed Amendments with respect thereto become operative on
the Exchange Date. If the Exchange Offer for a series of MFS Notes is
terminated or withdrawn, the Proposed Amendments in respect of such series
will never become operative. See "The Proposed Amendments."
   
  Consents may be revoked at any time prior to 11:59 p.m., New York City time,
on    , 1997 by the withdrawal of a tender of MFS Notes in accordance with the
instructions for such withdrawal (see "The Exchange Offer--Withdrawal of
Tenders and Revocation of Consents"). Any withdrawal of a tender of MFS Notes
shall also be deemed to be a revocation of the related Consent. Tenders of MFS
Notes may not be withdrawn and the related Consents may not be revoked at any
time after 11:59 p.m., New York City time, on    , 1997, unless the applicable
Exchange Offer is extended with changes in the terms of such Exchange Offer
that are materially adverse to the tendering Holder, in which case tenders of
MFS Notes may be withdrawn under the conditions described in the extension.
    
                                      55
<PAGE>
 
   
CONSENT PAYMENTS     
   
  On the Exchange Date, the Company will pay each Holder who gives a valid
Consent on or prior to the Expiration Date a Consent Payment equal to (i) with
respect to such Holder's MFS 2004 Notes, 0. % of the Accreted Value, as of the
Interest Accrual Date, of such MFS 2004 Notes and (ii) with respect to such
Holder's MFS 2006 Notes, 0. % of the Accreted Value, as of the Interest
Accrual Date, of such MFS 2006 Notes, in either case, with respect to which
such Consent has been given. If, on or prior to the Expiration Date, a
Holder's MFS Notes are not validly tendered and the related Consents are not
validly given pursuant to an Exchange Offer and Consent Solicitation, such
Holder will not receive a Consent Payment even if the Proposed Amendments
become effective with respect to such Holder's MFS Notes.     
 
  HOLDERS OF MFS NOTES OF EITHER SERIES MAY GIVE THEIR CONSENT TO THE PROPOSED
AMENDMENTS APPLICABLE TO THAT SERIES ONLY BY TENDERING SUCH MFS NOTES IN THE
APPLICABLE EXCHANGE OFFER AND WILL BE DEEMED TO HAVE GIVEN SUCH CONSENT BY SO
TENDERING. THE PROPER COMPLETION, EXECUTION AND DELIVERY OF A LETTER OF
TRANSMITTAL WITH RESPECT TO A PARTICULAR SERIES OF MFS NOTES WILL CONSTITUTE
THE DELIVERY OF A CONSENT WITH RESPECT TO SUCH MFS NOTES.
 
                                      56
<PAGE>
 
                            THE PROPOSED AMENDMENTS
   
  WorldCom is soliciting the Consent of the Holders of MFS Notes to the
Proposed Amendments. The 1994 Indenture and the 1996 Indenture contain
substantially similar covenants and terms. What follows are summaries of (i)
the covenants and terms proposed to be eliminated from each of the MFS
Indentures pursuant to the Consent Solicitations and (ii) the covenants and
terms proposed to be substantially revised pursuant to the Consent
Solicitations (collectively, the "Proposed Amendments"). Capitalized terms
appearing below which are not otherwise defined herein have the same meanings
as are given to such terms in the MFS Indentures, copies of which have been
filed as exhibits to the Registration Statement of which this Prospectus forms
a part. The definition of certain capitalized terms used herein are set forth
under "--Certain Definitions" below. The summaries do not purport to be
complete and are qualified in their entirety by reference to the 1994
Indenture, the 1996 Indenture and the forms of the supplemental indenture to
each of the 1994 Indenture and the 1996 Indenture that contain the Proposed
Amendments with respect to the MFS Notes (and that are to be executed in
respect of each series of MFS Notes by MFS and the MFS Trustee in the event
the Requisite Consent or the Supermajority Consent, as the case may be, with
respect to such series is obtained). The form of each such supplemental
indenture has been filed as an exhibit to the Registration Statement of which
this Prospectus forms a part and is available from the Company upon request.
Whenever particular sections or defined terms are referred to, it is intended
that such sections or defined terms shall be incorporated by reference.     
 
PROVISIONS TO BE DELETED
 
  Pursuant to the Consent Solicitations, the Company is proposing to eliminate
the following from each of the MFS Indentures with respect to each series of
MFS Notes:
 
  Limitation on Debt. MFS will not, directly or indirectly, incur any Debt
unless (i) after giving effect to such incurrence of Debt and the
contemporaneous application of the proceeds thereof, no Default or Event of
Default shall have occurred and be continuing at the time or would occur as a
consequence of the incurrence of such Debt, and (ii) such Debt is Permitted
Debt. (Section 1008 of 1994 Indenture; Section 5(e) of 1996 Indenture)
 
  Limitation of Debt and Preferred Stock of Restricted Subsidiaries. MFS will
not permit any of its Restricted Subsidiaries to incur, directly or
indirectly, any Debt or issue any preferred stock, except (a) Subsidiary
Vendor Debt; (b) Debt and preferred stock of Restricted Subsidiaries
outstanding as of January 26, 1994; (c) Debt and preferred stock of a
Restricted Subsidiary issued to and held by MFS; (d) Interest Swap
Obligations, provided that such obligations are related to payment obligations
on Debt otherwise permitted by the terms of this covenant, and Currency Hedge
Obligations; (e) Debt or preferred stock incurred in exchange for, or the
proceeds of which are used to refinance, Restricted Subsidiary Debt or
preferred stock referred to in clause (a) of this paragraph, provided that (i)
the principal amount of such Debt or the liquidation value of such preferred
stock so incurred does not exceed the principal amount or liquidation value of
the Debt or preferred stock being exchange or refinanced, and (ii) the Debt or
preferred stock so incurred has a stated maturity or final redemption date (if
any) no earlier than the stated maturity or final redemption date (if any) of,
and an Average Life that is no less than that of, the Debt or preferred stock
being exchanged or refinanced; provided, further, that the Debt or preferred
stock so incurred has no greater seniority and covenants not materially more
restrictive in the aggregate than those of the Debt or preferred stock being
exchanged or refinanced; (f) Debt or preferred stock of MFS Telecom, which is
convertible into Capital Stock of MFS, issued to a Strategic Equity Investor;
provided, however, that the proceeds of such incurrence or issuance are used
as though such proceeds were Net Cash Proceeds in accordance with the
provisions of the covenant described under "The Exchange Offers--Description
of Differences Between the MFS Notes and the WorldCom Notes-MFS Notes--
Limitations on Asset Sales;" and (g) Guarantees by Restricted Subsidiaries of
Debt of the Company described in clause (a) of the definition of Permitted
Debt. (Section 1009 of 1994 Indenture; Section 5(f) of 1996 Indenture)
 
                                      57
<PAGE>
 
  Limitation on Liens. MFS will not, and will not permit any of its Restricted
Subsidiaries to, directly or indirectly, enter into, create, incur, assume or
suffer to exist any Liens of any kind, other than Permitted Liens, on or with
respect to any of its Property or assets now owned or hereafter acquired, or
any interest therein or any income or profits therefrom, unless the Notes are
secured equally and ratably with (or prior to) such Debt and any and all other
Debt so secured by such Property or assets for so long as any and all other
Debt is so secured. (Section 1012 of 1994 Indenture; Section 5(g) of 1996
Indenture)
 
  Limitations on Sale and Leaseback Transactions. MFS will not, and will not
permit any of its Restricted Subsidiaries to, directly or indirectly, enter
into, assume, Guarantee or otherwise become liable with respect to any Sale
and Leaseback Transaction, unless (i) the obligation of MFS or such Restricted
Subsidiary with respect thereto is included as Debt and would be permitted
under the covenants described above under "--Limitation on Debt" or "--
Limitation of Debt and Preferred Stock of Restricted Subsidiaries,"
respectively, and any Liens granted thereby would be permitted by the covenant
described above under "--Limitation on Liens," (ii) the net proceeds from such
transaction are at least equal to the Fair Market Value of such Property being
transferred, and (iii) the Net Cash Proceeds from such transaction are applied
in accordance with the covenant described under "The Exchange Offers--
Description of Differences Between the MFS Notes and the WorldCom Notes--MFS
Notes--Limitations on Asset Sales." (Section 1016 of 1994 Indenture; Section
5(h) of 1996 Indenture)
   
  Limitations on Restricted Payments. MFS will not, and will not permit any of
its Restricted Subsidiaries to, directly or indirectly, make any Restricted
Payment unless, at the time of and after giving effect to the proposed
Restricted Payment (i) no Default or Event of Default shall have occurred and
be continuing or shall occur as a consequence thereof; (ii) after giving
effect, on a pro forma basis, to such Restricted Payment and the incurrence of
any Debt the net proceeds of which are used to finance such Restricted
Payment, MFS could incur at least $1.00 of additional Debt pursuant to clause
(h) or (i) of the definition of Permitted Debt; and (iii) after giving effect
to such Restricted Payment on a pro forma basis, the aggregate amount expended
or declared for all Restricted Payments on or after January 26, 1994 does not
exceed the sum of (A) 50 percent of the Consolidated Net Income of MFS (or, if
Consolidated Net Income shall be a deficit, minus 100 percent of such deficit)
for the period (taken as one accounting period) beginning on the last day of
the fiscal quarter immediately preceding January 26, 1994 and ending on the
last day of the fiscal quarter immediately preceding the date of such
Restricted Payment, and (B) 100 percent of the aggregate net cash proceeds
received by MFS subsequent to January 26, 1994 from the issuance or sale
(other than to a Restricted Subsidiary or a Joint Venture) of shares of its
Qualified Capital Stock, including Qualified Capital Stock issued upon
conversion of convertible Debt and from the exercise of options, warrants or
rights to purchase such Qualified Capital Stock.     
 
  The foregoing limitations do not prevent MFS from (i) paying a dividend on
its Capital stock at any time within 60 days after the declaration thereof if,
on the declaration date, MFS could have paid such dividend in compliance with
the Indenture, and (ii) making Permitted Investments; provided that any
Permitted Investments made pursuant to clause (a) of the definition of
Permitted Investments will be deemed to be Restricted Payments for the
purposes of clause (iii) of the preceding paragraph.
 
  For purposes of this covenant, if a particular Restricted Payment involves a
non-cash payment, including a distribution of assets, then such Restricted
Payment shall be deemed to be an amount equal to the cash portion of such
Restricted Payment, if any, plus an amount equal to the Fair Market Value of
the non-cash portion of such Restricted Payment as determined by the Board of
Directors, whose good faith determination shall be conclusive and evidenced by
a Board Resolution.
 
  Not later than the date of making any Restricted Payment, MFS shall deliver
to the Trustee an Officers' Certificate stating that such Restricted Payment
is permitted and setting forth the basis upon
 
                                      58
<PAGE>
 
   
which the required calculations were computed, which calculations may be based
upon MFS' latest available financial statements. (Section 1010 of 1994
Indenture; Section 5(i) of 1996 Indenture)     
 
  Limitation on Dividends and Other Payment Restrictions Affecting Restricted
Subsidiaries. MFS will not, and will not permit any Restricted Subsidiary to,
directly or indirectly, cause or suffer to exist or become effective or enter
into any encumbrance or restriction (other than pursuant to law or regulation)
on the ability of any Restricted Subsidiary (i) to pay dividends or make any
other distributions in respect of its Capital Stock or pay any Debt or other
obligation owed to MFS or any other Restricted Subsidiary of MFS; (ii) to make
loans or advances to MFS or any Restricted Subsidiary of MFS; or (iii) to
transfer any of its Property or assets to MFS or any other Restricted
Subsidiary of MFS, except:
 
    (a) any encumbrance or restriction pursuant to an agreement in effect at
  the Issue Date;
 
    (b) any encumbrance or restriction pursuant to an agreement relating to
  an acquisition of Property, so long as the encumbrances or restrictions in
  any such agreement relate solely to the Property so acquired (and are not
  or were not created in anticipation of or in connection with the
  acquisition thereof);
 
    (c) any encumbrance or restriction relating to any Debt of any Restricted
  Subsidiary at the date on which such Restricted Subsidiary was acquired by
  MFS or any Restricted Subsidiary (other than Debt issued by such Restricted
  Subsidiary in connection with or in anticipation of its acquisition);
 
    (d) any encumbrance or restriction pursuant to an agreement effecting a
  permitted refinancing of Debt issued pursuant to an agreement referred to
  in the foregoing clauses (a) through (c), or permitted replacement or
  increase of Debt referred to in the foregoing clause (a), so long as the
  encumbrances and restrictions contained in any such refinancing agreement
  are not materially more restrictive than the encumbrances and restrictions
  contained in such agreements;
 
    (e) customary provisions restricting subletting or assignment of any
  lease of MFS or any Restricted Subsidiary or provisions in agreements that
  restrict the assignment of such agreement or any rights thereunder; and
 
    (f) any restriction on the sale or other disposition of assets or
  property securing Debt as a result of a Permitted Lien on such assets or
  Property. (Section 1014 of 1994 Indenture; Section 5(j) of 1996 Indenture)
 
  Limitations on Issuance and Sale of Capital Stock of Restricted
Subsidiaries. MFS (i) shall not permit any Restricted Subsidiary to issue any
Capital Stock other than to MFS or a Restricted Subsidiary, other than
pursuant to certain specified agreements in existence on January 26, 1994,
unless MFS acquires at the same time not less than its Proportionate Interest
in such issuance of Capital Stock and (ii) shall not permit any Person other
than MFS or a Restricted Subsidiary to own any Capital Stock of any Restricted
Subsidiary of MFS (other than directors' qualifying shares), except for (a)
Capital Stock of a Restricted Subsidiary sold in a transaction not prohibited
by the covenant described under "The Exchange Offers--Description of
Differences Between the MFS Notes and the WorldCom Notes--MFS Notes--
Limitations on Asset Sales," provided that such Restricted Subsidiary would
remain a Restricted Subsidiary, (b) Capital Stock issued as permitted by
clause (i) above, (c) Capital Stock issued and outstanding on January 26, 1994
and held by Persons other than MFS or any of its Restricted Subsidiaries, (d)
Capital Stock of a Restricted Subsidiary issued and outstanding prior to the
time that such Person becomes a Restricted Subsidiary so long as such Capital
Stock was not issued in contemplation of such Person's becoming a Restricted
Subsidiary of MFS or otherwise being acquired by MFS and (e) an issuance of
preferred stock permitted under the covenant described above under "--
Limitation on Debt and Preferred Stock of Restricted Subsidiaries." (Section
1018 of 1994 Indenture; Section 5(k) of 1996 Indenture)
 
 
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<PAGE>
 
  Limitations on Transactions with Affiliates. MFS will not, and will not
permit any of its Restricted Subsidiaries to, directly or indirectly, conduct
any business or enter into or permit to exist any transaction or series of
related transactions (including, but not limited to, the purchase, sale or
exchange of Property, the making of any Investment, the giving of any
Guarantee or the rendering of any service) with any Affiliate of MFS or such
Restricted Subsidiary, as the case may be, unless (i) such business,
transaction or series of related transactions is in the best interest of MFS
or such Restricted Subsidiary, (ii) such business, transaction or series of
related transactions is on terms no less favorable to MFS or such Restricted
Subsidiary than those that could be obtained in a comparable arm's-length
transaction with a Person that is not such an Affiliate and (iii) (a) with
respect to such business, transaction or series of related transactions that
has a Fair Market Value or involves aggregate payments equal to, or in excess
of, $10.0 million but less than $15.0 million, MFS delivers to the Trustee an
Officer's Certificate stating that such business, transaction or series of
related transactions complies with clauses (i) and (ii) above; and (b) with
respect to such business, transaction or series of related transactions that
has a Fair Market Value or involves aggregate payments equal to, or in excess
of, $15.0 million such business, transaction or series of transactions is
approved by a majority of the Board of Directors (including a majority of the
Disinterested Directors), which approval is set forth in a resolution
delivered to the Trustee certifying that, in good faith, the Board of
Directors believes that such business, transaction or series of transactions
complies with clauses (i) and (ii) above. (Section 1011 of 1994 Indenture;
Section 5(m) of 1996 Indenture)
 
  Provision of Financial Information. Whether or not MFS is subject to Section
13(a) or 15(d) of the Exchange Act, or any successor provision thereto, MFS
shall file with the Commission the annual reports, quarterly reports and other
documents which MFS would have been required to file with the Commission
pursuant to such Section 13(a) or 15(d) or any successor provision thereto if
MFS were subject thereto, such documents to be filed with the Commission on or
prior to the respective dates (the "Required Filing Dates") by which MFS would
have been required to file them. MFS shall also in any event (a) within 15
days of each Required Filing Date (i) transmit by mail to all Holders, as
their names and addresses appear in the Security Register, without cost to
such Holders, and (ii) file with the Trustee copies of the annual reports,
quarterly reports and other documents (without exhibits) which MFS would have
been required to file with the Commission pursuant to Section 13(a) or 15(d)
of the Exchange Act or any successor provisions thereto if MFS were subject
thereto and (b) if filing such documents by MFS with the Commission is not
permitted under the Exchange Act, promptly upon written request supply copies
of such documents (without exhibits) to any prospective Holder. (Section 1017
of 1994 Indenture; Section 5(n) of 1996 Indenture)
 
PROVISIONS TO BE REVISED
 
  Pursuant to the Consent Solicitations, WorldCom is proposing to
substantially revise the definition of "Event of Default" contained in the MFS
Indentures with respect to each series of MFS Notes.
   
  Events of Default. Each of the following is an "Event of Default" with
respect to a series of MFS Notes under the applicable MFS Indenture:     
     
    (a) default in the payment of any installment of interest upon any MFS
  Note of that series when it becomes due and payable, and the continuance of
  such default for a period of 30 days;     
     
    (b) default in the payment of the principal of (or premium, if any, on)
  any MFS Note of that series at its Maturity, upon repurchase, acceleration,
  optional redemption, required repurchase;     
     
    (c) default, on the applicable Purchase Date, in the purchase of MFS
  Notes required to be purchased by MFS pursuant to an Offer to Purchase as
  to which an Offer has been mailed to Holders or the failure to make an
  Offer to Purchase as required in the applicable MFS Indenture;     
     
    (d) MFS fails to comply with any of its covenants or agreements in the
  MFS Indentures described in "--Provisions to be Deleted--Limitation on
  Debt" or "--Limitation on Debt and Preferred Stock of Restricted
  Subsidiaries" above, or fails to perform or comply with the provisions of
  the applicable MFS Indenture described in "The Exchange Offers--Description
  of Differences Between the MFS Notes and the WorldCom Notes--MFS Notes--
  Consolidation, Merger, Conveyance, Transfer or Lease" above;     
 
                                      60
<PAGE>
 
     
    (e) default in the performance, or breach, of any covenant or warranty of
  MFS in the applicable MFS Indenture (other than a covenant or warranty a
  default in whose performance or whose breach is specifically dealt with in
  (a), (b), (c) or (d) above) and continuance of such default or breach for a
  period of 60 days after specified written notice thereof has been given to
  MFS by the Trustee or to MFS and the Trustee by the Holders of at least 25
  percent of the aggregate principal amount of the Outstanding MFS Notes of
  that series;     
     
    (f) Debt of MFS or any Restricted Subsidiary is not paid when due within
  the applicable grace period, if any, or is accelerated by the holders
  thereof and, in either case, the principal amount of such unpaid or
  accelerated Debt exceeds $10.0 million;     
     
    (g) the entry by a court of competent jurisdiction of one or more
  judgments or orders against MFS or any Restricted Subsidiary in an
  uninsured or unindemnified aggregate amount in excess of $10.0 million
  which remains undischarged, unwaived, unstayed, unbonded or unsatisfied for
  a period of 60 consecutive days;     
     
    (h) the entry by a court having jurisdiction in the premises of (i) a
  decree or order for relief in respect of MFS or any Significant Restricted
  Subsidiary in an involuntary case or proceeding under U.S. bankruptcy laws,
  as now or hereafter constituted, or any other applicable federal, state, or
  foreign bankruptcy, insolvency, or other similar law or (ii) a decree or
  order adjudging MFS or any Significant Restricted Subsidiary a bankrupt or
  insolvent, or approving as properly filed a petition seeking
  reorganization, arrangement, adjustment or composition of or in respect of
  MFS or any Significant Restricted Subsidiary under U.S. bankruptcy laws, as
  now or hereafter constituted, or any other applicable federal, state, or
  foreign bankruptcy, insolvency, or similar law, or appointing a custodian,
  receiver, liquidator, assignee, trustee, sequestrator or other similar
  official of MFS or any Significant Restricted Subsidiary or of any
  substantial part of the Property or assets of MFS of any Significant
  Restricted Subsidiary, or ordering the winding up or liquidation of the
  affairs of MFS or any Significant Restricted Subsidiary, and the
  continuance of any such decree or order for relief or any such other decree
  or order unstayed and in effect for a period of 60 consecutive days; or
         
    (i) (A) the commencement by MFS or any Significant Restricted Subsidiary
  of a voluntary case or proceeding under U.S. bankruptcy laws, as now or
  hereafter constituted, or any other applicable federal, state, or foreign
  bankruptcy, insolvency or other similar law or of any other case or
  proceeding to be adjudicated a bankrupt or insolvent, or (B) the consent by
  MFS or any Significant Restricted Subsidiary to the entry of a decree or
  order for relief in respect of MFS or any Significant Restricted Subsidiary
  in an involuntary case or proceeding under U.S. bankruptcy laws, as now or
  hereafter constituted, or any other applicable federal, state, or foreign
  bankruptcy, insolvency, or other similar law or to the commencement of any
  bankruptcy or insolvency case or proceeding against MFS or any Significant
  Restricted Subsidiary, or (C) the filing by MFS or any Significant
  Restricted Subsidiary of a petition or answer or consent seeking
  reorganization or relief under U.S. bankruptcy laws, as now or hereafter
  constituted, or any other applicable federal, state, or foreign bankruptcy,
  insolvency or other similar law, or (D) the consent by MFS or any
  Significant Restricted Subsidiary to the filing of such petition or to the
  appointment of or taking possession by a custodian, receiver, liquidator,
  assignee, trustee, sequestrator or similar official of MFS or any
  Significant Restricted Subsidiary or of any substantial part of the
  Property or assets of MFS or any Significant Restricted Subsidiary, or the
  making by MFS or any Significant Restricted Subsidiary of an assignment for
  the benefit of creditors, or (E) the admission by MFS or any Significant
  Restricted Subsidiary in writing of its inability to pay its debts
  generally as they become due, or (F) the taking of corporate action by MFS
  or any Significant Restricted Subsidiary in furtherance of any such action.
  (Section 501 of 1994 Indenture; Section 4(a) of 1996 Indenture)     
   
  The above referenced provision defining "Event of Default" is the existing
provision within the MFS Indenture that will be replaced with the definition
of Event of Default substantially similar to that set forth in the WorldCom
Indenture; conforming changes would also be effected with respect to     
 
                                      61
<PAGE>
 
   
certain defined terms. For a summary of such provision, see "Description of
the WorldCom Notes--Events of Default; Notice and Waiver." In addition, under
the Proposed Amendments, the existing provision of each MFS Indenture
providing for the automatic acceleration of the Default Amount and any accrued
and unpaid interest on all Outstanding MFS Notes issued under such MFS
Indenture with respect to which any Event of Default described in paragraphs
(h) or (i) above has occurred (Section 502 of the 1994 Indenture; Section 4(b)
of the 1996 Indenture), shall be revised such that all Events of Default under
such MFS Indenture, without exception, shall entitle the MFS Trustee or the
Holders of not less than 25 percent of the Outstanding aggregate principal at
Stated Maturity (subject to reduction) of MFS Notes of such series to declare
any such Default Amount and accrued and unpaid interest to be immediately due
and payable.     
   
DEFINITION TO BE REVISED UPON RECEIPT OF SUPERMAJORITY CONSENT FROM HOLDERS OF
EACH SERIES OF MFS NOTES     
   
  Pursuant to the Consent Solicitations, the Company is proposing to
substantially revise the definition of "Change of Control" contained in the
MFS Indentures with respect to each series of MFS Notes only if Consents from
the Holders of at least 75% of the aggregate principal amount Outstanding of
MFS Notes of such series are received.     
 
  "Change of Control" means the occurrence of any of the following events:
 
    (a) any "person" or "group" (as such terms are used in Sections 13(d) and
  14(d) of the Exchange Act), other than Peter Kiewit Sons, Inc., a Delaware
  corporation ("PKS"), or its Affiliates (in the case of the 1994 Indenture
  only), the Employee Group or an underwriter engaged in a firm commitment
  underwriting on behalf of MFS, is or becomes the "beneficial owner" (as
  such term is used in Rules 13d-3 and 13d-5 under the Exchange Act) plus all
  shares that such person or group has the right to acquire, whether such
  right is exercisable immediately or only after a passage of time, directly
  or indirectly, of more than 35 percent of the total voting power of the
  Voting Stock of MFS and, in addition, beneficially owns more shares in MFS
  than beneficially owned by PKS (in the case of the 1994 Indenture only) and
  the Employee Group; or
 
    (b) during any period of two consecutive years, individuals who at the
  beginning of such period constituted the Board of Directors (together with
  any new directors whose election by the Board of Directors or whose
  nomination for election by the stockholders of MFS was approved by a vote
  of a majority of the directors of MFS then still in office who were either
  directors at the beginning of such period or whose election or nomination
  for election was previously so approved) cease for any reason to constitute
  66 2/3 percent of the Board of Directors then in office; or
 
    (c) MFS shall cease to own, directly or indirectly, at least 51 percent
  of the outstanding Capital Stock of MFS Telecom; provided, however, that
  any sale, conveyance or transfer of Capital Stock of MFS Telecom must be to
  a Strategic Equity Investor; or
 
    (d) MFS sells, conveys, transfers or leases (either in one transaction or
  a series of related transactions) all or substantially all of its assets to
  a Person other than a Restricted Subsidiary; or
 
    (e) MFS or a Subsidiary sells, conveys, transfers or leases (either in
  one transaction or a series of related transactions) all or substantially
  all of the assets of MFS Telecom to a Person other than the Company or a
  Restricted Subsidiary. (Section 101 of 1994 Indenture; Section 1(d) of 1996
  Indenture)
 
  The above referenced definition of "Change of Control" is the existing
definition within the MFS Indenture that will be replaced with the following
definition of Change of Control only if the Supermajority Consent is received.
 
  "Change of Control" means the occurrence of any of the following events:
 
    (a) any "person" or "group" (as such terms are used in Sections 13(d) and
  14(d) of the Exchange Act), other than WorldCom, Inc. or its Affiliates, or
  an underwriter engaged in a firm
 
                                      62
<PAGE>
 
  commitment underwriting on behalf of MFS, is or becomes the "beneficial
  owner" (as such term is used in Rules 13d-3 and 13d-5 under the Exchange
  Act) plus all shares that such person or group has the right to acquire,
  whether such right is exercisable immediately or only after a passage of
  time, directly or indirectly, of more than 50 percent of the total voting
  power of the Voting Stock of MFS and, in addition, beneficially owns more
  shares in MFS than beneficially owned by WorldCom, Inc.; or
 
    (b) MFS sells, conveys, transfers or leases (either in one transaction or
  a series of related transactions) all or substantially all of its assets to
  a Person other than an Affiliate.
   
  Upon a Change of Control, MFS has an obligation to make an offer to purchase
outstanding MFS Notes at a purchase price in cash equal to 101% of the
Accreted Value of such MFS Notes as of the applicable purchase date plus
accrued but unpaid interest. (Section 1013 of the 1994 Indenture; Section 5(r)
of the 1996 Indenture). By limiting the occurrences that create a Change of
Control, MFS' obligation to make such an offer to purchase would be
substantially reduced.     
 
CERTAIN DEFINITIONS
 
  Set forth below is a summary of certain of the defined terms used in the MFS
Indentures. Reference is made to the applicable MFS Indenture (Section 101 of
1994 Indenture; Sections 101 and 1(d) of 1996 Indenture) for the full
definition of all such terms, as well as any capitalized terms used herein for
which no definition is provided.
 
  "Accreted Value" of any outstanding MFS Note as of or to any date of
determination means an amount equal to the sum of (i) the issue price of such
MFS Note as determined in accordance with Section 1273 of the Internal Revenue
Code (the "Code") as in effect on the date such MFS Note was first issued plus
(ii) the aggregate of the portions of the original issue discount (the excess
of the amounts considered as part of the "stated redemption price at maturity"
of such MFS Note within the meaning of Section 1273(a)(2) of the Code or any
successor provisions, whether denominated as principal or interest, over the
issue price of such MFS Note) that shall theretofore have accrued pursuant to
Section 1272 of the Code (without regard to Section 1272(a)(7) of the Code)
from the date of issue of such MFS Note (a) for each six-month or shorter
period ending January 15 or July 15 prior to the date of determination and (b)
for the shorter period, if any, from the end of the immediately preceding six-
month or shorter period, as the case may be, to the date of determination,
plus (iii) accrued and unpaid interest to the date such Accreted Value is paid
(without duplication of any amount set forth in (ii) above), minus all amounts
theretofore paid in respect of such MFS Note which amounts are considered as
part of the "stated redemption price at maturity" of such MFS Note within the
meaning of Section 1273(a)(2) of the Code or any successor provisions (whether
such amounts paid were denominated principal or interest).
   
  "Affiliate" means, as to any Person, any other Person which directly or
indirectly controls, or is under common control with, or is controlled by,
such Person. As used in this definition, "control" (including, with its
correlative meanings, "controlled by" and "under common control with") shall
mean possession, directly or indirectly, of power to direct or cause the
direction of management or policies of such Person (whether through ownership
of securities or partnership or other ownership interest, by contract or
otherwise), provided that, in any event, (a) any Person which owns directly or
indirectly 10 percent or more of the securities having ordinary voting power
for the election of directors or other governing body of a corporation or 10
percent or more of the partnership or other ownership interests of any other
Person (other than as a limited partner of such other Person) will be deemed
to control such corporation or other Person and (b) each Unrestricted
Subsidiary shall be deemed to be an Affiliate of MFS and of each other
Subsidiary. Notwithstanding the foregoing, no individual shall be deemed to be
an Affiliate of a Person solely by virtue of his or her being an officer or
director (or     
 
                                      63
<PAGE>
 
equivalent) of such Person and neither MFS nor any of its Restricted
Subsidiaries shall be deemed to be Affiliates of each other.
 
  "Asset Sale" means, with respect to any Person, any transfer, conveyance,
sale, lease or other disposition (including, without limitation, dispositions
pursuant to any consolidation or merger, but excluding any Sale and Leaseback
Transaction) by such Person or any of its Restricted Subsidiaries to any
Person other than to such Person or its Restricted Subsidiaries in any single
transaction or series of transactions of (i) shares of Capital Stock or other
ownership interests of another Person (other than directors' qualifying
shares) or (ii) any other Property or assets of such Person or any of its
Restricted Subsidiaries other than sales of Property or assets in the ordinary
course of business and consistent with past practices. For purposes of this
definition, any series of related transactions that, if effected as a single
transaction, would constitute an Asset Sale, shall be deemed to be a single
Asset Sale when the last such transaction which is a part thereof is effected.
The term "Asset Sale" (i) when used with respect to MFS, shall not include any
asset disposition permitted as described above in "The Exchange Offers--
Description of Differences Between the MFS Notes and the WorldCom Notes--
Consolidation, Merger, Conveyance, Transfer or Lease" which constitutes a
disposition of all or substantially all of the assets of MFS and the
Restricted Subsidiaries taken as a whole, (ii) shall
exclude any Asset Sale of less than or equal to $1.0 million, (iii) shall
exclude sales of Investments defined in clause (b) of the definition of
Permitted Investments and (iv) shall exclude the sale, conveyance, disposition
or other transfer of the Capital Stock of an Unrestricted Subsidiary or other
Investment described in clause (iv) of the definition of Restricted Payment,
provided that such Investment was permitted by the terms of the applicable MFS
indenture.
 
  "Average Life" means, as of any date, with respect to any Debt security, the
quotient obtained by dividing (i) the sum of the products of (x) the number of
years from such date to the dates of each scheduled principal payment
(including any sinking fund or mandatory redemption payment requirements) of
such Debt security multiplied in each case by (y) the amount of such principal
payment by (ii) the sum of all such principal payments.
 
  "Business Day" means each Monday, Tuesday, Wednesday, Thursday and Friday
which is not a day on which banking institutions in the Borough of Manhattan,
The City of New York are authorized or obligated by law or executive order to
close.
 
  "Capital Lease Obligation" of any Person means the obligation to pay rent or
other payment amounts under a lease of (or other Debt arrangement conveying
the right to use) real or personal property of such Person which is required
to be classified and accounted for as a capital lease or a liability on the
face of a balance sheet of such Person in accordance with GAAP and the stated
maturity thereof shall be the date of the last payment of rent or any amount
due under such lease prior to the first day upon which such lease may be
terminated by the lessee without payment of a penalty.
 
  "Capital Stock" in any Person means any and all shares, interests,
participations or other equivalents in the equity interest (however
designated) in such Person and any rights (other than Debt securities
convertible into an equity interest), warrants or options to acquire an equity
interest in such Person.
 
  "Cash Proceeds" means, with respect to any Asset Sale by any Person or any
sale of Capital Stock by MFS, the aggregate consideration received for such
sale by such Person in the form of cash or, Eligible Cash Equivalents and, for
a period not to exceed 300 days, in the case of the MFS 2006 Notes, and 360
days, in the case of the MFS 2004 Notes, from the related Asset Sale, Debt or
Capital Stock of a Strategic Equity Investor.
 
 
                                      64
<PAGE>
 
   
  "Consolidated Net Worth" of any Person means the consolidated stockholders'
equity of such Person and, in the case of the MFS 2006 Notes, its Restricted
Subsidiaries, as determined on a consolidated basis in accordance with GAAP,
less amounts attributable to Redeemable Capital Stock of such Person.     
 
  "Credit Agreement" means a secured or unsecured credit agreement providing
for revolving credit loans, term loans and/or letters of credit between MFS
and one or more lenders, as such agreement may be amended, modified,
supplemented, refunded or replaced from time to time.
 
  "Debt" means at any time (without duplication), with respect to any Person,
whether recourse is to all or a portion of the assets of such Person, and
whether or not contingent, (i) any obligation of such Person for money
borrowed, (ii) any obligation of such Person evidenced by bonds, debentures,
notes, Guarantees or other similar instruments, including, without limitation,
any such obligations Incurred in connection with acquisition of Property,
assets or businesses, excluding trade accounts payable made in the ordinary
course of business, (iii) any reimbursement obligation of such Person with
respect to letters of credit, bankers' acceptances or similar facilities
issued for the account of such Person, (iv) any obligation of such Person
issued or assumed as the deferred purchase price of property or services (but
excluding trade accounts payable or accrued liabilities arising in the
ordinary course of business, which in either case are not more than 60 days
overdue or which are being contested in good faith), (v) any Capital Lease
Obligation of such Person, (vi) the maximum fixed redemption or repurchase
price of Redeemable Capital Stock of such Person at the time of determination,
(vii) any Interest Swap Obligations or Currency Hedge Obligations of such
Person at the time of determination, (viii) any obligation to pay rent or
other payment amounts of such Person with respect to any Sale and Leaseback
Transaction to which such Person is a party and (ix) any obligation of the
type referred to in clauses (i) through (viii) of this definition of another
Person and all dividends and distributions of another Person the payment of
which, in either case, such Person has Guaranteed or is responsible or liable,
directly or indirectly, as obligor, Guarantor or otherwise. For purposes of
the preceding sentence, the maximum fixed repurchase price of any Redeemable
Capital Stock that does not have a fixed repurchase price shall be calculated
in accordance with the terms of such Redeemable Capital Stock as if such
Redeemable Capital Stock were repurchased on any date on which Debt shall be
required to be determined pursuant to the applicable MFS Indenture; provided,
however, that if such Redeemable Capital Stock is not then permitted to be
repurchased, the repurchase price shall be the book value of such Redeemable
Capital Stock. The amount of Debt of any Person at any date shall be the
outstanding balance at such date of all unconditional obligations as described
above and the maximum liability of any Guarantees at such date; and in
furtherance of the foregoing, for purposes of calculating the amount of the
MFS Notes of a series outstanding at any date, the amount of the MFS Notes of
a series shall be the Accreted Value thereof as of such date, unless cash
interest has commenced to accrue prior to January 15, 1999 pursuant to the
1994 Indenture with respect to the MFS 2004 Notes and January 15, 2001
pursuant to the 1996 Indenture with respect to the MFS 2006 Notes, in which
case the amount of the MFS 2004 Notes and the MFS 2006 Notes outstanding will
be determined pursuant to the 1994 Indenture and the 1996 Indenture,
respectively, and will not include any accrued and unpaid cash interest which
would otherwise be included in Accreted Value because of clause (iii) of the
definition thereof.
 
  "Debt to EBITDA Ratio" means, as at any date of determination, the ratio of
(i) the aggregate amount of Debt of MFS and its Restricted Subsidiaries on a
consolidated basis as at the date of determination to (ii) the aggregate
amount of EBITDA of MFS and its Restricted Subsidiaries for the four preceding
fiscal quarters for which financial information is available immediately prior
to the date of determination; provided that any Debt incurred or retired by
MFS or any of its Restricted Subsidiaries during the fiscal quarter in which
the transaction date occurs shall be calculated as if such Debt was so
incurred or retired on the first day of the fiscal quarter in which the date
of determination occurs; and provided further that (x) if the transaction
giving rise to the need to calculate the Debt to EBITDA Ratio would have the
effect of increasing or decreasing Debt or EBITDA in the future, Debt or
 
                                      65
<PAGE>
 
EBITDA shall be calculated on a pro forma basis as if such transaction had
occurred on the first day of such four fiscal quarter period preceding the
date of determination, and (y) if during such four fiscal quarter period, MFS
or any of its Restricted Subsidiaries shall have engaged in any Asset Sale,
EBITDA for such period shall be reduced by an amount equal to the EBITDA (if
positive), or increased by an amount equal to the EBITDA (if negative),
directly attributable to the assets which are the subject of such Asset Sale
and any related retirement of Debt as if such Asset Sale and related
retirement of Debt had occurred on the first day of such period or (z) if
during such four fiscal quarter period, MFS or any of its Restricted
Subsidiaries shall have acquired any material assets out of the ordinary
course of business, EBITDA shall be calculated on a pro forma basis as if such
asset acquisition and related financing had occurred on the first day of such
period.
 
  "Debt to Total Capital Ratio" means as of the date of determination the
ratio of (i) the aggregate amount of Debt of MFS and its Restricted
Subsidiaries on a consolidated basis as at the date of determination to (ii)
the sum of (a) the total equity investment in MFS as of January 26, 1994
($947.1 million), (b) the aggregate net proceeds to MFS from the issuance of
any Qualified Capital Stock (including preferred stock) subsequent to January
26, 1994, (c) Subordinated Debt from a Control Group permitted under clause
(m) of the definition of Permitted Debt and (d) net cash proceeds from the
sales of Redeemable Capital Stock of MFS or Debt securities of MFS convertible
into Qualified Capital Stock, in either case upon conversion thereof into
Qualified Capital Stock; provided, however, that, for purposes of calculation
of the Debt to Total Capital Ratio (i) Debt described by clause (c) above
shall not be included if such Debt shall have been utilized to make a
Permitted Investment under clause (a) of the definition of Permitted
Investments; (ii) the net cash proceeds from the sale of Capital Stock of MFS,
including Capital Stock issued upon the conversion of convertible Debt
described in clauses (b) or (d) above, shall not be included if such proceeds
have been utilized to make a Restricted Payment or a Permitted Investment
under clause (a) of the definition of Permitted Investment and (iii) for
purposes of this definition, notwithstanding the definition of Debt, the
amount of the MFS 2004 Notes shall be the principal amount at the Stated
Maturity of such MFS 2004 Notes.
 
  "Default" means any event, act or condition the occurrence of which is, or
after notice or the passage of time or both would be, an Event of Default.
 
  "EBITDA" means with respect to any Person for any period, the sum for such
Person for such period of Consolidated Net Income plus, to the extent
reflected in the income statement of such Person for such period from which
Consolidated Net Income is determined, without duplication, (i) Consolidated
Interest Expense, (ii) income tax expense, (iii) depreciation expense, (iv)
amortization expense and (v) any charge related to any premium or penalty paid
in connection with redeeming or retiring any Debt prior to its stated
maturity.
 
  "Employee Group" means a group of employees of MFS, which includes the Chief
Executive Officer of MFS, who own, directly or indirectly, through an employee
stock ownership plan or similar employee stock ownership arrangement, shares
of MFS's Capital Stock.
 
  "Fair Market Value" means total consideration received or paid in any
transaction or series of transactions as determined in good faith by the Board
of Directors.
 
  "GAAP" means United States generally accepted accounting principles,
consistently applied, as set forth in the opinions and pronouncements of the
Accounting Principles Board of the American Institute of Certified Public
Accountants and statements and pronouncements of the Financial Accounting
Standards Board, or in such other statements by such other entity as may be
approved by a significant segment of the accounting profession of the United
States, that are applicable to the circumstances as of the date of
determination; provided, however, that, except as otherwise specifically
provided, all calculations made for purposes of determining compliance with
the terms of the provisions of the MFS Indentures shall utilize GAAP in effect
at the time of preparation of, and in
 
                                      66
<PAGE>
 
accordance with the GAAP used to prepare, the historical financial statements
of MFS on January 26, 1994.
 
  "Guarantee" means, as applied to any obligation of another Person, (i) a
guarantee (other than by endorsement of negotiable instruments for collection
in the ordinary course of business), direct or indirect, in any manner, of any
part or all of such obligation, (ii) any direct or indirect obligation,
contingent or otherwise, of a Person guaranteeing or having the effect of
guaranteeing the obligations of any other Person in any manner and (iii) an
agreement of a Person, direct or indirect, contingent or otherwise, the
practical effect of which is to assure in any way the payment or performance
(or payment of damages in the event of non-performance) of all or any part of
such obligation of another Person (and "Guaranteed", "Guaranteeing" and
"Guarantor" shall have meanings correlative to the foregoing).
   
  "Interest Payment Date" means January 15 and July 15 in each year.     
 
  "Investment" by any Person means any direct or indirect loan, advance (or
other extension of credit) or capital contribution to (by means of any
transfer of cash or other Property to others or any other payments for
Property of services for the account or use of others), the purchase or
acquisition of any Capital Stock, bonds, notes, debentures or other securities
of, the acquisition, by purchase or otherwise, of all or substantially all of
the business or assets or stock or other evidence of beneficial ownership of,
any Person or making of any Investment in any Person. Investments shall
exclude accounts receivable and other extensions of trade credit on
commercially reasonable terms in accordance with normal trade practices.
 
  "Issue Date" means the date on which the MFS Notes of a series are first
authenticated and delivered under the applicable MFS Indenture.
 
  "Joint Venture" means a telecommunications company in which MFS holds not
more than 50 percent of the shares of Voting Stock.
 
  "Lien" means, with respect to any Property or other asset, any mortgage or
deed of trust, pledge, hypothecation, assignment, deposit arrangement,
security interest, lien (statutory or other), charge, easement, encumbrance,
preference, priority or other security or similar agreement or preferential
arrangement of any kind or nature whatsoever on or with respect to such
Property or other asset (including, without limitation, any conditional sale
or other title retention agreement having substantially the same economic
effect as any of the foregoing).
 
  "Maturity", when used with respect to an MFS Note, means the date on which
the principal of such MFS Note becomes due and payable as provided therein or
in the applicable MFS Indenture, whether at the Stated Maturity, on the Change
of Control Payment Date (in the case of the MFS 2006 Notes) or Purchase Date
established pursuant to the terms of the applicable MFS Indenture with regard
to a Change of Control Offer (in the case of the MFS 2006 Notes) or an Asset
Sale Offer (in the case of the MFS 2006 Notes), as applicable, or an Offer to
Purchase (in the case of the MFS 2004 Notes), or by declaration of
acceleration, call for redemption or otherwise.
 
  "MFS Telecom" means MFS Telecom, Inc., a Delaware corporation, and its
successors (including any Restricted Subsidiary to which all or substantially
all of the assets of MFS Telecom are sold, transferred or conveyed).
 
  "Net Cash Proceeds" means, with respect to Asset Sales of any Property or
other assets by a Person or its Restricted Subsidiaries, cash and cash
equivalents received net of (i) all reasonable out-of-pocket expenses of such
Person or such Restricted Subsidiary incurred in connection with such a sale,
including, without limitation, all legal, title and recording tax expenses,
commissions and other fees and expenses incurred (but excluding any finder's
fee or brokers' fee payable to any Affiliate of such Person) and all federal,
state, foreign and local taxes arising in connection with such an Asset
 
                                      67
<PAGE>
 
Sale that are paid or required to be accrued as liability under GAAP by such
Person or its Restricted Subsidiaries, (ii) all payments made by such Person
or its Restricted Subsidiaries on any Debt which is secured by such Properties
or other assets in accordance with the terms of any Lien upon or with respect
to such Properties or other assets or which must, by the terms of such Lien,
or in order to obtain a necessary consent to such transaction or by applicable
law, be repaid in connection with such Asset Sale, and (iii) all contractually
required distributions and other payments made to minority interest holders
(but excluding distributions and payments to Affiliates of such Person) in
Restricted Subsidiaries of such Person as a result of such transaction;
provided that, in the event that any consideration for a transaction (which
would otherwise constitute Net Cash Proceeds) is required to be held in escrow
pending determination of whether a purchase price adjustment will be made,
such consideration (or any portion thereof) shall become Net Cash Proceeds
only at such time as it is released to such Person or its Restricted
Subsidiaries from escrow, and provided that any non-cash consideration
received in connection with any transaction, which is subsequently converted
to cash, shall be deemed to be Net Cash Proceeds at such time, for purposes of
an Asset Sale and shall thereafter be applied in accordance with the covenant
described in "The Exchange Offers -- Description of Differences Between the
MFS Notes and the WorldCom Notes -- Limitation on Asset Sales."
   
  "Outstanding", when used with respect to the MFS Notes of a series, means,
as of the date of determination, all such MFS Notes theretofore authenticated
and delivered under the applicable MFS Indenture, except: (i) MFS Notes of
such series theretofore cancelled by the Trustee or delivered to the Trustee
for cancellation; (ii) MFS Notes of such series for whose payment or
redemption money in the necessary amount has been theretofore deposited with
the Trustee or any Paying Agent (other than MFS or a Restricted Subsidiary) in
trust for the Holders of such Securities; provided that, if such MFS Notes are
to be redeemed, notice of such redemption has been duly given pursuant to the
applicable MFS Indenture or provision therefor satisfactory to the Trustee has
been made; (iii) MFS Notes of such series which have been paid pursuant to
Section 306 of the applicable MFS Indenture or in exchange for or in lieu of
which other MFS Notes of such series have been authenticated and delivered
pursuant to such MFS Indenture, other than any such MFS Notes in respect of
which there shall have been presented to the Trustee proof satisfactory to it
that such MFS Notes are held by a bona fide purchaser in whose hands such MFS
Notes are valid obligations of MFS; and (iv) MFS Notes of such series as to
which Defeasance has been effected pursuant to Section 1202 of the 1994
Indenture or Section 6(b) of the 1996 Indenture; provided, however, that in
determining whether the Holders of the requisite principal amount of the
Outstanding MFS Notes of a series have given, made or taken any request,
demand, authorization, direction, notice, consent, waiver or other action
under the applicable MFS Indenture as of any date, MFS Notes of such series
owned by MFS or any other obligor upon such MFS Notes or any Affiliate or
Restricted Subsidiary of MFS or of such other obligor shall be disregarded and
deemed not to be Outstanding, except that, in determining whether the Trustee
shall be protected in relying upon any such request, demand, authorization,
direction, notice, consent, waiver or other action, only MFS Notes of a series
so owned which have been pledged in good faith may be regarded as Outstanding
if the pledgee establishes to the satisfaction of the Trustee the pledgee's
right so to act with respect to such MFS Notes and that the pledgee is not MFS
or any other obligor upon such MFS Notes or any Affiliate or Restricted
Subsidiary of MFS or of such other obligor.     
 
  "Permitted Debt" means (a) Debt permitted to be borrowed under the Credit
Agreement in an aggregate principal amount up to $150.0 million outstanding at
any one time; (b) Debt under Interest Swap Obligations, provided that such
obligations are related to payment obligations on other Permitted Debt, and
Currency Hedge Obligations; (c) Debt of MFS to any Restricted Subsidiary of
MFS (but only so long as such Debt is held by such restricted Subsidiary); (d)
Guarantees and letters of credit incurred in the ordinary course of business
and consistent with industry practices; (e) Debt outstanding under the MFS
Notes of a series; (f) Debt of MFS outstanding as of the Issue Date of the
applicable series of MFS Notes other than Debt to be repaid with the proceeds
of the offering of such series of
 
                                      68
<PAGE>
 
   
MFS Notes; (g) Debt incurred in connection with a prepayment or redemption of
the MFS Notes of a series pursuant to a Change of Control provided that the
principal amount of such Debt does not exceed 101% of the principal amount of
the MFS Notes of a series prepaid (plus the amount of reasonable expenses
incurred in connection therewith) and that such Debt (i) has an Average Life
to Stated Maturity equal to or greater than the remaining Average Life to
Stated Maturity of the MFS Notes of a series and (ii) does not mature prior to
the Stated Maturity of the MFS Notes of a series; (h) Debt incurred on or
prior to December 31, 1998 if, after giving effect to the incurrence and
application of the proceeds thereof, the Debt to Total Capital Ratio would not
exceed 1.0; (i) Debt incurred after December 31, 1998 if after giving pro
forma effect to the incurrence and application of the proceeds thereof, the
Debt to EBITDA Ratio would not equal or exceed 5 to 1 in the case of any such
incurrence; (j) Debt incurred (including in the case of discount or paid in
kind Debt for the MFS 2006 Notes any accretion on such Debt or notes payable
in respect of such Debt) to finance the construction or acquisition of
Telecommunications Assets, provided that the net cash proceeds from the
issuance of such Debt do not exceed 100 percent of the lesser of cost or Fair
Market Value of such Telecommunications Assets constructed or acquired; (k)
Debt not otherwise permitted by this definition incurred in exchange for, or
the proceeds of which are used to refinance Debt referred to in clauses (d)
through (i) in the case of the MFS 2004 Notes, and (d) through (j) in the case
of the MFS 2006 Notes of this definition, provided that (i) such Debt is in an
aggregate principal amount not in excess of the aggregate principal amount
then outstanding of the Debt being refinanced plus any amounts related to
prepayment or redemption premiums and fees related thereto; (ii) such Debt is
scheduled to mature no earlier than the Debt being refinanced; and (iii) such
Debt has an Average Life at the time such Debt is incurred that is equal to or
greater than the Average Life of the Debt being refinanced; provided, further,
that such Debt does not have a higher relative ranking to the MFS Notes of a
series than the MFS Notes of a series have to the Debt being refinanced and
the covenants relating to such Debt are not materially more restrictive in the
aggregate than those of the Debt being refinanced; (l) Debt not otherwise
described in this definition in an amount not to exceed $25.0 million
outstanding at any one time; and (m) Subordinated Debt invested by a Control
Group.     
 
  "Permitted Investments" means (a) Investments in Joint Ventures in an
aggregate amount not to exceed the sum of (i) Invested Capital, (ii) the
aggregate net cash proceeds received by MFS and its Restricted Subsidiaries as
distributions on or from the sale or disposition of any such Investments made
in Joint Ventures since January 26, 1994, and (iii) $25.0 million; (b)
Eligible Cash Equivalents; (c) Investments in assets used in the ordinary
course of business; (d) Investments in any Person as a result of which such
Person becomes a Restricted Subsidiary; (e) Investments pursuant to any
agreement or obligation of MFS or a Restricted Subsidiary, in effect on the
Issue Date, to make such Investments; (f) Investments in prepaid expenses,
negotiable instruments held for collection and lease, utility and workers'
compensation, performance and other similar deposits; (g) loans and advances
to employees made in the ordinary course of business and consistent with past
practice; (h) Interest Swap Obligations and Currency Hedge Obligations; (i)
bonds, notes, debentures or other securities received as a result of Asset
Sales permitted under the covenant limiting MFS' ability to engage in Asset
Sales as described in the applicable covenant; (j) Investments in existence at
January 26, 1994; and (k) Investments incurred in the ordinary course of
business as partial payment for constructing a network using principally
Telecommunications Assets, provided, however, that MFS and its Restricted
Subsidiaries have received at least 85 percent of the aggregate consideration
therefrom in cash or cash equivalents.
 
  "Permitted Liens" means (a) Liens securing Debt incurred under the Credit
Agreement provided that (i) such Debt was incurred in compliance with clause
(a) of the definition of Permitted Debt; (b) Liens securing Debt incurred
under clause (j) of the definition of Permitted Debt and Subsidiary Vendor
Debt; (c) Liens on Property of a Person existing at the time such Person is
merged with or into or consolidated with MFS or becomes a Restricted
Subsidiary (and not incurred in anticipation of such transaction); provided
that such Liens are not extended to the Property and assets of MFS and its
 
                                      69
<PAGE>
 
Restricted Subsidiaries, other than the acquired Restricted Subsidiary; (d)
Liens on Telecommunications Assets existing during the time of the
construction thereof; (e) Liens incurred to secure the performance of
statutory obligations, surety or appeal bonds, performance bonds or other
obligations of a like nature incurred in the ordinary course of business
consistent with industry practice; (f) Liens existing as of the Issue Date;
(g) any Lien on Property and assets of MFS in favor of the United States of
America or any state thereof, or any instrumentality of either, to secure
certain payments pursuant to any contract or statute; (h) any Lien for taxes
or assessments or other governmental charges or levies not then due and
payable (or which, if due and payable, are being contested in good faith and
for which adequate reserves are being maintained, to the extent required by
GAAP); (i) any title exception, easement or other similar Lien that does not
materially impair the use of the property subject thereto in the ordinary
course of business of MFS or any of its Restricted Subsidiaries, as
applicable; (j) any Lien to secure obligations under workmen's compensation
laws or similar legislation, including any Lien with respect to judgments
which are not currently dischargeable; (k) any statutory warehousemen's,
materialmen's or other similar Liens for sums not then due and payable (or
which, if due and payable, are being contested in good faith and with respect
to which adequate reserves are being maintained, to the extent required by
GAAP); (l) Liens on Receivables, provided that the outstanding amount of the
Debt secured by such Liens would not represent more than 80 percent of
Eligible Receivables; and (m) Liens to secure any permitted extension,
renewal, refinancing or refunding (or successive extensions, renewals,
refinancings or refundings), in whole or in part, of any Debt secured by Liens
referred to in the foregoing clauses (b) through (e); provided that such Liens
do not extend to any other Property or assets and the principal amount of the
Debt secured by such Liens is not increased.
 
  "Person" means any individual, Corporation, partnership, joint venture,
trust, unincorporated organization or government or any agency or political
subdivision thereof.
 
  "Property" means, with respect to any Person, any interest of such Person in
any kind of property or assets, whether real, personal or mixed, or tangible
or intangible, excluding Capital Stock in any other Person.
 
  "Redeemable Capital Stock" of any Person means any equity security of such
Person that by its terms (or by the terms of any security into which it is
convertible or for which it is exchangeable), or otherwise (including on the
happening of an event), is required to be redeemed or is redeemable at the
option of the holder thereof, in whole or in part (including by operation of a
sinking fund), or is exchangeable for Debt, in whole or in part at any time,
prior to the Stated Maturity of the MFS Notes of a series.
 
  "Replacement Asset" means, with respect to any Asset Sale, a Property or
asset that, as determined by the Board of Directors as evidenced by a Board
Resolution, is used or will be used in the telecommunications business of MFS
or a Restricted Subsidiary.
 
  "Restricted Payment" means (i) a dividend or other distribution declared and
paid on the Capital Stock of MFS or to MFS' stockholders (in their capacity as
such), or declared and paid to any Person other than MFS or a Restricted
Subsidiary of MFS on the Capital Stock of any Restricted Subsidiary of MFS, in
each case, other than dividends, distributions or payments made solely in
Qualified Capital Stock of MFS or such Restricted Subsidiary, (ii) a payment
made by MFS (other than a payment made solely in Qualified Capital Stock of
MFS) or any of its Restricted Subsidiaries (other than a payment to MFS or any
Restricted Subsidiary of MFS or a payment made solely in Qualified Capital
Stock of such Restricted Subsidiary or of MFS) to purchase, redeem, acquire or
retire any Capital Stock of MFS or of a Restricted Subsidiary, (iii) a payment
made by MFS or of any of its Restricted Subsidiaries (other than a payment
made solely in Qualified Capital Stock of MFS) to redeem, repurchase, defease
(including an in-substance or legal defeasance) or otherwise acquire or retire
for value (including pursuant to mandatory repurchase covenants), prior to any
scheduled maturity, scheduled sinking fund
 
                                      70
<PAGE>
 
or mandatory redemption payment, Debt of MFS which is subordinate (whether
pursuant to its terms or by operation of law) in right of payment to either
series of the MFS Notes and which was scheduled to mature on or after the
Stated Maturity of either series of the MFS Notes or (iv) an Investment in any
Person, including an Unrestricted Subsidiary, other than (a) a Permitted
Investment, (b) an Investment by MFS in another Restricted Subsidiary or (c)
an Investment by a Restricted Subsidiary in MFS or a Restricted Subsidiary.
For calculation purposes upon any Person becoming a Restricted Subsidiary, all
investments in that person shall not be considered to be Restricted Payments.
 
  "Restricted Subsidiary" of any Person means (i) any corporation other than
an Unrestricted Subsidiary more than 50% of the outstanding shares of Voting
Stock of which is owned or controlled, directly or indirectly, by such person
or (ii) any limited partnership other than an Unrestricted Subsidiary of which
such Person or any Restricted Subsidiary of such Person is a general partner
or (iii) any other Person (other than a corporation or limited partnership)
other than an Unrestricted Subsidiary in which such Person, or one or more
other Restricted Subsidiaries of such Person, or such Person and one or more
other Restricted Subsidiaries thereof, directly or indirectly, have more than
50% of the outstanding partnership or similar interests or have the power, by
contract or otherwise, to direct or cause the direction of the policies,
management and affairs thereof.
 
  "Sale and Leaseback Transaction" means, with respect to any Person, any
direct or indirect arrangement pursuant to which Property is sold or
transferred by such Person or a Restricted Subsidiary of such Person and is
thereafter leased back from the purchaser or transferee thereof by such Person
or one of its Restricted Subsidiaries.
 
  "Stated Maturity" when used with respect to an MFS Note or any installment
of interest thereon, means the date specified in such MFS Note as the fixed
date on which the principal of such MFS Note or such installment of interest
is due and payable.
 
  "Strategic Equity Investor" means a Telecommunications Company rated
investment grade by Standard & Poor's Ratings Group and Moody's Investors
Service, Inc. and having a Total Market Capitalization (as defined) of debt
and equity of at least $10.0 billion.
 
  "Subsidiary" means, with respect to any Person, (i) any corporation more
than 50 percent of the outstanding shares of Voting Stock of which is owned,
directly or indirectly, by such Person, or by one or more other Subsidiaries
of such Person, or by such Person and one or more other Subsidiaries of such
Person, (ii) any general partnership, joint venture or similar entity, more
than 50 percent of the outstanding partnership or similar interests of which
are owned, directly or indirectly, by such Person, or by one or more other
Subsidiaries of such Person, or by such Person and one or more other
Subsidiaries of such Person and (iii) any limited partnership of which such
Person or any Subsidiary of such Person is a general partner.
 
  "Subsidiary Vendor Debt" means Debt incurred (which, with respect to the MFS
2006 Notes, includes in the case of discount or paid in kind Debt any
accretion on such Debt or notes payable in respect of such Debt) by a
Restricted Subsidiary to finance the construction or acquisition of
Telecommunication Assets or the acquisition of the Capital Stock of a
Restricted Subsidiary substantially all the assets of which are
Telecommunications Assets, provided that the net cash proceeds from the
issuance of such Debt do not exceed 100 percent of the lesser of cost or Fair
Market Value of such Telecommunications Assets so constructed or acquired (at
the time of incurrence in the case of the MFS 2004 Notes); provided, further,
however, that if an acquired Restricted Subsidiary has outstanding previously
incurred Debt, such previously incurred Debt will also constitute Subsidiary
Vendor Debt if and only if such previously incurred Debt was not incurred in
contemplation of such acquisition and all such Debt is non-recourse to MFS and
its Restricted Subsidiaries other than the acquired Restricted Subsidiary.
 
 
                                      71
<PAGE>
 
 "Telecommunications Assets" means, with respect to any Person, any asset that
is utilized by such Person, directly or indirectly, for the design,
development, installation, integration, management or provision of
telecommunications systems and/or services, including without limitation, any
businesses or services in which MFS is currently engaged. Telecommunications
Assets shall include stock, joint venture or partnership interests where
substantially all of the assets of the entity being acquired consist of
Telecommunications Assets.
 
  "Unrestricted Subsidiary" means (i) any Subsidiary of MFS (a) which at the
time of determination shall be an Unrestricted Subsidiary (as designated by
the Board of Directors of MFS, as provided below), (b) which shall be engaged
in the same or similar line of business as MFS and its Restricted
Subsidiaries, and (c) all the Debt of which shall be non-recourse to MFS and
its Subsidiaries other than its Unrestricted Subsidiaries and (ii) any
Subsidiary of an Unrestricted Subsidiary; provided that notwithstanding clause
(i)(c) above, MFS or a Restricted Subsidiary of MFS may guarantee, endorse,
agree to provide funds for the payment or maintenance of, or otherwise become
directly or indirectly liable with respect to, Debt of an Unrestricted
Subsidiary but only to the extent that MFS or such Restricted Subsidiary could
make an Investment in such Unrestricted Subsidiary pursuant to the covenant
described under "The Exchange Offers--Description of Differences Between the
MFS Notes and the WorldCom Notes--Limitations on Restricted Payments" and any
such Guarantee, endorsement or agreement shall be deemed an incurrence of Debt
by MFS for purposes of the covenant described under "The Exchange Offers--
Description of Differences Between the MFS Notes and the WorldCom Notes--
Limitation of Debt." The Board of Directors of MFS may designate any newly
acquired or newly formed Subsidiary to be an Unrestricted Subsidiary unless
such Subsidiary owns any capital stock of, or owns or holds any Lien on any
property of, any other Subsidiary of MFS which is not an Unrestricted
Subsidiary (other than a Subsidiary of the type referred to in clause (ii)
above).
 
  "Voting Stock" means, with respect to any Person, securities of any class or
classes of Capital Stock in such Person entitling the holders thereof (whether
at all times or at the times that such class of Capital Stock has voting power
by reason of the happening of any contingency) to vote in the election of
members of the board of directors or comparable body of such Person.
 
                       DESCRIPTION OF THE WORLDCOM NOTES
   
  The WorldCom Notes will be issued under the WorldCom Indenture, as
supplemented. The following summary of certain provisions of the WorldCom
Indenture does not purport to be complete and is subject to, and is qualified
in its entirety by reference to, the Trust Indenture Act of 1939, as amended
(the "Trust Indenture Act"), and to all of the provisions of the WorldCom
Indenture, including the definitions of certain terms therein and those terms
made a part of the WorldCom Indenture by reference to the Trust Indenture Act
as in effect on the date of the WorldCom Indenture. The WorldCom Indenture is
by its terms subject to and governed by the Trust Indenture Act. Unless
otherwise indicated, references under this caption to sections are references
to the WorldCom Indenture. Whenever particular sections or defined terms are
referred to, it is intended that such sections or defined terms shall be
incorporated herein by reference. A copy of the WorldCom Indenture may be
obtained from the Company and is also filed as an exhibit to the Registration
Statement of which this Prospectus is a part. The definitions of certain
capitalized terms used in the following summary are set forth below under "--
Certain Definitions". For purposes of the description of the WorldCom Notes,
the term "Company" refers to WorldCom, Inc. and does not include its
subsidiaries except for purposes of financial data determined on a
consolidated basis.     
 
 General
 
  The WorldCom 2004 Notes will be limited in aggregate principal amount to $
million and will mature on January 15, 2004. Interest on the WorldCom 2004
Notes will accrue at the rate of 9 3/8%
 
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<PAGE>
 
per annum. The WorldCom 2006 Notes will be limited in aggregate principal
amount to $   million and will mature on January 15, 2006. Interest on the
WorldCom 2006 Notes will accrue at the rate of 8 7/8% per annum.
   
  Interest on the WorldCom Notes will be payable semi-annually on January 15
and July 15, commencing on January 15, 1998, to the persons who are registered
holders of the WorldCom Notes at the close of business on the immediately
preceding December 31 and June 30, respectively. Interest on the WorldCom
Notes will accrue from and including the Interest Accrual Date. Interest will
be calculated on the basis of a 360-day year of twelve 30-day months.     
   
  Principal and interest will be payable at one or more offices of the Paying
Agent, one of which will be in the City of New York, but, at the option of the
Company, interest may be paid by check mailed to the registered holders at
their registered addresses. The WorldCom Notes will be issued without coupons
and in book-entry form only, in denominations of $1,000 and integral multiples
thereof. Unless otherwise designated by the Company, the Trustee shall act as
Paying Agent.     
 
 Ranking
   
  The WorldCom Notes will be senior, unsecured obligations of the Company,
will rank pari passu in right of payment with all other existing and future
senior, unsecured indebtedness of the Company and will rank senior in right of
payment to any future subordinated obligations of the Company. The WorldCom
Notes will be effectively subordinated to any secured indebtedness of the
Company to the extent of the value of the assets securing such indebtedness.
As of March 31, 1997, after giving effect to the issuance and sale by the
Company of the April WorldCom Notes, the aggregate amount of indebtedness of
the Company to which the WorldCom Notes would have ranked pari passu was
approximately $3.18 billion and the aggregate amount of secured indebtedness
of the Company was approximately $53 million. The WorldCom Notes will be
structurally subordinated to all obligations of the Company's subsidiaries,
including any MFS Notes not exchanged for WorldCom Notes in the Exchange
Offers, to the extent of the assets of such subsidiaries. As of March 31,
1997, the aggregate amount of the outstanding obligations of the Company's
subsidiaries to which the holders of WorldCom Notes would have been
structurally subordinated (including trade payables but excluding intercompany
indebtedness) was approximately $2.66 billion; of this amount, (i) $699.9
million represented the carrying value of the MFS 2004 Notes and (ii) $678.7
million represented the carrying value of the MFS 2006 Notes. See "Risk
Factors."     
 
 Optional Redemption
 
  The WorldCom 2004 Notes will not be redeemable at the option of the Company
prior to January 15, 1999. On or after January 15, 1999, the WorldCom 2004
Notes will be redeemable at the option of the Company, in whole at any time or
in part from time to time, at the following prices (expressed in percentages
of the principal amount thereof), if redeemed during the twelve months
beginning January 15 of the years indicated below, in each case together with
interest accrued to the redemption date (subject to the right of holders of
record on the relevant record date to receive interest due on the relevant
interest payment date):
 
<TABLE>
<CAPTION>
       YEAR                                                           PERCENTAGE
       ----                                                           ----------
       <S>                                                            <C>
       1999..........................................................  103.52%
       2000..........................................................  102.34%
       2001..........................................................  101.17%
       2002 and thereafter...........................................  100.00%
</TABLE>
 
  The WorldCom 2006 Notes will not be redeemable at the option of the Company
prior to January 15, 2001. On or after January 15, 2001, the WorldCom 2006
Notes will be redeemable at the option of
 
                                      73
<PAGE>
 
the Company, in whole at any time or in part from time to time, at the
following prices (expressed in percentages of the principal amount thereof),
if redeemed during the twelve months beginning January 15 of the years
indicated below, in each case together with interest accrued to the redemption
date (subject to the right of holders of record on the relevant record date to
receive interest due on the relevant interest payment date):
 
<TABLE>
<CAPTION>
       YEAR                                                           PERCENTAGE
       ----                                                           ----------
       <S>                                                            <C>
       2001..........................................................  103.32%
       2002..........................................................  102.21%
       2003..........................................................  101.11%
       2004 and thereafter...........................................  100.00%
</TABLE>
 
  If less than all of the WorldCom Notes of either series are to be redeemed,
the Trustee will select the WorldCom Notes or portions thereof in each series
to be redeemed pro rata, by lot or by any other method that the Trustee shall
deem fair and appropriate. (Section 1103 of the WorldCom Indenture) Notice of
redemption will be mailed at least 30 days but no more than 60 days before the
redemption date to each Holder of WorldCom Notes to be redeemed at its
registered address. (Section 1104 of the WorldCom Indenture) On or after the
redemption date, the WorldCom Notes shall cease to accrue interest, if the
Company makes the redemption payment.
 
 Consolidation, Merger, Conveyance, Sale or Lease
 
  The Company may consolidate with, or sell, lease or convey all or
substantially all of its assets to, or merge with or into any other
corporation, provided that (a) either the Company shall be the continuing
corporation, or the successor corporation (if other than the Company) formed
by or resulting from any such consolidation or merger or which shall have
received the transfer of such assets shall expressly assume payment of the
principal of (and premium, if any) and interest on all the WorldCom Notes and
the performance and observance of all the covenants and conditions of the
WorldCom Indenture; and (b) the Company or such successor corporation shall
not immediately thereafter be in default under the WorldCom Indenture (Section
801 of the WorldCom Indenture).
 
 Limitation on Liens
   
  The Company shall not, and shall not permit any Restricted Subsidiary to,
directly or indirectly, create, or suffer to be created or to exist, any Lien
(other than Permitted Liens) upon any of its Property or assets, whether now
owned or hereafter acquired, or any interest therein or any income or profits
therefrom, unless it has made or will make effective provision whereby the
WorldCom Notes will be secured by such Lien equally and ratably with (or prior
to) all other indebtedness of the Company or any Restricted Subsidiary secured
by such Lien for so long as any such other indebtedness of the Company or any
Restricted Subsidiary shall be so secured. Notwithstanding the foregoing, the
Company may, and may permit any Restricted Subsidiary to, issue, assume or
guarantee indebtedness secured by Liens on Property that are not Permitted
Liens without equally and ratably securing the WorldCom Notes, provided that
the sum of all such indebtedness then being issued, assumed or guaranteed
together with such indebtedness theretofore issued, assumed or guaranteed that
remains outstanding does not exceed 15% of the Consolidated Net Tangible
Assets immediately prior to the time such indebtedness was issued, assumed or
guaranteed (Section 1004 of the WorldCom Indenture).     
 
 Events of Default; Notice and Waiver
 
    Each of the following is an "Event of Default" under the WorldCom
  Indenture with respect to a series of WorldCom Notes:
 
    (a) default for 30 days in the payment of any installment of interest on
  any WorldCom Note of that series;
 
                                      74
<PAGE>
 
    (b) default in the payment of the principal of (or premium, if any, on)
  any WorldCom Note of that series at its Maturity;
     
    (c) default in the performance of any other covenant of the Company in
  the WorldCom Indenture with respect to a WorldCom Note of that series
  (other than a covenant a default on whose performance is otherwise
  specifically dealt with in the provisions relating to Events of Default)
  continued for 60 days after written notice as provided in the WorldCom
  Indenture;     
     
    (d) certain events of default resulting in the acceleration of the
  maturity of indebtedness aggregating in excess of $50,000,000 under any
  mortgages, indentures (including the WorldCom Indenture) or instruments
  under which the Company may have issued, or by which there may have been
  secured or evidenced, any other indebtedness (including any other series of
  securities issued under the WorldCom Indenture) of the Company, but only if
  such indebtedness is not discharged or such acceleration is not rescinded
  or annulled; and     
     
    (e) certain events of bankruptcy, insolvency or reorganization, or court
  appointment of a receiver, liquidator or trustee of the Company or all or
  substantially all of its property (Section 501 of the WorldCom Indenture).
         
  Within 90 days after the occurrence of any default under the WorldCom
Indenture, the Trustee shall transmit notice of such default (unless cured or
waived) known to the Trustee to the holders of the WorldCom Notes; provided,
however, the Trustee may withhold notice to the holders of WorldCom Notes of
any default with respect to such series (except a default in the payment of
the principal of (or premium, if any) or interest on any WorldCom Note or in
the payment of any sinking fund installment in respect of any WorldCom Note)
if the Responsible Officers of the Trustee consider such withholding to be in
the interest of such holders (Section 601 of the WorldCom Indenture).     
   
  If an Event of Default under the WorldCom Indenture with respect to a series
of WorldCom Notes at the time outstanding occurs and is continuing, then in
every such case the Trustee or the holders of not less than 25% in principal
amount of the outstanding WorldCom Notes of that series may declare the
principal amount of all of the WorldCom Notes of that series to be due and
payable immediately by written notice thereof to the Company (and to the
Trustee if given by the holders). However, at any time after such a
declaration of acceleration with respect to such series of WorldCom Notes (or
of all securities then outstanding under the WorldCom Indenture, as the case
may be) has been made, but before a judgment or decree for payment of the
money due has been obtained by the Trustee prior to the Stated Maturity
thereof, the holders of a majority in principal amount of outstanding WorldCom
Notes of such series (or of all securities then outstanding under the WorldCom
Indenture, as the case may be) may, subject to certain conditions, rescind and
annul such acceleration if all Events of Default, other than the non-payment
of accelerated principal (or specified portion thereof), with respect to
WorldCom Notes of such series (or of all securities then outstanding under the
WorldCom Indenture, as the case may be) have been cured or waived as provided
in the WorldCom Indenture. The WorldCom Indenture also provides that the
holders of not less than a majority in principal amount of the outstanding
WorldCom Notes of any series issued thereunder (or of all securities then
outstanding under the WorldCom Indenture, as the case may be) may waive
certain past defaults with respect to such series and its consequences
(Section 513 of the WorldCom Indenture). Within 120 days after the close of
each fiscal year, the Company must file with the Trustee a statement, signed
by specified officers, stating whether or not such officers have knowledge of
any default under the WorldCom Indenture and, if so, specifying each such
default and the nature and status thereof (Section 1006 of the WorldCom
Indenture).     
   
  Subject to provisions in the WorldCom Indenture relating to its duties in
case of default, the Trustee is under no obligation to exercise any of its
rights or powers under the WorldCom Indenture at the request or direction of
any holders of any series of WorldCom Notes then outstanding under the
WorldCom Indenture, unless such holders shall have offered to the Trustee
reasonable security or     
 
                                      75
<PAGE>
 
   
indemnity (Section 602 of the WorldCom Indenture). Subject to such provisions
for indemnification and certain limitations contained in the WorldCom
Indenture, the holders of not less than a majority in principal amount of the
outstanding WorldCom Notes of any series issued thereunder (or of all
Securities then outstanding under the WorldCom Indenture, as the case may be)
shall have the right to direct the time, method and place of conducting any
proceeding for any remedy available to the Trustee, or of exercising any trust
or power conferred upon the Trustee (Section 512 of the WorldCom Indenture).
    
 Amendment and Supplement
   
  The WorldCom Indenture contains provisions permitting WorldCom and the
Trustee to enter into one or more indentures supplemental to the WorldCom
Indenture without the consent of the holders of the WorldCom Notes for certain
purposes, including the following: (a) to evidence the succession of another
entity to the Company and the assumption by such entity of the covenants of
the Company contained in the WorldCom Indenture and the WorldCom Notes; (b) to
add to the covenants of the Company for the benefit of the holders of the
WorldCom Notes or to surrender any right or power conferred upon the Company
in the WorldCom Indenture; (c) to add any additional Events of Default for the
benefit of the holders of the WorldCom Notes; provided, however, that in
respect of any such additional Events of Default such supplemental indenture
may provide for a particular period of grace after default or may provide for
an immediate enforcement upon such default or may limit the remedies available
to the Trustee upon such default or may limit the right of the holders of a
majority in aggregate principal amount of that or those series of WorldCom
Notes to which such additional Events of Default apply to waive such default;
(d) to add to or change any of the provisions of the WorldCom Indenture to
permit or facilitate the issuance of the WorldCom Notes in uncertificated or
bearer form; (e) to change or eliminate any provisions of the WorldCom
Indenture which do not affect the rights of any holders of securities issued
in connection with the WorldCom Indenture; (f) to provide security for the
WorldCom Notes; (g) to evidence and provide for the acceptance of an
appointment of a successor Trustee with respect to the WorldCom Notes and to
add to or change any of the provisions of the WorldCom Indenture to provide
for or facilitate the administration of the trusts under the WorldCom
Indenture by more than one Trustee; (h) to cure any ambiguity, to correct or
supplement any provision of the WorldCom Indenture which may be defective or
inconsistent with any other provision, or to make any other provisions with
respect to matters or questions arising under the WorldCom Indenture which
shall not be inconsistent with the provisions of the WorldCom Indenture and
which additional provisions shall not adversely affect the interests of the
holders of the WorldCom Notes; or (i) to supplement any of the provisions of
the WorldCom Indenture to such extent as shall be necessary to permit or
facilitate the defeasance and discharge of the WorldCom Notes in accordance
with terms and conditions of the WorldCom Indenture provided that any such
action shall not adversely affect the interests of the holders of the WorldCom
Notes in any material respect (Section 901 of the WorldCom Indenture).     
   
  The WorldCom Indenture also contains provisions permitting WorldCom and the
Trustee, with the consent of the holders of not less than a majority in
principal amount of all the outstanding WorldCom Notes affected by the terms
of any such supplemental indenture, to execute supplemental indentures adding
any provisions to or changing in any manner or eliminating any of the
provisions of the WorldCom Indenture or of modifying in any manner the rights
of the holders of such WorldCom Notes, except that, without the consent of the
holders of each such WorldCom Note, no such supplemental indenture shall, (a)
change the Stated Maturity of the principal of (or premium, if any, on) or any
installment of principal of or interest on such WorldCom Notes; (b) reduce the
principal amount of such WorldCom Notes or the rate or amount of interest
thereon or any additional amounts payable in respect thereof pursuant to the
WorldCom Indenture or such WorldCom Notes, or any premium payable upon the
redemption thereof; (c) change any obligation of the Company to pay additional
amounts pursuant to Section 1007 of the WorldCom Indenture (except as
otherwise contemplated by the WorldCom Indenture); (d) adversely affect any
right of repayment at the option of the holder of     
 
                                      76
<PAGE>
 
   
such WorldCom Notes; (e) change any place of payment where, or the currency or
currencies, currency unit or units or composite currency or currencies in
which, such WorldCom Notes or any premium or the interest thereon is payable;
(f) impair the right to institute suit for the enforcement of any such payment
on or after the stated maturity thereof (or in the case of redemption or
repayment at the option of the holder of such WorldCom Notes, on or after the
Redemption Date or the Repayment Date, as the case may be); (g) reduce the
percentage in principal amount of the outstanding WorldCom Notes of such
series, the consent of whose holders is required for any such supplemental
indenture, or the consent of whose holders is required for any waiver with
respect to such series or compliance with certain provisions of the WorldCom
Indenture or certain defaults thereunder and their consequences; (h) reduce
the quorum or voting requirements as contained in the WorldCom Indenture with
respect to such WorldCom Notes; or (i) modify any of the provisions of the
WorldCom Indenture relating to supplemental indentures thereof or waiver of
past defaults with respect to such WorldCom Notes except to increase any such
percentage or to provide that certain other provisions of the WorldCom
Indenture cannot be modified or waived with respect to such WorldCom Notes
without the consent of the holders of each such WorldCom Note (Section 902 of
the WorldCom Indenture).     
 
  It is not necessary for the holders of the WorldCom Notes to approve the
particular form of any proposed supplemental indenture, but it is sufficient
if such holders approve the substance thereof. Every supplemental indenture
executed pursuant to the WorldCom Indenture will conform to the requirements
of the Trust Indenture Act as then in effect. (Section 905 of the WorldCom
Indenture)
 
 Satisfaction and Discharge of the WorldCom Indenture, Covenant Defeasance
   
  The Company may, at its option, elect to have either or both of (a) the
defeasance provision of the WorldCom Indenture or (b) the covenant defeasance
provision of the WorldCom Indenture apply to a series of WorldCom Notes upon
compliance with the applicable conditions set forth in the WorldCom Indenture.
(Section 1401 of the WorldCom Indenture) The Company shall be deemed to have
been discharged from its obligations with respect to a series of WorldCom
Notes on the date the conditions set forth below are satisfied (hereinafter,
"defeasance"), except for the following obligations which shall survive until
otherwise terminated or discharged pursuant to the WorldCom Indenture: (i) the
rights of holders of such WorldCom Notes to receive, solely from the trust
fund described in Section 1404 of the WorldCom Indenture, payments in respect
of the principal of (and premium, if any) and interest, if any, on such
WorldCom Notes when such payments are due, (ii) the Company's obligations with
respect to such WorldCom Notes under Sections 305, 306, 1002 and 1003 of the
WorldCom Indenture and with respect to the payment of additional amounts, if
any, as contemplated by Section 1007 of the WorldCom Indenture, (iii) the
rights, powers, trusts, duties and immunities of the Trustee under the
WorldCom Indenture and (iv) the obligations contained in the article of the
WorldCom Indenture relating to defeasance and covenant defeasance. The Company
shall be released from its obligations under any covenant with respect to such
WorldCom Notes on and after the date the conditions set forth below are
satisfied (hereinafter, "covenant defeasance"). (Sections 1402 and 1403 of the
WorldCom Indenture)     
   
  The following are the conditions that must be satisfied prior to defeasance
or covenant defeasance: (a) the Company shall irrevocably have deposited or
caused to be deposited with the Trustee as trust funds in trust for the
purpose of making the following payments, money and/or Government Obligations
sufficient, in the opinion of a nationally recognized firm of independent
public accountants expressed in a written certification thereof delivered to
the Trustee, to pay and discharge, and which shall be applied by the Trustee
(or other qualifying trustee) to pay and discharge, (i) the principal of (and
premium, if any) and interest, if any, on the WorldCom Notes to be defeased on
the Stated Maturity of such principal or installment of principal or interest
and (ii) any mandatory sinking fund payments or analogous payments applicable
to such WorldCom Notes; (b) such defeasance or     
 
                                      77
<PAGE>
 
   
covenant defeasance shall not result in a breach or violation of, or
constitute a default under, the WorldCom Indenture or any other material
agreement or instrument to which the Company is a party or by which it is
bound; (c) no Event of Default or event which with notice or lapse of time or
both would become an Event of Default with respect to such WorldCom Notes
shall have occurred and be continuing on the date of such deposit, or if
applicable, at any time during the period ending on the 91st day after the
date of such deposit; (d) the Company shall have delivered to the Trustee an
opinion of counsel to the effect that the holders of such WorldCom Notes will
not recognize income, gain or loss for Federal income tax purposes as a result
of such defeasance or covenant defeasance, as applicable, and will be subject
to Federal income tax on the same amounts, in the same manner and at the same
times as would have been the case if such defeasance or covenant defeasance,
as applicable, had not occurred; (e) the Company shall have delivered to the
Trustee an officers' certificate and an opinion of counsel, each stating that
all conditions precedent to the defeasance or the covenant defeasance (as the
case may be) have been complied with and an opinion of counsel to the effect
that either (i) as a result of a deposit pursuant to subsection (a) above,
registration is not required under the Investment Company Act of 1940, as
amended, by the Company, with respect to the trust funds representing such
deposit or by the Trustee for such trust funds or (ii) all necessary
registrations under said Act have been effected; and (f) such defeasance or
covenant defeasance shall be effected in compliance with any additional or
substitute terms, conditions or limitations which may be imposed on the
Company in connection therewith pursuant to Section 301 of the WorldCom
Indenture. (Section 1404 of the WorldCom Indenture)     
 
  WorldCom may exercise its defeasance option with respect to the WorldCom
Notes notwithstanding its prior exercise of its covenant defeasance option.
   
  In the event the Company effects covenant defeasance with respect to any
WorldCom Notes and such WorldCom Notes are declared due and payable because of
the occurrence of any Event of Default other than the Events of Default
described in clause (c) under "--Events of Default; Notice and Waiver" above,
the amount of money in which such WorldCom Notes are payable, and Government
Obligations on deposit with the relevant Trustee, will be sufficient to pay
amounts due on such WorldCom Notes at the time of their Stated Maturity but
may not be sufficient to pay amounts due on such WorldCom Notes at the time of
the acceleration resulting from such Event of Default. However, the Company
would remain liable to make payment of such amounts due at the time of
acceleration.     
 
 The Trustee
 
  Mellon Bank, N.A., the Trustee under the WorldCom Indenture, from time to
time may extend credit to the Company in the ordinary course of business. The
Trustee's current address is Two Mellon Bank Center, Room 325, Pittsburgh, PA
15259. Except during the continuance of an Event of Default, the Trustee is
required to perform only such duties as are specifically set forth in the
WorldCom Indenture. During the existence of an Event of Default, the Trustee
is required to exercise such of the rights and powers vested in it by the
WorldCom Indenture, and to use the same degree of care and skill in their
exercise, as a prudent person would exercise or use under the circumstances in
the conduct of such person's own affairs.
 
  The Trust Indenture Act contains certain limitations on the rights of the
Trustee, should it become a creditor of the Company to obtain payment of
claims in certain cases, or to realize on certain property received in respect
of any such claim as security or otherwise. The Trustee will be permitted to
engage in other transactions; however, if it acquires any "conflicting
interest" (as defined in the Trust Indenture Act) it must eliminate such
conflict within 90 days, apply to the Commission for permission to continue or
resign.
 
  The holders of a majority in principal amount of the outstanding WorldCom
Notes will have the right to direct the time, method and place of conducting
any proceeding for exercising any remedy
 
                                      78
<PAGE>
 
available to the Trustee, subject to certain exceptions. (Section 512 of the
WorldCom Indenture) The WorldCom Indenture provides that in case an Event of
Default shall occur (which shall not be cured), the Trustee will be required,
in the exercise of its power, to use the degree of care of a prudent man in
the conduct of his own affairs. Subject to such provisions, the Trustee will
be under no obligation to exercise any of its rights or powers under the
WorldCom Indenture at the request of any of the holders of the WorldCom Notes,
unless such holders shall have offered to the Trustee security and indemnity
satisfactory to it against any loss, liability or expense. (Section 602 of the
WorldCom Indenture)
 
 No Personal Liability of Stockholders, Officers or Directors
 
  No stockholder, employee, officer, director or incorporator as such, past,
present or future of the Company shall have any personal liability in respect
of the obligations of the Company under the WorldCom Indenture or the WorldCom
Notes by reasons of his or its status as such stockholder, employee, officer,
director or incorporator.
 
 Delivery and Form
   
  The WorldCom 2004 Notes and the WorldCom 2006 Notes initially will be
represented by one or more global securities ("Global Securities") deposited
with DTC and registered in the name of the nominee of DTC, except as set forth
below. Each of the WorldCom Notes will be issued in denominations of $1,000
and integral multiples thereof, in book-entry form only. Unless and until
certificated WorldCom Notes are issued under the limited circumstances
described below, no beneficial owner of a WorldCom Note shall be entitled to
receive a definitive certificate representing a WorldCom Note.     
 
  So long as DTC or any successor depository (collectively, the "Depository")
or its nominee is the registered holder of the Global Securities, the
Depository, or such nominee, as the case may be, will be considered to be the
sole owner or holder of the WorldCom Notes for all purposes of the Indenture.
Investors' interests in the Global Securities will be represented through
financial institutions acting on their behalf as direct and indirect
participants in the Depository. Such participants may include Morgan Guaranty
Trust Company of New York, Brussels, Belgium office ("Euroclear") or Cedel
Bank societe anonyme. Except as provided below, owners of beneficial interests
in a Global Security will not be entitled to have WorldCom Notes represented
by such Global Security registered in their names, will not receive or be
entitled to receive physical delivery of WorldCom Notes in certificated form
and will not be considered the owners or holders thereof under the WorldCom
Indenture. The laws of some states require that certain purchasers of
securities take physical delivery of such securities in certificated form;
accordingly, such laws may limit the transferability of beneficial interests
in a Global Security. Accordingly, each person owning a beneficial interest in
a Global Security must rely on DTC's procedures and, if such person is not a
participant, on the procedures of the participant through which such person
owns its interest, to exercise any rights of a holder under the WorldCom
Indenture. If the Company requests any action of holders or if an owner of a
beneficial interest in a Global Security desires to take any action that a
holder is entitled to take under the WorldCom Indenture, DTC will authorize
the participants holding the relevant beneficial interests to give or take
such action, and such participants will otherwise act upon the instructions of
beneficial owners holding through them.
 
  If DTC is at any time unwilling or unable to continue as depository or if at
any time DTC ceases to be a clearing agency registered under the Exchange Act
if so required by applicable law or regulation, and, in either case, a
successor depository is not appointed by the Company within 90 days, the
Company will issue individual WorldCom Notes in certificated form in exchange
for the Global Securities. In addition, the Company may at any time, and in
its sole discretion, determine not to have any WorldCom Notes represented by
one or more Global Securities, and, in such event, will issue individual
WorldCom Notes in certificated form in exchange for the relevant Global
Securities. In any such instance, an owner of a beneficial interest in a
Global Security will be entitled to physical delivery
 
                                      79
<PAGE>
 
of individual WorldCom Notes in certificated form of like tenor and rank,
equal in principal amount to such beneficial interest and to have such
WorldCom Notes in certificated form registered in its name. WorldCom Notes so
issued in certificated form will be issued in denominations of $1,000 or any
integral multiple thereof, and will be issued in registered form only, without
coupons.
 
  The following is based on information furnished by DTC:
 
    DTC will act as securities depository for the WorldCom Notes. The
  WorldCom Notes will be issued as fully registered securities registered in
  the name of Cede & Co. (DTC's partnership nominee). One fully registered
  WorldCom Note certificate is issued with respect to each $200 million of
  principal amount of the WorldCom Notes of a series, and an additional
  certificate is issued with respect to any remaining principal amount of
  such series.
 
    DTC is a limited-purpose trust company organized under the New York
  Banking Law, a "banking organization" within the meaning of the New York
  Banking Law, a member of the Federal Reserve System, a "clearing
  corporation" within the meaning of the New York Uniform Commercial Code,
  and a "clearing agency" registered pursuant to the provisions of Section
  17A of the Exchange Act. DTC holds securities that its participants
  ("Participants") deposit with DTC. DTC also facilitates the settlement
  among Participants of securities transactions, such as transfers and
  pledges, in deposited securities through electronic computerized book-entry
  changes in Participants' accounts, thereby eliminating the need for
  physical movement of securities certificates. Direct Participants include
  securities brokers and dealers, banks, trust companies, clearing
  corporations and certain other organizations ("Direct Participants"). DTC
  is owned by a number of its Direct Participants and by the New York Stock
  Exchange, Inc., the American Stock Exchange, Inc. and the National
  Association of Securities Dealers, Inc. Access to the DTC system is also
  available to others such as securities brokers and dealers, banks and trust
  companies that clear through or maintain a custodial relationship with a
  Direct Participant, either directly or indirectly ("Indirect
  Participants"). The rules applicable to DTC and its Participants are on
  file with the Commission.
 
    Purchases of WorldCom Notes under the DTC system must be made by or
  through Direct Participants, which will receive a credit for the WorldCom
  Notes on DTC's records. The ownership interest of each actual purchaser of
  each WorldCom Note ("Beneficial Owner") is in turn recorded on the Direct
  and Indirect Participants' records. A Beneficial Owner does not receive
  written confirmation from DTC of its purchase, but such Beneficial Owner is
  expected to receive a written confirmation providing details of the
  transaction, as well as periodic statements of its holdings, from the
  Direct or Indirect Participant through which such Beneficial Owner entered
  into the transaction. Transfers of ownership interests in WorldCom Notes
  are accomplished by entries made on the books of Participants acting on
  behalf of Beneficial Owners. Beneficial Owners do not receive certificates
  representing their ownership interests in WorldCom Notes, except in the
  event that use of the book-entry system for the WorldCom Notes is
  discontinued.
 
    To facilitate subsequent transfers, the WorldCom Notes are registered in
  the name of DTC's partnership nominee, Cede & Co. The deposit of the
  WorldCom Notes with DTC and their registration in the name of Cede & Co.
  will effect no change in beneficial ownership. DTC has no knowledge of the
  actual Beneficial Owners of the WorldCom Notes; DTC records reflect only
  the identity of the Direct Participants to whose accounts WorldCom Notes
  are credited, which may or may not be the Beneficial Owners. The
  Participants remain responsible for keeping account of their holdings on
  behalf of their customers.
 
    Delivery of notices and other communications by DTC to Direct
  Participants, by Direct Participants to Indirect Participants, and by
  Direct Participants and Indirect Participants to Beneficial Owners are
  governed by arrangements among them, subject to any statutory or regulatory
  requirements as may be in effect from time to time.
 
                                      80
<PAGE>
 
    Redemption notices shall be sent to Cede & Co. If less than all of the
  WorldCom Notes within an issue are being redeemed, DTC's practice is to
  determine by lot the amount of interest of each Direct Participant in such
  issue to be redeemed.
 
    Neither DTC nor Cede & Co. consents or votes with respect to the WorldCom
  Notes. Under its usual procedures, DTC mails a proxy (an "Omnibus Proxy")
  to the issuer as soon as possible after the record date. The Omnibus Proxy
  assigns Cede & Co.'s consenting or voting rights to those Direct
  Participants to whose accounts the WorldCom Notes are credited on the
  record date (identified on a list attached to the Omnibus Proxy).
 
    Principal, premium, if any, and interest payments on the WorldCom Notes
  are made to DTC. DTC's practice is to credit Direct Participants' accounts
  on the payable date in accordance with their respective holdings as shown
  on DTC's records unless DTC has reason to believe that it will not receive
  payment on the payable date. Payments by Participants to Beneficial Owners
  are governed by standing instructions and customary practices, as is the
  case with securities held for the accounts of customers in bearer form or
  registered in "street name," and are the responsibility of such Participant
  and not of DTC, the applicable Trustee or the Company, subject to any
  statutory or regulatory requirements as may be in effect from time to time.
  Payment of principal, premium, if any, and interest to DTC is the
  responsibility of the Company or the applicable Trustee, disbursement of
  such payments to Direct Participants is the responsibility of DTC, and
  disbursement of such payments to the Beneficial Owners is the
  responsibility of Direct and Indirect Participants.
 
    DTC may discontinue providing its services as securities depository with
  respect to the WorldCom Notes at any time by giving reasonable notice to
  the Company or the applicable Trustee. Under such circumstances, in the
  event that a successor securities depository is not appointed, WorldCom
  Note certificates are required to be printed and delivered.
 
    The Company may decide to discontinue use of the system of book-entry
  transfers through DTC (or a successor securities depository). In that
  event, WorldCom Note certificates will be printed and delivered.
   
  The information in this section concerning DTC and DTC's book-entry system
has been obtained from sources (including DTC) that the Company believes to be
reliable, but the Company takes no responsibility for the accuracy thereof.
    
  None of the Company, the Dealer Managers or any agent, the Trustee or any
applicable paying agent will have any responsibility or liability for any
aspect of the records relating to or payments made on account of beneficial
interests in a Global Security, or for maintaining, supervising or reviewing
any records relating to such beneficial interest.
 
 Same-Day Settlement and Payment
   
  So long as the WorldCom Notes are represented by the Global Securities, all
payments of principal and interest will be made by the Company in immediately
available funds. The WorldCom Notes will trade in DTC's Same-Day Funds
Settlement System until maturity, and secondary market trading activity in the
WorldCom Notes that is effected through DTC will be required to settle in
immediately available funds.     
 
 Certain Definitions
 
  Set forth below is a summary of certain of the defined terms used herein and
defined in Section 101 of the WorldCom Indenture. Reference is made to the
WorldCom Indenture for the full definition of all such terms, as well as any
capitalized terms used herein for which no definition is provided.
 
    "Capital Lease Obligations" means indebtedness represented by obligations
  under a lease that is required to be capitalized for financial reporting
  purposes in accordance with GAAP and
 
                                      81
<PAGE>
 
     
  the amount of such indebtedness shall be the capitalized amount of such
  obligations determined in accordance with GAAP. For purposes of the
  covenant relating to Limitations on Liens, a Capital Lease Obligation shall
  be deemed secured by a Lien on the Property being leased.     
 
    "Capital Stock" means, with respect to any person, any and all shares or
  other equivalents (however designated) of corporate stock, partnership
  interest or any other participation, right, warrant, option or other
  interest in the nature of an equity interest in such person, but excluding
  any debt security convertible or exchangeable into such equity interest.
 
    "Consolidated Net Tangible Assets" means the consolidated total assets of
  the Company and its Subsidiaries as reflected in the Company's most recent
  balance sheet prepared in accordance with GAAP, less (i) current
  liabilities (excluding current maturities of long-term debt and Capital
  Lease Obligations) and (ii) goodwill, trademarks, patents and minority
  interests of others.
 
    "GAAP" means United States generally accepted accounting principles as in
  effect as of the date of determination, unless stated otherwise.
     
    "Government Obligations" means securities which are (i) direct
  obligations of the United States of America or the government which issued
  the foreign currency in which the Debt Securities of a particular series
  are payable, for the payment of which its full faith and credit is pledged
  or (ii) obligations of a Person controlled or supervised by and acting as
  an agency or instrumentality of the United States of America or such
  government which issued the foreign currency in which the Debt Securities
  of such series are payable, the payment of which is unconditionally
  guaranteed as a full faith and credit obligation by the United States of
  America or such other government, which, in either case, are not callable
  or redeemable at the option of the issuer thereof, and shall also include a
  depository receipt issued by a bank or trust company as custodian with
  respect to any such Government Obligation or a specific payment of interest
  on or principal of any such Government Obligation held by such custodian
  for the account of the holder of a depository receipt; provided that
  (except as required by law) such custodian is not authorized to make any
  deduction from the amount payable to the holder of such depository receipt
  from any amount received by the custodian in respect of the Government
  Obligation or the specific payment of interest on or principal of the
  Government Obligation evidenced by such depository receipt.     
 
    "Lien" means, with respect to any Property of any person, any mortgage or
  deed of trust, pledge, hypothecation, assignment, deposit arrangement,
  security interest, lien, charge, easement or zoning restriction (other than
  any easement or zoning restriction not materially impairing usefulness or
  marketability), encumbrance, preference, priority or other security
  agreement or preferential arrangement of any kind or nature whatsoever on
  or with respect to such Property including any Capital Lease Obligation,
  conditional sale or other title retention agreement having substantially
  the same economic effect as any of the foregoing or any Sale and Leaseback
  Transaction.
 
    "Permitted Liens" means (i) Liens existing on the date of the Indenture;
  (ii) Liens on Property existing at the time of acquisition thereof or to
  secure the payment of all or any part of the purchase price thereof or to
  secure any indebtedness incurred prior to, at the time of or within 270
  days after the acquisition of such Property for the purpose of financing
  all or any part of the purchase price thereof; (iii) Liens securing
  indebtedness owing by a Restricted Subsidiary to the Company or any wholly-
  owned Subsidiary of the Company; (iv) Liens on Property of any entity, or
  on the stock, indebtedness or other obligations of such entity, existing at
  the time (a) such entity becomes a Restricted Subsidiary, (b) such entity
  is merged into or consolidated with the Company or a Restricted Subsidiary
  or (c) the Company or a Restricted Subsidiary acquires all or substantially
  all of the assets of such entity; provided that no such Lien extends to any
  other Property; (v) Liens on Property to secure any indebtedness incurred
  to provide funds for all or any part of the cost of development of or
  improvements to such Property; (vi) Liens on the Property of the Company or
  any of its Subsidiaries securing (a) nondelinquent performance of bids or
  contracts (other than for borrowed money, obtaining of advances or credit
  or the securing of debt),
 
                                      82
<PAGE>
 
  (b) contingent obligations on surety and appeal bonds and (c) other
  nondelinquent obligations of a like nature, in each case, incurred in the
  ordinary course of business; (vii) Liens securing Capital Lease
  Obligations, provided that (a) any such Lien attaches to the Property
  within 270 days after the acquisition thereof and (b) such Lien attaches
  solely to the Property so acquired; (viii) Liens arising solely by virtue
  of any statutory or common law provision relating to banker's liens, rights
  of set-off or similar rights and remedies as to deposit account or other
  funds, provided that such deposit account is not a dedicated cash
  collateral account and is not subject to restrictions against access by the
  Company in excess of those set forth by regulations promulgated by the
  Federal Reserve Board and such deposit account is not intended by the
  Company or any Subsidiary to provide collateral to the depository
  institution; (ix) pledges or deposits under worker's compensation laws,
  unemployment insurance laws or similar legislation; (x) statutory and tax
  Liens for sums not yet due or delinquent or which are being contested or
  appealed in good faith by appropriate proceedings; (xi) Liens arising
  solely by operation of law and in the ordinary course of business, such as
  mechanics', materialmen's, warehousemen's and carriers' Liens and Liens of
  landlords or of mortgages of landlords on fixtures and movable Property
  located on premises leased in the ordinary course of business; (xii) Liens
  on personal Property, other than shares of stock or indebtedness of any
  Restricted Subsidiary, to secure loans maturing not more than one year from
  the date of the creation thereof and on accounts receivable associated with
  a receivables financing program of the Company or any of its Subsidiaries;
  and (xiii) any renewal, extension or replacement (in whole or in part) for
  any Lien permitted pursuant to exceptions (i) through (xii) above or of any
  indebtedness secured thereby, provided that such extension, renewal or
  replacement Lien shall be limited to all or any part of the same Property
  that secured the Lien extended, renewed or replaced (plus improvements on
  such Property).
 
    "Property" means, with respect to any person, any interest of such person
  in any kind of property or asset, whether real, personal or mixed, or
  tangible or intangible, including, without limitation, Capital Stock in any
  other person (but excluding Capital Stock or other securities issued by
  such first mentioned person).
 
    "Receivables Subsidiary" means a special purpose wholly-owned Subsidiary
  created in connection with any transactions that may be entered into by the
  Company or any of its Subsidiaries pursuant to which the Company or any of
  its Subsidiaries may sell, convey, grant a security interest in or
  otherwise transfer undivided percentage interests in its receivables.
 
    "Restricted Subsidiary" means any Subsidiary of the Company if (i) such
  Subsidiary has substantially all of its Property in the United States
  (other than its territories and possessions) and (ii) at the end of the
  most recent fiscal quarter of the Company, the aggregate amount, determined
  in accordance with GAAP consistently applied, of securities of, loans and
  advances to, and other investments in, such Subsidiary held by the Company
  and its other Subsidiaries exceeded 10% of the Company's Consolidated Net
  Tangible Assets; provided, however, that the term Restricted Subsidiary
  shall not include (a) any of MFS Communications Company, Inc. or its
  Subsidiaries unless and until such time as such corporation is designated
  by the Company as a "Restricted Subsidiary" or otherwise similarly treated
  under the Company's $3.75 billion five-year revolving credit facility or
  any other agreement of the Company for indebtedness for borrowed money or
  (b) any Receivables Subsidiary.
 
    "Sale and Leaseback Transaction" means, with respect to any person, any
  direct or indirect arrangement pursuant to which Property is sold or
  transferred by such person or a Restricted Subsidiary of such person and is
  thereafter leased back from the purchaser or transferee thereof by such
  person or one of its Restricted Subsidiaries.
 
    "Subsidiary" means a corporation a majority of the outstanding voting
  stock of which is owned, directly or indirectly, by the Company or one or
  more other Subsidiaries of the Company. For the purposes of this
  definition, "voting stock" means stock having voting power for the election
  of directors, whether at all times or only so long as no senior class of
  stock has such voting power by reason of any contingency.
 
                                      83
<PAGE>
 
                  
               CERTAIN U.S. FEDERAL INCOME TAX CONSEQUENCES     
 
  The following is a discussion of certain material U.S. federal income tax
consequences resulting from the Exchange Offers and Consent Solicitations. The
discussion is based on U.S. federal income tax laws, regulations, rulings and
decisions now in effect, all of which are subject to change possibly with
retroactive effect. The discussion assumes that as to any holder, the WorldCom
Notes and MFS Notes are capital assets as of the Exchange Date. This
discussion does not address state, local, foreign or other tax laws and does
not purport to cover all aspects of U.S. federal income taxation that may be
relevant to, or the actual tax effect that any of the matters described herein
will have on, certain holders (including insurance companies, tax-exempt
organizations, financial institutions, securities- dealers, subsequent
purchasers of WorldCom Notes and taxpayers subject to the alternative minimum
tax) who may be subject to special rules not discussed below. HOLDERS OF MFS
NOTES ARE URGED TO CONSULT THEIR OWN TAX ADVISORS REGARDING THE FEDERAL,
STATE, LOCAL AND OTHER TAX CONSEQUENCES OF THE EXCHANGE OFFERS AND CONSENT
SOLICITATIONS AND OF THE CONTINUED HOLDING AND DISPOSITION OF MFS NOTES.
 
UNITED STATES HOLDERS
 
  As used herein, the term "U.S. Holder" means the beneficial owner of MFS
Notes or WorldCom Notes that is, for U.S. federal income tax purposes, (i) an
individual citizen or resident of the United States, (ii) a U.S. domestic
corporation or (iii) otherwise subject to U.S. federal income tax on a net
income basis in respect of the MFS Notes or WorldCom Notes.
 
 Tax Consequences of the Exchange Offers and Consent Solicitations
   
  The exchange of MFS Notes for WorldCom Notes (and cash in lieu of a WorldCom
Note in a principal amount that is not an integral multiple of $1,000) and
Consent Payments pursuant to the Exchange Offers and Consent Solicitations
will be a taxable transaction for United States federal income tax purposes.
Accordingly, a tendering U.S. Holder should generally recognize gain or loss
equal to the difference between the sum of the cash (including the Consent
Payments) and the issue price of the WorldCom Notes received (except to the
extent of any accrued original issue discount ("OID") on the MFS Notes not
previously included in the U.S. Holder's income, which will be taxable as
ordinary interest income) and the U.S. Holder's adjusted tax basis in the MFS
Notes. Such gain or loss will be long-term capital gain or loss if the U.S.
Holder's holding period is more than one year, and short-term capital gain or
loss if the U.S. Holder's holding period is one year or less, except such gain
will be subject to tax as ordinary income to the extent of any accrued "market
discount" on the MFS Notes not previously included in income. In general,
unless a U.S. Holder acquired its MFS Notes at their original issuance, market
discount is the excess, if any, of the "adjusted issued price," or Accreted
Value, of such MFS Notes over the U.S. Holder's tax basis therein at the time
of acquisition (unless the amount of such excess is less than a specified de
minimis amount, in which case market discount is considered zero). In general,
market discount accrues on a straight-line basis, unless a taxpayer elects to
accrue market discount on a constant-yield basis.     
 
  As illustrated above, the amount of gain or loss recognized as a result of
the exchange of the MFS Notes for WorldCom Notes and cash will depend in part
on the "issue price" of the WorldCom Notes. Where a new debt instrument is
issued in exchange for property (including an old debt instrument), the
determination of the issue price of the new debt instrument depends on whether
either the new debt instrument or the property for which it is exchanged is
"publicly traded." If neither the WorldCom Notes nor the MFS Notes are
publicly traded, the issue price of the WorldCom Notes will be their "stated
principal amount." A debt instrument's stated principal amount is the
aggregate amount of all payments under the debt instrument, excluding any
amount of stated interest. If, however, the WorldCom Notes are publicly
traded, their issue price will be their fair market value at the time they are
issued. If the WorldCom Notes are not publicly traded, but the MFS Notes are
publicly traded, the
 
                                      84
<PAGE>
 
issue price of the WorldCom Notes will be the fair market value of the MFS
Notes exchanged therefor. For purposes of this discussion, a debt instrument
is publicly traded if (i) it is listed on a national securities exchange, an
interdealer quotation system sponsored by a national securities association
(such as NASDAQ), or a designated foreign exchange or board of trade, (ii) it
is traded either on a board of trade designated as a contract market by the
Commodities Futures Trading Commission or on an interbank market, (iii) it
appears on a "quotation medium," i.e., a system of general circulation
(including a computer listing available to subscribing brokers and dealers)
that provides a reasonable basis to determine fair market value by
disseminating either recent price quotations of one or more identified
brokers, dealers or traders or actual prices of recent sales (but not "yellow
sheets") or (iv) it is a debt instrument that is "readily quotable" in that
price quotations are readily available from dealers, brokers or traders. Newly
issued debt instruments are treated as publicly traded property at the time of
their issuance if the debt instruments are publicly traded at any time during
the 60-day period ending 30 days after their issuance. Any temporary
restriction on trading, a purpose of which is to avoid characterization of
debt instruments as publicly traded property for federal income tax purposes,
is ineffective regardless of whether the temporary restriction is imposed by
the issuer. If either the WorldCom Notes or the MFS Notes are publicly traded,
the WorldCom Notes may be treated as having been issued at a discount or at a
premium. U.S. Holders should consult their tax advisors to determine how, and
to what extent, any such discount or premium, if any, will be included in such
U.S. Holder's income (in the case of any discount) or amortized (in the case
of any premium).
 
 Basis and Holding Period
 
  A U.S. Holder's tax basis in the WorldCom Notes will equal the issue price
of the WorldCom Notes. The holding period of the WorldCom Notes will commence
on the day after the WorldCom Notes are acquired by the U.S. Holder.
 
 Payment of Interest
 
  Assuming the WorldCom Notes will not be issued with OID, interest on the
WorldCom Notes generally will be taxable to the U.S. Holder as ordinary income
at the time that it is paid or accrued, in accordance with the U.S. Holder's
method of accounting for U.S. federal income tax purposes.
 
 Sale, Exchange or Redemption
 
  In general, a U.S. Holder of a WorldCom Note will recognize gain or loss
upon the sale, exchange, redemption, retirement or other disposition of the
WorldCom Note measured by the difference between the amount realized on the
disposition (to the extent such amount does not represent accrued but unpaid
interest) and the U.S. Holder's adjusted basis in the WorldCom Note. A U.S.
Holder's adjusted basis in a WorldCom Note will generally equal the issue
price of the WorldCom Note. Such gain or loss will be capital gain or loss and
will be long-term capital gain or loss if the U.S. Holder holds the WorldCom
Note for more than one year prior to disposition, and short-term capital gain
or loss if the U.S. Holder holds the WorldCom Note for less than one year
prior to disposition.
 
 U.S. Holders Not Tendering in an Exchange Offer
 
  For U.S. Holders of the MFS Notes who do not elect to exchange their MFS
Notes for the WorldCom Notes pursuant to the Exchange Offers, the proposed
modifications to the MFS Notes (see "The Proposed Amendments") should not be
treated as a taxable exchange of the MFS Notes for the new MFS Notes.
 
 Backup Withholding
 
  Backup withholding of U.S. federal income tax at a rate of 31% may apply to
payments made pursuant to the Exchange Offers and Consent Solicitations, to
payments of principal and interest made
 
                                      85
<PAGE>
 
in respect of WorldCom Notes, and to payments of proceeds from the sale,
exchange, redemption, retirement or other disposition of WorldCom Notes to or
through certain brokers, unless, in general, the beneficial owner of the MFS
Notes or the WorldCom Notes, as the case may be, complies with certain
information reporting procedures or is an exempt recipient. Any amount
withheld from a payment to a beneficial owner pursuant to these backup
withholding rules may be allowed as a refund or credit against the beneficial
owner's U.S. federal income tax.
 
NON-U.S. HOLDERS
   
  As used herein, the term "Non-U.S. Holder" means a beneficial owner of MFS
Notes or WorldCom Notes other than a U.S. Holder. For these purposes, a "Non-
U.S. Holder" does not include a nonresident alien, foreign corporation or
other foreign entity, to the extent that the income or gain with respect to
the Exchange Offers and Consent Solicitations or the WorldCom Notes is
"effectively connected with the conduct of a trade or business within the
United States." To the extent that such income or gain is "effectively
connected with the conduct of a trade or business within the United States,"
then the nonresident alien, foreign corporation or other foreign entity,
generally will be subject to tax as discussed above for U.S. Holders except to
the extent that an applicable treaty otherwise provides. In addition, foreign
corporations may also, under certain circumstances, be subject to a "branch
profits tax" at a 30% rate (or, if applicable, a lower treaty rate).     
 
  In general, any gain or loss realized on the exchange of MFS Notes for
WorldCom Notes (and cash in lieu of a WorldCom Note in a principal amount that
is not an integral multiple of $1,000) and Consent Payments by a Non-U.S.
Holder pursuant to the Exchange Offers and Consent Solicitations will not be
subject to United States federal income or withholding taxes unless, in the
case of an individual, such holder is present in the United States for 183
days in the taxable year of the Exchange and certain other conditions are met.
 
  Subject to the discussion of backup withholding below, payments of interest
on the WorldCom Notes to a Non-U.S. Holder generally will not be subject to
U.S. federal income or withholding taxes, provided that (i) such Non-U.S.
Holder does not actually or constructively own 10 percent or more of the total
combined voting power of all classes of stock of the Company, (ii) such Non-
U.S. Holder is not a controlled foreign corporation for U.S. tax purposes that
is related to the Company actually or constructively through stock ownership
and (iii) the Non-U.S. Holder certifies, under penalties of perjury, that it
is not a United States person for U.S. federal income tax purposes and
provides its name and address in accordance with applicable requirements.
 
  Any capital gain realized on the sale, exchange, redemption, retirement or
other disposition of WorldCom Notes by a Non-U.S. Holder generally will not be
subject to United States federal income or withholding taxes unless, in the
case of an individual, such holder is present in the United States for 183
days in the taxable year of the Exchange and certain other conditions are met.
 
  Payments made pursuant to the Exchange Offers and Consent Solicitations,
payments of principal and interest made in respect of WorldCom Notes and
payments of proceeds from the sale, exchange, redemption, retirement or other
disposition of WorldCom Notes to a Non-U.S. Holder generally will not be
subject to a backup withholding tax of 31% or to information reporting
requirements unless, in general, the holder fails to comply with certain
reporting procedures or otherwise fails to establish an exemption from such
tax or reporting requirements under applicable provisions of the Internal
Revenue Code of 1986, as amended.
 
  The backup withholding and information reporting rules described above are
under review by the United States Treasury and their application to the
WorldCom Notes could be changed by future regulations.
 
                                      86
<PAGE>
 
                        INFORMATION REGARDING WORLDCOM
   
  Information regarding the Company is contained in its filings with the
Commission pursuant to the Exchange Act. See "Available Information" and
"Incorporation of Certain Documents by Reference." On June 19, 1997, James Q.
Crowe accepted the position of President and Chief Executive Officer of Kiewit
Diversified Group, Inc., a coal mining and telecommunications company and
wholly-owned subsidiary of Peter Kiewit Sons', Inc., a construction and mining
company, and therefore resigned as Chairman of the Board and as a director of
the Company effective June 26, 1997.     
 
                           INFORMATION REGARDING MFS
 
  Information regarding MFS is contained in its filings with the Commission
pursuant to the Exchange Act. See "Available Information" and "Incorporation
of Certain Documents by Reference."
 
                         CERTAIN RELATED TRANSACTIONS
 
  During fiscal 1994, 1995 and 1996, WorldCom, MFS and/or UUNET entered into
certain interconnection or other services agreements with each other and
certain of their affiliates in the ordinary course of their businesses.
However, each of WorldCom, MFS and UUNET believe that the terms and conditions
of such interconnection or other services agreements were no less favorable to
WorldCom, MFS or UUNET than those that would have been available to WorldCom,
MFS or UUNET in comparable, arm's-length transactions at the date of such
agreements. Subsequent to the MFS Merger, WorldCom and MFS have engaged in
customary intercompany transactions, including certain intercompany
indebtedness of WorldCom to MFS represented by a subordinated demand
promissory note issued on March 4, 1997 in an amount not to exceed
$500,000,000 and bearing interest at the rate of 0.5% plus the 30-day LIBOR
rate per annum, and certain intercompany accounts receivable.
 
                    ACCOUNTING TREATMENT OF EXCHANGE OFFERS
 
  The Exchange will be accounted for by the Company as an exchange of debt as
provided for under generally accepted accounting principles.
 
                                 LEGAL MATTERS
 
   Certain legal matters with respect to the Exchange Offers and the Consent
Solicitations will be passed upon for WorldCom by Bryan Cave llp, St. Louis,
Missouri, and for the Dealer Managers by Cleary, Gottlieb, Steen & Hamilton,
New York, New York.
 
                                    EXPERTS
 
  The consolidated financial statements and schedule of the Company as of
December 31, 1996 and 1995, and for each of the years in the three-year period
ended December 31, 1996, have been audited by Arthur Andersen llp, independent
public accountants, as indicated in their report with respect thereto, and are
included in the Company's Annual Report on Form 10-K for the fiscal year ended
December 31, 1996, and are incorporated herein by reference, in reliance upon
the authority of such firm as experts in accounting and auditing in giving
said reports.
 
  The consolidated financial statements of MFS Communications Company, Inc. as
of December 31, 1996 and for the period then ended (See Note 1 to the MFS
Communications Company, Inc. Form 10-K), and for the year ended December 31,
1996, have been audited by Arthur Andersen llp, independent public
accountants, as indicated in their report with respect thereto, and are
included in the MFS Annual Report on Form 10-K for the fiscal year ended
December 31, 1996, and are
 
                                      87
<PAGE>
 
incorporated herein by reference, in reliance upon the authority of such firm
as experts in accounting and auditing in giving said reports.
 
  The consolidated financial statements of MFS as of December 31, 1995 and
1994 and for each of the three years in the period ended December 31, 1995,
included in WorldCom's Current Report on Form 8-K/A dated August 25, 1996
(filed November 4, 1996) and incorporated by reference into this registration
statement and the consolidated financial statements of MFS as of December 31,
1995 and for the two years in the period ended December 31, 1995 included in
the MFS Annual Report on Form 10-K for the fiscal year ended December 31, 1996
and incorporated by reference in this registration statement, have been
incorporated in reliance on the report of Coopers & Lybrand l.l.p.,
independent accountants, given upon the authority of that firm as experts in
accounting and auditing.
 
  The consolidated financial statements of UUNET Technologies, Inc. as of
December 31, 1995 and 1994 and for each of the three years in the period ended
December 31, 1995, included in WorldCom's Current Report on Form 8-K/A dated
August 25, 1996 (filed November 4, 1996) and incorporated by reference into
this registration statement, have been audited by Arthur Andersen llp,
independent public accountants, as indicated in their reports with respect
thereto and are incorporated herein by reference in reliance upon the
authority of said firm as experts in giving said reports.
 
                                      88
<PAGE>
 
            
         Any questions concerning the terms of the Exchange Offers     
                
             should be directed to the Joint Dealer Managers,     
 
        SALOMON BROTHERS INC                      GOLDMAN, SACHS & CO.
 
 
      Seven World Trade Center                       85 Broad Street
      New York, New York 10048                  New York, New York 10004
      (212) 783-3738 (collect)                  (212) 902-8200 (collect)
     (800) 558-3745 (toll free)                (800) 828-3182 (toll free)
   Attention: Liability Management           Attention: Liability Management
                Group                                     Group
       
          
Any questions concerning tender procedures or requests for additional copies of
 this Prospectus, the Letters of Transmittal, or Notices of Guaranteed Delivery
                 may be directed to the Information Agent,     
                            MACKENZIE PARTNERS, INC.
                                
                             156 Fifth Avenue     
                            
                         New York, New York 10010     
                            
                         (212) 929-5500 (collect)     
                           
                        (800) 322-2885 (toll free)     
                
 MFS Notes tendered, together with the requisite Letters of Transmittal and any
    other required documents, must be delivered to the Exchange Agent,     
                         HARRIS TRUST AND SAVINGS BANK
 
<TABLE>   
<S>                                        <C>                                         <C>
By Registered or Certified Mail:           Hand Delivery or Overnight Delivery:        By Facsimile:

  Harris Trust and Savings Bank               Harris Trust and Savings Bank             (212) 701-7636
c/o Harris Trust Company of New York        c/o Harris Trust Company of New York
       P.O. Box 1010                                77 Water Street                  Confirm by telephone:
     Wall Street Station                               4th Floor                       (212) 701-7624
    New York, New York 10268                     New York, New York 10004
</TABLE>    
<PAGE>
 
                                    PART II
 
                  INFORMATION NOT REQUIRED IN THE PROSPECTUS
 
ITEM 20. INDEMNIFICATION OF DIRECTORS AND OFFICERS.
 
  Section 14-2-202(b)(4) of the Georgia Business Corporation Code (the
"Georgia Code") provides that a corporation's articles of incorporation may
include a provision that eliminates or limits the personal liability of
directors for monetary damages to the corporation or its shareholders for
breach of their duty of care and other duties as directors; provided, however,
that the Section does not permit a corporation to eliminate or limit the
liability of a director for appropriating, in violation of his duties, any
business opportunity of the corporation, engaging in intentional misconduct or
a knowing violation of law, obtaining an improper personal benefit, or voting
for or assenting to an unlawful distribution (whether as a dividend, stock
repurchase or redemption, or otherwise) as provided in Section 14-2-832 of the
Georgia Code. Section 14-2-202(b)(4) also does not eliminate or limit the
rights of WorldCom or any shareholder to seek an injunction or other
nonmonetary relief in the event of a breach of a director's duty to the
corporation and its shareholders. Additionally, Section 14-2-202(b)(4) applies
only to claims against a director arising out of his role as a director, and
does not relieve a director from liability arising from his role as an officer
or in any other capacity.
 
  The provisions of Article Ten of WorldCom's Second Amended and Restated
Articles of Incorporation are similar in all substantive respects to those
contained in Section 14-2-202(b)(4) of the Georgia Code as outlined above.
Article Ten further provides that the liability of directors of WorldCom shall
be limited to the fullest extent permitted by amendments to Georgia law.
 
  Sections 14-2-850 to 14-2-859, inclusive, of the Georgia Code govern the
indemnification of directors, officers, employees, and agents. Section 14-2-
851 of the Georgia Code permits indemnification of a director of WorldCom for
liability incurred by him in connection with any threatened, pending or
completed action, suit or proceeding, whether civil, criminal, administrative
or investigative (including, subject to certain limitations, civil actions
brought as derivative actions by or in the right of WorldCom) in which he is
made a party by reason of being a director of WorldCom and for directors who,
at the request of WorldCom, act as directors, officers, partners, trustees,
employees or agents of another foreign or domestic corporation, partnership,
joint venture, trust, employee benefit plan or other enterprise. The Section
permits indemnification if the director acted in a manner he believed in good
faith to be in or not opposed to the best interest of WorldCom and, in
addition, in criminal proceedings, if he had no reasonable cause to believe
his conduct was unlawful. If the required standard of conduct is met,
indemnification may include judgments, settlements, penalties, fines or
reasonable expenses (including attorneys' fees) incurred with respect to a
proceeding. However, if the director is adjudged liable to WorldCom in a
derivative action or on the basis that personal benefit was improperly
received by him, the director is not entitled to indemnification by the
corporation; provided that the director may be entitled to indemnification for
reasonable expenses as determined by a court in accordance with the provisions
of Section 14-2-854, or unless WorldCom's Second Amended and Restated Articles
of Incorporation or Bylaws, or a contract or resolutions approved by
WorldCom's shareholders pursuant to Section 14-2-856, authorizes
indemnification.
 
  Section 14-2-852 of the Georgia Code provides that unless limited by the
articles of incorporation, directors who are successful with respect to any
claim brought against them, which claim is brought because they are or were
directors of WorldCom, are entitled to mandatory indemnification against
reasonable expenses incurred in connection therewith. Conversely, if the
charges made in any action are sustained, the determination of whether the
required standard of conduct has been met will be made, in accordance with the
provisions of Section 14-2-855 of the Georgia Code, as follows: (i) by the
majority vote of a quorum of the members of the board of directors not a party
to such action at that time, (ii) if a quorum cannot be obtained, by a
committee thereof duly designated by the board of
 
                                     II-1
<PAGE>
 
directors, consisting of two or more directors not a party to such action at
that time, (iii) by duly selected special legal counsel, or (iv) by the
shareholders, but, in such event, the shares owned by or voted under the
control of directors who are at the time parties to the proceeding may not be
voted.
   
  Section 14-2-857 of the Georgia Code provides that an officer of WorldCom
(but not an employee or agent generally) who is not a director has the
mandatory right of indemnification granted to directors under Section 14-2-
852, as described above. In addition, WorldCom may, as provided by WorldCom's
Second Amended and Restated Articles of Incorporation, Bylaws, general or
specific actions by its board of directors, or by contract, indemnify and
advance expenses to an officer, employee or agent who is not a director to the
extent that such indemnification is consistent with public policy.     
 
  The indemnification provisions of Article X of WorldCom's Bylaws and Article
Twelve of WorldCom's Second Amended and Restated Articles of Incorporation are
consistent with the foregoing provisions of the Georgia Code. However,
WorldCom's Second Amended and Restated Articles of Incorporation prohibit
indemnification of a director who did not believe in good faith that his
actions were in, or not contrary to, WorldCom's best interests. WorldCom's
Bylaws extend the indemnification available to officers under the Georgia Code
to employees and agents.
 
ITEM 21(A). EXHIBITS.
 
  See Exhibit Index.
 
ITEM 21(B). FINANCIAL STATEMENT SCHEDULES.
 
  All financial statement schedules of WorldCom and MFS which are required to
be included herein are included in the Annual Report of WorldCom on Form 10-K
for the fiscal year ended December 31, 1996 or the Annual Report on Form 10-K
of MFS for the fiscal year ended December 31, 1996, respectively, which are
incorporated herein by reference.
 
ITEM 22. UNDERTAKINGS.
 
  (1) Insofar as indemnification for liabilities arising under the Securities
Act of 1933 (the "Securities Act") may be permitted to directors, officers and
controlling persons of the registrant pursuant to the foregoing provisions, or
otherwise, the registrant has been advised that in the opinion of the
Securities and Exchange Commission such indemnification is against public
policy as expressed in the Securities Act and is, therefore, unenforceable. In
the event that a claim for indemnification against such liabilities (other
than the payment by the registrants of expenses incurred or paid by a
director, officer or controlling person of the registrants in the successful
defense of any action, suit or proceeding) is asserted by such director,
officer or controlling person in connection with the securities being
registered, the registrants will, unless in the opinion of its counsel the
matter has been settled by controlling precedent, submit to a court of
appropriate jurisdiction the question of whether such indemnification by it is
against public policy as expressed in the Securities Act and will be governed
by the final adjudication of such issue.
 
  (2) The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934 (the "Exchange Act") (and, where applicable,
each filing of an employee benefit plan's annual report pursuant to Section
15(d) of the Exchange Act) that is incorporated by reference in the
registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such
securities at that time shall be deemed to be the initial bona fide offering
thereof.
 
 
                                     II-2
<PAGE>
 
  (3) The undersigned registrant hereby undertakes to respond to requests for
information that is incorporated by reference into the prospectus pursuant to
Items 4, 10(b), 11 or 13 of this Form, within one business day of receipt of
such request, and to send the incorporated documents by first class mail or
other equally prompt means. This includes information contained in documents
filed subsequent to the effective date of the registration statement through
the date of responding to the request.
 
  (4) The undersigned registrant hereby undertakes to supply by means of a
post-effective amendment all information concerning a transaction, and the
company being acquired involved therein, that was not the subject of and
included in the registration statement when it became effective.
 
  (5) The undersigned registrant hereby undertakes:
 
    (a) To file, during any period in which offers and sales are being made,
  a post-effective amendment to this registration statement:
 
      (i) To include any prospectus required by Section 10(a)(3) of the
    Securities Act;
 
      (ii) To reflect in the prospectus any facts or events arising after
    the effective date of the Registration Statement (or the most recent
    post-effective amendment thereof) which, individually or in the
    aggregate, represent a fundamental change in the information set forth
    in the registration statement. Notwithstanding the foregoing, any
    increase or decrease in volume of securities offered (if the total
    dollar value of securities offered would not exceed that which was
    registered) and any deviation from the low or high and of the estimated
    maximum offering range may be reflected in the form of prospectus filed
    with the Commission pursuant to Rule 424(b) if, in the aggregate, the
    changes in volume and price represent no more than 20 percent change in
    the maximum aggregate offering price set forth in "Calculation of
    Registration Fee" table in the effective registration statement;
 
      (iii) To include any material information with respect to the plan of
    distribution not previously disclosed in the registration statement or
    any material change to such information in the registration statement;
 
    provided, however, that paragraphs 7(a)(i) and 7(a)(ii) do not apply if
    the registration statement is on Form S-3, Form S-8 or Form F-3, and
    the information required to be included in a post-effective amendment
    by those paragraphs is contained in periodic reports filed with or
    furnished to the Commission by the registrant pursuant to Section 13 or
    15(d) of the Exchange Act that are incorporated by reference in the
    registration statement.
 
    (b) That for the purposes of determining any liability under the
  Securities Act, each such post-effective amendment shall be deemed to be a
  new registration statement relating to the securities offered therein, and
  the offering of such securities at that time shall be deemed to be the
  initial bona fide offering thereof.
 
    (c) To remove from registration by means of a post-effective amendment
  any of the securities being registered which remain unsold at the
  termination of the offering.
 
                                     II-3
<PAGE>
 
                                  SIGNATURES
   
  PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT THE REGISTRANT HAS DULY
CAUSED THIS AMENDMENT NO. 2 TO THE REGISTRATION STATEMENT TO BE SIGNED ON ITS
BEHALF BY THE UNDERSIGNED, THEREUNTO DULY AUTHORIZED, IN THE CITY OF JACKSON,
STATE OF MISSISSIPPI, ON JUNE 26, 1997.     
 
                                          WORLDCOM, INC.
 
                                                   /s/ Scott D. Sullivan
                                          By: _________________________________
                                             Scott D. Sullivan
                                             Chief Financial Officer
   
  PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT OF 1933, THIS AMENDMENT
NO. 2 TO THE REGISTRATION STATEMENT HAS BEEN SIGNED BY THE FOLLOWING PERSONS
IN THE CAPACITIES AND ON THE DATES INDICATED.     
 
<TABLE>   
<CAPTION>
                   NAME                                TITLE                  DATE
                   ----                                -----                  ----
<S>                                         <C>                           <C>
                     *
___________________________________________ Director                      June 26, 1997
              CARL J. AYCOCK
                     *
___________________________________________ Director                      June 26, 1997
              MAX E. BOBBITT
                     *
___________________________________________ Director, President and       June 26, 1997
                                            Chief Executive Officer
                                            (Principal Executive Officer)
             BERNARD J. EBBERS
                     *
___________________________________________ Director                      June 26, 1997
             FRANCESCO GALESI
                     *
___________________________________________ Director                      June 26, 1997
             RICHARD R. JAROS
</TABLE>    
 
                                     II-4
<PAGE>
 
<TABLE>   
<CAPTION>
                   NAME                                TITLE                 DATE
                   ----                                -----                 ----
<S>                                         <C>                          <C>
                      
                     *                      Director                      June 26, 1997
 ------------------------------------------
          STILES A. KELLETT, JR.
                      
                     *                      Director                      June 26, 1997
 ------------------------------------------
             DAVID C. MCCOURT
                      
                     *                      Director                      June 26, 1997
 ------------------------------------------
              JOHN A. PORTER
                      
                     *                      Director                      June 26, 1997
 ------------------------------------------
             WALTER SCOTT, JR.
                      
                     *                      Director                      June 26, 1997
 ------------------------------------------
             JOHN W. SIDGMORE
                                            
                                            
           /s/ Scott D. Sullivan            Director and Chief Financial  June 26, 1997              
 ------------------------------------------ Officer (Principal Financial             
             SCOTT D. SULLIVAN              Officer and Principal                    
                                            Accounting Officer)          
                      
                     *                       Director                     June 26, 1997
 ------------------------------------------
           LAWRENCE C. TUCKER
                      
                     *                       Director                     June 26, 1997
 ------------------------------------------
             MICHAEL B. YANNEY              


 *By: /s/ Scott D. Sullivan                  
      -------------------------------------
      SCOTT D. SULLIVAN, ATTORNEY-IN-FACT

</TABLE>    
 
 
                                      II-5
<PAGE>
 
                                 EXHIBIT INDEX
 
<TABLE>   
<CAPTION>
 EXHIBIT
   NO.                                 DESCRIPTION
 -------                               -----------
 <C>     <S>
 1.1     Form of Dealer Managers Agreement between WorldCom, Inc. ("WorldCom")
         and Salomon Brothers Inc and Goldman, Sachs & Co.
 2.1     Amended and Restated Agreement and Plan of Merger by and among
         WorldCom, HIJ Corp. and MFS Communications Company, Inc. ("MFS") dated
         as of August 25, 1996 (attached as Appendix I to the Joint Proxy
         Statement/Prospectus included in WorldCom's Registration Statement on
         Form S-4 (Registration No. 333-16015) and incorporated by reference
         herein)**
 4.1     Second Amended and Restated Articles of Incorporation of WorldCom
         (including preferred stock designations) as of December 31, 1996
         (incorporated herein by reference to Exhibit 3.1 to the Current Report
         on Form 8-K of WorldCom (File No. 0-11258) dated December 31, 1996
         (filed January 15, 1997))
 4.2     Restated Bylaws of WorldCom (incorporated herein by reference to
         Exhibit 4.2 to the Annual Report on Form 10-K filed by WorldCom (File
         No. 0-11258) for the fiscal year ended December 31, 1996)
 4.3     Amended and Restated Credit Agreement among WorldCom, NationsBank of
         Texas, N.A. (Managing Agent and Administrative Agent), Bank of America
         Illinois, The Bank of New York, The Bank of Nova Scotia, Canadian
         Imperial Bank of Commerce, Chemical Bank, Credit Lyonnais New York
         Branch, First Union National Bank of North Carolina, The Industrial
         Bank of Japan, Limited, Atlanta Agency, The First National Bank of
         Chicago, The Long-Term Credit Bank of Japan, Limited, New York Branch,
         Toronto Dominion (Texas), Inc., and Wachovia Bank of Georgia N.A.
         (Agents) and the Lenders named therein (Lenders) dated as of June 28,
         1996, (incorporated herein by reference to Exhibit 10.1 to the
         Quarterly Report on Form 10-Q filed by WorldCom (File No. 0-11258) for
         the quarter ended June 30, 1996)
 4.4     First Amendment to Amended and Restated Credit Agreement and Consent
         to MFS Acquisition (incorporated herein by reference to Exhibit 10.2
         to the Annual Report on Form 10-K filed by WorldCom (File No. 0-11258)
         for the fiscal year ended December 31, 1996)
 4.5     Indenture of WorldCom to Mellon Bank, N.A. dated as of March 1, 1997
         for Senior Debt Securities (incorporated herein by reference to
         Exhibit 4.6 to the Quarterly Report on Form 10-Q filed by WorldCom
         (File No. 0-11258) for the quarter ended March 31, 1997)
 4.6     Form of 7.55% Senior Note due 2004 (incorporated herein by reference
         to Exhibit 4.1 to the Current Report on Form 8-K dated March 26, 1997
         filed by WorldCom (File No. 0-11258))
 4.7     Form of 7.75% Senior Note due 2007 (incorporated herein by reference
         to Exhibit 4.2 to the Current Report on Form 8-K dated March 26, 1997
         filed by WorldCom (File No. 0-11258))
 4.8     Form of 7.75% Senior Note due 2027 (incorporated herein by reference
         to Exhibit 4.3 to the Current Report on Form 8-K dated March 26, 1997
         filed by WorldCom (File No. 0-11258))
 4.9     Form of First Supplemental Indenture of WorldCom to Mellon Bank, N.A.
         Relating to 9 3/8% Senior Notes Due 2004 and 8 7/8% Senior Notes Due
         2006 (including form of 9 3/8% Senior Note Due 2004 attached as
         Exhibit A thereto and form of 8 7/8% Senior Note Due 2006 attached as
         Exhibit B thereto)
 4.10    Indenture of MFS to IBJ Schroder Bank & Trust Company dated January
         15, 1994 for 9 3/8% Senior Discount Notes Due 2004 (incorporated
         herein by reference to Exhibit 10.2 to MFS' Current Report on Form 8-K
         dated January 26, 1994 (File No. 0-21594))
 4.11    First Supplemental Indenture of MFS to IBJ Schroder Bank & Trust
         Company dated as of March 31, 1995 for Due 2004 (incorporated herein
         by reference to Exhibit 10.3 to MFS' Current Report on Form 8-K dated
         April 27, 1995 (File No. 0-21594))
 4.12    Indenture of MFS to IBJ Schroder Bank & Trust Company dated January
         15, 1996 for Senior Discount Notes (incorporated herein by reference
         to Exhibit 4.1 to MFS' Current Report on Form 8-K dated January 23,
         1996 (File No. 0-21594))
</TABLE>    
 
 
                                      II-6
<PAGE>
 
<TABLE>   
<CAPTION>
 EXHIBIT
   NO.                                 DESCRIPTION
 -------                               -----------
 <C>     <S>
   4.13  First Supplemental Indenture of MFS to IBJ Schroder Bank & Trust
         Company dated as of January 15, 1996 for 8 7/8% Senior Discount Notes
         Due 2006 (incorporated herein by reference to Exhibit No. 4.2 to MFS'
         Current Report on Form 8-K dated January 23, 1996 (File No. 0-21594))
   4.14  Form of Second Supplemental Indenture of MFS to IBJ Schroder Bank &
         Trust Company for 9 3/8% Senior Discount Notes Due 2004
   4.15  Form of Second Supplemental Indenture to IBJ Schroder Bank & Trust
         Company dated as of January 15, 1996 for 8 7/8% Senior Discount Notes
         Due 2006
   5.1   Legality Opinion of P. Bruce Borghardt, Esq.
   8.1   Tax Opinion of Bryan Cave LLP
 *12.1   Statement regarding Computation of Ratio of Earnings to Fixed Charges
  23.1   Consent of Arthur Andersen LLP
  23.2   Consent of Coopers & Lybrand LLP
  23.3   Consent of Arthur Andersen LLP
  23.4   Consent of Arthur Andersen LLP
  23.5   Consent of P. Bruce Borghardt, Esq. (included in Exhibit 5.1)
  23.6   Consent of Bryan Cave LLP (included in Exhibit 8.1)
 *24.1   Power of Attorney
 *25.1   Statement of Eligibility of Mellon Bank, N.A. on Form T-1 with respect
         to the WorldCom Indenture
  99.1   Letter of Transmittal and Consent with respect to the MFS 2004 Notes
  99.2   Letter of Transmittal and Consent with respect to the MFS 2006 Notes
  99.3   Notice of Guaranteed Delivery with respect to MFS 2004 Notes
  99.4   Notice of Guaranteed Delivery with respect to MFS 2006 Notes
  99.5   Letter to Brokers, Dealers, Commercial Banks, Trust Companies and
         Other Nominees
  99.6   Letter to Clients
</TABLE>    
- --------
          
* Previously filed.     
   
** The Registrant hereby agrees to furnish supplementally a copy of any
  omitted schedules to this Agreement to the Securities and Exchange
  Commission upon its request.     
 
                                     II-7

<PAGE>
 
                                                                    EXHIBIT 1.1

 
                                WorldCom, Inc.
                           Dealer Managers Agreement

                                June [  ], 1997

Salomon Brothers Inc
Seven World Trade Center
New York, New York 10048


Goldman, Sachs & Co.
85 Broad Street
New York, New York 10004


Ladies and Gentlemen:

          WorldCom, Inc., a Georgia corporation (the "Company"), plans to make
an offer to exchange (i) its 9-3/8% Senior Notes due January 15, 2004 (the
"WorldCom 2004 Notes") for any and all outstanding 9-3/8% Senior Discount Notes
due January 15, 2004 (the "MFS 2004 Notes") of MFS Communications Company, Inc.,
a Delaware corporation and wholly owned subsidiary of the Company ("MFS"),
properly tendered, and (ii) its 8-7/8% Senior Notes due January 15, 2006 (the
"WorldCom 2006 Notes" and, together with the WorldCom 2004 Notes, the "WorldCom
Notes") for any and all outstanding 8-7/8% Senior Discount Notes due January 15,
2006 of MFS (the "MFS 2006 Notes" and, together with the MFS 2004 Notes, the
"MFS Notes") properly tendered (each an "Exchange Offer" and collectively, the
"Exchange Offers"), in each case on the terms and subject to the conditions set
forth in the Prospectus (as hereinafter defined).

          Concurrently with the Exchange Offers, the Company is soliciting
consents ("Consents") from (i) the holders of the MFS 2004 Notes to certain
amendments to the indenture dated as of January 15, 1994 (as supplemented by the
First Supplemental Indenture thereto dated as of March 31, 1995, the "1994
Indenture") between MFS and IBJ Schroder Bank & Trust Company (the "MFS
Trustee") pursuant to which the MFS 2004 Notes were issued and (ii) the holders
of the MFS 2006 Notes to certain amendments to the indenture dated as of January
15, 1996 (as supplemented by the First Supplemental Indenture thereto dated as
of January 15, 1996, the "1996 Indenture") between MFS and the MFS Trustee
pursuant to which the MFS 2006 Notes were issued (each a "Solicitation" and
collectively, the "Solicitations").

          The WorldCom Notes are to be issued pursuant to the Senior Indenture
(the "Original Indenture"), dated as of March 1, 1997 between the Company and
Mellon Bank, N.A., as trustee (the "Trustee"), as supplemented by a first
supplemental indenture establishing the terms of the WorldCom Notes (the "First
Supplemental Indenture" and together with the Original Indenture, the
"Indenture").  The Company has filed with the Securities and Exchange Commission
(the "Commission") a registration statement (File No. 333-27345) on Form S-4 for
the registration of the WorldCom Notes under the Securities Act of 1933, as
amended, and the rules and regulations thereunder (collectively, the "Act") and
the offering thereof pursuant to the
<PAGE>
 
Exchange Offers, including a prospectus relating to such offering. The Company
proposes to file with the Commission one of the following: (i) prior to
effectiveness of such registration statement, an amendment to such registration
statement, including the form of final prospectus or (ii) a final prospectus in
accordance with Rule 424(b) under the Act ("Rule 424(b)"). As filed, such
amendment and form of final prospectus, or such final prospectus, shall be in
the form furnished to you prior to the execution of this Dealer Managers
Agreement (the "Agreement") or, to the extent not completed at the time of
execution of this Agreement, in such form as the Company and you shall agree to
prior to the filing thereof. Such registration statement either has been
declared effective by the Commission or will be declared effective by the
Commission prior to the date that the Prospectus is first distributed to the
holders of the MFS Notes (the "Commencement Date"). The term "Registration
Statement" means the aforementioned registration statement, including
incorporated documents, exhibits and financial statements, as amended to the
date of execution of this Agreement (or, if not effective at such execution
time, in the form in which it shall become effective) and, in the event any
post-effective amendment thereto becomes effective prior to the Exchange Date
(as defined in the Prospectus), shall also mean such registration statement as
so amended. The term "Prospectus" means the prospectus relating to the
aforementioned offering that is first filed pursuant to Rule 424(b) after the
execution of this Agreement or, if no filing pursuant to Rule 424(b) is
required, shall mean the form of final prospectus relating to such offering
included in the Registration Statement when it was declared effective. Any
reference herein to the Registration Statement or the Prospectus shall include,
in each case, the material, if any, incorporated by reference therein on or
before the effective date or issue date of such Registration Statement or
Prospectus; any reference herein to the terms "amend", "amendment" or
"supplement" with respect to the Registration Statement or the Prospectus shall
be deemed to refer to and include the filing of any document under the
Securities Exchange Act of 1934, as amended and the applicable rules and
regulations of the Commission thereunder (collectively, the "Exchange Act")
after the effective date of the Registration Statement or the issue date of the
Prospectus, as the case may be, deemed to be incorporated therein by reference.
The term "you" or "your" as used herein, unless the context otherwise requires,
shall mean Salomon Brothers Inc and Goldman, Sachs & Co.

          Section 1.  Appointment as Dealer Managers.
                      ------------------------------ 

          (a)  Each of you, severally, and the Company hereby agree that each of
you (the "Dealer Managers") will act, in accordance with your customary
practices, as the exclusive Dealer Managers for the Exchange Offers and the
Solicitations including, without limitation, the solicitation of tenders
pursuant to the Exchange Offers, the solicitation of Consents pursuant to the
Solicitations and assisting in the distribution of the Prospectus.  Nothing
contained in this Agreement shall constitute the Dealer Managers partners or
joint venturers with the Company or any of its subsidiaries.

          (b)  The Company agrees that it will not file, use or publish any
material in connection with either Exchange Offer or either Solicitation, or
refer to either of you in any such material, without first consulting each of
you.  The Company will promptly inform each of you of any litigation or
administrative action with respect to either Exchange Offer or either
Solicitation. Each of you agrees not to give any written information to
beneficial owners or

                                       2
<PAGE>
 
holders of the MFS Notes in connection with the Exchange Offers and
Solicitations other than any written information which has been previously
approved by the Company in writing, it being understood that each of the
following documents are approved by the Company: (i) the Prospectus and
documents incorporated by reference in the Prospectus; and (ii) the Ancillary
Documents (as defined below in Section 2(b)). Each of you agrees not to make any
representations to beneficial owners or holders of MFS Notes in connection with
the Exchange Offers and Solicitations that are inconsistent with the Prospectus
or the Ancillary Documents.

          (c)  Each of you, severally, agree that all actions taken by you as a
Dealer Manager will comply in all material respects with all applicable laws,
regulations and rules of the United States including, without limitation, the
applicable rules and regulations of the registered national securities exchanges
of which you are a member and of the National Association of Securities Dealers,
Inc.  You further agree to be regarded as the broker-dealers that are making the
Exchange Offers on behalf of the Company to holders of MFS Notes in any states
of the United States in which it is required that such offers be made by or
through a registered or licensed broker-dealer, and you represent that you are
registered or licensed in each of such states.

          (d)   The Company acknowledges and agrees that (i) the Dealer
Managers, in their sole discretion, may continue to own or dispose of, in any
manner they may elect, any MFS Notes they may beneficially own at the date
hereof or hereafter acquire, in any such case, subject to applicable law, and
(ii) in particular, the Dealer Managers have no obligation to the Company,
pursuant to this Agreement or otherwise, to tender or refrain from tendering MFS
Notes beneficially owned by them in either Exchange Offer (and thereby deliver
Consents in the related Solicitation).  The Dealer Managers acknowledge and
agree that if either Exchange Offer or either Solicitation is not consummated
for any reason, the Company shall have no obligation, pursuant to this Agreement
or otherwise, to acquire any MFS Notes from the Dealer Managers or to otherwise
hold the Dealer Managers harmless with respect to any losses they may incur in
connection with the resale to any third parties of any MFS Notes.

          Section 2.  Representations and Warranties.  The Company represents
                      ------------------------------                         
and warrants to each of you as of the date hereof that:

          (a)   The Company meets the requirements for the use of Form S-4
under the Act. The Registration Statement has become effective or will become
effective prior to the Commencement Date, as applicable; if the Registration
Statement has become effective, no stop order suspending the effectiveness of
the Registration Statement is in effect, and no proceedings for such purpose are
pending before or threatened by the Commission.

          (b)   (i) Each document, if any, filed or to be filed pursuant to the
Exchange Act, and incorporated by reference in the Prospectus, or in the
Prospectus as supplemented, complied or will comply when so filed in all
material respects with the Exchange Act, (ii) each part of the Registration
Statement, when such part became effective (each such date, the "Effective
Date"), did not contain, and each such part, when amended or supplemented, if
applicable, will not contain any untrue statement of a material fact or omit to
state a material fact

                                       3
<PAGE>
 
required to be stated therein or necessary to make the statements therein not
misleading, (iii) on the Effective Date the Registration Statement did or will,
and when the Prospectus is first filed (if required) in accordance with Rule
424(b) and on the Exchange Date, the Prospectus (and any supplements thereto)
did or will, comply in all material respects with the Act, the Exchange Act, and
the Trust Indenture Act of 1939, as amended, and the applicable rules and
regulations of the Commission thereunder (collectively, the "Trust Indenture
Act") and (iv) on the Effective Date, the Prospectus, if not filed pursuant to
424(b), did not or will not, and on the date of any filing pursuant to Rule
424(b) and on the Exchange Date, the Prospectus (together with any supplement
thereto) will not, and on each of such dates the Letters of Transmittal and
Consent, Guidelines for Certification of Taxpayer Identification Number on
Substitute Form W-9, Notices of Guaranteed Delivery, Letter to Brokers, Letter
to Clients (each of the foregoing, substantially in the form attached hereto as
Exhibit E) and, if in existence on such date, any press release or "tombstone"
advertisement issued by the Company in connection with this transaction
(collectively, the "Ancillary Documents") did not and will not, contain any
untrue statement of a material fact or omit to state a material fact necessary
to make the statements therein, in the light of the circumstances under which
they were made, not misleading; provided, however, that the Company makes no
                                --------  -------                  
representations or warranties as to (A) the information contained in or
omitted from the Registration Statement, the Prospectus (or any supplement
thereto) or the Ancillary Documents in reliance upon and in conformity with
information furnished in writing to the Company by or on behalf of either of you
specifically for inclusion in the Registration Statement, the Prospectus (or any
supplement thereto) or the Ancillary Documents or (B) to that part, if any, of
the Registration Statement that constitutes the Statement of Eligibility and
Qualification (Form T-1) under the Trust Indenture Act.  The only information
furnished in writing to the Company by or on behalf of the Dealer Managers is
described in Section 6(b) hereof.

          (c)   No action has been taken and no statute, rule, regulation or
order has been enacted, adopted or issued by any governmental agency or body
that would prevent the issuance of the WorldCom Notes, suspend the effectiveness
of the Registration Statement, prevent or suspend the use of the Prospectus (or
any supplement thereto), or suspend the sale of the WorldCom Notes in any
jurisdiction; provided, however, that to the extent this representation relates
to state securities or "blue sky" laws and laws of jurisdictions other than the
United States and its political subdivisions, it shall be limited to the
knowledge of the Company. No injunction, restraining order or order of any
nature by a Federal or state court of competent jurisdiction has been issued and
served on the Company or any of its subsidiaries with respect to the Company or
any of the subsidiaries that relates to any document incorporated in the
Registration Statement, that would prevent or suspend the issuance or sale of
the WorldCom Notes, the effectiveness of the Registration Statement, or the use
of the Prospectus (or any supplement thereto).

          (d)   Subsequent to the respective dates as of which information is
given in the Registration Statement and the Prospectus, except as set forth in
the Prospectus (as supplemented), neither the Company nor any of the
Subsidiaries has incurred any liabilities or obligations, direct or contingent,
that are material to the Company and the Subsidiaries taken as a whole, nor
entered into any material transaction not in the ordinary course of business,
and there

                                       4
<PAGE>
 
has not been, singularly or in the aggregate, any material adverse change in the
properties, business, results of operations, financial condition, affairs or
business prospects of the Company and its Subsidiaries taken as a whole (a
"Material Adverse Change"). Without limiting the foregoing, neither the Company
nor any of its Subsidiaries has sustained since the date of the latest audited
financial statements included, or incorporated by reference, in the Prospectus
(as supplemented) any material loss or interference with its business from fire,
explosion, flood or other calamity, whether or not covered by insurance, or from
any labor dispute or court or governmental action, order or decree, otherwise
than as set forth or contemplated in the Prospectus (as supplemented); and,
since the respective dates as of which information is given in the Registration
Statement and the Prospectus, except as set forth in the Prospectus (as
supplemented), there has not been any material change in the capital stock or
long-term debt of the Company or any of the Subsidiaries.

          (e)   The Subsidiaries of the Company listed on Exhibit A hereto
(individually a "Subsidiary" and collectively, the "Subsidiaries") are the only
Significant Subsidiaries of the Company (within the meaning of Rule 405 under
the Act).  Each of the Company and the Subsidiaries (x) has been duly organized
and is validly existing as a corporation in good standing under the laws of its
jurisdiction of organization, (y) has the requisite corporate power and
authority to carry on its business as it is currently being conducted and as
described in the Prospectus (as supplemented), and to own, lease and operate its
properties and (z) is duly qualified and is authorized to do business and is in
good standing in each jurisdiction where the operation, ownership or leasing of
property or the conduct of its business requires such qualification, except
where any failure to be so qualified or be in good standing would not,
singularly or when aggregated with failures to be qualified elsewhere, have a
material adverse effect on the properties, business, results of operations,
financial condition, affairs or prospects of the Company and its Subsidiaries
taken as a whole (a "Material Adverse Effect").  The Company has the requisite
power and authority to authorize the offering of the WorldCom Notes to be sold
by it, to execute, deliver and perform this Agreement and to issue, sell and
deliver the WorldCom Notes to be sold by it.

          (f)   The Company has an authorized capitalization as set forth in the
Prospectus (as supplemented), and all of the issued shares of capital stock of
the Company have been duly and validly authorized and are fully paid and non-
assessable.  All of the issued and outstanding shares of capital stock of each
Subsidiary have been duly and validly authorized and issued, are fully paid and
non-assessable and (except as set forth in the Prospectus (as supplemented)) are
owned, directly or through Subsidiaries, by the Company, free and clear of any
liens, claims or encumbrances ("Liens").  There are no outstanding
subscriptions, rights, warrants, options, calls, convertible securities,
commitments of sale or Liens related to or entitling any person to purchase or
otherwise to acquire any shares of the capital stock of any Subsidiary, except
as set forth in the Prospectus (as supplemented).

          (g)   This Agreement has been duly authorized and validly executed and
delivered by the Company and constitutes a valid and legally binding agreement
of the Company, enforceable against the Company in accordance with its terms
(assuming the due execution and delivery of this Agreement by the Dealer
Managers).

                                       5
<PAGE>
 
          (h)   The Original Indenture has been duly qualified under the Trust
Indenture Act and has been duly authorized, executed and delivered by the
Company, and constitutes the valid and legally binding obligation of the Company
enforceable against the Company in accordance with its terms, subject to
applicable bankruptcy, insolvency, fraudulent transfer, reorganization,
moratorium and similar laws of general applicability relating to or affecting
creditors' rights and to general principles of equity.

          (i)   The First Supplemental Indenture has been or will be prior to
the Exchange Date duly qualified under the Trust Indenture Act and has been or
will be prior to the Exchange Date duly authorized, executed and delivered by
the Company, and does or will prior to the Exchange Date constitute the valid
and legally binding obligation of the Company enforceable against the Company in
accordance with its terms, subject to applicable bankruptcy, insolvency,
fraudulent transfer, reorganization, moratorium and similar laws of general
applicability relating to or affecting creditors' rights and to general
principles of equity.

          (j)   The WorldCom Notes have been or will be prior to the Exchange
Date duly authorized, and, when executed by the Company and authenticated by the
Trustee in accordance with the terms of the Indenture, and delivered to the
holders of MFS Notes who tender their MFS Notes in accordance with the terms of
the Exchange Offers, will be entitled to the benefits of the Indenture and will
conform in all material respects to the description thereof in the Prospectus
(as supplemented) and will constitute valid and legally binding obligations of
the Company enforceable against the Company in accordance with their respective
terms, subject to applicable bankruptcy, insolvency, fraudulent transfer,
reorganization, moratorium and similar laws of general applicability relating to
or affecting creditors' rights and to general principles of equity.

          (k)   The performance by the Company of the Exchange Offers and the
Solicitations, and the execution and delivery by the Company of, and the
performance by the Company of its obligations under, this Agreement, the
Original Indenture, the First Supplemental Indenture, the Indenture and the
WorldCom Notes will not (x) conflict with or result in a breach or violation of
any of the respective charters or by-laws of the Company or any of the
Subsidiaries or (y) after giving effect to the waivers and consents obtained on
or prior to the date hereof, if any, conflict with or result in a breach or
violation of any term or provision of, constitute a default or cause an
acceleration of any obligation under, or result in the imposition or creation of
(or the obligation to create or impose) a Lien with respect to, any bond, note,
debenture or other evidence of indebtedness or any indenture, mortgage, deed of
trust or other agreement or instrument to which the Company or any of the
Subsidiaries is a party or by which it or any of them is bound, or to which any
properties of the Company or any of the Subsidiaries is subject, or (z)
contravene any order of any court or governmental agency or body having
jurisdiction over the Company or any of the Subsidiaries or any of their
properties, or violate or conflict with any statute, rule or regulation or
administrative or court decree applicable to the Company or any of the
Subsidiaries, or any of their respective properties except, in the case of state
public utility commissions exercising jurisdiction over the Company or any of
its Subsidiaries ("State Regulatory Agencies"), where such contravention,
violation or conflict would not have a Material Adverse Effect.  No
authorization, approval or consent or order of, or 

                                       6
<PAGE>
 
filing, registration or qualification with, any court or governmental body or
agency is required for the performance by the Company of either Exchange Offer
or either Solicitation or its obligations under this Agreement, the Indenture,
or the WorldCom Notes except (i) such as may have been or will be obtained prior
to the Commencement Date under the Act, (ii) such as may be required by and made
with or obtained prior to the Commencement Date from the National Association of
Securities Dealers, Inc. (the "NASD") or state securities or "blue sky" laws or
regulations or have been obtained and made prior to the Commencement Date under
the Act and (iii) in the case of authorizations, approvals, consents,
registrations or qualifications required by State Regulatory Agencies, where the
failure to obtain such authorizations, approvals, consents, registrations or
qualifications would not have a Material Adverse Effect.

          (l)   There is no action, suit or proceeding before or by any court,
arbitrator or governmental official, agency or body, domestic or foreign,
pending against or affecting the Company or any of the Subsidiaries, or any of
their respective properties, that is required to be disclosed in the
Registration Statement or the Prospectus (as supplemented) and is not so
disclosed, or that, if determined adversely, is reasonably expected to affect
adversely the performance by the Company of the Exchange Offers or the
Solicitations or issuance of the WorldCom Notes or in any manner draw into
question the validity of this Agreement, the Exchange Offers, the Solicitations
or the WorldCom Notes or to result, singularly or when aggregated with other
pending actions and actions known to be threatened, in a Material Adverse
Effect, or that is reasonably expected to materially and adversely affect the
consummation of the Exchange Offers or the Solicitations as contemplated in the
Prospectus (as supplemented), and, to the best of the Company's knowledge, no
such proceedings are contemplated or threatened.  No contract or document of a
character required to be described in the Registration Statement or the
Prospectus (as supplemented) or to be filed as an exhibit to the Registration
Statement is not so described or filed and the statements included or
incorporated in the Registration Statement and the Prospectus (as supplemented)
describing any legal proceedings or material contracts or agreements relating to
the Company fairly summarize such matters.

          (m)   The firm of accountants that has certified or shall certify the
applicable consolidated financial statements and supporting schedules of the
Company filed or to be filed as part of the Registration Statement or the
Prospectus (as supplemented) are independent public accountants with respect to
the Company and its subsidiaries, as required by the Act.  The consolidated
historical statements and any pro forma information, together with related
                              --- -----                                   
schedules and notes, if any, included in the Registration Statement or the
Prospectus (as supplemented) comply as to form in all material respects with the
requirements of the Act.  Such historical financial statements fairly present
the consolidated financial position of the Company and its Subsidiaries at the
respective dates indicated and the results of their operations and their cash
flows for the respective periods indicated, in accordance with generally
accepted accounting principles ("GAAP"), except as otherwise expressly stated
therein, as consistently applied throughout such periods.  Such pro forma
                                                               ---- -----
information has been prepared on a basis consistent with such historical
financial statements, except for the pro forma adjustments specified therein,
                                     --- -----                               
and gives effect to assumptions made on a reasonable basis and fairly presents
and gives effect to the transactions described therein pertaining to such pro
                                                                          ---
forma information.  The other financial and statistical information and data
- -----                                                                       
included in the Registration Statement and in the Prospectus

                                       7
<PAGE>
 
(as supplemented), historical and pro forma, are, in all material respects,
                                  ---------
accurately presented and prepared on a basis consistent with such financial
statements and the books and records of the Company.

          (n)   Each of the Company and the Subsidiaries has all certificates,
consents, exemptions, orders, permits, licenses, authorizations, or other
approvals (each, an "Authorization") of and from, and has made all declarations
and filings with, all Federal, state, local and other governmental authorities,
all self-regulatory organizations and all courts and other tribunals, necessary
or required to own, lease, license and use its properties and assets and to
conduct its business in the manner described in the Registration Statement and
the Prospectus (as supplemented), except to the extent that the failure to
obtain or file any such Authorizations would not, singularly or in the
aggregate, reasonably be expected to have a Material Adverse Effect.  All such
Authorizations are in full force and effect with respect to the Company and the
Subsidiaries, and the Company and the Subsidiaries are in compliance in all
material respects with the terms and conditions of all such Authorizations and
with the rules and regulations of the regulatory authorities and governing
bodies having jurisdiction with respect thereto.

          (o)   Except as disclosed in the Prospectus (as supplemented), no
holder of any security of the Company has or will have any right to require the
registration of such security by virtue of the filing of the Registration
Statement or any transactions contemplated by this Agreement other than any such
right that has been expressly waived in writing. No holder of any of the
outstanding shares of capital stock of the Company or other person is entitled
to preemptive or other rights to subscribe for the WorldCom Notes.

          (p)   Subsequent to the initial filing of the Registration Statement,
the Company did not and will not, except as contemplated by this Agreement, (i)
take, directly or indirectly, any action designed to cause or to result in, or
that has constituted or which might reasonably be expected to constitute, the
stabilization or manipulation of the price of any security of the Company or MFS
to facilitate the sale or resale of the WorldCom Notes; or (ii) sell, bid for,
purchase, or pay anyone any compensation for soliciting purchases of, the
WorldCom Notes, the MFS Notes or any other debt securities of the Company or MFS
which were offered, or will be offered, by the Company pursuant to a
registration statement filed under the Act or pursuant to the exemption from
registration provided by Rule 144A promulgated under the Act.

          (q)   The Company has, or has arranged to obtain, sufficient funds
available and authority to use such funds under applicable law to pay, in
accordance with the terms and subject to the conditions of the Exchange Offers
and the Solicitations, the cash portion of the purchase price for the WorldCom
Notes, any related consent fee and all fees and expenses related thereto; the
Company will cause each MFS Note accepted pursuant to the Exchange Offers to be
cancelled promptly thereafter.

          (r)   The Company has complied with and will comply with, in all
material respects, all laws, regulations and rules and corporate requirements
applicable to the Exchange Offers, the Solicitations and this Agreement and the
Company has provided or filed, as applicable, all exchange and other notices
required to be provided or filed by the Company in

                                       8
<PAGE>
 
connection with the Exchange Offers and the Solicitations. The Exchange Offer
and the Solicitation with respect to the MFS 2004 Notes are in full compliance
with all provisions of the 1994 Indenture and the Exchange Offer and the
Solicitation with respect to the MFS 2006 Notes are in full compliance with all
provisions of the 1996 Indenture.

          (s)   At such time as the second supplemental indenture, as
contemplated in the Prospectus (as supplemented), to the 1994 Indenture (the
"1994 Second Supplemental Indenture") is executed by MFS and the MFS Trustee
(assuming receipt of the Requisite Consent or the Supermajority Consent, as the
case may be, as such terms are defined in the Prospectus (as supplemented)) (x)
the 1994 Second Supplemental Indenture will be duly authorized, executed and
delivered by MFS, (y) assuming the due authorization, execution and delivery of
the 1994 Second Supplemental Indenture by the MFS Trustee, the 1994 Second
Supplemental Indenture will constitute a valid amendment to the 1994 Indenture
that is permitted by the terms of the 1994 Indenture and that conforms in all
material respects to the description thereof contained in the Prospectus (as
supplemented) and (z) assuming the due authorization, execution and delivery of
the 1994 Second Supplemental Indenture by the MFS Trustee, the 1994 Indenture as
amended by the 1994 Second Supplemental Indenture, will constitute a valid and
legally binding obligation of MFS, enforceable against MFS in accordance with
its terms subject to applicable bankruptcy, insolvency, fraudulent transfer,
reorganization, moratorium and similar laws of general applicability relating to
or affecting creditors' rights and to general principles of equity.

          (t)   At such time as the second supplemental indenture, as
contemplated in the Prospectus (as supplemented), to the 1996 Indenture (the
"1996 Second Supplemental Indenture") is executed by MFS and the MFS Trustee
(assuming receipt of the Requisite Consent or the Supermajority Consent, as the
case may be, as such terms are defined in the Prospectus (as supplemented)) (x)
the 1996 Second Supplemental Indenture will be duly authorized, executed and
delivered by MFS, (y) assuming the due authorization, execution and delivery of
the 1996 Second Supplemental Indenture by the MFS Trustee, the 1996 Second
Supplemental Indenture will constitute a valid amendment to the 1996 Indenture
that is permitted by the terms of the 1996 Indenture and that conforms in all
material respects to the description thereof contained in the Prospectus (as
supplemented) and (z) assuming the due authorization, execution and delivery of
the 1996 Second Supplemental Indenture by the MFS Trustee, the 1996 Indenture as
amended by the 1996 Second Supplemental Indenture, will constitute a valid and
legally binding obligation of MFS, enforceable against MFS in accordance with
its terms subject to applicable bankruptcy, insolvency, fraudulent transfer,
reorganization, moratorium and similar laws of general applicability relating to
or affecting creditors' rights and to general principles of equity.

          Section 3.  Agreements.  The Company agrees with each of you, and in
                      ----------                                              
the case of paragraph (f) of this Section 3, each of you agree with the Company:

          (a)   The Company will use its reasonable efforts to maintain the
effectiveness of the Registration Statement, and to cause any amendment thereof
to be declared effective by the Commission.  Between the date of entering into
this Agreement and the termination of the offering of the WorldCom Notes
pursuant to the Exchange Offers, the Company will not file (x) any amendment to
the Registration Statement, (y) any document incorporated in the Prospectus,

                                       9
<PAGE>
 
or (z) any supplement to the Prospectus without first providing each of you
with a copy of such amendment or supplement, and will not file such amendment or
supplement if either of you reasonably objects to such filing.  Subject to the
foregoing sentence, if filing of the Prospectus is required under Rule 424(b),
the Company will cause the Prospectus, properly completed, and any supplement
thereto to be filed with the Commission pursuant to the applicable paragraph of
Rule 424(b) within the time period prescribed and will provide evidence
satisfactory to each of you of such timely filing.  The Company will promptly
advise each of you (i) when the Registration Statement, and any amendment
thereto, shall have become effective, (ii) when the Prospectus, and any
supplement thereto or any document incorporated therein, shall have been filed
(if required) with the Commission pursuant to Rule 424(b), (iii) when, prior to
termination of the offering of the WorldCom Notes pursuant to the Exchange
Offers, any amendment to the Registration Statement shall have been filed or
become effective, (iv) of any request by the Commission for any amendment of the
Registration Statement or supplement to the Prospectus or for any additional
information, (v) of the issuance by the Commission of any order relating to any
document incorporated in the Prospectus or any stop order suspending the
effectiveness of the Registration Statement or the Company becoming aware of the
institution or threatening of any proceeding for any such purpose and (vi) of
the receipt by the Company of any notification with respect to the suspension of
the qualification of the WorldCom Notes for sale in any jurisdiction or the
initiation or threatening of any proceeding for such purpose.  The Company will
use its reasonable efforts to prevent the issuance of any such stop order and,
if issued, to obtain as soon as possible the withdrawal thereof.

          (b)   As soon as practicable, the Company will make generally
available to its security holders and to the Dealer Managers an earnings
statement or statements of the Company and its Subsidiaries which will satisfy
the provisions of Section 11(a) of the Act and Rule 158 under the Act.

          (c)   To furnish each of you, without charge, two manually or
facsimile signed copies of the Registration Statement (as originally filed) and
each amendment thereto (including exhibits thereto and documents incorporated
therein by reference) and, during the period mentioned in paragraph (d) below,
as many copies of the Prospectus, any documents incorporated therein by
reference, and any supplements thereto as each of you may reasonably request.

          (d)   If, at any time prior to the Termination Date (as defined in
Section 11 of this Agreement), any event occurs as a result of which the
Prospectus as then supplemented would include any untrue statement of a material
fact or omit to state any material fact necessary to make the statements
therein, in the light of the circumstances under which they were made, not
misleading, or if it shall be necessary to amend the Registration Statement or
supplement the Prospectus to comply with the Act, the Exchange Act, the Company
will (i) promptly prepare and file with the Commission, subject to the second
sentence of paragraph (a) of this Section 3, an amendment or supplement which
will correct such statement or omission or effect such compliance and (ii) give
each of the Dealer Managers immediate notice, confirmed in writing, to cease the
Exchange Offers and the Solicitations.

                                       10
<PAGE>
 
          (e)   The Company will cooperate with the Dealer Managers and counsel
for the Dealer Managers in connection with obtaining, and use its reasonable
efforts to obtain, qualification of the WorldCom Notes for offering and sale
under the laws of such jurisdictions as the Dealer Managers may designate, will
maintain such qualifications in effect so long as required for the distribution
of the Dealer Managers, and will pay the fee of the NASD, if any, in connection
with its review of the offering; provided, however, that the Company shall not
be required to file any general consent to service of process or to qualify as a
foreign corporation or as a dealer in securities in any jurisdiction in which it
is not so qualified or to subject itself to taxation in respect of doing
business in any jurisdiction in which it is not otherwise so subject. The
Company will file such statements and reports as may be required by the laws of
each jurisdiction in which the WorldCom Notes have been qualified as above
provided. The Company will promptly advise you of the receipt by the Company of
any notification with respect to the suspension of the qualification of the
WorldCom Notes for sale in any such state or jurisdiction or the initiating or
threatening of any proceeding for such purpose.

          (f)   During the period beginning on the Commencement Date and
continuing to and including the Termination Date, the Company will not offer,
sell, contract to sell or otherwise dispose of any debt securities of the
Company which were offered, or will be offered, by the Company pursuant to a
registration statement filed under the Act or pursuant to the exemption from
registration provided by Rule 144A promulgated under the Act (other than the
WorldCom Notes) without the prior written consent of Salomon Brothers Inc. The
foregoing shall not restrict the Company from borrowings under existing or new
revolving credit agreements and lines of credit and issuances of commercial
paper or interest rate swaps.

          Section 4.  Conditions of the Dealer Managers' Obligations.  The
                      ----------------------------------------------      
obligations of the Dealer Managers under this Agreement are at all times subject
to the following conditions:

          (a)   That, at the Commencement Date and the Exchange Date, the
Company shall have furnished to the Dealer Managers opinions of the General
Counsel--Corporate Development or other authorized legal representative of the
Company, addressed to the Dealer Managers and dated the Commencement Date and
the Exchange Date, respectively, substantially to the effect described in
Exhibit B hereto, opinions of Bryan Cave LLP, special counsel to the Company,
addressed to the Dealer Managers and dated the Commencement Date and the
Exchange Date, respectively, substantially to the effect described in Exhibit C
hereto, and opinions of Kelley Drye & Warren LLP, special communications counsel
to the Company, addressed to the Dealer Managers and dated the Commencement Date
and the Exchange Date, respectively, substantially to the effect described in
Exhibit D hereto.

          (b)   That, at the Exchange Date, the Dealer Managers shall have
received an opinion of counsel for the Dealer Managers, addressed to the Dealer
Managers and dated the Exchange Date, in form and substance satisfactory to the
Dealer Managers.

          (c)   That the representations and warranties of the Company in this
Agreement shall be true and correct in all material respects and that the
statements of the Company made in any certificates pursuant to Section 4(h) of
this Agreement shall be accurate (and in the case of

                                       11
<PAGE>
 
certificates pursuant to any other provision of this Agreement, accurate in all
material respects or where statements or representations contained therein are
qualified as to materiality, accurate), in either case, on the Commencement Date
and at all times thereafter up to and including the Exchange Date with the same
effect as if made on the Commencement Date or at such time, respectively, and
the Company shall have complied with all the agreements and satisfied all the
conditions on its part to be performed or satisfied at or prior to the
Commencement Date and the Exchange Date; it is understood that the agreement of
any Dealer Manager to act in such capacity at a time when it should know that
any such representation or warranty is or may be untrue or incorrect in a
material respect shall be without prejudice to any rights it has to subsequently
to cease so to act by reason of such untruth or incorrectness.

          (d)   That no order relating to any document incorporated in the
Prospectus (as supplemented) or any stop order suspending the effectiveness of
the Registration Statement shall have been issued and no proceedings for such
purpose shall have been instituted or, to the Company's knowledge, threatened.

          (e)   That subsequent to the execution and delivery of this Agreement
and on or prior to the Exchange Date, there shall not have occurred any
downgrading, nor shall any notice have been given to the Company of (A) any
intended or potential downgrading or (B) any review or possible change that does
not indicate the direction of a possible change, in the rating accorded any of
the Company's securities by any of Standard & Poor's Ratings Group, Moody's
Investors Service, Inc. or any other "nationally recognized statistical rating
organization" (as defined for purpose of Rule 436(g) under the Act).

          (f)   Subsequent to the date of the most recent financial statements
included in the Prospectus (exclusive of any supplement thereto), there shall
have occurred no Material Adverse Change, whether or not arising from
transactions in the ordinary course of business, except as set forth in or
contemplated in the Prospectus (exclusive of any supplement thereto).

          (g)   That, at the Commencement Date and at the Exchange Date, there
shall not have been (i) any change or decrease specified in the letter to be
delivered pursuant to (i) of this Section 5, except as disclosed or contemplated
in the Prospectus (exclusive of any supplement thereto), or (ii) any change, or
any development involving a prospective change, in or affecting the business or
properties of the Company and the Subsidiaries the effect of which, in any case
referred to in clause (i) or (ii) above, is, in the judgment of each of the
Dealer Managers, so material and adverse as to make it impractical or
inadvisable to proceed with the Exchange Offers and Solicitations or the
delivery of the WorldCom Notes as contemplated by the Registration Statement
(exclusive of any amendment thereto) and the Prospectus (exclusive of any
supplement thereto).

          (h)   That, at the Commencement Date and at the Exchange Date, the
Company shall have furnished to the Dealer Managers a certificate of the
Company, signed by the Chief Executive Officer, the President, the Chief
Operating Officer or any Senior Vice-President and by the principal financial or
accounting officer, the Treasurer or the Controller of the Company, each in his
official capacity as an officer of the Company and not as an individual, dated

                                       12
<PAGE>
 
respectively as of the Commencement Date and the Exchange Date, to the effect of
subparagraphs (c) through (g) of this Section 4.

          (i)   That, at the Commencement Date and at the Exchange Date, the
Company's independent public accountants shall have furnished to the Dealer
Managers a letter or letters, dated respectively as of the Commencement Date and
the Exchange Date, in form and substance satisfactory to the Dealer Managers.

          (j)   That the Company shall have delivered to the Dealer Managers
and their counsel such documents as they may reasonably request relating to the
Exchange Offers, the Solicitations, the issuance and sale of the WorldCom Notes
or otherwise related to the matters contemplated hereby.

          (k)   No stop order or restraining order shall have been issued and no
litigation shall have been commenced or threatened with respect to the Exchange
Offers, the Solicitations or with respect to any of the transactions in
connection with, or contemplated by, the Exchange Offers, the Solicitations or
this Agreement before any agency, court or other governmental body of any
jurisdiction which you, in good faith after consultation with us, believe
renders it inadvisable for you to continue to act hereunder.

          (l)   The Company shall have obtained all consents, approvals,
authorizations and orders of, and shall have duly made all registrations,
qualifications and filings with, any court or regulatory authority or other
governmental agency or instrumentality in the United States required in
connection with the making and consummation of the Exchange Offers and the
Solicitations and the execution, delivery and performance of this Agreement, and
will have available funds, and authorization to use such funds under applicable
law, to pay the cash portion of the purchase price of the MFS Notes that it may
become committed to purchase pursuant to the Exchange Offers, to make Consent
Payments (as defined in the Prospectus) that it may become committed to pay in
connection with the Solicitations and, in each case, to pay all related fees and
expenses.

          (m)   If any of the conditions specified in this Section 4 shall not
have been fulfilled in all material respects when and as provided in this
Agreement, or if any of the opinions and certificates mentioned above or
elsewhere in this Agreement shall not be in all material respects reasonably
satisfactory in form and substance to the Dealer Managers and their counsel,
this Agreement and all obligations of the Dealer Managers hereunder may be
cancelled at, or at any time prior to, the Exchange Date by either of the Dealer
Managers. Notice of such cancellation shall be given to the Company in writing
or by telephone or fax confirmed in writing.

          Section 5.  Payment of Fees and Reimbursement of Dealer Managers'
                      -----------------------------------------------------
Expenses.  We agree to pay each of you a fee in connection with each Exchange
- --------                                                                     
Offer and the related Solicitation as set forth on Schedule A hereto.  We will
also promptly reimburse you, regardless of whether any MFS Notes are tendered or
accepted pursuant to the Exchange Offers, for your reasonable out-of-pocket
expenses in preparing for and performing your functions as Dealer Managers,
including the reasonable fees, costs and out-of-pocket expenses of a single

                                       13
<PAGE>
 
firm as counsel for their representation of you in connection herewith. You
shall provide to the Company documentation with reasonable detail in connection
with and at the time of your request for reimbursement for such expenses.

          Section 6.  Indemnification and Contribution.
                      -------------------------------- 

          (a)   The Company agrees to indemnify and hold harmless each Dealer
Manager, each officer and director of each Dealer Manager and each person who
controls any Dealer Manager within the meaning of the Act against any and all
losses, claims, expenses, damages or liabilities, joint or several, to which
they or any of them may become subject under the Act, the Exchange Act or other
Federal or state statutory law or regulation, at common law or otherwise,
insofar as such losses, claims, expenses, damages or liabilities (or actions in
respect thereof) arise out of or are based upon any untrue statement or alleged
untrue statement of a material fact contained in the Registration Statement,
Prospectus or the Prospectus (as supplemented if the Company shall have
furnished any supplements thereto) or in any Ancillary Document, or arise out of
or are based upon the omission or alleged omission to state therein a material
fact required to be stated therein or necessary to make the statements therein,
in the light of the circumstances in which they were made, not misleading, and
agrees to reimburse each such indemnified party, as incurred, for any legal or
other expenses reasonably incurred by them in connection with investigating or
defending any such loss, claim, expense, damage, liability or action; provided,
                                                                      --------
however, the Company will not be liable in any such case to the extent that any
- -------
such loss, claim, expense, damage or liability arises out of or is based upon
any such untrue statement or alleged untrue statement or omission or alleged
omission made therein in reliance upon and in conformity with written
information furnished to the Company by or on behalf of any Dealer Manager
specifically for inclusion in such document. This indemnity agreement is in
addition to any liability which the Company may otherwise have.

          (b)   Each of the Dealer Managers severally agrees to indemnify and
hold harmless the Company, each of its directors, each of its officers who signs
the Registration Statement, and each person who controls the Company within the
meaning of the Act, to the same extent as the foregoing indemnity from the
Company to each Dealer Manager, but only with reference to written information
furnished to the Company by or on behalf of such Dealer Manager specifically for
inclusion in the documents referred to in the foregoing indemnity. This
indemnity agreement will be in addition to any liability which any Dealer
Manager may otherwise have. The Dealer Managers and the Company acknowledge and
agree that the information set forth (i) in the third to last sentence on the
cover page of the Prospectus which specifies the identity of the Dealer Managers
for the Exchange Offers and the Solicitations; (ii) in the second sentence of
the penultimate paragraph on the continuation cover page of the Prospectus which
describes the Dealer Managers' intentions to make a market in the WorldCom
Notes; (iii) in the first sentence of the back cover page of the Prospectus
which specifies the identity of the Dealer Managers for the Exchange Offers and
the Solicitations, and gives their respective addresses and phone numbers; (iv)
under the captions "Prospectus Summary - Dealer Managers", "Prospectus Summary -
Dealer Manager Market Activity," and "the Exchange Offers - Dealer Managers";
(v) in paragraphs [ ], [ ] and [ ] of the Ancillary Documents, is the only

                                       14
<PAGE>
 
information furnished to the Company by or on behalf of the Dealer Managers
specifically for inclusion in the documents referred to in the foregoing
indemnity.

          (c)   Promptly after receipt by an indemnified party under this
Section 6 of notice of the commencement of any action, such indemnified party
will, if a claim in respect thereof is to be made against the indemnifying party
under this Section 6, notify the indemnifying party in writing of the
commencement thereof; but the omission so to notify the indemnifying party (i)
will not relieve it from liability under paragraph (a) or (b) above except to
the extent such failure results in an increase in the amount of the liability of
the indemnifying party or the forfeiture or impairment of any substantial rights
or defenses of the indemnifying party and (ii) will not, in any event, relieve
the indemnifying party from any obligations to any indemnified party other than
the indemnification obligation provided in paragraph (a) or (b) above. In case
any such action is brought against any indemnified party, and it notifies the
indemnifying party of the commencement thereof, the indemnifying party will be
entitled to appoint counsel satisfactory to such indemnified party to represent
the indemnified party in such action (in which case the indemnifying party shall
not thereafter be responsible for the fees and expenses of any separate counsel
retained by the indemnified party or parties except as set forth below);
provided, however, that if the defendants in any such action include both the
- --------  -------                                                            
indemnified party and the indemnifying party and the indemnified party shall
have reasonably concluded that there may be legal defenses available to it
and/or other indemnified parties which are different from or additional to those
available to the indemnifying party, the indemnified party or parties shall have
the right to select separate counsel to defend such action on behalf of such
indemnified party or parties.  Upon receipt of notice from the indemnifying
party to such indemnified party of its election so to appoint counsel to defend
such action and approval by the indemnified party of such counsel, the
indemnifying party will not be liable to such indemnified party under this
Section 6 for any legal or other expenses subsequently incurred by such
indemnified party in connection with the defense thereof unless (i) the
indemnified party shall have employed separate counsel in accordance with the
proviso to the next preceding sentence (it being understood, however, that the
indemnifying party shall not be liable for the expenses of more than one
separate counsel (plus any local counsel), approved by each of the Dealer
Managers in the case of paragraph (a) of this Section 6, representing the
indemnified parties under such paragraph (a) who are parties to such action),
(ii) the indemnifying party shall not have employed counsel reasonably
satisfactory to the indemnified party to represent the indemnified party within
a reasonable time after notice of commencement of the action or (iii) the
indemnifying party has authorized the employment of counsel for the indemnified
party at the expense of the indemnifying party; and except that, if clause (i)
or (iii) is applicable, such liability shall be only in respect of the counsel
referred to in such clause (i) or (iii).  An indemnifying party will not,
without the prior written consent of each of the indemnified parties, settle or
compromise or consent to the entry of any judgment with respect to any pending
or threatened claim, action, suit or proceeding in respect of which
indemnification or contribution may be sought hereunder (whether or not the
indemnified parties are actual or potential parties to such claim or action)
unless such settlement, compromise or consent includes an unconditional release
of each indemnified party from all liability arising out of such claim, action,
suit or proceeding.

                                       15
<PAGE>
 
          (d)  In order to provide for just and equitable contribution in
circumstances in which the indemnification provided for in paragraph (a) or (b)
of this Section 6 is due in accordance with its terms but is for any reason held
by a court to be unavailable from the Company on grounds of policy or otherwise,
the Company and the Dealer Managers shall contribute to the aggregate losses,
claims, expenses, damages and liabilities (including legal or other expenses
reasonably incurred in connection with investigating or defending same)
(collectively, the "Losses") to which the Company and one or more of the Dealer
Managers may be subject (i) in such proportion as is appropriate to reflect the
relative benefits received (or anticipated to be received) by the Company on the
one hand and the Dealer Managers on the other from the Exchange Offers and the
Solicitations provided, however, that in no case shall any Dealer Manager be
              -----------------
responsible for any amount in excess of the fee received (or anticipated to be
received) by such Dealer Manager hereunder or (ii) if the allocation provided by
clause (i) above is not permitted by applicable law, in such proportion as is
appropriate to reflect not only the relative benefits referred to in clause (i)
above but also the relative fault of the Company on the one hand and the Dealer
Managers on the other in connection with the statements or omissions which
resulted in such losses, claims, demands or liabilities as well as any other
relevant equitable considerations. The relative benefits received (or
anticipated to be received) by the Company on the one hand and the Dealer
Managers on the other shall be deemed to be in the same proportion as the
aggregate consideration payable (or anticipated to be paid) by the Company in
cash or securities in the Exchange Offers and the Solicitations (before
deducting expenses) bears to the total compensation payable (or anticipated to
be paid) by the Company to the Dealer Managers, in each case, pursuant to this
Agreement. The relative fault shall be determined by reference to, among other
things, whether the untrue or alleged untrue statement of a material fact or the
omission or alleged omission to state a material fact relates to information
supplied by the Company or the Dealer Managers and the parties' relative intent,
knowledge, access to information and opportunity to correct or prevent such
untrue statement or omission. The amount paid by an indemnified party as a
result of the losses, claims, expenses, damages or liabilities referred to in
the first sentence of this subsection (d) shall be deemed to include any legal
or other expenses reasonably incurred by such indemnified party in connection
with investigating or defending any action or claim which is the subject of this
subsection (d). No person guilty of fraudulent misrepresentation (within the
meaning of Section 11(f) of the Act) shall be entitled to contribution from any
person who was not guilty of such fraudulent misrepresentation. The Company and
the Dealer Managers agree that it would not be just and equitable if
contribution were determined by pro rata allocation or any other method of
allocation which does not take account of the equitable considerations referred
to above. For purposes of this Section 6, each person who controls a Dealer
Manager within the meaning of either the Act or the Exchange Act and each
director, officer, employee and agent of a Dealer Manager shall have the same
rights to contribution as such Dealer Manager, and each person who controls the
Company within the meaning of either the Act or the Exchange Act, each officer
of the Company who shall have signed the Registration Statement and each
director of the Company shall have the same rights to contribution as the
Company, subject in each case to the applicable terms and conditions of this
paragraph (d). The Dealer Managers' obligations in this subsection (d) to
contribute are several in proportion to their respective rights to receive a
percentage of the aggregate fees payable to the Dealer Managers hereunder and
not joint. Any party entitled to contribution will, promptly after receipt of
notice of commencement of any action, suit or

                                       16
<PAGE>
 
proceeding against such party in respect of which a claim for contribution may
be made against another party or parties under this paragraph (d), notify such
party or parties from whom contribution may be sought, but the omission to so
notify such party or parties shall not relieve the party or parties from whom
contribution may be sought from any other obligation it or they may have
hereunder or otherwise than under this paragraph (d).

          Section 7.  Survival.  The respective agreements, representations,
                      --------                                              
warranties, indemnities and other statements of the Company or its officers and
of the Dealer Managers set forth in or made pursuant to this Agreement will
remain in full force and effect, regardless of any investigation made by or on
behalf of any Dealer Manager or the Company or any of the officers, directors or
controlling persons referred to in Section 6 hereof, and Sections 1, 2, 3(b), 5,
6, 7, 8, 9 and 10 hereof shall survive the termination or cancellation of this
Agreement.

          Section 8.  Notices.  All communications hereunder will be in writing
                      -------                                                  
and effective only on receipt, and,  if sent to the Dealer Managers, will be
mailed, delivered or faxed and confirmed to them, at Salomon Brothers Inc, 7
World Trade Center, New York, NY  10048, to the attention of Scott Miller (fax:
212-783-4142) or, if sent to the Company, will be mailed, delivered or faxed and
confirmed to it at 515 East Amite Street, Jackson, Mississippi 39201, to the
attention of Stephanie Q. Scott, Director of Financial Reporting (fax: 601-360-
8671) with a copy mailed, delivered or faxed to P. Bruce Borghardt, General
Counsel-Corporate Development (fax: 314-909-4101).

          Section 9.  Successors.  This Agreement will inure to the benefit of
                      ----------                                              
and be binding upon the parties hereto and their respective successors and the
officers and directors and controlling persons referred to in Section 6 hereof,
and no other person will have any right or obligation hereunder.

          Section 10.  Applicable Law.  This Agreement will be governed by and
                       --------------                                         
construed in accordance with the substantive laws of the State of New York
without regard to such state's rules concerning conflicts of laws.  Any right to
trial by jury with respect to any claim or proceeding related to or arising out
of this engagement or any transactions or conduct in connection herewith, is
waived.

          Section 11.  Termination.  This Agreement shall terminate with respect
                       ------------                                             
to each Exchange Offer and the related Solicitation upon the earliest to occur
of (i) the Exchange Date, (ii) the earliest date on which the Dealer Managers
shall have both (a) given notice to the Company that any of the conditions
specified in Section 4 have not been fulfilled in all material respects as of
any date such conditions are required to be fulfilled pursuant to Section 4 with
respect to such Exchange Offer and the related Solicitation and (b) given notice
that the conditions specified pursuant to clause (ii)(a) of this sentence have
not been satisfied within a time satisfactory to the Dealer Managers following
the date of notice given pursuant to clause (ii)(a) of this sentence or (iii)
the date on which the Company terminates or withdraws such Exchange Offer and
the related Solicitation for any reason (the earliest to occur of clauses (i),
(ii) or (iii) being referred to as the "Termination Date").

                                       17
<PAGE>
 
          Section 12.  General.
                       ------- 

          This Agreement may be executed in one or more counterparts, each of
which shall be deemed an original.


                                    WORLDCOM, INC.


                                    By:
                                       --------------------------------
                                       Name:
                                       Title:

The foregoing Agreement is
hereby confirmed and accepted
as of the date first above written.


SALOMON BROTHERS INC



By:
   ----------------------
   Name:
   Title:



GOLDMAN, SACHS & CO.



By:
   ----------------------
   Name:
   Title:

                                       18
<PAGE>
 
                                                                     SCHEDULE A

          If, as of the expiration or termination of the applicable Exchange
Offer and Solicitation, a majority in aggregate principal amount at stated
maturity of the Outstanding (as defined in the 1994 Indenture) MFS 2004 Notes
have been tendered (and not validly revoked) in such Exchange Offer and
Solicitation, then the Dealer Managers shall be entitled to receive an aggregate
fee equal to 0.25% of the aggregate Accreted Value (as defined in the
Prospectus), as of July 15, 1997, of all MFS 2004 Notes tendered (and not
validly revoked) as of such expiration or termination.  Of the foregoing amount,
the Company shall pay 60% to Salomon Brothers Inc and 40% to Goldman, Sachs &
Co.  The parties acknowledge that 0.25% of the Accreted Value, as of July 15,
1997, of an MFS 2004 Note having a principal amount of $1,000 at stated maturity
is equal to [$    ].

          If, as of the expiration or termination of the applicable Exchange
Offer and Solicitation, a majority in aggregate principal amount at stated
maturity of the Outstanding (as defined in the 1996 Indenture) MFS 2006 Notes
have been tendered (and not validly revoked) in such Exchange Offer and
Solicitation, then the Dealer Managers shall be entitled to receive an aggregate
fee equal to 0.25% of the aggregate Accreted Value (as defined in the
Prospectus), as of July 15, 1997, of all MFS 2006 Notes tendered (and not
validly revoked) as of such expiration or termination.  Of the foregoing amount,
the Company shall pay 60% to Salomon Brothers Inc and 40% to Goldman, Sachs &
Co.  The parties acknowledge that 0.25% of the Accreted Value, as of July 15,
1997, of an MFS 2004 Note having a principal amount of $1,000 at stated maturity
is equal to [$    ].

                                       19
<PAGE>
 
                                                                       EXHIBIT A

                                 WORLDCOM, INC.

                            SIGNIFICANT SUBSIDIARIES
                            ------------------------

<TABLE>
<CAPTION>

Name                                Jurisdiction in which Organized
- ----                                -------------------------------
<S>                                 <C>
WorldCom Network Services, Inc.     Delaware

MFS Communications Company, Inc.    Delaware

IDB WorldCom, Inc.                  Delaware

UUNET Technologies, Inc.            Delaware
</TABLE>

                                       20
<PAGE>
 
                                                                       EXHIBIT B

          The opinion of General Counsel-Corporate Development for the Company
shall be substantially to the effect that:

          (1) The Significant Subsidiaries on Exhibit A to the Dealer Managers
Agreement (the "Subsidiaries") are the only Significant Subsidiaries (within the
meaning of Rule 405 under the Act) of the Company.  Each of the Company and the
Subsidiaries has been duly incorporated or formed and is validly existing as a
corporation in the jurisdiction of its incorporation or formation, and has all
consents, authorizations, approvals, orders, certificates, permits and
exemptions (together, "Authorizations") of and from, has made all declarations
and filings with, all federal, state, local and other governmental authorities,
all self-regulatory organizations, and all courts or other tribunals, and has
the corporate power and authority, necessary to conduct its business and to own
lease, license and use its property and assets in the manner described in the
Prospectus except to the extent that the lack of such Authorizations would not
have a material adverse effect on the Company and its Subsidiaries, taken as a
whole. The Company has the requisite corporate power and authority to authorize
the Exchange Offers and the Solicitations, to execute, deliver and perform the
Dealer Managers Agreement and to issue, offer, sell and deliver the WorldCom
Notes.

          (2) All the outstanding shares of capital stock of each Subsidiary
have been duly and validly authorized and are duly issued and are fully paid and
nonassessable, and have not been issued and are not owned or held in violation
of any statutory preemptive right of stockholders; to the knowledge of such
counsel after due inquiry such shares are not held in violation of any other
preemptive right of stockholders; and all outstanding shares of capital stock of
the Subsidiaries are owned by the Company either directly or through wholly-
owned Subsidiaries free and clear of any perfected security interest and, to my
knowledge after due inquiry, any other material security interests,
stockholders' agreements or voting trusts.

          (3) To the knowledge of such counsel, there is no pending or
threatened action, suit or proceeding before any court or governmental agency,
authority or body or any arbitrator involving the Company or any of the
Subsidiaries, or any of their respective properties, of a character required to
be disclosed in the Registration Statement or the Prospectus that is not
adequately disclosed in the Registration Statement or the Prospectus, and there
is no contract or other document of a character required to be described in the
Registration Statement or the Prospectus or to be filed as an exhibit to the
Registration Statement, which is not described or filed as required.

          (4) (A)  As of the Commencement Date, an opinion to the effect that
neither the performance by the Company of the Exchange Offers or the
Solicitations and the execution and delivery by the Company of, and the
performance by the Company of its obligations under, the Dealer Managers
Agreement and the Original Indenture (as supplemented by the First Supplemental
Indenture, if and when executed by the Company and the Trustee) nor the issuance
and sale of the WorldCom Notes, nor the execution and delivery by MFS of, and
the

                                       21
<PAGE>
 
performance by MFS of its obligations under, the 1994 Indenture (as supplemented
by the 1994 Second Supplemental Indenture, if and when executed by MFS and the
MFS Trustee) or the 1996 Indenture (as supplemented by the 1996 Second
Supplemental Indenture, if and when executed and delivered by MFS and the MFS
Trustee) nor the consummation of any other of the transactions contemplated in
the Dealer Managers Agreement nor the fulfillment of the terms thereof will
conflict with, result in a breach of or constitute a default under the articles
of incorporation or the bylaws of the Company or MFS or the terms of any
agreement filed as an exhibit to the Registration Statement or the Prospectus to
which the Company or any of its Subsidiaries is a party or by which the Company
is bound or any of its properties is subject, or any judgment, order or
regulation known to such counsel to be applicable to the Company or any of its
Subsidiaries, or any of their properties, of any court, regulatory body,
administrative agency, governmental body or arbitrator having jurisdiction over
the Company or any of its Subsidiaries or any of their respective properties,
except in the case of any judgment, order or regulation of any State Regulatory
Agency (as defined in the Dealer Managers Agreement) to the extent that any such
conflict, breach or default would not have a Material Adverse Effect on the
Company and its Subsidiaries.

          (B)  As of the Exchange Date, an opinion to the effect that neither
the performance by the Company of the Exchange Offers or the Solicitations and
the execution and delivery by the Company of, and the performance by the Company
of its obligations under, the Dealer Managers Agreement and the Original
Indenture (as supplemented by the First Supplemental Indenture) nor the issuance
and sale of the WorldCom Notes, nor the execution and delivery by MFS of, and
the performance by MFS of its obligations under, the 1994 Indenture (as
supplemented by the 1994 Second Supplemental Indenture) or the 1996 Indenture
(as supplemented by the 1996 Second Supplemental Indenture) nor the consummation
of any other of the transactions contemplated in the Dealer Managers Agreement
nor the fulfillment of the terms thereof will conflict with, result in a breach
of or constitute a default under the articles of incorporation or the bylaws of
the Company or MFS or the terms of any agreement filed as an exhibit to the
Registration Statement or the Prospectus to which the Company or any of its
Subsidiaries is a party or by which the Company is bound or any of its
properties is subject, or any judgment, order or regulation known to such
counsel to be applicable to the Company or any of its Subsidiaries, or any of
their properties, of any court, regulatory body, administrative agency,
governmental body or arbitrator having jurisdiction over the Company or any of
its Subsidiaries or any of their respective properties, except in the case of
any judgment, order or regulation of any State Regulatory Agency (as defined in
the Dealer Managers Agreement) to the extent that any such conflict, breach or
default would not have a Material Adverse Effect on the Company and its
Subsidiaries.

          (5) To my knowledge, no consent, approval, authorization, license,
certificate, permit or order of, or filing, registration or qualification with,
any court or governmental agency or body is required for the performance of the
Exchange Offers, the Solicitations or any of the transactions contemplated under
the Dealer Managers Agreement, except such as have been obtained under the Act
and such as may be required by the Federal Communications Commission or similar
state regulatory authorities or under the blue sky laws of any jurisdiction in
connection with the Exchange Offers and the Solicitations (as to which such
counsel expresses

                                       22
<PAGE>
 
no opinion regarding such requirements or the consequence of any failure to
comply with the same on any of the foregoing opinions herein) as described in
the Prospectus and such other approvals as have been obtained.

          Such counsel shall also state that he has not checked the accuracy or
completeness of, or otherwise verified, the information furnished with respect
to other matters in the Registration Statement or the Prospectus.  He has
generally reviewed and discussed with certain other officers and employees of
and counsel for the Company the information so furnished.  On the basis of such
communication, review and discussion, but without independent check or
verification, except as stated, nothing has come to his attention that would
lead him to believe that (i) the Registration Statement (other than the
financial statements and related schedules and other financial and statistical
information contained therein, omitted therefrom, or incorporated by reference
therein, as to which he need not express a belief), except for that part of the
Registration Statement that constitutes the Statement of Eligibility and
Qualification (Form T-1 under the Trust Indenture Act), contains, or on the date
of the effectiveness of the Registration Statement did contain, any untrue
statement of a material fact or omits, or on the date of the effectiveness of
the Registration Statement did omit, to state a material fact required to be
stated therein or necessary to make the statements therein, in the light of the
circumstances in which they were made, not misleading or (ii) the Prospectus
(except as aforesaid) on the date such opinion is given contains any untrue
statement of a material fact or omits to state a material fact necessary in
order to make the statements therein, in light of the circumstances under which
they were made, not misleading or (iii) the Registration Statement or the
Prospectus (other than the financial statements and related schedules and other
financial and statistical information contained therein, omitted therefrom as to
which such counsel need not express a belief) did not comply as to form in all
material respects with the Act, the Exchange Act and the Trust Indenture Act, as
applicable. As used in this opinion, the term "Prospectus" shall refer to the
Prospectus as supplemented on the date such opinion is given.

                                       23
<PAGE>
 
                                                                       EXHIBIT C

          The opinion of Bryan Cave LLP shall be substantially to the effect
that:

          (1) The Original Indenture, in the case of an opinion delivered at the
Commencement Date, and the Indenture, in the case of an opinion delivered at the
Exchange Date has been duly qualified under the Trust Indenture Act and has been
duly authorized, executed and delivered by the Company and is a valid and
legally binding agreement of the Company, enforceable against the Company in
accordance with its terms, subject to applicable bankruptcy, insolvency,
fraudulent transfer, reorganization, moratorium or similar laws of general
applicability relating to or affecting creditors' rights and to general
principles of equity (regardless of whether such enforceability is considered in
a proceeding in equity or at law), and except to the extent enforceability of
any indemnification provisions may be limited by public policy.

          (2) The WorldCom Notes have been duly authorized and, when executed by
the Company and authenticated by the Trustee in accordance with the provisions
of the Indenture and delivered in exchange for the MFS Notes in accordance with
the Exchange Offers will be valid and legally binding obligations of the
Company, enforceable against the Company in accordance with their respective
terms, and will be entitled to the benefits of the Indenture, subject to
applicable bankruptcy, insolvency, fraudulent transfer, reorganization,
moratorium or similar laws of general applicability relating to or affecting
creditors' rights and to general principles of equity (regardless of whether
such enforceability is considered in a proceeding in equity or at law), and
except to the extent enforceability of any indemnification provisions may be
limited by public policy, and, in the case of the opinion delivered as of the
Exchange Date, all conditions precedent to the issuance of the WorldCom Notes
provided for in the Indenture have been complied with and the terms of the
WorldCom Notes have been established in conformity with the provisions of the
Indenture.

          (3) The MFS Notes outstanding after completion of the Exchange Offers
and the Solicitations will be valid and legally binding obligations of MFS,
enforceable against MFS in accordance with their respective terms, and will be
entitled to the benefits of the 1994 Indenture as supplemented by the 1994
Second Supplemental Indenture or the 1996 Indenture as supplemented by the 1996
Second Supplemental Indenture, as the case may be, subject to applicable
bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium or
similar laws of general applicability relating to or affecting creditors' rights
and to general principles of equity (regardless of whether such enforceability
is considered in a proceeding in equity or at law), and except to the extent
enforceability of any indemnification provisions may be limited by public
policy.

          (4) (A) As of the Commencement Date, an opinion to the effect that if
the holders of a majority in aggregate principal amount outstanding (or the
holders of at least 75% of the aggregate principal amount outstanding with
respect to the modification of the term "Change in Control") of the MFS 2004
Notes consent to the Proposed Amendments to the 1994 Indenture, then the 1994
Second Supplemental Indenture, if executed and delivered in the manner and in
the

                                       24
<PAGE>
 
form contemplated in the Prospectus, will be a valid amendment to the 1994
Indenture, permitted by the terms of the 1994 Indenture; assuming due
authorization and execution by the parties thereto the 1994 Indenture as amended
by the 1994 Second Supplemental Indenture, will constitute a valid and binding
obligation of MFS, enforceable against MFS in accordance with its terms, subject
to applicable bankruptcy, insolvency, fraudulent transfer, reorganization,
moratorium or similar laws of general applicability relating to or affecting
creditors' rights and to general principles of equity (regardless of whether
such enforceability is considered in a proceeding in equity or at law), and
except to the extent enforceability of any indemnification provisions may be
limited by public policy.

             (B) As of the Exchange Date, an opinion to the effect that the 1994
Second Supplemental Indenture (x) is duly authorized, executed and delivered by
MFS and (y) is a valid amendment to the 1994 Indenture, permitted by the terms
of the 1994 Indenture; the 1994 Indenture as amended by the 1994 Second
Supplemental Indenture constitutes a valid and binding obligation of MFS,
enforceable against MFS in accordance with its terms, subject to the applicable
bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium or
similar laws of general applicability relating to or affecting creditors' rights
and to general principles of equity (regardless of whether such enforceability
is considered in a proceeding in equity or at law).

          (5) At the Commencement Date and the Exchange Date, opinions regarding
the MFS 2006 Notes, the 1996 Indenture and the 1996 Second Supplemental
Indenture substantially similar to the opinions required by paragraph 4 above
regarding the MFS 2004 Notes, the 1994 Indenture and the 1994 Second
Supplemental Indenture.

          (6) The Dealer Manager Agreement has been duly authorized and validly
executed and delivered by the Company and is a valid and legally binding
agreement of the Company.

          (7) The statements under "Description of the WorldCom Notes" in the
Prospectus which purport to summarize the terms of the Indenture and the
WorldCom Notes do fairly summarize the material terms of the Indenture and the
WorldCom Notes.

          (8) The Registration Statement has become effective under the Act; any
required filing of the Prospectus and any supplement or amendment thereto has
been made in the manner and within the time period required by the Act and the
rules thereunder; and, to our knowledge, no stop order suspending the
effectiveness of the Registration Statement has been issued, no proceedings for
that purpose have been instituted or threatened, and the Registration Statement
and the Prospectus (excluding financial and statistical information contained
therein or omitted therefrom and any information incorporated by reference
therein) appear on their face to have been appropriately responsive in all
material respects to the applicable requirements of the Act.  The Company met
the requirements for the use of Form S-4 at the time it filed the Registration
Statement.

                                       25
<PAGE>
 
                                                                       EXHIBIT D

          The opinion of the Kelley Drye & Warren LLP shall be substantially to
the effect that:

          The Company and its Significant Subsidiaries have the consents,
approvals authorizations, licenses, certificates or permits required by the FCC,
if any, for the performance of the Exchange Offers and the Solicitations, and
the consummation of the transactions contemplated in the Dealer Managers
Agreement.  Where necessary, if at all, the Company and its Significant
Subsidiaries have the consents, approvals, authorizations, licenses,
certificates, or permits required by the State Regulatory Agencies for the
consummation of the transactions contemplated in the Agreement, where the
failure to obtain such a consent, approval, authorization, license, certificate,
permit or order would have a Material Adverse Effect.

                                       26
<PAGE>
 
                                                                       EXHIBIT E

                                       27

<PAGE>
 
                                                                     EXHIBIT 4.9
                  ------------------------------------------


                                 WORLDCOM, INC.

                                       To

                               MELLON BANK, N.A.

                                    Trustee


                  ------------------------------------------


                          First Supplemental Indenture


                        Dated as of ______________, 1997


                                  to Indenture


                           Dated as of March 1, 1997


                  ------------------------------------------


                                  Relating to


                                $686,398,000

                    9-3/8% Senior Notes Due January 15, 2004


                                     and to


                                $671,850,000

                   8-7/8% Senior Notes Due January 15,  2006


                  ------------------------------------------
<PAGE>
 
          FIRST SUPPLEMENTAL INDENTURE, dated as of _________________, 1997
("First Supplemental Indenture"), to the Indenture, dated as of March 1, 1997,
between WorldCom, Inc., a corporation duly organized and existing under the laws
of the State of Georgia (hereinafter called the "Company"), having its principal
office at 515 East Amite Street, Jackson, Mississippi 39201 and MELLON BANK,
N.A., a corporation duly organized and existing under the laws of the United
States, as Trustee hereunder (hereinafter called the "Trustee"), having its
Corporate Trust Office at Two Mellon Bank Center, Pittsburgh, Pennsylvania
15259.

                            RECITALS OF THE COMPANY

          WHEREAS, the Company has heretofore executed and delivered to the
Trustee an Indenture, dated as of March 1, 1997 (the "Indenture"), providing for
the issuance from time to time of its senior debt securities (the "Securities")
to be issued in one or more series as therein provided;

          WHEREAS, Section 901 of the Indenture provides that the Company, when
authorized by or pursuant to a Board Resolution, and the Trustee, at any time
and from time to time, may enter into an indenture supplemental to the Indenture
without the consent of any Holders (as defined in the Indenture) to establish
the form or terms of the Securities of any series;

          WHEREAS, the Company has duly authorized the creation of (i) an issue
of its Securities to be known as the 9-3/8% Senior Notes Due January 15, 2004
(the "9-3/8% Notes") and (ii) an issue of its Securities to be known as the
8-7/8% Senior Notes Due January 15, 2006 (the "8-7/8% Notes" and, together with
the 9-3/8% Notes, the "Notes") and to provide therefor the Company has duly
authorized the execution and delivery of this First Supplemental Indenture; and

          WHEREAS, all things necessary to make the Notes, when executed by the
Company and authenticated and delivered in accordance with Section 303 of the
Indenture and duly issued by the Company, the valid obligations of the Company,
and to make this First Supplemental Indenture a valid agreement of the Company,
in accordance with their and its terms, have been done;

          NOW, THEREFORE, THIS FIRST SUPPLEMENTAL INDENTURE WITNESSETH:

          For and in consideration of the premises and the purchase of the Notes
by the Holders thereof, it is mutually covenanted and agreed, for the equal and
proportionate benefit of all Holders of the Notes as follows:

     1.  Definitions.
         ----------- 

          (a) Capitalized terms used but not defined in this First Supplemental
Indenture shall have the meanings ascribed to them in the Indenture.

          (b) References in this First Supplemental Indenture to section numbers
shall be deemed to be references to section numbers of this First Supplemental
Indenture unless otherwise specified.
<PAGE>
 
          (c) In the case of capitalized terms defined in this First
Supplemental Indenture that are also defined in the Indenture, the meanings
ascribed to such terms in this First Supplemental Indenture shall apply with
respect to the Notes.

     2.  The Securities.
         -------------- 

          (a) In accordance with Section 301 of the Indenture, there is hereby
created a series of Securities under the Indenture with the following terms:

               (i) the title of the Securities created hereby is the "9-3/8%
          Senior Notes Due January 15, 2004";

               (ii) the aggregate principal amount of the 9-3/8% Notes which may
          be authenticated and delivered (except for 9-3/8% Notes authenticated
          and delivered upon registration of transfer of, or in exchange for, or
          in lieu of, other 9-3/8% Notes pursuant to Sections 304, 305, 306 or
          906 of the Indenture) is limited to $686,398,000;

               (iii)  the principal of the 9-3/8% Notes shall be payable on
          January 15, 2004 unless earlier repaid in accordance with the
          Indenture, as modified by this First Supplemental Indenture;

               (iv) the 9-3/8% Notes shall accrue interest at the rate of 9-3/8%
          per annum (computed on the basis of a 360-day year consisting of
          twelve 30-day months), and interest on the 9-3/8% Notes will accrue
          from and including the most recent Interest Payment Date to which
          interest has been paid or duly provided for, or if no interest has
          been paid, from July 15, 1997, as the case may be, and will be
          payable in cash semi-annually in arrears on January 15 and July 15
          of each year (the "Interest Payment Dates"), commencing on January
          15, 1998, to the Holders of record on the immediately preceding
          December 31 and June 30, respectively (the "Regular Record Dates"),
          until principal thereof is paid or duly provided for. Interest on
          any overdue principal or premium shall be payable on demand;

               (v) the Place of Payment of the 9-3/8% Notes, and the place where
          the 9-3/8% Notes may be surrendered for registration of transfer and
          where the 9-3/8% Notes may be surrendered for exchange and where
          notices or demands may be served to or upon the Company with respect
          to the 9-3/8% Notes, shall be the Corporate Trust Office of the
          Trustee in the City of Pittsburgh, Pennsylvania and at the office of
          an affiliate of the Trustee in New York, New York, which office on
          the date hereof is located at 120 Broadway, 13th Floor, New York,
          New York 10271;

               (vi) the 9-3/8% Notes will not be redeemable at the option of the
          Company prior to January 15, 1999. On or after January 15, 1999, the
          9-3/8% Notes will be redeemable at the option of the Company, in whole
          at any time or in part from time to time, at the following prices
          (expressed in percentages of the principal amount thereof) in Dollars,
          if redeemed during the twelve months beginning January 15 of the years
          indicated below, in each case together with

                                       2
<PAGE>
 
          interest accrued to the Redemption Date (subject to the right of
          Holders of record on the relevant Regular or Special Record Date to
          receive interest due on the relevant Interest Payment Date):

<TABLE>
<CAPTION>

               Year                           Percentage
               ----                           ----------
               <S>                            <C>   
               1999.......................... 103.52%
               2000.......................... 102.34%
               2001.......................... 101.17%
               2002 and thereafter........... 100.00%
</TABLE>

         On and after the  Redemption Date, interest will cease to accrue on the
         9-3/8% Notes (or any portion thereof) if so called for redemption.

               (vii)  there shall be no sinking fund provided for the 9-3/8%
          Notes;

               (viii)  the 9-3/8% Notes shall be issuable only in denominations
          of $1,000 principal amount and any integral multiple thereof;

               (ix) the Trustee shall act as Security Registrar and Paying Agent
          with respect to the 9-3/8% Notes;

               (x) payment of the principal of (and premium, if any) or interest
          on the 9-3/8% Notes shall be denominated and payable only in Dollars;

               (xi) no payment on the 9-3/8% Notes shall be determined with
          reference to an index, formula or other such method;

               (xii)  no Additional Amounts shall be payable in respect of the
          9-3/8% Notes;

               (xiii)  except as stated in this First Supplemental Indenture,
          the 9-3/8% Notes do not contain any provisions granting special rights
          to the Holders thereof;

               (xiv)  with respect to the 9-3/8% Notes, there shall not be any
          deletions from, modifications of or additions to the Events of Default
          or covenants of the Company set forth in the Indenture;

               (xv) the 9-3/8% Notes shall be issuable only as Registered
          Securities without coupons and in book-entry form; the 9-3/8% Notes
          shall not be Bearer Securities; the 9-3/8% Notes shall be issuable
          initially by one or more global Securities in permanent global form
          without coupons and deposited with and registered in the name of (or
          in the name of the nominee of) The Depository Trust Company, New York,
          New York, acting as the depositary for the 9-3/8% Notes (together with
          any successor depositary, the "Depositary"); and the form of the
          9-3/8% Notes is attached hereto as Exhibit A;

               (xvi)  the provisions of Sections 1402 and 1403 of the Indenture
          shall apply to the 9-3/8% Notes without modification thereof;

                                       3
<PAGE>
 
               (xvii)  no portion of the 9-3/8% Notes is convertible into Common
          Stock or Preferred Stock; and

               (xviii)  (a) the provisions of Sections 109, 110, 111 and 112 of
          the Indenture shall not apply to the 9-3/8% Notes, and in lieu thereof
          the provisions set forth below in Sections 3, 4, 5 and 6,
          respectively, shall apply to the 9-3/8% Notes; (b) the provisions of
          Articles Twelve and Thirteen and of Sections 307(b) and 308 of the
          Indenture shall not apply to the 9-3/8% Notes; and (c) the additional
          provisions set forth below in Sections 7 through 10 shall apply to the
          9-3/8% Notes.

          (b) In accordance with Section 301 of the Indenture, there is hereby
created a series of Securities under the Indenture with the following terms:

               (i) the title of the Securities created hereby is the "8-7/8%
          Senior Notes Due January 15, 2006";

               (ii) the aggregate principal amount of the 8-7/8% Notes which may
          be authenticated and delivered (except for 8-7/8% Notes authenticated
          and delivered upon registration of transfer of, or in exchange for, or
          in lieu of, other 8-7/8% Notes pursuant to Sections 304, 305, 306 or
          906 of the Indenture) is limited to $671,850,000;

               (iii)  the principal of the 8-7/8% Notes shall be payable on
          January 15, 2006 unless earlier repaid in accordance with the
          Indenture, as modified by this First Supplemental Indenture;

               (iv) the 8-7/8% Notes shall accrue interest at the rate of 8-7/8%
          per annum (computed on the basis of a 360-day year consisting of
          twelve 30-day months), and interest on the 8-7/8% Notes will accrue
          from and including the most recent Interest Payment Date to which
          interest has been paid or duly provided for, or if no interest has
          been paid, from July 15, 1997, as the case may be, and will be
          payable in cash semi-annually in arrears on January 15 and July 15 of
          each year (the "Interest Payment Dates"), commencing on January 15,
          1998, to the Holders of record on the immediately preceding December
          31 and June 30, respectively (the "Regular Record Dates"), until
          principal thereof is paid or duly provided for.  Interest on any
          overdue principal or premium shall be payable on demand;

               (v) the Place of Payment of the 8-7/8% Notes, and the place where
          the 8-7/8% Notes may be surrendered for registration of transfer and
          where the 8-7/8% Notes may be surrendered for exchange and where
          notices or demands may be served to or upon the Company with respect
          to the 8-7/8% Notes, shall be the Corporate Trust Office of the
          Trustee in the City of Pittsburgh, Pennsylvania and at the office of
          an affiliate of the Trustee in New York, New York, which office on
          the date hereof is located at 120 Broadway, 13th Floor, New York,
          New York 10271;

                                       4
<PAGE>
 
               (vi) the 8-7/8% Notes will not be redeemable at the option of the
          Company prior to January 15, 1999. On or after January 15, 1999, the
          8-7/8% Notes will be redeemable at the option of the Company, in whole
          at any time or in part from time to time, at the following prices
          (expressed in percentages of the principal amount thereof) in Dollars,
          if redeemed during the twelve months beginning January 15 of the years
          indicated below, in each case together with interest accrued to the
          Redemption Date (subject to the right of Holders of record on the
          relevant Regular or Special Record Date to receive interest due on the
          relevant Interest Payment Date):

<TABLE>
<CAPTION>

               Year                           Percentage
               ----                           ----------
               <S>                            <C>
               2001.......................... 103.32%
               2002.......................... 102.21%
               2003.......................... 101.11%
               2004 and thereafter........... 100.00%
</TABLE>


          On and after the Redemption Date, interest will cease to accrue on the
          8-7/8% Notes (or any portion thereof), if so called for redemption.

               (vii)  there shall be no sinking fund provided for the 8-7/8%
          Notes;

               (viii)  the 8-7/8% Notes shall be issuable only in denominations
          of $1,000 principal amount and any integral multiple thereof;

               (ix) the Trustee shall act as Security Registrar and Paying Agent
          with respect to the 8-7/8% Notes;

               (x) payment of the principal of (and premium, if any) or interest
          on the 8-7/8% Notes shall be denominated and payable only in Dollars;

               (xi) no payment on the 8-7/8% Notes shall be determined with
          reference to an index, formula or other such method;

               (xii)  no Additional Amounts shall be payable in respect of the
          8-7/8% Notes;

               (xiii)  except as stated in this First Supplemental Indenture,
          the 8-7/8% Notes do not contain any provisions granting special rights
          to the Holders thereof;

               (xiv)  with respect to the 8-7/8% Notes, there shall not be any
          deletions from, modifications of or additions to the Events of Default
          or covenants of the Company set forth in the Indenture;

               (xv) the 8-7/8% Notes shall be issuable only as Registered
          Securities without coupons and in book-entry form; the 8-7/8% Notes
          shall not be Bearer Securities; the 8-7/8% Notes shall be issuable
          initially by one or more global Securities in permanent global form
          without coupons and deposited with and registered in the name of (or
          in the name of the nominee of) the Depositary; and the form of the
          8-7/8% Notes is attached hereto as Exhibit B;

                                       5
<PAGE>
 
               (xvi)  the provisions of Sections 1402 and 1403 of the Indenture
          shall apply to the 8-7/8% Notes without modification thereof;

               (xvii)  no portion of the 8-7/8% Notes is convertible into Common
          Stock or Preferred Stock; and

               (xviii) (a) the provisions of Sections 109, 110, 111, and 112 of
          the Indenture shall not apply to the 8-7/8% Notes, and in lieu thereof
          the provisions set forth below in Sections 3, 4, 5 and 6,
          respectively, shall apply to the 8-7/8% Notes; (b) the provisions of
          Articles Twelve and Thirteen and of Sections 307(b) and 308 of the
          Indenture shall not apply to the 8-7/8% Notes; and (c) the additional
          provisions set forth below in Sections 7 through 10 shall apply to the
          8-7/8% Notes.

          (c) All of the covenants, agreements and provisions of this First
Supplemental Indenture shall be deemed to be and construed as part of the
Indenture to the same extent as if fully set forth verbatim therein and shall be
fully enforceable in the manner provided in the Indenture.  To the extent not
expressly amended or modified by this First Supplemental Indenture, the
Indenture shall remain in full force and effect.

     3.  Separability Clause.  In case any provision in the Indenture, as
         -------------------                                             
modified by this First Supplemental Indenture, or in the Notes shall be invalid,
illegal or unenforceable, the validity, legality and enforceability of the
remaining provisions shall not in any way be affected or impaired thereby.

     4.  Benefits of Indenture.  Nothing in the Indenture, this First
         ---------------------                                       
Supplemental Indenture or the Notes, express or implied, shall give to any
Person other than the parties hereto, any Security Registrar, any Paying Agent,
any Authenticating Agent, and their successors hereunder or thereunder and the
Holders of the Notes, any benefit or any legal or equitable right, remedy or
claim under the Indenture, this First Supplemental Indenture or the Notes.  This
First Supplemental Indenture may not be used to interpret another indenture,
loan agreement or debt agreement of the Company or any of its Subsidiaries
(other than the Indenture).  Any such indenture, loan or debt agreement may not
be utilized to interpret this First Supplemental Indenture.

     5.  Governing Law.  The Indenture, as modified by this First Supplemental
         -------------                                                        
Indenture, and the Notes shall be governed by and construed in accordance with
the law of the State of New York without regard to the conflicts of laws
principles thereof.  The Indenture, as modified by this First Supplement
Indenture, is subject to the provisions of the TIA that are required to be part
of the Indenture, as modified by this First Supplemental Indenture, and shall,
to the extent applicable, be governed by such provisions.

     6.  Legal Holidays.  In any case where any Interest Payment Date,
         --------------                                               
Redemption Date, Stated Maturity or Maturity of the Notes shall not be a
Business Day at any Place of Payment, then (notwithstanding any other provision
of the Indenture, as modified by this First Supplemental Indenture, or the
Notes) payment of interest or principal (and premium, if any) need not be made
at such Place of Payment on such date, but may be made on the next succeeding
Business Day at such Place of Payment with the same force and effect as if made
on the Interest Payment Date or Redemption Date, or at the Stated Maturity or
Maturity, provided that no interest shall accrue on
          --------                                                           

                                       6
<PAGE>
 
the amount so payable for the period from and after such Interest Payment Date,
Redemption Date, Stated Maturity or Maturity, as the case may be, to the date of
such payment.

     7.  Conflict with Trust Indenture Act.  If any provision of the Indenture,
         ---------------------------------                                     
as modified by the First Supplemental Indenture, limits, qualifies or conflicts
with a provision of the Trust Indenture Act that is required under such Act to
be part of and govern the Indenture, as modified by the First Supplemental
Indenture, the latter provision shall control.  If any provision of the
Indenture, as modified by the First Supplemental Indenture, modifies or excludes
any provision of the Trust Indenture Act that may be so modified or excluded,
the latter provision shall be deemed to apply to the Indenture, as modified this
First Supplemental Indenture, as so modified or to be excluded, as the case may
be.

     8.  CUSIP Numbers.  The Company in issuing the Notes may use "CUSIP"
         -------------                                                   
numbers (if then generally in use), and, if so, the Trustee shall use CUSIP
numbers in notices of redemption as a convenience to the Holders; provided that
any such notice may state that no representation is made as to the correctness
of such numbers either as printed on the Notes or as contained in any notice of
a redemption and that reliance may be placed only on the other identification
numbers printed on the Notes, and any such redemption shall not be affected by
any defect in or omission of such numbers.

     9.  No Recourse Against Others.  No recourse shall be had for the payment
         --------------------------                                           
of the principal of (or premium, if any) or interest, if any, on the Notes, the
Indenture or this First Supplemental Indenture, or any part hereof or thereof,
or for any claim based hereon or thereon or otherwise in respect hereof or
thereof, or of the indebtedness represented hereby or thereby, or upon any
obligation, covenant or agreement under the Notes, the Indenture or this First
Supplemental Indenture, against, and no personal liability whatsoever shall
attach to, or be incurred by, any incorporator, shareholder, officer or
director, as such, past, present or future, of (i) the Company or (ii) any
predecessor or successor corporation (either directly or through the Company
or a predecessor or successor corporation), whether by virtue of any
constitutional provision, statute or rule of law, or by the enforcement of any
assessment or penalty or otherwise. Each Holder by accepting a Note waives and
releases all such liability. Such waiver and release are part of the
consideration for the issuance of the Notes.

     10.  Counterparts.  This instrument may be executed in any number of
          ------------                                                   
counterparts, each of which so executed shall be deemed to be an original, but
all such counterparts shall together constitute but one and the same instrument.

     11.  Effect of Headings.  The section headings herein are for convenience
          ------------------                                                  
only and shall not affect the construction hereof.

     12.  Effectiveness.  This First Supplemental Indenture shall become
          -------------                                                 
effective in accordance with the provisions of Article Nine of the Indenture.

          IN WITNESS WHEREOF, parties hereto have caused this First Supplemental
Indenture to be duly executed, and their respective corporate seals to be
hereunto affixed, all as of the day and year first above written.

                                       7
<PAGE>
 
[SEAL]                                  WORLDCOM, INC.



                                        By:________________________________
                                        Title:  Chief Financial Officer


[SEAL]                                  MELLON BANK, N.A.



                                        By:_________________________________
                                        Title:  Vice President

                                       8
<PAGE>
 
                                                                     EXHIBIT A
                                                                     ---------
                            Form of Face of Security
                            ------------------------

                                  GLOBAL NOTE


Unless this certificate is presented by an authorized representative of The
Depository Trust Company, a New York corporation ("DTC"), to WorldCom, Inc. (the
"Company") or its agent for registration of transfer, exchange or payment, and
any certificate issued is registered in the name of Cede & Co. or in such other
name as is requested by an authorized representative of DTC (and any payment is
made to Cede & Co. or to such other entity as is requested by an authorized
representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner
hereof, Cede & Co., has an interest herein.

                                 WORLDCOM, INC.
                    9-3/8% Senior Note Due January 15, 2004
                                        
Principal Amount                                        No._______________
$                                                       CUSIP ____________

          WORLDCOM, INC., a corporation duly organized and existing under the
laws of the State of Georgia (herein called the "Company," which term includes
any successor corporation under the Indenture referred to below), for value
received, hereby promises to pay to Cede & Co., or registered assigns, the
principal sum of _________ Dollars on January 15, 2004 (the
"Stated Maturity"), and to pay interest thereon from the most recent Interest
Payment Date to which interest has been paid or duly provided for or, if no
interest has been paid, from July 15, 1997, payable semiannually in arrears
on January 15 and July 15 in each year (each, an "Interest Payment Date"),
commencing on January 15, 1998, and at Maturity, at the rate of 9-3/8% per
annum, until the principal hereof is paid or duly provided for.  Each payment of
interest in respect of an Interest Payment Date shall include interest accrued
through the day prior to such Interest Payment Date. The interest so payable,
and paid or duly provided for, on any Interest Payment Date shall, as provided
in the Indenture, be paid to the Person in whose name this Note (or one or more
Predecessor Securities) is registered at the close of business on the Regular
Record Date for such interest, which shall be December 31 or June 30 (whether or
not a Business Day), as the case may be, next preceding such Interest Payment
Date, at the office or agency of the Company maintained for such purpose in the
City of New York, New York.  Interest shall be computed on the basis of a 360-
day year consisting of twelve 30-day months.

          Except as otherwise provided in the Indenture, any such interest not
so paid or duly provided for shall forthwith cease to be payable to the Holder
on the related Regular Record Date and may either be paid to the Person in whose
name this Note (or one or more Predecessor Securities) is registered at the
close of business on a Special Record Date for the payment of such Defaulted
Interest to be fixed by the Trustee, notice whereof shall be given to Holders of
Notes  not less than 10 days prior to such Special Record Date, or be paid at
any time in any other lawful

                                      A-1
<PAGE>
 
manner not inconsistent with the requirements of any securities exchange on
which the Notes may be listed, and upon such notice as may be required by such
exchange, all as more fully provided in the Indenture.

          If any Interest Payment Date, any Redemption Date, the Stated Maturity
or the Maturity shall not be a Business Day (as hereinafter defined), payment of
the amount due on this Note on such date may be made on the next succeeding
Business Day; and, if such payment is made or duly provided for on such Business
Day, no interest shall accrue on such amounts for the period from and after such
Interest Payment Date, such Redemption Date, the Stated Maturity or the
Maturity, as the case may be, to such Business Day.

          Payment of the principal of (and premium, if any) and interest on this
Note at Maturity shall be made upon presentation hereof at the office or agency
of the Company, one of which will be maintained in Pittsburgh, Pennsylvania
(which initially will be the Corporate Trust Office of Mellon Bank, N.A. in
Pittsburgh, Pennsylvania) or at such other office or agency permitted under the
Indenture, including the office or agency of the Company maintained for such
purpose in the City of New York, New York.  Payment of the principal of (and
premium, if any) and interest on this Note shall be payable in immediately
available funds; provided however, that payment of interest may be made at the
option of the Company by check mailed to the address of the Person entitled
thereto as such address shall appear in the Security Register.  Payment of the
principal of (and premium, if any) and interest, if any, on this Note, as
aforesaid, shall be made in such coin or currency of the United States of
America as at the time of payment shall be legal tender for the payment of
public and private debts. Interest payable on any Interest Payment Date will be
paid to DTC, Euroclear and/or CEDEL, as the case may be, with respect to the
portion of this Note held for its account by Cede & Co. or a successor
depositary, as the case may be, for the purpose of permitting such party to
credit the interest received by it in respect of this Note to the accounts of
the beneficial owners hereof.

          This Note is one of a duly authorized issue of unsecured senior debt
securities of the Company known as the Company's 9-3/8% Senior Notes Due
January 15, 2004 limited to the aggregate principal amount of $686,398,000
(herein called the "Notes" or the "Securities"), issued under an Indenture
dated as of March 1, 1997 (such Indenture as originally executed and delivered
and as supplemented by the First Supplemental Indenture dated _____________,
1997 being herein called the "Indenture") from the Company to Mellon Bank
N.A., as trustee (herein called the "Trustee," which term includes any
successor trustees under the Indenture), to which Indenture, all indentures
supplemental thereto and all Board Resolutions relating thereto reference is
hereby made for a statement of the respective rights, limitations of rights,
duties and immunities thereunder of the Company, the Trustee and the Holders
of the Notes and of the terms upon which the Notes are, and are to be,
authenticated and delivered. The acceptance of this Note shall be deemed to
constitute the consent and agreement of the Holder hereof to all of the terms
and provisions of the Indenture. All capitalized terms used in this Note which
are not defined herein shall have the meaning assigned to them in the
Indenture.

          This Note shall not be redeemable at the option of the Company prior
to January 15, 1999.  On or after January 15, 1999, this Note will be redeemable
at the option of the Company, in whole at any time or in part from time to time,
at the following prices (expressed in percentages of the principal amount
thereof), if redeemed during the twelve months beginning January 15 of the years
indicated below, in each case together with interest accrued to the

                                      A-2
<PAGE>
 
Redemption Date (subject to the right of Holders of record on the relevant
Regular or Special Record Date to receive interest due on the relevant Interest
Payment Date):

<TABLE>
<CAPTION>

               Year                           Percentage
               ----                           ----------
               <S>                            <C>   
               1999.......................... 103.52%
               2000.......................... 102.34%
               2001.......................... 101.17%
               2002 and thereafter........... 100.00%
</TABLE>

Notice of redemption shall be given by mail to Holders of the Notes, not less
than 30 days nor more than 60 days prior to the Redemption Date, all as provided
in the Indenture. As provided in the Indenture, on or prior to the Redemption
Date, the Company shall deposit with the Trustee or with a Paying Agent an
amount of money sufficient to pay the Redemption Price of, and (except if the
Redemption Date shall be an Interest Payment Date) accrued interest on, the
Notes to be redeemed on such date.  In the event of redemption of this Note in
part only, a new Note or Notes, of like tenor, for the unredeemed portion hereof
will be issued in the name of the Holder hereof upon the surrender hereof, all
as provided in the Indenture.  On and after the Redemption Date, interest will
cease to accrue on this Note (or any portion thereof) if so called for
redemption.

          Reference is made to the further provisions of this Note set forth on
the reverse hereof, which provisions shall for all purposes have the same effect
as if set forth at this place.

          Unless the certificate of authentication hereon has been executed by
the Trustee by manual signature, this Note shall not be entitled to any benefit
under the Indenture or be valid or obligatory for any purpose.

          IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed under its corporate seal.


                                           WORLDCOM, INC.

Attested:
                                           By:__________________________
                                           President and Chief Executive Officer
________________________
    Secretary



This is one of the Securities of the series designated therein referred to in
the within-mentioned Indenture.



Dated:  ____________________, 1997         MELLON BANK, N.A.,  as Trustee


                                           By:__________________________
                                           Authorized Representative

                                      A-3
<PAGE>
 
                                Reverse Of Note
                                ---------------

                                 WORLDCOM, INC.
                    9-3/8% Senior Note Due January 15, 2004


          If an Event of Default with respect to Notes shall occur and be
continuing, the principal of all Notes may be declared due and payable in any
manner and with the effect provided in the Indenture.

          The Notes do not have the benefit of any sinking fund obligations and
do not provide for repayment at the option of the Holders.

          The Company's obligations under this Note and under the covenants
provided in the Indenture are subject to defeasance and discharge as provided in
the Indenture.

          The Indenture permits, with certain exceptions as thereby provided,
the Trustee to enter into one or more supplemental indentures for the purpose of
adding any provisions to, or changing in any manner or eliminating any of the
provisions of, the Indenture or of modifying in any manner the rights of the
Holders of Securities, in any such case, with the consent of the Holders of not
less than a majority in aggregate principal amount of all Outstanding Securities
affected by such supplemental indenture; provided, however, that no such
supplemental indenture shall, without the consent of the Holder of each of the
Outstanding Securities affected thereby, affect certain rights of such Holders
as more fully described in the Indenture.

          The Indenture also contains provisions permitting the Holders of
specified percentages in principal amount of the Securities then Outstanding, on
behalf of the Holders of all Securities affected thereby, to waive certain past
defaults by the Company under the Indenture and their consequences.  In
addition, without the consent of any Holder of a Security, the Indenture and the
Securities may be amended and supplemented to cure any defect, ambiguity or
inconsistency, make other changes which will not adversely affect in any
material respect the rights of the Holders or certain other matters specified in
the Indenture.  Any such consent or waiver by the Holder of this Note shall be
conclusive and binding upon such Holder and upon all future Holders of this Note
and of any Note issued upon the registration of transfer hereof or in exchange
herefor or in lieu hereof, whether or not notation of such consent or waiver is
made upon this Note.

          As provided in and subject to the provisions of the Indenture, the
Holder of this Note shall not have the right to institute any proceeding with
respect to the Indenture or for the appointment of a receiver or trustee, or for
any other remedy thereunder, unless such Holder shall have previously given the
Trustee written notice of a continuing Event of Default with respect to the
Notes, the Holders of not less than 25 percent in principal amount of the Notes
Outstanding shall have made written request to the Trustee to institute
proceedings in respect of such Event of Default as Trustee and offered the
Trustee reasonable indemnity and the Trustee shall not have received from the
Holders of a majority in principal amount of the Notes Outstanding a direction
inconsistent with such request, and shall have failed to institute any such
proceeding, for 60 days after receipt of such notice, request and offer of
indemnity.  The foregoing shall not apply to certain suits described in the
Indenture, including any suit instituted by the Holder of this Note for the
enforcement of any payment of principal hereof or any premium or interest hereon
on or after


                                      A-4
<PAGE>
 
the respective due dates expressed herein (or, in the case of redemption, on or
after the Redemption Date).

          No reference herein to the Indenture and no provision of this Note or
of the Indenture shall alter or impair the obligation of the Company, which is
absolute and unconditional, to pay the principal of (and premium, if any) and
interest, if any, on this Note at the times, place and rate, in the coin or
currency, and in the manner, herein prescribed.

          The Notes are issuable only in registered form, without coupons, in
denominations of $1,000 and any integral multiple of $1,000, and in book-entry
form. The Notes may be represented by one or more global Notes deposited with
DTC and registered in the name of the nominee of DTC, with certain limited
exceptions.  So long as DTC or any successor depository or its nominee is the
registered Holder of a global Note, DTC, such depository or such nominee, as the
case may be, will be considered to be the sole Holder of the Notes for all
purposes of the Indenture.  Except as provided below, an owner of a beneficial
interest in a global Note will not be entitled to have Notes represented by such
global Note registered in such owner's name, will not receive or be entitled to
receive physical delivery of the Notes in certificated form and will not be
considered the owner or Holder thereof under the Indenture.  Each person owning
a beneficial interest in a global Note must rely on DTC's procedures and, if
such person is not a participant, on the procedures of the participant through
which such person owns its interest, to exercise any rights of a Holder under
the Indenture.  If the Company requests any action of Holders or if an owner of
a beneficial interest in a global Note desires to take any action that a Holder
is entitled to take under the Indenture, DTC will authorize the participants
holding the relevant beneficial interests to give or take such action, and such
participants will otherwise act upon the instructions of beneficial owners
holding through them.

          If at any time DTC notifies the Company that it is unwilling or unable
to continue as depository for the global Note or Notes or if at any time DTC
ceases to be a clearing agency registered under the Securities Exchange Act of
1934, as amended, if so required by applicable law or regulation, the Company
shall appoint a successor depository with respect to such global Note or Notes.
If (x) a successor depository for such global Note or Notes is not appointed by
the Company within 90 days after the Company receives such notice or becomes
aware of such unwillingness, inability or ineligibility, (y) an Event of Default
has occurred and is continuing and the beneficial owners representing a majority
in principal amount of the Notes represented by such global Note or Notes advise
DTC to cease acting as depository for such global Note or Notes or (z) the
Company, in its sole discretion, determines at any time that all Outstanding
Notes (but not less than all) issued or issuable in the form of one or more
global Notes shall no longer be represented by such global Notes, then the
Company shall execute, and the Trustee shall authenticate and deliver,
definitive Notes of like series, rank, tenor and terms in definitive form in an
aggregate principal amount equal to the principal amount of such global Note or
Notes. If any beneficial owner of an interest in a permanent global Note is
otherwise entitled to exchange such interest for Notes of such series and of
like tenor and principal amount of another authorized form and denomination, as
contemplated by the Indenture and provided that any applicable notice provided
in the permanent global Note shall have been given, then without unnecessary
delay but in any event not later than the earliest date on which such interest
may be so exchanged, the Company shall execute, and the Trustee shall
authenticate and deliver, definitive Notes in aggregate principal amount equal
to the principal amount of such beneficial owner's interest in such permanent
global Note. On or after the earliest date on which such interests may be so

                                      A-5
<PAGE>
 
exchanged, such permanent global Note shall be surrendered for exchange
by DTC or such other depository as the Company shall specify to the Trustee;
provided, however, that no such exchanges may occur during a period beginning at
- --------- --------
the opening of business 15 days before any selection of Notes to be redeemed and
ending on the relevant Redemption Date if the Note for which exchange is
requested may be among those selected for redemption.

          None of the Company, the Trustee, any Paying Agent or the Security
Registrar will have any responsibility or liability for any aspect of the
records relating to or payments made on account of beneficial ownership
interests in this Note in global form or for maintaining, supervising or
reviewing any records relating to such beneficial ownership interests.
Notwithstanding the foregoing, nothing herein shall prevent the Company, the
Trustee, or any agent of the Company or the Trustee, from giving effect to any
written certification, proxy or other authorization furnished by any depository,
as a Holder, with respect to this Note in global form or impair, as between such
depository and owners of beneficial interests in such global Note, the operation
of customary practices governing the exercise of the rights of such depository
(or its nominee) as Holder of such global Note.

          THE INDENTURE AND THE SECURITIES SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD TO CONFLICTS
OF LAW PRINCIPLES THEREOF.

          As used herein, "Business Day", when used with respect to any Place of
Payment or any other particular location referred to in this Note or in the
Indenture, means any day, other than a Saturday or Sunday, that is neither a
legal holiday nor a day on which banking institutions in that Place of Payment
or particular location are authorized or required by law, regulation or
executive order to be closed.

          The Company may cause CUSIP numbers to be printed on the Notes as a
convenience to Holders of Notes.  No representation is made as to the accuracy
of such numbers as printed on the Notes, and reliance may be placed only on the
other identification numbers printed thereon.

          This Note shall not be entitled to any benefit under the Indenture or
be valid or obligatory until the Trustee or authenticating agent signs the
certificate of authenticity on the Notes.

          No recourse shall be had for the payment of the principal of (or
premium, if any) or interest, if any, on this Note, or any part hereof, or for
any claim based hereon or otherwise in respect hereof, or of the indebtedness
represented hereby, or upon any obligation, covenant or agreement under the
Indenture, against, and no personal liability whatsoever shall attach to, or be
incurred by, any incorporator, shareholder, officer or director, as such,
past, present or future, of (i) the Company or (ii) any predecessor or
successor corporation (either directly or through the Company or a predecessor
or successor corporation), whether by virtue of any constitutional provision,
statute or rule of law, or by the enforcement of any assessment or penalty or
otherwise; it being expressly agreed and understood that the Indenture and all
of the Notes are solely corporate obligations and that any such personal
liability is hereby expressly waived and released as a condition of, and as
part of the consideration for, the execution of the Indenture and the issuance
of the Notes.


                                      A-6
<PAGE>
 
                                                                       EXHIBIT B
                                                                       ---------
                            Form of Face of Security
                            ------------------------

                                  GLOBAL NOTE

Unless this certificate is presented by an authorized representative of The
Depository Trust Company, a New York corporation ("DTC"), to WorldCom, Inc. (the
"Company") or its agent for registration of transfer, exchange or payment, and
any certificate issued is registered in the name of Cede & Co. or in such other
name as is requested by an authorized representative of DTC (and any payment is
made to Cede & Co. or to such other entity as is requested by an authorized
representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner
hereof, Cede & Co., has an interest herein.

                                 WORLDCOM, INC.
                    8-7/8% Senior Note Due January 15, 2006
                                        
Principal Amount                                        No._______________
$                                                       CUSIP_____________

          WORLDCOM, INC., a corporation duly organized and existing under the
laws of the State of Georgia (herein called the "Company," which term includes
any successor corporation under the Indenture referred to below), for value
received, hereby promises to pay to Cede & Co., or registered assigns, the
principal sum of _________________________ Dollars on January 15, 2006 (the
"Stated Maturity"), and to pay interest thereon from the most recent Interest
Payment Date to which interest has been paid or duly provided for or, if no
interest has been paid, from July 15, 1997, payable semiannually in
arrears on January 15 and July 15 in each year (each, an "Interest Payment
Date"), commencing on January 15, 1998 and at Maturity, at the rate of 8-7/8%
per annum, until the principal hereof is paid or duly provided for.  Each
payment of interest in respect of an Interest Payment Date shall include
interest accrued through the day prior to such Interest Payment Date. The
interest so payable, and paid or duly provided for, on any Interest Payment Date
shall, as provided in the Indenture, be paid to the Person in whose name this
Note (or one or more Predecessor Securities) is registered at the close of
business on the Regular Record Date for such interest, which shall be December
31 or June 30 (whether or not a Business Day), as the case may be, next
preceding such Interest Payment Date, at the office or agency of the Company
maintained for such purpose in the City of New York, New York.  Interest shall
be computed on the basis of a 360-day year consisting of twelve 30-day months.

          Except as otherwise provided in the Indenture, any such interest not
so paid or duly provided for shall forthwith cease to be payable to the Holder
on the related Regular Record Date and may either be paid to the Person in whose
name this Note (or one or more Predecessor Securities) is registered at the
close of business on a Special Record Date for the payment of such Defaulted
Interest to be fixed by the Trustee, notice whereof shall be given to Holders of
Notes  not less than 10 days prior to such Special Record Date, or be paid at
any time in any other lawful manner not inconsistent with the requirements of
any securities exchange on which the Notes may

                                      B-1
<PAGE>
 
be listed, and upon such notice as may be required by such exchange, all as more
fully provided in the Indenture.

          If any Interest Payment Date, any Redemption Date, the Stated Maturity
or the Maturity shall not be a Business Day (as hereinafter defined), payment of
the amount due on this Note on such date may be made on the next succeeding
Business Day; and, if such payment is made or duly provided for on such Business
Day, no interest shall accrue on such amounts for the period from and after such
Interest Payment Date, such Redemption Date, the Stated Maturity or the
Maturity, as the case may be, to such Business Day.

          Payment of the principal of (and premium, if any) and interest on this
Note at Maturity shall be made upon presentation hereof at the office or agency
of the Company, one of which will be maintained in Pittsburgh, Pennsylvania
(which initially will be the Corporate Trust Office of Mellon Bank, N.A. in
Pittsburgh, Pennsylvania) or at such other office or agency permitted under the
Indenture, including the office or agency of the Company maintained for such
purpose in the City of New York, New York.  Payment of the principal of (and
premium, if any) and interest on this Note shall be payable in immediately
available funds; provided however, that payment of interest may be made at the
option of the Company by check mailed to the address of the Person entitled
thereto as such address shall appear in the Security Register.  Payment of the
principal of (and premium, if any) and interest, if any, on this Note, as
aforesaid, shall be made in such coin or currency of the United States of
America as at the time of payment shall be legal tender for the payment of
public and private debts. Interest payable on any Interest Payment Date will be
paid to DTC, Euroclear and/or CEDEL, as the case may be, with respect to the
portion of this Note held for its account by Cede & Co. or a successor
depositary, as the case may be, for the purpose of permitting such party to
credit the interest received by it in respect of this Note to the accounts of
the beneficial owners hereof.

          This Note is one of a duly authorized issue of unsecured senior debt
securities of the Company known as the Company's 8-7/8% Senior Notes Due January
15, 2006 limited to the aggregate principal amount of $671,850,000 (herein
called the "Notes" or the "Securities"), issued under an Indenture dated as of
March 1, 1997 (such Indenture as originally executed and delivered and as
supplemented by the First Supplemental Indenture dated _____________, 1997
being herein called the "Indenture") from the Company to Mellon Bank N.A., as
trustee (herein called the "Trustee," which term includes any successor
trustees under the Indenture), to which Indenture, all indentures supplemental
thereto and all Board Resolutions relating thereto reference is hereby made
for a statement of the respective rights, limitations of rights, duties and
immunities thereunder of the Company, the Trustee and the Holders of the Notes
and of the terms upon which the Notes are, and are to be, authenticated and
delivered. The acceptance of this Note shall be deemed to constitute the
consent and agreement of the Holder hereof to all of the terms and provisions
of the Indenture. All capitalized terms used in this Note which are not
defined herein shall have the meaning assigned to them in the Indenture.

          This Note shall not be redeemable at the option of the Company prior
to January 15, 2001.  On or after January 15, 2001, this Note will be redeemable
at the option of the Company, in whole at any time or in part from time to time,
at the following prices (expressed in percentages of the principal amount
thereof), if redeemed during the twelve months beginning January 15 of the years
indicated below, in each case together with interest accrued to the Redemption
Date (subject to the right of Holders of record on the relevant Regular or
Special Record Date to


                                      B-2
<PAGE>
 
receive interest due on the relevant Interest Payment Date):


<TABLE>
<CAPTION>

               Year                           Percentage
               ----                           ----------
               <S>                            <C>   
               2001.......................... 103.32%
               2002.......................... 102.21%
               2003.......................... 101.11%
               2004 and thereafter........... 100.00%
</TABLE>

          Notice of redemption shall be given by mail to Holders of the Notes,
not less than 30 days nor more than 60 days prior to the Redemption Date, all as
provided in the Indenture. As provided in the Indenture, on or prior to the
Redemption Date, the Company shall deposit with the Trustee or with a Paying
Agent an amount of money sufficient to pay the Redemption Price of, and (except
if the Redemption Date shall be an Interest Payment Date) accrued interest on,
the Notes to be redeemed on such date.  In the event of redemption of this Note
in part only, a new Note or Notes, of like tenor, for the unredeemed portion
hereof will be issued in the name of the Holder hereof upon the surrender
hereof, all as provided in the Indenture.  On and after the Redemption Date,
interest will cease to accrue on this Note (or any portion thereof) if so called
for redemption.

          Reference is made to the further provisions of this Note set forth on
the reverse hereof, which provisions shall for all purposes have the same effect
as if set forth at this place.

          Unless the certificate of authentication hereon has been executed by
the Trustee by manual signature, this Note shall not be entitled to any benefit
under the Indenture or be valid or obligatory for any purpose.

          IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed under its corporate seal.



                                           WORLDCOM, INC.

Attested:
                                           By:__________________________
                                           President and Chief Executive Officer
________________________
    Secretary



This is one of the Securities of the series designated therein referred to in
the within-mentioned Indenture.



Dated:  ____________________, 1997         MELLON BANK, N.A.,  as Trustee


                                           By:__________________________
                                           Authorized Representative

                                      B-3
<PAGE>
 
                                Reverse Of Note
                                ---------------

                                 WORLDCOM, INC.
                    8-7/8% Senior Note Due January 15, 2006


          If an Event of Default with respect to Notes shall occur and be
continuing, the principal of all Notes may be declared due and payable in any
manner and with the effect provided in the Indenture.

          The Notes do not have the benefit of any sinking fund obligations and
do not provide for repayment at the option of the Holders.

          The Company's obligations under this Note and under the covenants
provided in the Indenture are subject to defeasance and discharge as provided in
the Indenture.

          The Indenture permits, with certain exceptions as thereby provided,
the Trustee to enter into one or more supplemental indentures for the purpose of
adding any provisions to, or changing in any manner or eliminating any of the
provisions of, the Indenture or of modifying in any manner the rights of the
Holders of Securities, in any such case, with the consent of the Holders of not
less than a majority in aggregate principal amount of all Outstanding Securities
affected by such supplemental indenture; provided, however, that no such
supplemental indenture shall, without the consent of the Holder of each of the
Outstanding Securities affected thereby, affect certain rights of such Holders
as more fully described in the Indenture.

          The Indenture also contains provisions permitting the Holders of
specified percentages in principal amount of the Securities then Outstanding, on
behalf of the Holders of all Securities affected thereby, to waive certain past
defaults by the Company under the Indenture and their consequences.  In
addition, without the consent of any Holder of a Security, the Indenture and the
Securities may be amended and supplemented to cure any defect, ambiguity or
inconsistency, make other changes which will not adversely affect in any
material respect the rights of the Holders or certain other matters specified in
the Indenture.  Any such consent or waiver by the Holder of this Note shall be
conclusive and binding upon such Holder and upon all future Holders of this Note
and of any Note issued upon the registration of transfer hereof or in exchange
herefor or in lieu hereof, whether or not notation of such consent or waiver is
made upon this Note.

          As provided in and subject to the provisions of the Indenture, the
Holder of this Note shall not have the right to institute any proceeding with
respect to the Indenture or for the appointment of a receiver or trustee, or for
any other remedy thereunder, unless such Holder shall have previously given the
Trustee written notice of a continuing Event of Default with respect to the
Notes, the Holders of not less than 25 percent in principal amount of the Notes
Outstanding shall have made written request to the Trustee to institute
proceedings in respect of such Event of Default as Trustee and offered the
Trustee reasonable indemnity and the Trustee shall not have received from the
Holders of a majority in principal amount of the Notes Outstanding a direction
inconsistent with such request, and shall have failed to institute any such
proceeding, for 60 days after receipt of such notice, request and offer of
indemnity.  The foregoing shall not apply to certain suits described in the
Indenture, including any suit instituted by the Holder of this Note for the
enforcement of any payment of principal hereof or any premium or interest hereon
on or after


                                      B-4
<PAGE>
 
the respective due dates expressed herein (or, in the case of redemption, on or
after the Redemption Date).

          No reference herein to the Indenture and no provision of this Note or
of the Indenture shall alter or impair the obligation of the Company, which is
absolute and unconditional, to pay the principal of (and premium, if any) and
interest, if any, on this Note at the times, place and rate, in the coin or
currency, and in the manner, herein prescribed.

          The Notes are issuable only in registered form, without coupons, in
denominations of $1,000 and any integral multiple of $1,000, and in book-entry
form. The Notes may be represented by one or more global Notes deposited with
DTC and registered in the name of the nominee of DTC, with certain limited
exceptions.  So long as DTC or any successor depository or its nominee is the
registered Holder of a global Note, DTC, such depository or such nominee, as the
case may be, will be considered to be the sole Holder of the Notes for all
purposes of the Indenture.  Except as provided below, an owner of a beneficial
interest in a global Note will not be entitled to have Notes represented by such
global Note registered in such owner's name, will not receive or be entitled to
receive physical delivery of the Notes in certificated form and will not be
considered the owner or Holder thereof under the Indenture.  Each person owning
a beneficial interest in a global Note must rely on DTC's procedures and, if
such person is not a participant, on the procedures of the participant through
which such person owns its interest, to exercise any rights of a Holder under
the Indenture.  If the Company requests any action of Holders or if an owner of
a beneficial interest in a global Note desires to take any action that a Holder
is entitled to take under the Indenture, DTC will authorize the participants
holding the relevant beneficial interests to give or take such action, and such
participants will otherwise act upon the instructions of beneficial owners
holding through them.

          If at any time DTC notifies the Company that it is unwilling or unable
to continue as depository for the global Note or Notes or if at any time DTC
ceases to be a clearing agency registered under the Securities Exchange Act of
1934, as amended, if so required by applicable law or regulation, the Company
shall appoint a successor depository with respect to such global Note or Notes.
If (x) a successor depository for such global Note or Notes is not appointed by
the Company within 90 days after the Company receives such notice or becomes
aware of such unwillingness, inability or ineligibility, (y) an Event of Default
has occurred and is continuing and the beneficial owners representing a majority
in principal amount of the Notes represented by such global Note or Notes advise
DTC to cease acting as depository for such global Note or Notes or (z) the
Company, in its sole discretion, determines at any time that all Outstanding
Notes (but not less than all) issued or issuable in the form of one or more
global Notes shall no longer be represented by such global Notes, then the
Company shall execute, and the Trustee shall authenticate and deliver,
definitive Notes of like series, rank, tenor and terms in definitive form in an
aggregate principal amount equal to the principal amount of such global Note or
Notes.  If any beneficial owner of an interest in a permanent global Note is
otherwise entitled to exchange such interest for Notes of such series and of
like tenor and principal amount of another authorized form and denomination, as
contemplated by the Indenture and provided that any applicable notice provided
in the permanent global Note shall have been given, then without unnecessary
delay but in any event not later than the earliest date on which such interest
may be so exchanged, the Company shall execute, and the Trustee shall
authenticate and deliver, definitive Notes in aggregate principal amount equal
to the principal amount of such beneficial owner's interest in such permanent
global Note. On or after the earliest date on which such interests may be so


                                      B-5
<PAGE>
 
exchanged, such permanent global Note shall be surrendered for exchange
by DTC or such other depository as the Company shall specify to the Trustee;
provided, however, that no such exchanges may occur during a period beginning at
- --------- --------
the opening of business 15 days before any selection of Notes to be redeemed and
ending on the relevant Redemption Date if the Note for which exchange is
requested may be among those selected for redemption.

          None of the Company, the Trustee, any Paying Agent or the Security
Registrar will have any responsibility or liability for any aspect of the
records relating to or payments made on account of beneficial ownership
interests in this Note in global form or for maintaining, supervising or
reviewing any records relating to such beneficial ownership interests.
Notwithstanding the foregoing, nothing herein shall prevent the Company, the
Trustee, or any agent of the Company or the Trustee, from giving effect to any
written certification, proxy or other authorization furnished by any depository,
as a Holder, with respect to this Note in global form or impair, as between such
depository and owners of beneficial interests in such global Note, the operation
of customary practices governing the exercise of the rights of such depository
(or its nominee) as Holder of such global Note.

          THE INDENTURE AND THE SECURITIES SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD TO CONFLICTS
OF LAW PRINCIPLES THEREOF.

          As used herein, "Business Day", when used with respect to any Place of
Payment or any other particular location referred to in this Note or in the
Indenture, means any day, other than a Saturday or Sunday, that is neither a
legal holiday nor a day on which banking institutions in that Place of Payment
or particular location are authorized or required by law, regulation or
executive order to be closed.

          The Company may cause CUSIP numbers to be printed on the Notes as a
convenience to Holders of Notes.  No representation is made as to the accuracy
of such numbers as printed on the Notes, and reliance may be placed only on the
other identification numbers printed thereon.

          This Note shall not be entitled to any benefit under the Indenture or
be valid or obligatory until the Trustee or authenticating agent signs the
certificate of authenticity on the Notes.

          No recourse shall be had for the payment of the principal of (or
premium, if any) or interest, if any, on this Note, or any part hereof, or for
any claim based hereon or otherwise in respect hereof, or of the indebtedness
represented hereby, or upon any obligation, covenant or agreement under the
Indenture, against, and no personal liability whatsoever shall attach to, or be
incurred by, any incorporator, shareholder, officer or director, as such, past,
present or future, of the Company or of any predecessor or successor corporation
(either directly or through the Company or a predecessor or successor
corporation), whether by virtue of any constitutional provision, statute or rule
of law, or by the enforcement of any assessment or penalty or otherwise; it
being expressly agreed and understood that the Indenture and all of the Notes
are solely corporate obligations and that any such personal liability is hereby
expressly waived and released as a condition of, and as part of the
consideration for, the execution of the Indenture and the issuance of the Notes.




                                      B-6

<PAGE>
 
                                                                    EXHIBIT 4.14

- --------------------------------------------------------------------------------

- --------------------------------------------------------------------------------

                        MFS COMMUNICATIONS COMPANY, INC.

                                      and

                       IBJ SCHRODER BANK & TRUST COMPANY
                                           Trustee

                        ________________________________
                                     SECOND

                             SUPPLEMENTAL INDENTURE

                           Dated as of _______, 1997

                                       to

                                   INDENTURE

                          Dated as of January 15, 1994

                        ________________________________
                                  $788,320,000

                     Principal Amount at Stated Maturity of

                     9-3/8% Senior Discount Notes Due 2004

                                        

- --------------------------------------------------------------------------------

- --------------------------------------------------------------------------------
 
<PAGE>
 
          THIS SECOND SUPPLEMENTAL INDENTURE, dated as of _______, 1997 (the
"Second Supplement"), by and between MFS COMMUNICATIONS COMPANY, INC., a
corporation duly organized and existing under the laws of the State of Delaware
(herein called "MFS" or the "Company"), having its principal office at 3555
Farnam Street, Suite 200, Omaha, Nebraska 68131, and IBJ SCHRODER BANK & TRUST
COMPANY, a New York banking corporation, as Trustee (herein called the
"Trustee").

          WHEREAS, pursuant to the terms of the Indenture, dated as of January
15, 1994 (the "Original Indenture"), as supplemented and amended by the First
Supplemental Indenture, dated as of March 31, 1995 (the "First Supplement" and,
together with the Original Indenture, the "Indenture"), between the Company and
the Trustee, the Company has issued $788,320,000 principal amount at Stated
Maturity of its 9-3/8% Senior Discount Notes Due 2004 (herein called the
"Securities"); and

          WHEREAS, effective as of December 31, 1996, pursuant to the terms of
that certain Amended and Restated Agreement and Plan of Merger (the "Merger
Agreement"), dated as of  August 25, 1996, by and among WorldCom, Inc., a
Georgia corporation ("WorldCom"), HIJ Corp., a Delaware corporation and a wholly
owned subsidiary of WorldCom ("Merger Sub"), and MFS, Merger Sub was merged with
and into MFS, which thereby became a wholly owned subsidiary of WorldCom;

          WHEREAS, WorldCom is offering (the "Offer"), upon the terms and
subject to the conditions set forth in the Prospectus and Consent Solicitation
(together, the "Prospectus") dated ______, 1997 and the accompanying Letter of
Transmittal and Consent, to exchange (the "Exchange") [$________ ] principal
amount of its 9-3/8% Senior Notes due January 15, 2004 for each $1,000 principal
amount at Stated Maturity of outstanding Securities;

          WHEREAS, Section 902 of the Original Indenture provides that the
Company, when authorized by a Board Resolution, may with the consent of the
Holders of not less than a majority in principal amount at Stated Maturity of
the Outstanding Securities, and subject to Section 903 of the Original
Indenture, the Trustee shall enter into an indenture or indentures supplemental
to the Original Indenture, in form satisfactory to the Trustee, to add any
provisions to or change in any manner or eliminate any of the provisions of the
Indenture or modify in any manner the rights of the Holders of Securities,
except with respect to certain matters set forth therein, [and except that the
consent of Holders of not less than 75% in principal amount at Stated Maturity
of the Outstanding Securities is required to make any amendment to Section 1013
of the Original Indenture and the definition of "Change of Control"] /1/


 
          WHEREAS, Holders of Securities who tender their Securities pursuant to
the Offer will be deemed, as a condition to a valid tender, to have given their
consent to certain proposed amendments to the Indenture as described in the
Prospectus;


- --------------------------------------
/1/    Bracketed language will be included in this supplemental indenture only
if a Supermajority Consent is obtained by WorldCom in connection with the Offer
and the Exchange.
<PAGE>
          WHEREAS, as a condition to the Exchange, Holders of a majority in
aggregate principal amount of Outstanding Securities must have consented (the
"Requisite Consent") to amend the Indenture as described in the Prospectus;

          [WHEREAS, with respect to the modification of the term "Change in
Control," the Holders of 75% of the aggregate principal amount of Outstanding
Securities must have consented to such modification (the "Supermajority
Consent");]/1/


          WHEREAS, the Board of Directors of the Company has authorized the
execution of this Second Supplement and its delivery to the Trustee; and

          WHEREAS, all acts and things necessary, including the receipt of the
Requisite Consent [and the Supermajority Consent]/2/ to make this Second
Supplement the valid, binding and legal obligation of the Company in accordance
with its terms have been done.

          NOW, THEREFORE, THIS SECOND SUPPLEMENTAL INDENTURE WITNESSETH:

          Section 101.  Definitions.  Except as otherwise expressly provided
                        ------------                                        
herein, capitalized terms used herein shall have the meanings ascribed to them
in the Indenture.

          Section 102.  Amendment of Indenture.
                        ---------------------- 

          (a) Section 1008 (Limitation on Debt) of the Indenture is hereby
amended and restated in its entirety to read as follows:

              "Intentionally omitted."

          (b) Section 1009 (Limitation on Incurrence of Debt and Preferred Stock
of Restricted Subsidiaries) of the Indenture is hereby amended and restated in
its entirety to read as follows:

              "Intentionally omitted."

          (c) Section 1010 (Limitation on Restricted Payments) of the Indenture
is hereby amended and restated in its entirety to read as follows:

              "Intentionally omitted."

          (d) Section 1011 (Transactions with Affiliates) of the Indenture is
hereby amended and restated in its entirety to read as follows:

              "Intentionally omitted."

- ---------------------------
/2/     Bracketed language will be included in this supplemental indenture only
if a Supermajority Consent is obtained by WorldCom in connection with the Offer
and the Exchange.

                                       2
<PAGE>
 
          (e) Section 1012 (Limitations on Liens) of the Indenture is hereby
amended and restated in its entirety to read as follows:

              "Intentionally omitted."

          (f) Section 1014 (Limitation on Dividend and Other Payment
Restrictions Affecting Restricted Subsidiaries) of the Indenture is hereby
amended and restated in its entirety to read as follows:

              "Intentionally omitted."

          (g) Section 1016 (Limitations on Sale and Leaseback Transactions) of
the Indenture is hereby amended and restated in its entirety to read as follows:

              "Intentionally omitted."

          (h) Section 1017 (Provision of Financial Information) of the Indenture
is hereby amended and restated in its entirety to read as follows:

              "Intentionally omitted."

          (i) Section 1018 (Limitations on Issuance and Sale of Capital Stock of
Restricted Subsidiaries) of the Indenture is hereby amended and restated in its
entirety to read as follows:

              "Intentionally omitted."

          (j) Section 501 (Events of Default) of the Indenture is hereby 
amended and restated in its entirety to read as follows:

          " "Event of Default", wherever used herein means any one of the
following events (whatever the reason for such Event of Default and whether or
not it shall be voluntary or involuntary or be effected by operation of law or
pursuant to any judgment, decree or order of any court or any order, rule or
regulation of any administrative or governmental body):

          (1) default in the payment of any interest upon any Security when such
     interest becomes due and payable, and continuance of such default for a
     period of 30 days; or

          (2) default in the payment of the principal of (or premium, if any,
     on) any Security when it becomes due and payable at its Maturity; or

          (3) default in the performance, or breach, of any covenant or warranty
     of the Company in this Indenture with respect to any Security (other than a
     covenant or warranty a default in whose performance or whose breach is
     elsewhere in this Section specifically dealt with), and continuance of such
     default or breach for a period of 60 days after there has been given, by
     registered or certified mail, to the Company by the Trustee or to the
     Company and the Trustee by the Holders of at least 25% in principal amount
     of the

                                       3
<PAGE>
 
     Outstanding Securities, a written notice specifying such default or breach
     and requiring it to be remedied and stating that such notice is a "Notice
     of Default" hereunder; or

          (4) a default under any bond, debenture, note or other evidence of
     indebtedness of the Company or under any mortgage, indenture or instrument
     under which there may be issued or by which there may be secured or
     evidenced any indebtedness of the Company (including this Indenture),
     whether such indebtedness now exists or shall hereafter be created, which
     default shall constitute a failure to pay an aggregate principal amount
     exceeding $50,000,000 of such indebtedness when due and payable after the
     expiration of any applicable grace period with respect thereto and shall
     have resulted in such indebtedness in an aggregate principal amount
     exceeding $50,000,000 becoming or being declared due and payable prior to
     the date on which it would otherwise have become due and payable, without
     such indebtedness having been discharged, or such acceleration having been
     rescinded or annulled, within a period of 10 days after there shall have
     been given, by registered or certified mail, to the Company by the Trustee
     or to the Company and the Trustee by the Holders of at least 10% in
     principal amount of the Outstanding Securities of that series a written
     notice specifying such default and requiring the Company to cause such
     indebtedness to be discharged or cause such acceleration to be rescinded or
     annulled and stating that such notice is a "Notice of Default" hereunder;
     provided, however, that if such default under such bond, debenture, note,
     --------  -------                                                        
     mortgage, indenture or other instrument or evidence of indebtedness shall
     be remedied or cured by the Company or waived pursuant to such agreement or
     instrument, then, unless the Stated Maturity of the Securities shall have
     been accelerated as provided herein, the Event of Default hereunder by
     reason thereof shall be deemed likewise to have been thereupon remedied,
     cured or waived without further action upon the part of either the Trustee
     or the Holders; or

          (5) the Company pursuant to or within the meaning of any Bankruptcy
     Law:

               (A)  commences a voluntary case,

               (B)  consents to the entry of an order for relief against it in
                    an involuntary case,

               (C)  consents to the appointment of a Custodian of it or for all
                    or substantially all of its property, or

               (D)  makes a general assignment for the benefit of its creditors;
          or

          (6) a court of competent jurisdiction enters an order or decree under
     any Bankruptcy Law that:

               (A)  is for relief against the Company in an involuntary case,

               (B)  appoints a Custodian of the Company or for all or
                    substantially all of its property, or

                                       4
<PAGE>
 
               (C) orders the liquidation of the Company,

     and, in any such case, such order or decree remains unstayed and in effect
     for 90 days.

The term "Bankruptcy Law" means title 11, U.S. Code or any similar Federal or
State law for the relief of debtors.  The term "Custodian" means any receiver,
trustee, assignee, liquidator or other similar official under any "Bankruptcy
Law."

          (k) The first paragraph of Section 502 (Acceleration of Maturity;
Rescission and Annulment) of the Indenture is hereby amended and restated to
read as follows:

          "If an Event of Default occurs and is continuing, then and in every
such case the Trustee or the Holders of not less than 25% in principal amount at
Stated Maturity of the Outstanding Securities may declare the Default Amount of
all the Securities to be due and payable immediately by a notice in writing to
the Company (and to the Trustee if given by the Holders), and upon any such
declaration such Default Amount shall become immediately due and payable."

          [(l)  The definition of "Change of Control" contained in Section 101
of the Indenture is hereby amended and restated in its entirety to read as
follows:



          "Change of Control"  means the occurrence of any of the following
events:

          (a) any "person" or "group" (as such terms are used in Sections 13(d)
and 14(d) of the Exchange Act), other than WorldCom, Inc., a Georgia corporation
("WorldCom"), or its Affiliates or an underwriter engaged in a firm commitment
underwriting on behalf of the Company, is or becomes the "beneficial owner" (as
such term is used in Rules 13d-3 and13d-5 under the Exchange Act) plus all
shares that such person or group has the right to acquire, whether such right is
exercisable immediately or only after a passage of time, directly or indirectly,
of more than 50 percent of the total voting power of the Voting Stock of the
Company and, in addition, beneficially owns more shares in the Company than
beneficially owned by WorldCom and the Employee Group; or

          (b) the Company sells, conveys, transfers or leases (either in one
transaction or a series of related transactions) all or substantially all of its
assets to a Person other than an Affiliate."]/3/

          Section 103.  Construction with Indenture.  All of the covenants,
                        ---------------------------                        
agreements and provisions of this Second Supplement shall be deemed to be and
construed as part of the Indenture and vice versa to the same extent as if fully
set forth verbatim therein and herein and shall be fully enforceable in the
manner provided in the Indenture.  Except as provided in this Second Supplement,
the Indenture shall remain in full force and effect and the terms and conditions
thereof are hereby confirmed.

- -------------------------------
/3/  This Section 102(l) will be included in this supplemental indenture only
if a Supermajority Consent is obtained by WorldCom in connection with the Offer
and the Exchange.

                                       5
<PAGE>
 
          Section 104.  Conflict with Trust Indenture Act.  If any provision
                        ---------------------------------                   
hereof limits, qualifies or conflicts with a provision of the Trust Indenture
Act that is required under such Act to be part of and govern the Indenture or
this Second Supplement, the latter provision shall control.  If any provision
hereof modifies or excludes any provision of the Trust Indenture Act that may be
so modified or excluded, the latter provision shall be deemed to apply to this
Second Supplement as so modified or to be excluded, as the case may be.

          Section 105.  Effect of Headings.  The Section headings herein are for
                        ------------------                                      
convenience only and shall not affect the construction hereof.

          Section 106.  Separability Clause.  In case any provision in this
                        -------------------                                
Second Supplement shall be invalid, illegal or unenforceable, the validity,
legality and enforceability of the remaining provisions shall not in any way be
affected or impaired thereby, it being intended that all of the provisions
hereof shall be enforceable to the full extent permitted by law.

          Section 107.  Benefit of Second Supplement and Indenture.  Nothing in
                        ------------------------------------------             
this Second Supplement or the Indenture or in the Securities, express or
implied, shall give to any Person other than the parties hereto and thereto and
their successors hereunder and thereunder and the Holders of Securities, any
benefit or any legal or equitable right, remedy or claim under this Second
Supplement or the Indenture.  Neither this Second Supplement nor the Indenture
may be used to interpret another indenture, loan agreement or debt agreement of
the Company or any of its Subsidiaries.  No such other indenture or loan or debt
agreement may be utilized to interpret this Second Supplement or the Indenture.

          Section 108.  Governing Law.  This Second Supplement shall be governed
                        -------------                                           
by and construed in accordance with the laws of the State of New York, as
applied to contracts made and performed within the State of New York, without
regard to principles of conflicts of law.  The Company hereby irrevocably
submits to the jurisdiction of any New York state court sitting in the Borough
of Manhattan in The City of New York or any Federal court sitting in the Borough
of Manhattan in The City of New York in respect of any suit, action or
proceeding arising out of or relating to this Second Supplement, and irrevocably
accepts for itself and in respect of its Property, generally and
unconditionally, jurisdiction of the aforesaid courts.  The Company irrevocably
waives, to the fullest extent that it may effectively do so under applicable
law, trial by jury and any objection which it may now or hereafter have to the
laying of the venue of any such suit, action or proceeding brought in any such
court and any claim that any such suit, action or proceeding brought in any such
court has been brought in an inconvenient forum.  Nothing herein shall affect
the right of the Trustee or any Holder of the Securities to serve process in any
other manner permitted by law or to commence legal proceedings or otherwise
proceed against the Company in any other jurisdiction.

          Section 109.  No Recourse Against Others.  A director, officer,
                        --------------------------                       
employee, stockholder or incorporator, as such, of the Company shall not have
any liability for any obligations of the Company under this Second Supplement or
for any claim based on, in respect or by reason of such obligations or their
creation.

                                       6
<PAGE>
 
          Section 110.  Duplicate Originals.  All parties may sign any number of
                        -------------------                                     
copies or counterparts of this Second Supplement.  Each signed copy or
counterpart shall be an original, but all of them together shall represent the
same agreement.

          Section 111.  Effectiveness.  This Second Supplement shall become
                        -------------                                      
effective in accordance with the provisions of Article Nine of the Indenture.

          IN WITNESS WHEREOF, the parties hereto have caused this Second
Supplement to be duly executed, and their respective corporate seals to be
hereunto affixed and attested, all as of the day and year first above written.

(SEAL)                        MFS COMMUNICATIONS COMPANY, INC.

                              By:
                                  --------------------------------
Attest:                       Title:
                                    ------------------------------


- ----------------------------
 

(SEAL)

                              IBJ SCHRODER BANK & TRUST COMPANY

                              By:
                                  --------------------------------
                              Title:
                                    ------------------------------
Attest:

 

- ----------------------------

                                       7
<PAGE>
 
STATE OF ____________      )
                            ss.:
COUNTY OF __________       )

     On the ___ day of _______, 1997, before me personally came _________, to me
known, who, being by me duly sworn, did depose and say that he/she is the
______________ of MFS COMMUNICATIONS COMPANY, INC., one of the corporations
described in and which executed the foregoing instrument; that he/she knows the
seal of said corporation; that the seal affixed to said instrument is such
corporate seal; that it was so affixed by authority of the Board of Directors of
said corporation, and that he/she signed his/her name thereto by like authority.

                                           ---------------------------------
 

STATE OF _____________  )

                     ss.:

COUNTY OF ___________  )

     On the ___ day of _______, 1997, before me personally came _________, to me
known, who, being by me duly sworn, did depose and say that he/she is
_______________ of IBJ SCHRODER BANK & TRUST COMPANY, one of the corporations
described in and which executed the foregoing instrument; that he/she knows the
seal of said corporation; that the seal affixed to said instrument is such
corporate seal; that it was so affixed by authority of the Board of Directors of
said corporation, and that he/she signed his/her name thereto by like authority.

 

                                           ---------------------------------

                                       8

<PAGE>
 
                                                                    EXHIBIT 4.15

================================================================================
 
                        MFS COMMUNICATIONS COMPANY, INC.

                                      and

                       IBJ SCHRODER BANK & TRUST COMPANY
                                           Trustee

                        ________________________________
                                     SECOND

                             SUPPLEMENTAL INDENTURE

                            Dated as of ______, 1997

                                       to

                                   INDENTURE

                          Dated as of January 15, 1996

                        ________________________________
                                  $924,000,000

                     Principal Amount at Stated Maturity of

                     8-7/8% Senior Discount Notes Due 2006

                                        
================================================================================

 
<PAGE>
 
          THIS SECOND SUPPLEMENTAL INDENTURE, dated as of _____, 1997 (the
"Second Supplement"), by and between MFS COMMUNICATIONS COMPANY, INC., a
corporation duly organized and existing under the laws of the State of Delaware
(herein called "MFS" or the "Company"), having its principal office at 3555
Farnam Street, Suite 200, Omaha, Nebraska 68131, and IBJ SCHRODER BANK & TRUST
COMPANY, a New York banking corporation, as Trustee (herein called the
"Trustee").

          WHEREAS, pursuant to the terms of the Indenture, dated as of January
15, 1996 (the "Original Indenture"), as supplemented and amended by the First
Supplemental Indenture, dated as of January 15, 1996 (the "First Supplement"
and, together with the Original Indenture, the "Indenture"), between the Company
and the Trustee, the Company has issued $924,000,000 principal amount at Stated
Maturity of its 8-7/8% Senior Discount Notes Due 2006 (herein called the
"Notes"); and

          WHEREAS, effective as of December 31, 1996, pursuant to the terms of
that certain Amended and Restated Agreement and Plan of Merger (the "Merger
Agreement"), dated as of  August 25, 1996, by and among WorldCom, Inc., a
Georgia corporation ("WorldCom"), HIJ Corp., a Delaware corporation and a wholly
owned subsidiary of WorldCom ("Merger Sub"), and MFS, Merger Sub was merged with
and into MFS, which thereby became a wholly owned subsidiary of WorldCom;

          WHEREAS, WorldCom is offering (the "Offer"), upon the terms and
subject to the conditions set forth in the Prospectus and Consent Solicitation
(together, the "Prospectus") dated ______, 1997 and the accompanying Letter of
Transmittal and Consent, to exchange (the "Exchange") [$             ] principal
                                                        --------------          
amount of its 8-7/8% Senior Notes due January 15, 2006 ("WorldCom 2006 Notes")
for each $1,000 principal amount at Stated Maturity of outstanding Notes;

          WHEREAS, Section 8(b) of the First Supplement provides that the
Company, when authorized by a Board Resolution, may with the consent of the
Holders of not less than a majority in principal amount at Stated Maturity of
the Outstanding Notes, and subject to Section 903 of the Original Indenture, the
Trustee shall enter into an indenture or indentures supplemental to the Original
Indenture, in form satisfactory to the Trustee, to add any provisions to or
change in any manner or eliminate any of the provisions of the Indenture or
modify in any manner the rights of the Holders of Notes, except with respect to
certain matters set forth therein, [and except that the consent of Holders of
not less than 75% in principal amount at Stated Maturity of the Outstanding
Notes is required to make any amendment to Section 5(r) of the First Supplement
and the definition of "Change of Control"];/1/



          WHEREAS, Holders of Notes who tender their Notes pursuant to the Offer
will be deemed, as a condition to a valid tender, to have given their consent to
certain proposed amendments to the Indenture as described in the Prospectus;

- ------------------------
/1/  Bracketed language will be included in this supplemental indenture only if
     a Supermajority Consent is obtained by WorldCom in connection with the
     Offer and the Exchange.
<PAGE>
 
          WHEREAS, as a condition to the Exchange, Holders of a majority in
aggregate principal amount of Outstanding Notes must have consented (the
"Requisite Consent") to amend the Indenture as described in the Prospectus;

          [WHEREAS, with respect to the modification of the term "Change in
Control," the Holders of 75% of the aggregate principal amount of Outstanding
Notes must have consented to such modification (the "Supermajority
Consent");]/1/



          WHEREAS, the Board of Directors of the Company has authorized the
execution of this Second Supplement and its delivery to the Trustee; and

          WHEREAS, all acts and things necessary, including the receipt of the
Requisite Consent [and the Supermajority Consent]/1/, to make this Second
Supplement the valid, binding and legal obligation of the Company in accordance
with its terms have been done.

          NOW, THEREFORE, THIS SECOND SUPPLEMENTAL INDENTURE WITNESSETH:

          Section 101.  Definitions.  Except as otherwise expressly provided
                        ------------                                        
herein, capitalized terms used herein shall have the meanings ascribed to them
in the Indenture.

          Section 102.  Amendment of First Supplement.
                        ----------------------------- 

          (a) Section 5(e) (Limitation on Debt) of the First Supplement is
hereby amended and restated in its entirety to read as follows:

          "Intentionally omitted."



          (b) Section 5(f) (Limitation of Debt and Preferred Stock of Restricted
Subsidiaries) of the First Supplement is hereby amended and restated in its
entirety to read as follows:

          "Intentionally omitted."

          (c) Section 5(g) (Limitation on Liens) of the First Supplement is
hereby amended and restated in its entirety to read as follows:

          "Intentionally omitted."

          (d) Section 5(h) (Limitation on Sale and Leaseback Transactions) of
the First Supplement is hereby amended and restated in its entirety to read as
follows:

          "Intentionally omitted."


- ------------------------
/1/  Bracketed language will be included in this supplemental indenture only if
     a Supermajority Consent is obtained by WorldCom in connection with the
     Offer and the Exchange.

                                       2
<PAGE>
 
          (e) Section 5(i) (Limitations on Restricted Payments) of the First
Supplement is hereby amended and restated in its entirety to read as follows:

          "Intentionally omitted."

          (f) Section 5(j) (Limitation on Dividends and Other Payment
Restrictions Affecting Restricted Subsidiaries) of the First Supplement is
hereby amended and restated in its entirety to read as follows:

          "Intentionally omitted."

          (g) Section 5(k) (Limitations on Issuance and Sale of Capital Stock of
Restricted Subsidiaries) of the First Supplement Indenture is hereby amended and
restated in its entirety to read as follows:

          "Intentionally omitted."

          (h) Section 5(m) (Transactions with Affiliates) of the First
Supplement is hereby amended and restated in its entirety to read as follows:

          "Intentionally omitted."

          (i) Section 5(n) (Provision of Financial Information) of the First
Supplement is hereby amended and restated in its entirety to read as follows:

          "Intentionally omitted."

          (j) Section 4(a) (Events of Default) of the First Supplement is hereby
amended and restated in its entirety to read as follows:

          "Each of the following is an "Event of Default" whenever used with
respect to the Notes (whatever the reason for such Event of Default and whether
or not it shall be voluntary or involuntary or be effected by operation of law
or pursuant to any judgment, decree or order of any court or any order, rule or
regulation of any administrative or governmental body):

          (1) default in the payment of any interest upon any Note, when such
     interest becomes due and payable, and continuance of such default for a
     period of 30 days; or

          (2) default in the payment of the principal of (or premium, if any,
     on) any Note when it becomes due and payable at its Maturity; or

          (3) default in the performance, or breach, of any covenant or warranty
     of the Company in this Indenture with respect to any Note (other than a
     covenant or warranty a default in whose performance or whose breach is
     elsewhere in this Section specifically dealt with), and continuance of such
     default or breach for a period of 60 days after there has been given, by
     registered or certified mail, to the Company by the Trustee or to the
     Company and the Trustee by the Holders of at least 25% in principal amount
     of the

                                       3
<PAGE>
 
     Outstanding Notes a written notice specifying such default or breach
     and requiring it to be remedied and stating that such notice is a "Notice
     of Default" hereunder; or

          (4) a default under any bond, debenture, note or other evidence of
     indebtedness of the Company or under any mortgage, indenture or instrument
     under which there may be issued or by which there may be secured or
     evidenced any indebtedness of the Company (including this Indenture),
     whether such indebtedness now exists or shall hereafter be created, which
     default shall constitute a failure to pay an aggregate principal amount
     exceeding $50,000,000 of such indebtedness when due and payable after the
     expiration of any applicable grace period with respect thereto and shall
     have resulted in such indebtedness in an aggregate principal amount
     exceeding $50,000,000 becoming or being declared due and payable prior to
     the date on which it would otherwise have become due and payable, without
     such indebtedness having been discharged, or such acceleration having been
     rescinded or annulled, within a period of 10 days after there shall have
     been given, by registered or certified mail, to the Company by the Trustee
     or to the Company and the Trustee by the Holders of at least 10% in
     principal amount of the Outstanding Securities of that series a written
     notice specifying such default and requiring the Company to cause such
     indebtedness to be discharged or cause such acceleration to be rescinded or
     annulled and stating that such notice is a "Notice of Default" hereunder;
     provided, however, that if such default under such bond, debenture, note,
     --------  -------                                                        
     mortgage, indenture or other instrument or evidence of indebtedness shall
     be remedied or cured by the Company or waived pursuant to such agreement or
     instrument, then, unless the Stated Maturity of the Notes shall have been
     accelerated as provided herein, the Event of Default hereunder by reason
     thereof shall be deemed likewise to have been thereupon remedied, cured or
     waived without further action upon the part of either the Trustee or the
     Holders; or

          (5) the Company pursuant to or within the meaning of any Bankruptcy
     Law:

               (A)  commences a voluntary case,

               (B)  consents to the entry of an order for relief against it in
                    an involuntary case,

               (C)  consents to the appointment of a Custodian of it or for all
                    or substantially all of its property, or

               (D)  makes a general assignment for the benefit of its creditors;
                    or

          (6) a court of competent jurisdiction enters an order or decree under
     any Bankruptcy Law that:

               (A)  is for relief against the Company in an involuntary case,

               (B)  appoints a Custodian of the Company or for all or
                    substantially all of its property, or

                                       4
<PAGE>
 
               (C)  orders the liquidation of the Company,

          and, in any such case, such order or decree remains unstayed and in
          effect for 90 days.

The term "Bankruptcy Law" means title 11, U.S. Code or any similar Federal or
State law for the relief of debtors.  The term "Custodian" means any receiver,
trustee, assignee, liquidator or other similar official under any Bankruptcy
Law."

          (k) The first paragraph of Section 4(b) of the First Supplement is
hereby amended and restated in its entirety to read as follows:

          "If an Event of Default occurs and is continuing, then and in every
such case the Trustee or the Holders of not less than 25% in principal amount at
Stated Maturity of the Outstanding Notes may declare the Default Amount of all
the Notes to be due and payable immediately by a notice in writing to the
Company (and to the Trustee if given by the Holders), and upon any such
declaration such Default Amount shall become immediately due and payable."

          [(l)  The definition of "Change of Control" contained in Section 1(d)
of the First Supplement is hereby amended and restated in its entirety to read
as follows:/*/

          "Change of Control"  means the occurrence of any of the following
events:

          (a) any "person" or "group" (as such terms are used in Sections 13(d)
and 14(d) of the Exchange Act), other than WorldCom, Inc., a Georgia corporation
("WorldCom"), or its Affiliates or an underwriter engaged in a firm commitment
underwriting on behalf of the Company, is or becomes the "beneficial owner" (as
such term is used in Rules 13d-3 and13d-5 under the Exchange Act) plus all
shares that such person or group has the right to acquire, whether such right is
exercisable immediately or only after a passage of time, directly or indirectly,
of more than 50 percent of the total voting power of the Voting Stock of the
Company and, in addition, beneficially owns more shares in the Company than
beneficially owned by WorldCom and the Employee Group; or

          (b) the Company sells, conveys, transfers or leases (either in one
transaction or a series of related transactions) all or substantially all of its
assets to a Person other than an Affiliate."]/2/

          Section 103.  Construction with Indenture.  All of the covenants,
                        ---------------------------                        
agreements and provisions of this Second Supplement shall be deemed to be and
construed as part of the Indenture to the same extent as if fully set forth
verbatim therein and shall be fully enforceable in the manner provided in the
Indenture.  Except as provided in this Second Supplement, the Indenture shall
remain in full force and effect and the terms and conditions thereof are hereby
confirmed.


- ----------------------------
/*/  This Section 102(l) will be included in this supplemental indenture only if
     a Supermajority Consent is obtained by WorldCom in connection with the
     Offer and the Exchange.

                                       5
<PAGE>
 
          Section 104.  Conflict with Trust Indenture Act.  If any provision
                        ---------------------------------                   
hereof limits, qualifies or conflicts with a provision of the Trust Indenture
Act that is required under such Act to be part of and govern the Indenture or
this Second Supplement, the latter provision shall control.  If any provision
hereof modifies or excludes any provision of the Trust Indenture Act that may be
so modified or excluded, the latter provision shall be deemed to apply to this
Second Supplement as so modified or to be excluded, as the case may be.

          Section 105.  Effect of Headings.  The Section headings herein are for
                        ------------------                                      
convenience only and shall not affect the construction hereof.

          Section 106.  Separability Clause.  In case any provision in this
                        -------------------                                
Second Supplement shall be invalid, illegal or unenforceable, the validity,
legality and enforceability of the remaining provisions shall not in any way be
affected or impaired thereby, it being intended that all of the provisions
hereof shall be enforceable to the full extent permitted by law.

          Section 107.  Benefit of Second Supplement and Indenture.  Nothing in
                        ------------------------------------------             
this Second Supplement or the Indenture or in the Notes, express or implied,
shall give to any Person other than the parties hereto and thereto and their
successors hereunder and thereunder and the Holders of Notes, any benefit or any
legal or equitable right, remedy or claim under this Second Supplement or the
Indenture.  Neither this Second Supplement nor the Indenture may be used to
interpret another indenture, loan agreement or debt agreement of the Company or
any of its Subsidiaries.  No such other indenture or loan or debt agreement may
be utilized to interpret this Second Supplement or the Indenture.

          Section 108.  Governing Law.  This Second Supplement shall be governed
                        -------------                                           
by and construed in accordance with the laws of the State of New York, as
applied to contracts made and performed within the State of New York, without
regard to principles of conflicts of law.  The Company hereby irrevocably
submits to the jurisdiction of any New York state court sitting in the Borough
of Manhattan in The City of New York or any Federal court sitting in the Borough
of Manhattan in The City of New York in respect of any suit, action or
proceeding arising out of or relating to this Second Supplement, and irrevocably
accepts for itself and in respect of its Property, generally and
unconditionally, jurisdiction of the aforesaid courts.  The Company irrevocably
waives, to the fullest extent that it may effectively do so under applicable
law, trial by jury and any objection which it may now or hereafter have to the
laying of the venue of any such suit, action or proceeding brought in any such
court and any claim that any such suit, action or proceeding brought in any such
court has been brought in an inconvenient forum.  Nothing herein shall affect
the right of the Trustee or any Holder of the Notes to serve process in any
other manner permitted by law or to commence legal proceedings or otherwise
proceed against the Company in any other jurisdiction.

          Section 109.  No Recourse Against Others.  A director, officer,
                        --------------------------                       
employee, stockholder or incorporator, as such, of the Company shall not have
any liability for any obligations of the Company under this Second Supplement or
for any claim based on, in respect or by reason of such obligations or their
creation.

                                       6
<PAGE>
 
          Section 110.  Duplicate Originals.  All parties may sign any number of
                        -------------------                                     
copies or counterparts of this Second Supplement.  Each signed copy or
counterpart shall be an original, but all of them together shall represent the
same agreement.

          Section 111.  Effectiveness.  This Second Supplement shall become
                        -------------                                      
effective in accordance with the provisions of Article Nine of the Indenture.

          IN WITNESS WHEREOF, the parties hereto have caused this Second
Supplement to be duly executed, and their respective corporate seals to be
hereunto affixed and attested, all as of the day and year first above written.

(SEAL)                        MFS COMMUNICATIONS COMPANY, INC.

                              By:____________________________________

                              Title:_________________________________

Attest:

 
_________________________

(SEAL)

                              IBJ SCHRODER BANK & TRUST COMPANY

                              By:____________________________________

                              Title:_________________________________

Attest:

 
_________________________

 

                                       7
<PAGE>
 
STATE OF ____________            )
                                 ss.:
COUNTY OF __________             )

     On the ___ day of _____, 1997, before me personally came _________, to me
known, who, being by me duly sworn, did depose and say that he/she is the
______________ of MFS COMMUNICATIONS COMPANY, INC., one of the corporations
described in and which executed the foregoing instrument; that he/she knows the
seal of said corporation; that the seal affixed to said instrument is such
corporate seal; that it was so affixed by authority of the Board of Directors of
said corporation, and that he/she signed his/her name thereto by like authority.


                                      _______________________________
 

STATE OF _____________          )
                                ss.:
COUNTY OF ___________           )

     On the __ day of _____, 1997, before me personally came _____________, to
me known, who, being by me duly sworn, did depose and say that he/she is
_______________ of IBJ SCHRODER BANK & TRUST COMPANY, one of the corporations
described in and which executed the foregoing instrument; that he/she knows the
seal of said corporation; that the seal affixed to said instrument is such
corporate seal; that it was so affixed by authority of the Board of Directors of
said corporation, and that he/she signed his/her name thereto by like authority.

 
                                      _______________________________

                                       8

<PAGE>
 
                                                                     EXHIBIT 5.1

                                 June 26, 1997



Board of Directors of
WorldCom, Inc.
515 East Amite Street
Jackson, Mississippi 39201

Ladies and Gentlemen:

     I am General Counsel - Corporate Development of WorldCom, Inc., a Georgia
corporation (the "Company"), and have acted as counsel in connection with the
Registration Statement on Form S-4 (Registration No. 333-27345), as amended (the
"Registration Statement"), originally filed by the Company on May 16, 1997 with
the Securities and Exchange Commission (the "Commission") under the Securities
Act of 1933, as amended (the "Securities Act"), relating to the exchange of up
to $686,398,000 9 3/8 % Senior Notes due January 15, 2004 of the Company for any
and all outstanding 9 3/8% Senior Discount Notes due January 15, 2004 of MFS
Communications Company, Inc., a Delaware corporation and wholly owned subsidiary
of the Company ("MFS"), and up to $671,850,000 8 7/8% Senior Notes due January
15, 2006 of the Company for any and all outstanding 8 7/8% Senior Discount Notes
due January 15, 2006 of MFS, and the solicitation of consents of holders of MFS
Notes to certain amendments to the respective indentures applicable to each
series of such MFS Notes.  Terms not defined herein shall have the meanings
contained in the Prospectus.

     In connection herewith, I have examined and relied without investigation as
to matters of fact upon the Registration Statement, the Second Amended and
Restated Articles of Incorporation and Bylaws of the Company, certificates of
public officials, certificates and statements of officers of the Company, and
such other corporate records, documents, certificates and instruments as I have
deemed necessary or appropriate to enable me to render the opinions expressed
herein.  I have assumed the genuineness of all signatures on all documents
examined by me, the authenticity of all documents submitted to me as originals,
and the conformity to authentic originals of all documents submitted to me as
certified or photostatic copies.  I have also assumed the due authorization,
execution and delivery of all documents.

     Based upon the foregoing and in reliance thereon and subject to the
limitations and qualifications stated herein and to the effectiveness of the
Registration Statement under the Securities Act, I am of the opinion that:
<PAGE>
 
     1.   The Company is a corporation validly existing under the laws of the
State of Georgia; and

     2.  Each of the WorldCom Notes when duly executed, authenticated and issued
as provided in the WorldCom Indenture and delivered against payment, will
constitute valid and legally binding obligations of the Company and will be
enforceable in accordance with their terms and entitled to the benefits of the
WorldCom Indenture except to the extent that enforceability may be limited by
applicable bankruptcy, insolvency, reorganization, receivership, moratorium,
fraudulent conveyance or other similar laws now or hereafter in effect relating
to or affecting the rights and remedies of creditors generally, and by general
principles of equity, including, without limitation, concepts of materiality,
reasonableness, good faith and fair dealing and the possible unavailability of
specific performance, injunctive relief or other equitable remedies, regardless
of whether enforceability is considered in a proceeding in equity or at law.

     This opinion is not rendered with respect to any laws other than the latest
codification of the Georgia Business Corporation Code available to me.  This
opinion has not been prepared by an attorney admitted to practice in Georgia.

     I hereby consent to the filing of this opinion as Exhibit 5.1 to the
aforesaid Registration Statement.  I also consent to your filing copies of this
opinion as an exhibit to the Registration Statement with agencies of such states
as you deem necessary in the course of complying with the laws of such states
regarding the offering and sale of the Notes.  In giving this consent, I do not
admit that I am in the category of persons whose consent is required under
Section 7 of the Act or the rules and regulations of the Commission.

                                 Very truly yours,


                                 /s/ P. Bruce Borghardt

                                 P.  Bruce Borghardt
                                 General Counsel - Corporate Development

<PAGE>
 
                                                                EXHIBIT 8.1


 
 
                                 June 26, 1997



WorldCom, Inc.
515 East Amite Street
Jackson, Mississippi  39201

Gentlemen:

          We have acted as special tax counsel to WorldCom, Inc., a Georgia
corporation (the "Company"), in connection with the Offers to Exchange (the
"Exchange Offers") WorldCom, Inc. 9-3/8% Senior Notes due January 15, 2004, for
all outstanding MFS Communications Company, Inc. 9-3/8% Senior Discount Notes
due January 15, 2004, and WorldCom, Inc. 8-7/8% Senior Notes due January 15,
2006, for all outstanding MFS Communications Company, Inc. 8-7/8% Senior
Discount Notes due January 15, 2006 (the "Exchange Offers"), as described in the
Prospectus (the "Prospectus") included as a part of the Registration Statement
(Form S-4) filed with the Securities and Exchange Commission on June 27, 1997
(the "Registration Statement").  In connection therewith, you have requested our
opinion regarding whether the discussion of the federal income tax consequences
set forth in the Prospectus under the caption "Certain Federal Income Tax
Consequences" fairly describes the material federal income tax consequences of
the Exchange Offers.  Except as otherwise indicated herein, all capitalized
terms used in this letter have the same meaning assigned to them in the
Prospectus.

          In rendering our opinion, we have examined the Prospectus and such
other documents as we have considered relevant for purposes of this opinion.  We
have assumed that the Prospectus reflects all the material facts and our opinion
is expressly conditioned on, among other things, the accuracy as of the date
hereof, and the continuing accuracy, of all of such facts, information,
covenants, statements and representations through and as of the effective date
of the Exchange Offers.  Any material changes in the facts referred to, set
forth or assumed herein or in the Prospectus may affect the conclusions stated
herein.

          We have assumed the genuineness of all signatures, the legal capacity
of all natural persons, the authenticity of all documents submitted to us as
originals, the conformity to original documents of all documents submitted to us
as certified or photostatic copies and the authenticity of the originals of such
documents.
<PAGE>
 
WorldCom, Inc.
June 26, 1997
Page 2

          In rendering our opinion, we have considered the applicable provisions
of the Internal Revenue Code of 1986, as amended (the "Code"), Treasury
Regulations promulgated thereunder by the Treasury Department (the
"Regulations"), pertinent judicial authorities, rulings of the Internal Revenue
Service (the "Service") and such other authorities as we have considered
relevant.  It should be noted that such laws, Code, Regulations, judicial
decisions and administrative interpretations are subject to change at any time
and, in some circumstances, with retroactive effect.  A material change in any
of the authorities upon which our opinion is based could affect our conclusions
herein.

          Based solely upon and subject to the foregoing, we are of the opinion
that the statements in the Prospectus under the caption "Certain Federal Income
Tax Consequences" fairly describes the material federal income tax consequences
of the Exchange Offers.

          Except as expressly set forth above, we express no other opinion.
This opinion is for your benefit and is not to be used, circulated, quoted or
otherwise referred to for any purpose except that we consent to the filing of
this opinion as Exhibit 8.1 of the Registration Statement.  In giving such
consent, we do not thereby admit that we are in the category of persons whose
consent is required under Section 7 of the Securities Act of 1933.


                                    Very truly yours,



                                    /s/ Bryan Cave LLP
                                    -------------------------------
                                    Bryan Cave LLP

JPB/bmr

<PAGE>
 
                                                                   EXHIBIT 23.1
 
                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTS
   
  As independent public accountants, we hereby consent to the incorporation by
reference in this Amendment No. 2 to Registration Statement No. 333-27345, of
our report dated February 26, 1997, included in WorldCom, Inc.'s Form 10-K for
the year ended December 31, 1996 and to all references to our Firm in this
registration statement.     
 
                                          ARTHUR ANDERSEN LLP
   
Jackson, Mississippi, June 24, 1997     

<PAGE>
 
                                                                   EXHIBIT 23.2
 
                      CONSENT OF INDEPENDENT ACCOUNTANTS
 
  We consent to the incorporation by reference in this registration statement
on Form S-4 (File No. 333-27345) of WorldCom, Inc. of our report dated
February 14, 1996, on our audits of the consolidated financial statements of
MFS Communications Company, Inc. as of December 31, 1995 and for the years
ended December 31, 1995 and 1994 which report is included in MFS Communication
Company's Annual Report on Form 10-K, and of our report dated February 14,
1996, on our audits of the consolidated financial statements of MFS
Communications Company, Inc. as of December 31, 1995 and 1994 and for the
three years in the period ended December 31, 1995 which report is included in
WorldCom Inc.'s Current Report on Form 8-K/A dated August 25, 1996 (as amended
on November 4, 1996). We also consent to the reference to our firm under the
caption "Experts".
 
Coopers & Lybrand L.L.P.
Omaha, Nebraska
   
June 24, 1997     

<PAGE>
 
                                                                   EXHIBIT 23.3
 
                   CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS
   
  As independent public accountants, we hereby consent to the incorporation by
reference in this Amendment No. 2 to Registration Statement No. 333-27345, of
our reports dated February 20, 1997, included in MFS Communications Company,
Inc.'s Form 10-K for the year ended December 31, 1996 and to all references to
our Firm in this registration statement.     
 
                                          ARTHUR ANDERSEN LLP
   
Omaha, Nebraska, June 24, 1997     

<PAGE>
 
                                                                    EXHIBIT 23.4
 
                   CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS
   
  As independent public accountants, we hereby consent to the incorporation by
reference in this Amendment No. 2 to Registration Statement No. 333-27345, of
our report dated January 31, 1996 on the Consolidated Financial Statements of
UUNET Technologies, Inc. included in WorldCom, Inc.'s Current Report on Form 8-
K dated August 25, 1996 as amended by Form 8-K/A filed November 4, 1996 and to
all references to our Firm included in this registration statement.     
 
                                          ARTHUR ANDERSEN LLP
   
Washington, D.C., June 24, 1997     

<PAGE>
 
                                                                   EXHIBIT 99.1

[YELLOW]
                       LETTER OF TRANSMITTAL AND CONSENT
                         To Tender and to Give Consent
                                 in Respect of
               9 3/8% Senior Discount Notes due January 15, 2004
                             CUSIP No. 55272T-AA-9
                                       of
                        MFS COMMUNICATIONS COMPANY, INC.
            In Exchange for 9 3/8% Senior Notes due January 15, 2004
                                       of
                                 WORLDCOM, INC.
              Pursuant to the Prospectus and Consent Solicitation
                              dated ________, 1997

THE EXCHANGE OFFER (AS DEFINED BELOW) WILL EXPIRE AT 11:59 P.M., NEW YORK CITY
TIME, ON          , 1997, UNLESS EXTENDED (SUCH TIME AND DATE, AS EXTENDED, THE
"EXPIRATION DATE" WITH RESPECT TO SUCH EXCHANGE OFFER).  TENDERS OF MFS 2004
NOTES MAY NOT BE WITHDRAWN (AND THE RELATED CONSENTS THEREBY REVOKED) AT ANY
TIME AFTER 11:59 P.M., NEW YORK CITY TIME, ON          , 1997, UNLESS THE
APPLICABLE EXCHANGE OFFER IS EXTENDED AND CONTAINS NEW TERMS MATERIALLY ADVERSE
TO THE TENDERING HOLDERS THEREOF.

          Delivery To:  Harris Trust and Savings Bank,  Exchange Agent

<TABLE>

 By Registered or Certified Mail:           Overnight or Hand Delivery:          Facsimile Transmission:
<S>                                         <C>                                  <C> 
   Harris Trust and Savings Bank            Harris Trust and Savings Bank             (212) 701-7636
c/o Harris Trust Company of New York      c/o Harris Trust Company of New York 
   P.O. Box 1010                                    77 Water Street     
 Wall Street Station                                   4th Floor                  Confirm by Telephone:
 New York, NY  10268                              New York, NY  10004                 (212) 701-7624
</TABLE>

Questions regarding the Exchange Offer or completion of this Letter of
Transmittal may be directed to MacKenzie Partners, Inc., the Information Agent
for the Exchange Offer, at (800) 322-2885 (toll free).

Delivery of this Letter of Transmittal and Consent (this "Letter of
Transmittal") to an address, or transmission of instructions via a facsimile
number, other than as set forth above or other than in accordance with the
instructions herein, will not constitute valid delivery.  The instructions
accompanying this Letter of Transmittal should be read carefully before this
Letter of Transmittal is completed.

This Letter of Transmittal is to be used in connection with (i) the physical
delivery of MFS 2004 Notes (as defined herein) to Harris Trust and Savings Bank,
as exchange agent (the "Exchange Agent"), or (ii) the delivery of MFS 2004 Notes
by book-entry transfer to the account of the Exchange Agent at The Depository
Trust Company ("DTC"), in accordance with the procedures described in the
Prospectus and Consent Solicitation dated __________, 1997 (together, the
"Prospectus") under the heading "The Exchange Offers--Procedures for Tendering."

All capitalized terms used and not defined herein have the meanings ascribed to
them in the Prospectus.

Pursuant to the Prospectus, receipt of which is hereby acknowledged, WorldCom,
Inc. (the "Company") is offering to exchange $871.597 principal amount of
WorldCom 2004 Notes for each $1,000 principal amount at stated maturity of
outstanding MFS 2004 Notes properly tendered for exchange and accepted.  If the
aggregate principal amount of WorldCom 2004 Notes that otherwise would be issued
in exchange for the MFS 2004 Notes tendered by a Holder and accepted by the
Company pursuant to the Exchange Offer is not an integral multiple of $1,000,
such principal amount will be reduced to the nearest such multiple and the
Company will pay to such Holder an amount in cash equal to the reduction of such
principal amount.

The Company is also offering, pursuant to the Prospectus, to pay each Holder who
gives a valid Consent (as defined herein) to the Proposed Amendments (as defined
herein) on or prior to the Expiration Date a cash fee in an amount equal to
0.__% of the Accreted Value, as of July 15, 1997 (the "Interest Accrual Date"),
of such Holder's MFS 2004 Notes with respect to which Consent has been given.

Holders may give their Consent to the Proposed Amendments only by tendering MFS
2004 Notes in the Exchange Offer, will be required to consent as a condition to
a valid tender and will be deemed to have given such Consent by so tendering.
The proper completion, execution and delivery of this Letter of Transmittal will
constitute a Consent to the Proposed Amendments with respect to the MFS 2004
Notes.

Upon the terms and subject to the conditions of the Exchange Offer, the Company
will accept for exchange all MFS 2004 Notes that are properly tendered (and not
withdrawn) on or prior to 11:59 p.m., New York City time, on the Expiration
Date.
<PAGE>
 
Holders who are unable to properly tender their MFS 2004 Notes (including
delivery of this Letter of Transmittal and all other documents required hereby)
on or prior to the Expiration Date, may nevertheless tender their MFS 2004 Notes
(and thereby consent to the Proposed Amendments) according to the guaranteed
delivery procedures set forth in the Prospectus under the heading "The Exchange
Offers--Procedures for Tendering--Guaranteed Delivery Procedures."  See
Instruction 2.

Holders who wish to tender their MFS 2004 Notes (and thereby consent to the
Proposed Amendments) pursuant to this Letter of Transmittal must, at a minimum,
fill in the necessary account information in the table below entitled "Account
Information" (the "Account Information Table"), complete columns (1) through (3)
in the table below entitled "Description of MFS 2004 Notes Tendered and In
Respect of Which Consent Is Given" (the "Description Table") and complete and
sign in the box below entitled "SIGN HERE."   If only columns (1) through (3)
are completed in the Description Table, the Holder will be deemed to have
consented to the Proposed Amendments in respect of, and to have tendered, all
MFS 2004 Notes listed in the Description Table.  If a Holder wishes to tender
less than all of such MFS 2004 Notes delivered to the Exchange Agent, column (4)
of the Description Table must be completed in full.  See Instruction 4.

                                       2
<PAGE>
 
In order to effect a valid tender of MFS 2004 Notes the undersigned must
complete the Account Information Table below.  WorldCom 2004 Notes will be
delivered only in book-entry form through DTC and only to the DTC account of the
undersigned or the undersigned's custodian.  Accordingly, if the undersigned
tenders (i) by book-entry transfer to the Exchange Agent's account at DTC, the
first box in the account information table must be checked and any WorldCom 2004
Notes will be delivered to the DTC participant from which tender was effected,
or (ii) by physical delivery of certificates to the Exchange Agent, the second
box in the account information table must be checked and any WorldCom 2004 Notes
will be delivered to the DTC participant indicated by the Holder in such table.
Failure to provide the information necessary to effect delivery of WorldCom 2004
Notes will render such Holder's tender defective and the Company will have the
right, which it may waive, to reject such tender.

ATTENTION ANY TENDERING HOLDER WHOSE MFS 2004 NOTES WILL NOT BE DELIVERED TO THE
EXCHANGE AGENT THROUGH DTC:  Because WorldCom 2004 Notes will be delivered only
in book-entry form through DTC, you are urged to contact promptly a bank, broker
or other intermediary (that has the facility to hold securities custodially
through DTC) to arrange for receipt of any WorldCom 2004 Notes delivered
pursuant to the Exchange Offer and to obtain the information necessary to
complete the Account Information Table.

TO VALIDLY COMPLETE THE LETTER OF TRANSMITTAL (AND THEREBY CONSENT TO THE
PROPOSED AMENDMENTS), COMPLETE PAGES ____ AND ____, COMPLETE AND SIGN PAGE ____,
AND (IF NECESSARY) COMPLETE AND SIGN PAGES ____, ____ AND ____.

THE INSTRUCTIONS STARTING ON PAGE ____ FORM A PART OF THE TERMS AND CONDITIONS
OF THE EXCHANGE OFFER AND RELATED CONSENT SOLICITATION AND SHOULD BE READ
CAREFULLY.



                              ACCOUNT INFORMATION
                     (Complete One Method of Tender Only*)

VIA DTC

[_]    Check here if tendered MFS 2004 Notes are being delivered by book-entry
transfer to the Exchange Agent's account at DTC and complete the following:

Name of DTC Participant
                       ---------------------------------------------------------
DTC Participant Number
                       ---------------------------------------------------------

VIA PHYSICAL DELIVERY

[_]    Check here if tendered MFS 2004 Notes are being delivered in physical
form and complete the following:

Name of Registered Holder(s)
                             ---------------------------------------------------

DTC Participant Receiving WorldCom 2004 Notes**:

       Name of DTC Participant
                               ------------------------------------------------

       DTC Participant Number
                               ------------------------------------------------

       Customer Account Number
                               ------------------------------------------------

       DTC Participant Contact Name/Phone Number
                                                -------------------------------


- ------------------------------------------------------------------------------- 

*    Failure to complete one, and only one, method of tender will render the
     undersigned's tender defective.
**   Failure to provide the information necessary to effect delivery of
     WorldCom 2004 Notes will render the undersigned's tender defective.


[_]    Check here if this Letter of Transmittal and the MFS 2004 Notes tendered
hereby are being delivered pursuant to a Notice of Guaranteed Delivery
previously delivered in accordance with the Guaranteed Delivery Procedures
described in Instruction 2 hereof.

                                       3
<PAGE>
 
       List below the MFS 2004 Notes to which this Letter of Transmittal
relates.  If the space provided below is inadequate, the certificate numbers and
principal amount of MFS 2004 Notes should be listed on a separate signed
schedule affixed hereto.
 
DESCRIPTION OF MFS 2004 NOTES TENDERED AND IN RESPECT OF WHICH CONSENT IS GIVEN
                          (SEE INSTRUCTIONS 3 AND 4)

<TABLE>
<CAPTION>

  Name(s) and Address(es) of Holder(s)  
(please fill in exactly as  name appears                  MFS Notes Tendered and In Respect
  on the face of the MFS 2004 Notes                            of Which Consent is Given
 tendered or on a security  position                 (attach additional signed schedule if necessary)
    listing with respect thereto)  

                                                                       Aggregate          Principal
                                                     Certificate       Principal            Amount
                                                      Number(s)*    Amount at Stated       at Stated
                                                                      Maturity of          Maturity
                                                                    MFS 2004 Note(s)     Tendered and
                                                                                         in Respect of
                                                                                         Which Consent
                                                                                        is Given (if less
                                                                                           than all)**
(1)                                                      (2)               (3)                (4)
<S>                                                  <C>           <C>                 <C>
                                       
                                       
                                       
                                       
                                       
                                       
                                                        Total
</TABLE>
*   Need not be completed if MFS 2004 Notes are being tendered by book-entry 
    transfer.
**  You must consent to the Proposed Amendments in respect of all MFS
    2004 Notes tendered by you; completion of column (3) will constitute a 
    Consent to the Proposed Amendments in respect of such MFS 2004 Notes, 
    unless less than all MFS 2004 Notes are to be tendered as specified in
    column (4), in which case Consents only with respect to such lesser amount
    of MFS 2004 Notes shall be given. See Instruction 4. The principal amount
    at stated maturity of MFS 2004 Notes tendered hereby must be in
    denominations of $1,000 and any integral multiple thereof. 
    See Instruction 4.

                                       4
<PAGE>
 
                    NOTE: SIGNATURES MUST BE PROVIDED BELOW.
              PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY.

Ladies and Gentlemen:

The undersigned hereby (i) consents (the "Consent") to the proposed amendments
described in the Prospectus (the "Proposed Amendments"), to the Indenture, dated
as of January 15, 1994 (as supplemented by First Supplemental Indenture dated as
of March 31, 1995, the "1994 Indenture"), between MFS Communications Company,
Inc. ("MFS") and IBJ Schroder Bank & Trust Company, as Trustee (the "MFS
Trustee"), pursuant to which the 9 3/8% Senior Discount Notes due  January 15,
2004 of MFS (the "MFS 2004 Notes") indicated above were issued, and (ii) tenders
to the Company the MFS 2004 Notes indicated above in exchange for 9 3/8% Senior
Notes due January 15, 2004 of the Company (the "WorldCom 2004 Notes") in a ratio
equal to $871.597 principal amount of WorldCom 2004 Notes per $1,000 principal
amount at stated maturity of the MFS 2004 Notes, upon the terms and subject to
the conditions set forth in the Prospectus (receipt of which is hereby
acknowledged) and in this Letter of Transmittal, both of which together
constitute the Company's offer (the "Exchange Offer") to exchange WorldCom 2004
Notes for MFS 2004 Notes properly tendered.

Interest on the WorldCom 2004 Notes will accrue from the Interest Accrual Date.
The principal amount of WorldCom 2004 Notes being offered in exchange for the
MFS 2004 Notes tendered hereby is equal to the Accreted Value (as defined in the
Prospectus) of such MFS 2004 Notes as of the Interest Accrual Date.   WorldCom
2004 Notes will be issued only in denominations of $1,000 and integral multiples
thereof.  If the aggregate principal amount of WorldCom 2004 Notes that
otherwise would be issued in exchange for the MFS 2004 Notes tendered by a
Holder and accepted by the Company pursuant to the Exchange Offer is not an
integral multiple of $1,000, such principal amount will be reduced to the
nearest such multiple and the Company will pay to such Holder an amount in cash
equal to the reduction of such principal amount.

In connection with the undersigned's Consent, the undersigned shall receive a
cash fee in an amount equal to 0.___% of the Accreted Value, as of the Interest
Accrual Date, of the undersigned's MFS 2004 Notes with respect to which Consent
has been given (a "Consent Payment").

The undersigned understands that (i) the Proposed Amendments will be adopted
with respect to the MFS 2004 Notes tendered herewith and (ii) the applicable
Consent Payment will be paid to such Holder, in both cases, only upon
consummation of the Exchange Offer with respect to such MFS 2004 Notes.

The WorldCom 2004 Notes will be delivered by book-entry transfer to the DTC
account of the undersigned or the undersigned's custodian as specified in the
Account Information Table above, and the appropriate Consent Payment, and other
cash payment, if any, will be made by check to the undersigned (unless specified
otherwise "Special Delivery Instructions" or "Special Issuance and Payment
Instructions" below) in New York (Clearing House) funds, on the third business
day following the Expiration Date (the "Exchange Date"), or as soon as possible
thereafter.  The undersigned acknowledges that tendering MFS 2004 Notes in
accordance with the Exchange Offer constitutes a Consent to the Proposed
Amendments with respect to all MFS 2004 Notes so tendered.

Subject to, and effective upon, acceptance for exchange of the MFS 2004 Notes
tendered hereby in accordance with the terms of the Exchange Offer, the
undersigned hereby sells, assigns and transfers to or upon the order of the
Company all right, title and interest in and to, and any and all claims in
respect of or arising or having arisen as a result of the undersigned's status
as a Holder of, all MFS 2004 Notes tendered hereby.  The undersigned hereby
irrevocably constitutes and appoints the Exchange Agent as the true and lawful
agent and attorney-in-fact of the undersigned [(with full knowledge that the
Exchange Agent also acts as the agent of the Company)], with full power of
substitution (such power of attorney being deemed to be an irrevocable power
coupled with an interest), to (a) deliver certificates for such MFS 2004 Notes
or transfer ownership of such MFS 2004 Notes on the account books maintained by
DTC, in either such case, together with all accompanying evidences of transfer
and authenticity, to or upon the order of the Company, (b) present such MFS 2004
Notes for transfer of ownership on the books of the Company, (c) deliver the
Consent contained herein to the MFS Trustee, and (d) receive all benefits and
otherwise exercise all rights of beneficial ownership of such MFS 2004 Notes,
all in accordance with the terms of the Exchange Offer as described in the
Prospectus.

The undersigned hereby represents and warrants that: (a) the undersigned (i) has
full power and authority to tender the MFS 2004 Notes tendered hereby and to
sell, assign and transfer all right, title and interest in and to such MFS 2004
Notes and (ii) either has full power and authority to consent to the Proposed
Amendments or is delivering a duly executed Consent (which is included in this
Letter of Transmittal) from a person or entity having such power and authority;
and (b) the Company will acquire good, indefeasible and unencumbered title to
such MFS 2004 Notes, free and clear of all security interests, liens,
restrictions, charges, encumbrances, conditional sales agreements or other
obligations and not subject to any adverse claim or right, when the same are
accepted by the Company. The undersigned, upon request, will execute and deliver
any additional documents deemed by the Exchange Agent or the Company to be
necessary or desirable to complete the sale, assignment and transfer to the
Company of the MFS 2004 Notes tendered hereby or to perfect the undersigned's
Consent to the Proposed Amendments.

                                       5
<PAGE>
 
The undersigned understands that, upon the terms and subject to the conditions
of the Exchange Offer, MFS 2004 Notes properly tendered and accepted and not
withdrawn in accordance with the terms and conditions of the Exchange Offer will
be exchanged for WorldCom 2004 Notes.  The undersigned understands that, under
certain circumstances, the Company may not be required to accept any of the MFS
2004 Notes tendered (including any such MFS 2004 Notes tendered after the
Expiration Date).  If any MFS 2004 Notes are not accepted for exchange for any
reason or if MFS 2004 Notes are withdrawn or are submitted for a greater
principal amount than the undersigned desires to exchange, such unexchanged,
withdrawn or non-exchanged MFS 2004 Notes will be returned without expense to
the undersigned (or, in the case of MFS 2004 Notes by book-entry transfer into
the Exchange Agent's account at DTC pursuant to the book-entry transfer
procedures described in the Prospectus) as promptly as practicable after the
expiration or termination of the Exchange Offer.

The undersigned understands that tenders of MFS 2004 Notes pursuant to the
procedures described in the Prospectus under the headings "The Exchange Offers--
Procedures for Tendering" and "Proper Execution and Delivery of Letters of
Transmittal" and "The Consent Solicitations" and in the instructions hereto and
acceptance hereof by the Company will constitute a binding agreement between the
undersigned and the Company upon the terms and subject to the conditions
described in the Prospectus.

All authority conferred or deemed to be conferred by this Letter of Transmittal
shall not be affected by and shall survive the death or incapacity of the
undersigned, and any obligation of the undersigned hereunder shall be binding
upon the heirs, personal representatives, executors, administrators, successors,
assigns, trustees in bankruptcy, and personal and other legal representatives of
the undersigned.

Tenders of MFS 2004 Notes may not be withdrawn (and the related Consents thereby
revoked) at any time after 11:59 p.m., New York City time, on               ,
1997, unless the Exchange Offer is extended and contains new terms materially
adverse to the tendering Holders thereof.  A purported notice of withdrawal will
be effective only if delivered to the Exchange Agent in accordance with the
specific procedures set forth in the Prospectus under the heading "The Consent
Solicitations - Required Consents" and "The Exchange Offers - Withdrawal Of
Tenders And Revocation Of Consents."  Consents may only be revoked by withdrawal
of a tender of MFS 2004 Notes.

Please credit all WorldCom 2004 Notes issued for any MFS 2004 Notes exchanged to
the DTC account of the undersigned or the undersigned's custodian as specified
in the Account Information Table above.  Unless otherwise indicated under
"Special Issuance and Payment Instructions," please issue the check for the
appropriate Consent Payment and other cash payments, if any, for any MFS 2004
Notes exchanged and issue any MFS 2004 Notes not tendered or not exchanged in
the name of the undersigned.  Similarly, unless otherwise indicated under
"Special Delivery Instructions," please mail the check for the appropriate
Consent Payment and other cash payments, if any, for any MFS 2004 Notes
exchanged and deliver any MFS 2004 Notes not tendered or not exchanged (unless
tender was effected by book-entry transfer, in which case credit such MFS 2004
Notes to the DTC account from which tender was effected) to the undersigned at
the address shown below the undersigned's signature.

In the event that "Special Issuance and Payment Instructions" is completed,
please issue the check for the appropriate Consent Payment and other cash
payments, if any, for any MFS 2004 Notes exchanged and/or issue any MFS 2004
Notes not tendered or not exchanged in the name of the person so indicated.  In
the event that "Special Delivery Instructions" is completed, please mail the
check for the appropriate Consent Payment and other cash payments, if any, for
any MFS 2004 Notes exchanged and/or deliver any certificates for MFS 2004 Notes
not tendered or not exchanged (unless tender was effected by book-entry
transfer, in which case credit such MFS 2004 Notes to the DTC account from which
tender was effected) to the person at the address so indicated.  The undersigned
recognizes that the Company has no obligation under the "Special Issuance and
Payment Instructions" provision or the "Special Delivery Instructions" provision
of this Letter of Transmittal to effect the transfer of any MFS 2004 Notes from
the name of the Holder thereof if the Company does not accept for exchange any
of the principal amount of the MFS 2004 Notes tendered pursuant to this Letter
of Transmittal.

                                       6
<PAGE>
 
                         SPECIAL DELIVERY INSTRUCTIONS
                     (See Instructions 1, 4, 5,  6 and 7)

  To be completed ONLY if MFS 2004 Notes to be issued in the principal amount of
MFS 2004 Notes not tendered or not exchanged and/or the check for the
appropriate Consent Payment and other cash payments, if any, for any MFS 2004
Notes exchanged, are to be sent to someone other than the undersigned, or to the
undersigned at an address other than that shown below the undersigned's
signature.
   
Please issue (check one or both)                              
[ ] check      [ ] MFS 2004 Notes not tendered or not exchanged, to:
 
Name(s).............................................................
                    (Please Type or Print)
 

 ....................................................................
                    (Please Type or Print)

Address.............................................................

 ....................................................................
                                                          (Zip Code)




                   SPECIAL ISSUANCE AND PAYMENT INSTRUCTIONS
                      (See Instructions 1, 4, 5, 6 and 7)

  To be completed ONLY if  MFS 2004 Notes to be returned in the principal 
amount of MFS 2004 Notes not tendered and not exchanged and/or the check for the
appropriate Consent Payment for any MFS 2004 Notes exchanged, and other cash
payments, if any, are to be issued in the name of someone other than the
undersigned.

                                                  
Please issue (check one or both)                 
[ ] check      [ ] MFS 2004 Notes not tendered or not exchanged, to:
                                                  
Name(s).............................................................    
              (Please Type or Print)              

 ....................................................................    
              (Please Type or Print)              

 Address............................................................    


 ....................................................................    
                                                          (Zip Code)


 ................................................................................
             (Employer Identification or Social Security Number(s)
                                   of Payee)
                      (Please also complete the enclosed
                          Substitute Form W-9 herein)

                                        
                                   SIGN HERE
                  (TO BE COMPLETED BY ALL TENDERING HOLDERS)
                  (Complete Accompanying Substitute Form W-9)

 . . . . . . . . . . . . . . . . . .      . . . . . . . . . . . . . . . . . .

 . . . . . . . . . . . . . . . . . .      . . . . . . . . . . . . . . . . . .

 . . . . . . . . . . . . . . . . . .      . . . . . . . . . . . . . . . . . . 
     Signature(s) of Owner                   Date

    Area Code and Telephone Number..........................................

    Employer Identification or Social Security Number:......................

    (Please complete Substitute Form W-9 herein.)

    If a holder is tendering any MFS 2004 Notes, this Letter of Transmittal 
must be signed by the registered holder(s) as the name(s) appear(s) on the
certificate(s) for the MFS 2004 Notes or on a securities position listing or by
any person(s) authorized to become registered holder(s) by endorsements and
documents transmitted herewith. If the signature is by a trustee, executor,
administrator, guardian, attorney-in-fact, officer or other person acting in a
fiduciary or representative capacity, please set forth at the line entitled
"Capacity" full title and submit evidence satisfactory to the Exchange Agent and
the Company of such person's authority to so act. See Instruction 5.


Name(s):........................................................................


 ................................................................................
                               (Please Type or Print)


Capacity (full title):..........................................................

Address:........................................................................


 ................................................................................
                             (Including Zip Code)


         SIGNATURE GUARANTEE (If required -- See Instructions 1 and 5)

Signature(s) Guaranteed by
an Eligible Institution:........................................................
                                    (Authorized Signature)
 
 ................................................................................
                                    (Title)
 
 ................................................................................
                                (Name and Firm)
 
 ................................................................................
                                   (Address)

Dated:...................................................................., 1997

                                       7
<PAGE>
 
                                  INSTRUCTIONS
         FORMING PART OF THE TERMS AND CONDITIONS OF THE EXCHANGE OFFER

1.  SIGNATURE GUARANTEES.  All signatures on this Letter of Transmittal must be
guaranteed by a firm or other entity identified in Rule 17Ad-15 under the
Securities Exchange Act of 1934, as amended, including (as such terms are
defined therein): (i) a bank; (ii) a broker, dealer, municipal securities
dealer, municipal securities broker, government securities dealer or government
securities broker; (iii) a credit union; (iv) a national securities exchange,
registered securities association or clearing agency; or (v) a savings
institution that is a participant in a Securities Transfer Association
recognized program (each an "Eligible Institution"); however no guarantee of
signature is required if the MFS 2004 Notes tendered hereby are tendered (a) by
a record Holder who has not completed the box entitled "Special Issuance and
Payment Instructions," or the box entitled "Special Delivery Instructions" or
(b) for the account of an Eligible Institution. If the record Holder of the MFS
2004 Notes tendered hereby is a person other than the signer of this Letter of
Transmittal, see Instruction 5.

2.  DELIVERY OF LETTER OF TRANSMITTAL AND MFS 2004 NOTES; GUARANTEED DELIVERY
PROCEDURES; ISSUANCE OF WORLDCOM 2004 NOTES IN BOOK-ENTRY FORM.  All physically
tendered MFS 2004 Notes, or a confirmation of a book-entry transfer into the
Exchange Agent's account at DTC of all MFS 2004 Notes delivered electronically
or Notice of Guaranteed Delivery for tenders of MFS 2004 Notes, together with a
properly completed and duly executed Letter of Transmittal, and any other
documents required by this Letter of Transmittal, should be mailed or delivered
to the Exchange Agent at its address set forth on the front page hereof and must
be received by the Exchange Agent prior to 11:59 p.m., New York City time, on
the Expiration Date.

Holders of MFS 2004 Notes whose certificates for MFS 2004 Notes are not
immediately available or who cannot deliver their certificates and all other
required documents to the Exchange Agent on or prior to the Expiration Date, or
who cannot complete the procedure for book-entry transfer on a timely basis, may
tender their MFS 2004 Notes pursuant to the guaranteed delivery procedures set
forth in the Prospectus under the heading "The Exchange Offers--Procedures for
Tendering--Guaranteed Delivery Procedures".  Pursuant to such procedures, (i)
such tender must be made by or through an Eligible Institution, (ii) on or prior
to the Expiration Date, the Exchange Agent must receive from such Eligible
Institution a properly completed and duly executed Notice of Guaranteed Delivery
(by facsimile transmission, mail or hand delivery), substantially in the form
provided by the Company, setting forth the name and address of the Holder of MFS
2004 Notes, the certificate number(s) of such MFS 2004 Notes, and the principal
amount at stated maturity of MFS 2004 Notes tendered, stating that the tender is
being made thereby and guaranteeing that within two New York Stock Exchange
("NYSE") trading days after the Expiration Date, the Letter of Transmittal (or a
facsimile thereof) together with the certificates for all physically tendered
MFS 2004 Notes or a timely confirmation of a book-entry transfer (a "Book-Entry
Confirmation"), as the case may be, and any other documents required by this
Letter of Transmittal will be delivered by the Eligible Institution with the
Exchange Agent, and (iii) such properly executed Letter of Transmittal (or
facsimile thereof) as well as the certificates for all physically tendered MFS
2004 Notes, in proper form for transfer, or Book-Entry Confirmation, as the case
may be, and all other documents required by this Letter of Transmittal, are
received by the Exchange Agent within two NYSE trading days after the Expiration
Date.

Because all WorldCom 2004 Notes will be delivered only in book-entry form
through DTC, the appropriate DTC participant name and number (along with any
other required account information) to permit such delivery must be provided in
the Account Information Table. Failure to do so will render a tender of MFS 2004
Notes defective, and the Company will have the right, which it may waive, to
reject such tender. Holders who anticipate tendering by a method other than
through DTC are urged to promptly contact a bank, broker or other intermediary
(that has the facility to hold securities custodially through DTC) to arrange
for receipt of any WorldCom 2004 Notes delivered pursuant to the Exchange Offer
and to obtain the information necessary to complete the Account Information
Table.

THE METHOD OF DELIVERY OF MFS 2004 NOTES, THIS LETTER OF TRANSMITTAL AND ALL
OTHER REQUIRED DOCUMENTS TO THE EXCHANGE AGENT IS AT THE ELECTION AND RISK OF
THE HOLDER.  INSTEAD OF DELIVERY BY MAIL, IT IS RECOMMENDED THAT HOLDERS USE AN
OVERNIGHT OR HAND DELIVERY SERVICE, PROPERLY INSURED.  IN ALL CASES, SUFFICIENT
TIME SHOULD BE ALLOWED TO ASSURE DELIVERY TO AND RECEIPT BY THE EXCHANGE AGENT
ON OR BEFORE THE EXPIRATION DATE.  DO NOT SEND THE LETTER OF TRANSMITTAL OR ANY
MFS 2004 NOTES TO ANYONE OTHER THAN THE EXCHANGE AGENT.  HOLDERS MAY REQUEST
THEIR RESPECTIVE BROKERS, DEALERS, COMMERCIAL BANKS, TRUST COMPANIES OR NOMINEES
TO EFFECT THE ABOVE TRANSACTIONS FOR SUCH HOLDERS.

All tendering Holders, by execution of this Letter of Transmittal, waive any
right to receive any notice of the acceptance of their tender, except as
expressly provided in the Prospectus.

3.  INADEQUATE SPACE.  If the space provided in the Description Table is
inadequate, the numbers and principal amounts at stated maturity of the MFS 2004
Notes tendered should be listed on a separate signed schedule and attached
hereto.

4.  PARTIAL TENDERS AND CONSENTS.  Tenders of MFS 2004 Notes will be accepted
only in integral multiples of $1,000.  The aggregate principal amount at stated
maturity of all MFS 2004 Notes delivered to the Exchange Agent will be deemed to
have been tendered and a Consent given with respect thereto unless otherwise
indicated in the Description Table.  Book-entry transfers to the Exchange Agent
should be made in the exact principal amount at stated maturity of MFS 2004
Notes tendered and in respect of which a Consent is given.  With respect to a
tender of MFS 2004 Notes held in

                                       8
<PAGE>
 
physical form, if the tender is made with respect to less than the entire
principal amount at stated maturity of the MFS 2004 Notes delivered herewith,
enter the principal amount at stated maturity (in integral multiples of $1,000)
of the MFS 2004 Notes that are to be tendered and in respect of which a Consent
is given in the column in the Description Table entitled "Principal Amount at
stated maturity Tendered and in Respect of Which Consent is Given" In such case,
a new MFS 2004 Note for the principal amount at stated maturity of the
untendered MFS 2004 Notes will be issued.

5.  SIGNATURES ON LETTER OF TRANSMITTAL, BOND POWERS AND ENDORSEMENTS.  IF THIS
LETTER OF TRANSMITTAL IS SIGNED BY A PERSON OTHER THAN THE RECORD HOLDER, A
CONSENT IN THE FORM PROVIDED IN THIS LETTER OF TRANSMITTAL MUST BE OBTAINED FROM
THE RECORD HOLDER WITH THE SIGNATURE GUARANTEED BY AN ELIGIBLE INSTITUTION.

If this Letter of Transmittal is signed by the record Holder(s) of the MFS 2004
Notes tendered hereby, the signature(s) must correspond with the name(s) as
written on the face of the MFS 2004 Notes or on a security position listing with
respect thereto without any alteration, enlargement or change whatsoever. If any
of the tendered MFS 2004 Notes are held by two or more record Holders, all such
persons must sign this Letter of Transmittal. If any of the tendered MFS 2004
Notes are registered in different names on several certificates, it will be
necessary to complete, sign and submit as many separate Letters of Transmittal
and any necessary accompanying documents as there are different registrations.

If this Letter of Transmittal is signed by the record Holder(s) of the MFS 2004
Notes tendered and if any MFS 2004 Notes not tendered or not exchanged are to be
returned to the undersigned, then no endorsements of MFS 2004 Notes or separate
bond powers or other instruments of transfer are required to effect a valid
tender. If the Letter of Transmittal is signed by someone other than the record
Holder or if any MFS 2004 Notes not tendered or not exchanged are to be returned
to someone other than the undersigned, then endorsement of the MFS 2004 Notes or
separate bond powers or other instruments of transfer (signed exactly as the
name of the registered owner appears on the certificates), will be required to
effect a valid tender. Signatures on any such MFS 2004 Notes or bond powers must
be guaranteed by an Eligible Institution. See Instruction 1.

If this Letter of Transmittal, any Consent or any MFS 2004 Notes or bond powers
or other instruments of transfer are signed by a trustee, executor,
administrator, guardian, attorney-in-fact, officer of a corporation, agent or
other person(s) acting in a fiduciary or representative capacity, such
person(s) should so indicate when signing, unless waived by the Company, and
must submit proper evidence satisfactory to the Company of their authority so
to act.

6.  TRANSFER TAXES.  The Company will pay or cause to be paid security transfer
taxes, if any, with respect to the sale and transfer of any MFS 2004 Notes to it
pursuant to the Exchange Offer.  If, however, payment of the appropriate Consent
Payment or other cash payment, if any, is made to, or WorldCom 2004 Notes and/or
substitute MFS 2004 Notes for amounts not tendered or not exchanged are to be
delivered to, or are to be registered in the name of, any person other than the
Holder of MFS 2004 Notes tendered, or if tendered MFS 2004 Notes are registered
in the name of any person other than the person signing the Letter of
Transmittal, or if a transfer tax is imposed for any reason other than the
transfer or sale of MFS 2004 Notes to the Company pursuant to the Exchange
Offer, the amount of any such transfer taxes (whether imposed on the registered
Holder or any other persons) shall be payable by the tendering Holder.  If
satisfactory evidence of payment of such taxes or exemption therefrom is not
submitted with the appropriate Letter of Transmittal, the amount of such
transfer taxes will be billed directly to such tendering Holder and/or withheld
from any payments due with respect to the MFS 2004 Notes tendered by such
Holder.

7.  SPECIAL ISSUANCE AND PAYMENT AND DELIVERY INSTRUCTIONS.  If MFS 2004 Notes
representing the aggregate principal amount at stated maturity of MFS 2004 Notes
not tendered or not exchanged under the Exchange Offer and/or checks for the
appropriate Consent Payment and other cash, if any, for any MFS 2004 Notes
exchanged, are to be issued in the name of a person other than the undersigned,
or if such MFS 2004 Notes and/or checks are to be sent to someone other than the
undersigned or to the undersigned at a different address than that appearing
below the signature of the undersigned in the signature box above, the boxes
entitled "Special Issuance and Payment Instructions" and "Special Delivery
Instructions" in this Letter of Transmittal must be completed as appropriate.
Regardless of any information appearing in "Special Issuance and Payment
Instructions" or "Special Delivery Instructions," all WorldCom 2004 Notes will
be delivered only in book-entry form through DTC and only to the DTC account of
the undersigned or the undersigned's custodian.

8.  REQUESTS FOR ASSISTANCE OR ADDITIONAL COPIES. Requests for assistance or
additional copies of the Prospectus, this Letter of Transmittal or the Notice of
Guaranteed Delivery should be directed to the Information Agent at the address
and telephone number set forth on the back cover page hereof and on the back
cover page of the Prospectus.

9.  SUBSTITUTE FORM W-9. Each Holder tendering MFS 2004 Notes (or other payee)
is required to provide the Exchange Agent with the Holder's correct taxpayer
identification number ("TIN"), generally the Holder's Social Security or
federal Employer Identification Number, and with certain other information, on
Substitute Form W-9, which is provided herein, or, alternatively, to establish
another basis for exemption from backup withholding. Foreign individuals
claiming an exemption from these backup withholding and reporting requirements
must submit a statement signed under penalty of perjury attesting as to that
status. Forms for such statement can be obtained from the Information Agent.
Additionally, a Holder must cross out item (2) in the Certification box on
Substitute Form W-9 if the Holder is subject to backup withholding. Failure to
provide the information on the form may subject the Holder to a $50 penalty
imposed by the Internal Revenue Service and 31% federal income tax backup
withholding on the payments made to the Holder or other payee with respect to
the WorldCom 2004 Notes and payments received pursuant to the Exchange Offer
and related Consent Solicitation. If the Holder has not been issued a TIN and
has applied for a TIN or intends to apply for a TIN in the near future, such
Holder shall write "Applied For" in the space provided in Part I of the form.
If the Exchange Agent

                                       9

<PAGE>
 
is not provided with a TIN within 60 days thereafter, the Exchange Agent will
withhold 31% on all such WorldCom 2004 Notes and payments until a TIN is
provided to the Exchange Agent. See the Prospectus under the heading "Certain U.
S. Federal Income Tax Considerations."

10.  DETERMINATION OF VALIDITY.  The Company will determine, in its sole
discretion, all questions as to the form of documents, validity, eligibility
(including time of receipt) and acceptance and withdrawal of any tender of MFS
2004 Notes, which determination shall be final and binding on all parties.  The
Company reserves the absolute right to reject any and all tenders determined by
it not to be in proper form or not to be properly tendered or the acceptance of
which, or exchange for which, would,  in the opinion of counsel to the Company,
be unlawful.  The Company also reserves the right, in its sole discretion, to
waive any defects, irregularities or conditions of tenders in any tender of MFS
2004 Notes of any particular holder whether or not similar defects,
irregularities or conditions are waived in the case of other holders.

The Company's interpretation of the terms and conditions of the Exchange Offer
and the related Consent Solicitation (including this Letter of Transmittal and
the instructions hereto) will be final and binding.  No tender of MFS 2004 Notes
will be deemed to have been validly made until all defects or irregularities
with respect to such tender have been cured or waived.  Although the Company
intends to notify holders of defects or irregularities with respect to tenders
of MFS 2004 Notes, neither the Company, any employees, agents, affiliates or
assigns of the Company, the Exchange Agent, nor any other person shall be under
any duty to give such notification or incur any liability for failure to give
any such notification.

IMPORTANT:  THIS LETTER OF TRANSMITTAL TOGETHER WITH THE MFS 2004 NOTES TENDERED
AND ANY OTHER DOCUMENTS REQUIRED BY THIS LETTER OF TRANSMITTAL MUST BE RECEIVED
BY THE EXCHANGE AGENT ON OR PRIOR TO 11:59 P.M., NEW YORK CITY TIME, ON THE
EXPIRATION DATE.

                                       10
<PAGE>
 
PAYER'S NAME:  HARRIS TRUST & SAVINGS BANK
                                                         Social Security Number
SUBSTITUTE
FORM W-9                     Part I -- PLEASE PROVIDE              or
                                   YOUR TAXPAYER
                             IDENTIFICATION NUMBER IN   Employer Identification
                             THE BOX AT THE RIGHT AND            Number
                              CERTIFY BY SIGNING AND
                                   DATING BELOW
 
                                                        -----------------------
Department of the Treasury                               (If awaiting TIN write
Internal Revenue Service                                     "Applied For")
 
 
Payer's Request for          Part II -- For Payees exempt from backup
 Taxpayer                    withholding, see Instruction 9 above and the
Identification Number        "Instructions for Certification of Taxpayer
 (TIN) and Certifications    Identification Number on Substitute Form W-9"
                             enclosed herewith and complete as Instructed
                             therein.
 
 
 
 
Certifications -- Under penalties of perjury, I certify that:

(1)   The number shown on this form is my correct Taxpayer Identification 
      Number (or a Taxpayer Identification Number has not been issued to me and
      either (a) I have mailed or delivered an application to receive a Taxpayer
      Identification Number to the appropriate Internal Revenue Service Center
      or Social Security Administration office or (b) I intend to mail or
      deliver an application in the near future). I understand that if I do not
      provide a Taxpayer Identification Number to the payer, 31% of all
      reportable payments made to me thereafter will be withheld until I provide
      a number to the payer and that, if I do not provide my Taxpayer
      Identification Number within sixty (60) days, such retained amounts shall
      be remitted to the Internal Revenue Service ("IRS") as backup withholding.

(2)   I am not subject to backup withholding either because I have not been 
      notified by the IRS that I am subject to backup withholding as a result of
      a failure to report all interest or dividends or the IRS has notified me
      that I am no longer subject to backup withholding.




Certification Instruction -- You must cross out Item (2) above if you have been
notified by the IRS that you are currently subject to backup withholding because
of underreporting interest or dividends on your tax return. However, if after
being notified by the IRS that you were subject to withholding you received
another notification form the IRS that you are no longer subject to backup
withholding, do not cross out Item (2).



Name
    ___________________________________________________________________________ 
                                    (Please Print)

Address________________________________________________________________________ 

  _____________________________________________________________________________
                                  (Include Zip Code)

Signature________________________________________________Date__________________
 
 
NOTE: FAILURE TO COMPLETE AND RETURN THIS FORM MAY RESULT IN BACKUP WITHHOLDING 
      OF 31% OF ANY PAYMENTS MADE TO YOU PURSUANT TO THE EXCHANGE OFFER AND
      RELATED CONSENT SOLICITATION. PLEASE REVIEW INSTRUCTION 9 AND THE
      "INSTRUCTIONS FOR CERTIFICATION OF TAXPAYER IDENTIFICATION NUMBER ON
      SUBSTITUTE FORM W-9" FOR ADDITIONAL DETAILS.
 
 

                                       11
<PAGE>
 
         Any questions concerning the terms of the Exchange Offers and
      Consent Solicitations may be directed to the Joint Dealer Managers,


                              Salomon Brothers Inc
                            Seven World Trade Center
                            New York, New York 10006
                     Telephone:  (800) 558-3745 (toll free)
                   Telephone:  (212) 783-3738 (call collect)
                     Attention:  Liability Management Group

                                      and

                              Goldman, Sachs & Co.
                                85 Broad Street
                           New York, New York  10004
                     Telephone:  (800) 828-3182 (toll free)
                   Telephone:  (212) 902-8200 (call collect)
                     Attention:  Liability Management Group


 Any questions concerning the completion of this form, or tender procedures or
requests for additional copies of the Prospectus or this Letter of Transmittal 
  may be directed to the Information Agent for the Exchange Offer and Related
                             Consent Solicitation,


                            MacKenzie Partners, Inc.
                                156 Fifth Avenue
                           New York, New York  10010
                     Telephone:  (800) 322-2885 (toll free)
                   Telephone:  (212) 929-5500 (call collect)



                  MFS 2004 Notes tendered, together with this
                  Letter of Transmittal and any other required
               documents, must be delivered to the Exchange Agent
               at its address set forth on the front page hereof.

                                       12

<PAGE>
 
                                                                    EXHIBIT 99.2

[BLUE]
                       LETTER OF TRANSMITTAL AND CONSENT
                         To Tender and to Give Consent
                                 in Respect of
               8 7/8% Senior Discount Notes due January 15, 2006
                             CUSIP No. 55272T-AB-7
                                       of
                        MFS COMMUNICATIONS COMPANY, INC.
            In Exchange for 8 7/8% Senior Notes due January 15, 2006
                                       of
                                 WORLDCOM, INC.
              Pursuant to the Prospectus and Consent Solicitation
                              dated ________, 1997

THE EXCHANGE OFFER (AS DEFINED BELOW) WILL EXPIRE AT 11:59 P.M., NEW YORK CITY
TIME, ON          , 1997, UNLESS EXTENDED (SUCH TIME AND DATE, AS EXTENDED, THE
"EXPIRATION DATE" WITH RESPECT TO SUCH EXCHANGE OFFER).  TENDERS OF MFS 2006
NOTES MAY NOT BE WITHDRAWN (AND THE RELATED CONSENTS THEREBY REVOKED) AT ANY
TIME AFTER 11:59 P.M., NEW YORK CITY TIME, ON          , 1997, UNLESS THE
APPLICABLE EXCHANGE OFFER IS EXTENDED AND CONTAINS NEW TERMS MATERIALLY ADVERSE
TO THE TENDERING HOLDERS THEREOF.

          Delivery To:  Harris Trust and Savings Bank,  Exchange Agent

<TABLE>
<CAPTION>
By Registered or Certified Mail:              Overnight or Hand Delivery:           Facsimile Transmission:
<S>                                        <C>                                   <C>
     Harris Trust and Savings Bank            Harris Trust and Savings Bank               (212) 701-7636
 c/o Harris Trust Company of New York      c/o Harris Trust Company of New York      
           P.O. Box 1010                              77 Water Street             
       Wall Street Station                              4th Floor                     Confirm by Telephone:
       New York, NY  10268                         New York, NY  10004                   (212) 701-7624
</TABLE>

Questions regarding the Exchange Offer or completion of this Letter of
Transmittal may be directed to MacKenzie Partners, Inc., the Information Agent
for the Exchange Offer, at (800) 322-2885 (toll free).

Delivery of this Letter of Transmittal and Consent (this "Letter of
Transmittal") to an address, or transmission of instructions via a facsimile
number, other than as set forth above or other than in accordance with the
instructions herein, will not constitute valid delivery.  The instructions
accompanying this Letter of Transmittal should be read carefully before this
Letter of Transmittal is completed.

This Letter of Transmittal is to be used in connection with (i) the physical
delivery of MFS 2006 Notes (as defined herein) to Harris Trust and Savings Bank,
as exchange agent (the "Exchange Agent"), or (ii) the delivery of MFS 2006 Notes
by book-entry transfer to the account of the Exchange Agent at The Depository
Trust Company ("DTC"), in accordance with the procedures described in the
Prospectus and Consent Solicitation dated __________, 1997 (together, the
"Prospectus") under the heading "The Exchange Offers--Procedures for Tendering."

All capitalized terms used and not defined herein have the meanings ascribed to
them in the Prospectus.

Pursuant to the Prospectus, receipt of which is hereby acknowledged, WorldCom,
Inc. (the "Company") is offering to exchange $737.912 principal amount of
WorldCom 2006 Notes for each $1,000 principal amount at stated maturity of
outstanding MFS 2006 Notes properly tendered for exchange and accepted.  If the
aggregate principal amount of WorldCom 2006 Notes that otherwise would be issued
in exchange for the MFS 2006 Notes tendered by a Holder and accepted by the
Company pursuant to the Exchange Offer is not an integral multiple of $1,000,
such principal amount will be reduced to the nearest such multiple and the
Company will pay to such Holder an amount in cash equal to the reduction of such
principal amount.

The Company is also offering, pursuant to the Prospectus, to pay each Holder who
gives a valid Consent (as defined herein) to the Proposed Amendments (as defined
herein) on or prior to the Expiration Date a cash fee in an amount equal to
0.__% of the Accreted Value, as of July 15, 1997 (the "Interest Accrual Date"),
of such Holder's MFS 2006 Notes with respect to which Consent has been given.

Holders may give their Consent to the Proposed Amendments only by tendering MFS
2006 Notes in the Exchange Offer, will be required to consent as a condition to
a valid tender and will be deemed to have given such Consent by so tendering.
The proper completion, execution and delivery of this Letter of Transmittal will
constitute a Consent to the Proposed Amendments with respect to the MFS 2006
Notes.

Upon the terms and subject to the conditions of the Exchange Offer, the Company
will accept for exchange all MFS 2006 Notes that are properly tendered (and not
withdrawn) on or prior to 11:59 p.m., New York City time, on the Expiration
Date.
<PAGE>
 
Holders who are unable to properly tender their MFS 2006 Notes (including
delivery of this Letter of Transmittal and all other documents required hereby)
on or prior to the Expiration Date, may nevertheless tender their MFS 2006 Notes
(and thereby consent to the Proposed Amendments) according to the guaranteed
delivery procedures set forth in the Prospectus under the heading "The Exchange
Offers--Procedures for Tendering--Guaranteed Delivery Procedures."  See
Instruction 2.

Holders who wish to tender their MFS 2006 Notes (and thereby consent to the
Proposed Amendments) pursuant to this Letter of Transmittal must, at a minimum,
fill in the necessary account information in the table below entitled "Account
Information" (the "Account Information Table"), complete columns (1) through (3)
in the table below entitled "Description of MFS 2006 Notes Tendered and In
Respect of Which Consent Is Given" (the "Description Table") and complete and
sign in the box below entitled "SIGN HERE."   If only columns (1) through (3)
are completed in the Description Table, the Holder will be deemed to have
consented to the Proposed Amendments in respect of, and to have tendered, all
MFS 2006 Notes listed in the Description Table.  If a Holder wishes to tender
less than all of such MFS 2006 Notes delivered to the Exchange Agent, column (4)
of the Description Table must be completed in full.  See Instruction 4.

                                       2
<PAGE>
 
In order to effect a valid tender of MFS 2006 Notes the undersigned must
complete the Account Information Table below.  WorldCom 2006 Notes will be
delivered only in book-entry form through DTC and only to the DTC account of the
undersigned or the undersigned's custodian.  Accordingly, if the undersigned
tenders (i) by book-entry transfer to the Exchange Agent's account at DTC, the
first box in the account information table must be checked and any WorldCom 2006
Notes will be delivered to the DTC participant from which tender was effected,
or (ii) by physical delivery of certificates to the Exchange Agent, the second
box in the account information table must be checked and any WorldCom 2006 Notes
will be delivered to the DTC participant indicated by the Holder in such table.
Failure to provide the information necessary to effect delivery of WorldCom 2006
Notes will render such Holder's tender defective and the Company will have the
right, which it may waive, to reject such tender.

ATTENTION ANY TENDERING HOLDER WHOSE MFS 2006 NOTES WILL NOT BE DELIVERED TO THE
EXCHANGE AGENT THROUGH DTC:  Because WorldCom 2006 Notes will be delivered only
in book-entry form through DTC, you are urged to contact promptly a bank, broker
or other intermediary (that has the facility to hold securities custodially
through DTC) to arrange for receipt of any WorldCom 2006 Notes delivered
pursuant to the Exchange Offer and to obtain the information necessary to
complete the Account Information Table.

TO VALIDLY COMPLETE THE LETTER OF TRANSMITTAL (AND THEREBY CONSENT TO THE
PROPOSED AMENDMENTS), COMPLETE PAGES ____ AND ____, COMPLETE AND SIGN PAGE ____,
AND (IF NECESSARY) COMPLETE AND SIGN PAGES ____, ____ AND ____.

THE INSTRUCTIONS STARTING ON PAGE ____ FORM A PART OF THE TERMS AND CONDITIONS
OF THE EXCHANGE OFFER AND RELATED CONSENT SOLICITATION AND SHOULD BE READ
CAREFULLY.



                              ACCOUNT INFORMATION
                     (Complete One Method of Tender Only*)

VIA DTC

[_]    Check here if tendered MFS 2006 Notes are being delivered by book-entry
transfer to the Exchange Agent's account at DTC and complete the following:

Name of DTC Participant
                       -------------------------------------------------------- 

DTC Participant Number
                       -------------------------------------------------------- 

VIA PHYSICAL DELIVERY

[_]    Check here if tendered MFS 2006 Notes are being delivered in physical
form and complete the following:

Name of Registered Holder(s)
                            ---------------------------------------------------

DTC Participant Receiving WorldCom 2006 Notes**:

       Name of DTC Participant
                              -------------------------------------------------

       DTC Participant Number
                              -------------------------------------------------

       Customer Account Number
                              -------------------------------------------------

       DTC Participant Contact Name/Phone Number
                                                -------------------------------

 
- -------------------------------------------------------------------------------
*  Failure to complete one, and only one, method of tender will render the
   undersigned's tender defective.
** Failure to provide the information necessary to effect delivery of
   WorldCom 2006 Notes will render the   undersigned's tender defective.


[_]   Check here if this Letter of Transmittal and the MFS 2006 Notes tendered
hereby are being delivered pursuant to a Notice of Guaranteed Delivery
previously delivered in accordance with the Guaranteed Delivery Procedures
described in Instruction 2 hereof.

                                       3
<PAGE>
 
       List below the MFS 2006 Notes to which this Letter of Transmittal
relates.  If the space provided below is inadequate, the certificate numbers and
principal amount of MFS 2006 Notes should be listed on a separate signed
schedule affixed hereto.
 
DESCRIPTION OF MFS 2006 NOTES TENDERED AND IN RESPECT OF WHICH CONSENT IS GIVEN
                          (SEE INSTRUCTIONS 3 AND 4)


<TABLE>
<CAPTION>

Name(s) and Address(es) of Holder(s)     
(please fill in exactly as name appears                        MFS Notes Tendered and In Respect                     
  on the face of the MFS 2006 Notes                                 of Which Consent is Given
 tendered or on a security position                       (attach additional signed schedule if necessary)
   listing with respect thereto)
 
                                                                               Aggregate          Principal
                                                             Certificate       Principal            Amount
                                                              Number(s)*    Amount at Stated       at Stated
                                                                              Maturity of          Maturity
                                                                            MFS 2006 Note(s)     Tendered and
                                                                                                 in Respect of
                                                                                                 Which Consent
                                                                                                is Given (if less
                                                                                                   than all)**
                                              
<S>                                                          <C>            <C>                 <C>
(1)                                                               (2)               (3)                (4)
                                              
                                              
                                              
                                              
                                              
                                              
                                                                Total
</TABLE>

*   Need not be completed if MFS 2006 Notes are being tendered by book-entry 
    transfer.
 ** You must consent to the Proposed Amendments in respect of all MFS 2006 
    Notes tendered by you; completion of column (3) will constitute a Consent to
    the Proposed Amendments in respect of such MFS 2006 Notes, unless less than
    all MFS 2006 Notes are to be tendered as specified in column (4), in which
    case Consents only with respect to such lesser amount of MFS 2006 Notes
    shall be given. See Instruction 4. The principal amount at stated maturity
    of MFS 2006 Notes tendered hereby must be in denominations of $1,000 and any
    integral multiple thereof. See Instruction 4.

                                       4
<PAGE>
 
                    NOTE: SIGNATURES MUST BE PROVIDED BELOW.
              PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY.

Ladies and Gentlemen:

The undersigned hereby (i) consents (the "Consent") to the proposed amendments
described in the Prospectus (the "Proposed Amendments"), to the Indenture, dated
as of January 15, 1996 (as supplemented by First Supplemental Indenture dated as
of January 15, 1996, the "1996 Indenture"), between MFS Communications Company,
Inc. ("MFS") and IBJ Schroder Bank & Trust Company, as Trustee (the "MFS
Trustee"), pursuant to which the 8 7/8% Senior Discount Notes due January 15,
2006 of MFS (the "MFS 2006 Notes") indicated above were issued, and (ii) tenders
to the Company the MFS 2006 Notes indicated above in exchange for 8 7/8% Senior
Notes due January 15, 2006 of the Company (the "WorldCom 2006 Notes") in a ratio
equal to $737.912 principal amount of WorldCom 2006 Notes per $1,000 principal
amount at stated maturity of the MFS 2006 Notes, upon the terms and subject to
the conditions set forth in the Prospectus (receipt of which is hereby
acknowledged) and in this Letter of Transmittal, both of which together
constitute the Company's offer (the "Exchange Offer") to exchange WorldCom 2006
Notes for MFS 2006 Notes properly tendered.

Interest on the WorldCom 2006 Notes will accrue from the Interest Accrual Date.
The principal amount of WorldCom 2006 Notes being offered in exchange for the
MFS 2006 Notes tendered hereby is equal to the Accreted Value (as defined in the
Prospectus) of such MFS 2006 Notes as of the Interest Accrual Date.   WorldCom
2006 Notes will be issued only in denominations of $1,000 and integral multiples
thereof.  If the aggregate principal amount of WorldCom 2006 Notes that
otherwise would be issued in exchange for the MFS 2006 Notes tendered by a
Holder and accepted by the Company pursuant to the Exchange Offer is not an
integral multiple of $1,000, such principal amount will be reduced to the
nearest such multiple and the Company will pay to such Holder an amount in cash
equal to the reduction of such principal amount.

In connection with the undersigned's Consent, the undersigned shall receive a
cash fee in an amount equal to 0.___% of the Accreted Value, as of the Interest
Accrual Date, of the undersigned's MFS 2006 Notes with respect to which Consent
has been given (a "Consent Payment").

The undersigned understands that (i) the Proposed Amendments will be adopted
with respect to the MFS 2006 Notes tendered herewith and (ii) the applicable
Consent Payment will be paid to such Holder, in both cases, only upon
consummation of the Exchange Offer with respect to such MFS 2006 Notes.

The WorldCom 2006 Notes will be delivered by book-entry transfer to the DTC
account of the undersigned or the undersigned's custodian as specified in the
Account Information Table above, and the appropriate Consent Payment, and other
cash payment, if any, will be made by check to the undersigned (unless specified
otherwise "Special Delivery Instructions" or "Special Issuance and Payment
Instructions" below) in New York (Clearing House) funds, on the third business
day following the Expiration Date (the "Exchange Date"), or as soon as possible
thereafter.  The undersigned acknowledges that tendering MFS 2006 Notes in
accordance with the Exchange Offer constitutes a Consent to the Proposed
Amendments with respect to all MFS 2006 Notes so tendered.

Subject to, and effective upon, acceptance for exchange of the MFS 2006 Notes
tendered hereby in accordance with the terms of the Exchange Offer, the
undersigned hereby sells, assigns and transfers to or upon the order of the
Company all right, title and interest in and to, and any and all claims in
respect of or arising or having arisen as a result of the undersigned's status
as a Holder of, all MFS 2006 Notes tendered hereby.  The undersigned hereby
irrevocably constitutes and appoints the Exchange Agent as the true and lawful
agent and attorney-in-fact of the undersigned [(with full knowledge that the
Exchange Agent also acts as the agent of the Company)], with full power of
substitution (such power of attorney being deemed to be an irrevocable power
coupled with an interest), to (a) deliver certificates for such MFS 2006 Notes
or transfer ownership of such MFS 2006 Notes on the account books maintained by
DTC, in either such case, together with all accompanying evidences of transfer
and authenticity, to or upon the order of the Company, (b) present such MFS 2006
Notes for transfer of ownership on the books of the Company, (c) deliver the
Consent contained herein to the MFS Trustee, and (d) receive all benefits and
otherwise exercise all rights of beneficial ownership of such MFS 2006 Notes,
all in accordance with the terms of the Exchange Offer as described in the
Prospectus.

The undersigned hereby represents and warrants that: (a) the undersigned (i) has
full power and authority to tender the MFS 2006 Notes tendered hereby and to
sell, assign and transfer all right, title and interest in and to such MFS 2006
Notes and (ii) either has full power and authority to consent to the Proposed
Amendments or is delivering a duly executed Consent (which is included in this
Letter of Transmittal) from a person or entity having such power and authority;
and (b) the Company will acquire good, indefeasible and unencumbered title to
such MFS 2006 Notes, free and clear of all security interests, liens,
restrictions, charges, encumbrances, conditional sales agreements or other
obligations and not subject to any adverse claim or right, when the same are
accepted by the Company. The undersigned, upon request, will execute and deliver
any additional documents deemed by the Exchange Agent or the Company to be
necessary or desirable to complete the sale, assignment and transfer to the
Company of the MFS 2006 Notes tendered hereby or to perfect the undersigned's
Consent to the Proposed Amendments.

                                       5
<PAGE>
 
The undersigned understands that, upon the terms and subject to the conditions
of the Exchange Offer, MFS 2006 Notes properly tendered and accepted and not
withdrawn in accordance with the terms and conditions of the Exchange Offer will
be exchanged for WorldCom 2006 Notes.  The undersigned understands that, under
certain circumstances, the Company may not be required to accept any of the MFS
2006 Notes tendered (including any such MFS 2006 Notes tendered after the
Expiration Date).  If any MFS 2006 Notes are not accepted for exchange for any
reason or if MFS 2006 Notes are withdrawn or are submitted for a greater
principal amount than the undersigned desires to exchange, such unexchanged,
withdrawn or non-exchanged MFS 2006 Notes will be returned without expense to
the undersigned (or, in the case of MFS 2006 Notes by book-entry transfer into
the Exchange Agent's account at DTC pursuant to the book-entry transfer
procedures described in the Prospectus) as promptly as practicable after the
expiration or termination of the Exchange Offer.

The undersigned understands that tenders of MFS 2006 Notes pursuant to the
procedures described in the Prospectus under the headings "The Exchange Offers--
Procedures for Tendering" and "Proper Execution and Delivery of Letters of
Transmittal" and "The Consent Solicitations" and in the instructions hereto and
acceptance hereof by the Company will constitute a binding agreement between the
undersigned and the Company upon the terms and subject to the conditions
described in the Prospectus.

All authority conferred or deemed to be conferred by this Letter of Transmittal
shall not be affected by and shall survive the death or incapacity of the
undersigned, and any obligation of the undersigned hereunder shall be binding
upon the heirs, personal representatives, executors, administrators, successors,
assigns, trustees in bankruptcy, and personal and other legal representatives of
the undersigned.

Tenders of MFS 2006 Notes may not be withdrawn (and the related Consents thereby
revoked) at any time after 11:59 p.m., New York City time, on               ,
1997, unless the Exchange Offer is extended and contains new terms materially
adverse to the tendering Holders thereof.  A purported notice of withdrawal will
be effective only if delivered to the Exchange Agent in accordance with the
specific procedures set forth in the Prospectus under the heading "The Consent
Solicitations - Required Consents" and "The Exchange Offers - Withdrawal Of
Tenders And Revocation Of Consents."  Consents may only be revoked by withdrawal
of a tender of MFS 2006 Notes.

Please credit all WorldCom 2006 Notes issued for any MFS 2006 Notes exchanged to
the DTC account of the undersigned or the undersigned's custodian as specified
in the Account Information Table above.  Unless otherwise indicated under
"Special Issuance and Payment Instructions," please issue the check for the
appropriate Consent Payment and other cash payments, if any, for any MFS 2006
Notes exchanged and issue any MFS 2006 Notes not tendered or not exchanged in
the name of the undersigned.  Similarly, unless otherwise indicated under
"Special Delivery Instructions," please mail the check for the appropriate
Consent Payment and other cash payments, if any, for any MFS 2006 Notes
exchanged and deliver any MFS 2006 Notes not tendered or not exchanged (unless
tender was effected by book-entry transfer, in which case credit such MFS 2006
Notes to the DTC account from which tender was effected) to the undersigned at
the address shown below the undersigned's signature.

In the event that "Special Issuance and Payment Instructions" is completed,
please issue the check for the appropriate Consent Payment and other cash
payments, if any, for any MFS 2006 Notes exchanged and/or issue any MFS 2006
Notes not tendered or not exchanged in the name of the person so indicated.  In
the event that "Special Delivery Instructions" is completed, please mail the
check for the appropriate Consent Payment and other cash payments, if any, for
any MFS 2006 Notes exchanged and/or deliver any certificates for MFS 2006 Notes
not tendered or not exchanged (unless tender was effected by book-entry
transfer, in which case credit such MFS 2006 Notes to the DTC account from which
tender was effected) to the person at the address so indicated.  The undersigned
recognizes that the Company has no obligation under the "Special Issuance and
Payment Instructions" provision or the "Special Delivery Instructions" provision
of this Letter of Transmittal to effect the transfer of any MFS 2006 Notes from
the name of the Holder thereof if the Company does not accept for exchange any
of the principal amount of the MFS 2006 Notes tendered pursuant to this Letter
of Transmittal.

                                       6
<PAGE>
 
                         SPECIAL DELIVERY INSTRUCTIONS
                     (See Instructions 1, 4, 5,  6 and 7)

  To be completed ONLY if MFS 2006 Notes to be issued in the principal amount of
MFS 2006 Notes not tendered or not exchanged and/or the check for the
appropriate Consent Payment and other cash payments, if any, for any MFS 2006
Notes exchanged, are to be sent to someone other than the undersigned, or to the
undersigned at an address other than that shown below the undersigned's
signature.
                            
Please issue (check one or both)                      
[ ] check   [ ] MFS 2006 Notes not tendered or not exchanged, to:
 
Name(s)..........................................................
                       (Please Type or Print)
 
 .................................................................
                       (Please Type or Print)

Address..........................................................

 .................................................................
                                                       (Zip Code)
 
 



                   SPECIAL ISSUANCE AND PAYMENT INSTRUCTIONS
                      See Instructions 1, 4. 5. 6 and 7)

  To be completed ONLY if MFS 2006 Notes to be returned in the principal amount
of MFS 2006 Notes not tendered and not exchanged and/or the check for the
appropriate Consent Payment for any MFS 2006 Notes exchanged, and other cash
payments, if any, are to be issued in the name of someone other than the
undersigned.

Please issue (check one or both)
[ ] check     [ ] MFS 2006 Notes not tendered or not exchanged, to:

Name(s)............................................................
                        (Please Type or Print)

 ...................................................................
                        (Please Type or Print)

Address............................................................

 ...................................................................
                                                         (Zip Code)

             (Employer Identification or Social Security Number(s)
                                   of Payee)
                      (Please also complete the enclosed
                          Substitute Form W-9 herein)


                                   SIGN HERE
                  (TO BE COMPLETED BY ALL TENDERING HOLDERS)
                  (Complete Accompanying Substitute Form W-9)


 . . . . . . . . . . . . . . . . . .     . . . . . . . . . . . . . . . . . .

 . . . . . . . . . . . . . . . . . .     . . . . . . . . . . . . . . . . . .

 . . . . . . . . . . . . . . . . . .     . . . . . . . . . . . . . . . . . .
        Signature(s) of Owner                 Date

    Area Code and Telephone Number..............................................

    Employer Identification or SocialSecurity Number:...........................

    (Please complete Substitute Form W-9 herein.)

 If a holder is tendering any MFS 2006 Notes, this Letter of Transmittal must 
be signed by the registered holder(s) as the name(s) appear(s) on the
certificate(s) for the MFS 2006 Notes or on a securities position listing or by
any person(s) authorized to become registered holder(s) by endorsements and
documents transmitted herewith. If the signature is by a trustee, executor,
administrator, guardian, attorney-in-fact, officer or other person acting in a
fiduciary or representative capacity, please set forth at the line entitled
"Capacity" full title and submit evidence satisfactory to the Exchange Agent and
the Company of such person's authority to so act. See Instruction 5.


Name(s):........................................................................

 ................................................................................
                              (Please Type or Print)

Capacity (full title):..........................................................

Address:........................................................................

 ................................................................................
                                (Including Zip Code)


         SIGNATURE GUARANTEE (If required -- See Instructions 1 and 5)


Signature(s) Guaranteed by
an Eligible Institution:........................................................
                                      (Authorized Signature)
 
 ................................................................................
                                    (Title)
 
 ................................................................................
                                (Name and Firm)
 
 ................................................................................
                                   (Address)

Dated:...................................................................., 1997

                                       7
<PAGE>
 
                                  INSTRUCTIONS
         FORMING PART OF THE TERMS AND CONDITIONS OF THE EXCHANGE OFFER

1.  SIGNATURE GUARANTEES.  All signatures on this Letter of Transmittal must be
guaranteed by a firm or other entity identified in Rule 17Ad-15 under the
Securities Exchange Act of 1934, as amended, including (as such terms are
defined therein): (i) a bank; (ii) a broker, dealer, municipal securities
dealer, municipal securities broker, government securities dealer or government
securities broker; (iii) a credit union; (iv) a national securities exchange,
registered securities association or clearing agency; or (v) a savings
institution that is a participant in a Securities Transfer Association
recognized program (each an "Eligible Institution"); however no guarantee of
signature is required if the MFS 2006 Notes tendered hereby are tendered (a) by
a record Holder who has not completed the box entitled "Special Issuance and
Payment Instructions," or the box entitled "Special Delivery Instructions" or
(b) for the account of an Eligible Institution. If the record Holder of the MFS
2006 Notes tendered hereby is a person other than the signer of this Letter of
Transmittal, see Instruction 5.

2.  DELIVERY OF LETTER OF TRANSMITTAL AND MFS 2006 NOTES; GUARANTEED DELIVERY
PROCEDURES; ISSUANCE OF WORLDCOM 2006 NOTES IN BOOK-ENTRY FORM.  All physically
tendered MFS 2006 Notes, or a confirmation of a book-entry transfer into the
Exchange Agent's account at DTC of all MFS 2006 Notes delivered electronically
or Notice of Guaranteed Delivery for tenders of MFS 2006 Notes, together with a
properly completed and duly executed Letter of Transmittal, and any other
documents required by this Letter of Transmittal, should be mailed or delivered
to the Exchange Agent at its address set forth on the front page hereof and must
be received by the Exchange Agent prior to 11:59 p.m., New York City time, on
the Expiration Date.

Holders of MFS 2006 Notes whose certificates for MFS 2006 Notes are not
immediately available or who cannot deliver their certificates and all other
required documents to the Exchange Agent on or prior to the Expiration Date, or
who cannot complete the procedure for book-entry transfer on a timely basis, may
tender their MFS 2006 Notes pursuant to the guaranteed delivery procedures set
forth in the Prospectus under the heading "The Exchange Offers--Procedures for
Tendering--Guaranteed Delivery Procedures".  Pursuant to such procedures, (i)
such tender must be made by or through an Eligible Institution, (ii) on or prior
to the Expiration Date, the Exchange Agent must receive from such Eligible
Institution a properly completed and duly executed Notice of Guaranteed Delivery
(by facsimile transmission, mail or hand delivery), substantially in the form
provided by the Company, setting forth the name and address of the Holder of MFS
2006 Notes, the certificate number(s) of such MFS 2006 Notes, and the principal
amount at stated maturity of MFS 2006 Notes tendered, stating that the tender is
being made thereby and guaranteeing that within two New York Stock Exchange
("NYSE") trading days after the Expiration Date, the Letter of Transmittal (or a
facsimile thereof) together with the certificates for all physically tendered
MFS 2006 Notes or a timely confirmation of a book-entry transfer (a "Book-Entry
Confirmation"), as the case may be, and any other documents required by this
Letter of Transmittal will be delivered by the Eligible Institution with the
Exchange Agent, and (iii) such properly executed Letter of Transmittal (or
facsimile thereof) as well as the certificates for all physically tendered MFS
2006 Notes, in proper form for transfer, or Book-Entry Confirmation, as the case
may be, and all other documents required by this Letter of Transmittal, are
received by the Exchange Agent within two NYSE trading days after the Expiration
Date.

Because all WorldCom 2006 Notes will be delivered only in book-entry form
through DTC, the appropriate DTC participant name and number (along with any
other required account information) to permit such delivery must be provided in
the Account Information Table. Failure to do so will render a tender of MFS 2006
Notes defective, and the Company will have the right, which it may waive, to
reject such tender. Holders who anticipate tendering by a method other than
through DTC are urged to promptly contact a bank, broker or other intermediary
(that has the facility to hold securities custodially through DTC) to arrange
for receipt of any WorldCom 2006 Notes delivered pursuant to the Exchange Offer
and to obtain the information necessary to complete the Account Information
Table.

THE METHOD OF DELIVERY OF MFS 2006 NOTES, THIS LETTER OF TRANSMITTAL AND ALL
OTHER REQUIRED DOCUMENTS TO THE EXCHANGE AGENT IS AT THE ELECTION AND RISK OF
THE HOLDER.  INSTEAD OF DELIVERY BY MAIL, IT IS RECOMMENDED THAT HOLDERS USE AN
OVERNIGHT OR HAND DELIVERY SERVICE, PROPERLY INSURED.  IN ALL CASES, SUFFICIENT
TIME SHOULD BE ALLOWED TO ASSURE DELIVERY TO AND RECEIPT BY THE EXCHANGE AGENT
ON OR BEFORE THE EXPIRATION DATE.  DO NOT SEND THE LETTER OF TRANSMITTAL OR ANY
MFS 2006 NOTES TO ANYONE OTHER THAN THE EXCHANGE AGENT.  HOLDERS MAY REQUEST
THEIR RESPECTIVE BROKERS, DEALERS, COMMERCIAL BANKS, TRUST COMPANIES OR NOMINEES
TO EFFECT THE ABOVE TRANSACTIONS FOR SUCH HOLDERS.

All tendering Holders, by execution of this Letter of Transmittal, waive any
right to receive any notice of the acceptance of their tender, except as
expressly provided in the Prospectus.

3.  INADEQUATE SPACE.  If the space provided in the Description Table is
inadequate, the numbers and principal amounts at stated maturity of the MFS 2006
Notes tendered should be listed on a separate signed schedule and attached
hereto.

4.  PARTIAL TENDERS AND CONSENTS.  Tenders of MFS 2006 Notes will be accepted
only in integral multiples of $1,000.  The aggregate principal amount at stated
maturity of all MFS 2006 Notes delivered to the Exchange Agent will be deemed to
have been tendered and a Consent given with respect thereto unless otherwise
indicated in the Description Table.  Book-entry transfers to the Exchange Agent
should be made in the exact principal amount at stated maturity of MFS 2006
Notes tendered and in respect of which a Consent is given.  With respect to a
tender of MFS 2006 Notes held in

                                       8
<PAGE>
 
physical form, if the tender is made with respect to less than the entire
principal amount at stated maturity of the MFS 2006 Notes delivered herewith,
enter the principal amount at stated maturity (in integral multiples of $1,000)
of the MFS 2006 Notes that are to be tendered and in respect of which a Consent
is given in the column in the Description Table entitled "Principal Amount at
stated maturity Tendered and in Respect of Which Consent is Given" In such case,
a new MFS 2006 Note for the principal amount at stated maturity of the
untendered MFS 2006 Notes will be issued.

5.  SIGNATURES ON LETTER OF TRANSMITTAL, BOND POWERS AND ENDORSEMENTS.  IF THIS
LETTER OF TRANSMITTAL IS SIGNED BY A PERSON OTHER THAN THE RECORD HOLDER, A
CONSENT IN THE FORM PROVIDED IN THIS LETTER OF TRANSMITTAL MUST BE OBTAINED FROM
THE RECORD HOLDER WITH THE SIGNATURE GUARANTEED BY AN ELIGIBLE INSTITUTION.

If this Letter of Transmittal is signed by the record Holder(s) of the MFS 2006
Notes tendered hereby, the signature(s) must correspond with the name(s) as
written on the face of the MFS 2006 Notes or on a security position listing with
respect thereto without any alteration, enlargement or change whatsoever. If any
of the tendered MFS 2006 Notes are held by two or more record Holders, all such
persons must sign this Letter of Transmittal. If any of the tendered MFS 2006
Notes are registered in different names on several certificates, it will be
necessary to complete, sign and submit as many separate Letters of Transmittal
and any necessary accompanying documents as there are different registrations.

If this Letter of Transmittal is signed by the record Holder(s) of the MFS 2006
Notes tendered and if any MFS 2006 Notes not tendered or not exchanged are to be
returned to the undersigned, then no endorsements of MFS 2006 Notes or separate
bond powers or other instruments of transfer are required to effect a valid
tender. If the Letter of Transmittal is signed by someone other than the record
Holder or if any MFS 2006 Notes not tendered or not exchanged are to be returned
to someone other than the undersigned, then endorsement of the MFS 2006 Notes or
separate bond powers or other instruments of transfer (signed exactly as the
name of the registered owner appears on the certificates), will be required to
effect a valid tender. Signatures on any such MFS 2006 Notes or bond powers must
be guaranteed by an Eligible Institution. See Instruction 1.

If this Letter of Transmittal, any Consent or any MFS 2006 Notes or bond powers
or other instruments of transfer are signed by a trustee, executor,
administrator, guardian, attorney-in-fact, officer of a corporation, agent or
other person(s) acting in a fiduciary or representative capacity, such
person(s) should so indicate when signing, unless waived by the Company, and
must submit proper evidence satisfactory to the Company of their authority so
to act.

6.  TRANSFER TAXES.  The Company will pay or cause to be paid security transfer
taxes, if any, with respect to the sale and transfer of any MFS 2006 Notes to it
pursuant to the Exchange Offer.  If, however, payment of the appropriate Consent
Payment or other cash payment, if any, is made to, or WorldCom 2006 Notes and/or
substitute MFS 2006 Notes for amounts not tendered or not exchanged are to be
delivered to, or are to be registered in the name of, any person other than the
Holder of MFS 2006 Notes tendered, or if tendered MFS 2006 Notes are registered
in the name of any person other than the person signing the Letter of
Transmittal, or if a transfer tax is imposed for any reason other than the
transfer or sale of MFS 2006 Notes to the Company pursuant to the Exchange
Offer, the amount of any such transfer taxes (whether imposed on the registered
Holder or any other persons) shall be payable by the tendering Holder.  If
satisfactory evidence of payment of such taxes or exemption therefrom is not
submitted with the appropriate Letter of Transmittal, the amount of such
transfer taxes will be billed directly to such tendering Holder and/or withheld
from any payments due with respect to the MFS 2006 Notes tendered by such
Holder.

7.  SPECIAL ISSUANCE AND PAYMENT AND DELIVERY INSTRUCTIONS.  If MFS 2006 Notes
representing the aggregate principal amount at stated maturity of MFS 2006 Notes
not tendered or not exchanged under the Exchange Offer and/or checks for the
appropriate Consent Payment and other cash, if any, for any MFS 2006 Notes
exchanged, are to be issued in the name of a person other than the undersigned,
or if such MFS 2006 Notes and/or checks are to be sent to someone other than the
undersigned or to the undersigned at a different address than that appearing
below the signature of the undersigned in the signature box above, the boxes
entitled "Special Issuance and Payment Instructions" and "Special Delivery
Instructions" in this Letter of Transmittal must be completed as appropriate.
Regardless of any information appearing in "Special Issuance and Payment
Instructions" or "Special Delivery Instructions," all WorldCom 2006 Notes will
be delivered only in book-entry form through DTC and only to the DTC account of
the undersigned or the undersigned's custodian.

8.  REQUESTS FOR ASSISTANCE OR ADDITIONAL COPIES. Requests for assistance or
additional copies of the Prospectus, this Letter of Transmittal or the Notice of
Guaranteed Delivery should be directed to the Information Agent at the address
and telephone number set forth on the back cover page hereof and on the back
cover page of the Prospectus.

9.  SUBSTITUTE FORM W-9. Each Holder tendering MFS 2006 Notes (or other payee)
is required to provide the Exchange Agent with the Holder's correct taxpayer
identification number ("TIN"), generally the Holder's Social Security or
federal Employer Identification Number, and with certain other information, on
Substitute Form W-9, which is provided herein, or, alternatively, to establish
another basis for exemption from backup withholding. Foreign individuals
claiming an exemption from these backup withholding and reporting requirements
must submit a statement signed under penalty of perjury attesting as to that
status. Forms for such statement can be obtained from the Information Agent.
Additionally, a Holder must cross out item (2) in the Certification box on
Substitute Form W-9 if the Holder is subject to backup withholding. Failure to
provide the information on the form may subject the Holder to a $50 penalty
imposed by the Internal Revenue Service and 31% federal income tax backup
withholding on the payments made to the Holder or other payee with respect to
the WorldCom 2006 Notes and payments received pursuant to the Exchange Offer
and related Consent Solicitation. If the Holder has not been issued a TIN and
has applied for a TIN or intends to apply for a TIN in the near future, such
Holder shall write "Applied For" in the space provided in Part I of the form.
If the Exchange Agent

                                       9
<PAGE>
 
is not provided with a TIN within 60 days thereafter, the Exchange Agent will
withhold 31% on all such WorldCom 2006 Notes and payments until a TIN is
provided to the Exchange Agent. See the Prospectus under the heading "Certain U.
S. Federal Income Tax Considerations."

10.  DETERMINATION OF VALIDITY.  The Company will determine, in its sole
discretion, all questions as to the form of documents, validity, eligibility
(including time of receipt) and acceptance and withdrawal of any tender of MFS
2006 Notes, which determination shall be final and binding on all parties.  The
Company reserves the absolute right to reject any and all tenders determined by
it not to be in proper form or not to be properly tendered or the acceptance of
which, or exchange for which, would,  in the opinion of counsel to the Company,
be unlawful.  The Company also reserves the right, in its sole discretion, to
waive any defects, irregularities or conditions of tenders in any tender of MFS
2006 Notes of any particular holder whether or not similar defects,
irregularities or conditions are waived in the case of other holders.

The Company's interpretation of the terms and conditions of the Exchange Offer
and the related Consent Solicitation (including this Letter of Transmittal and
the instructions hereto) will be final and binding.  No tender of MFS 2006 Notes
will be deemed to have been validly made until all defects or irregularities
with respect to such tender have been cured or waived.  Although the Company
intends to notify holders of defects or irregularities with respect to tenders
of MFS 2006 Notes, neither the Company, any employees, agents, affiliates or
assigns of the Company, the Exchange Agent, nor any other person shall be under
any duty to give such notification or incur any liability for failure to give
any such notification.

IMPORTANT:  THIS LETTER OF TRANSMITTAL TOGETHER WITH THE MFS 2006 NOTES TENDERED
AND ANY OTHER DOCUMENTS REQUIRED BY THIS LETTER OF TRANSMITTAL MUST BE RECEIVED
BY THE EXCHANGE AGENT ON OR PRIOR TO 11:59 P.M., NEW YORK CITY TIME, ON THE
EXPIRATION DATE.

                                       10
<PAGE>
 
PAYER'S NAME:  HARRIS TRUST & SAVINGS BANK
                                                         Social Security Number
SUBSTITUTE
FORM W-9                     Part I -- PLEASE PROVIDE              or
                                   YOUR TAXPAYER
                             IDENTIFICATION NUMBER IN   Employer Identification
                             THE BOX AT THE RIGHT AND            Number
                              CERTIFY BY SIGNING AND
                                   DATING BELOW
 
                                                         ---------------------- 
Department of the Treasury                               (If awaiting TIN write
Internal Revenue Service                                     "Applied For")
 
 
Payer's Request for          Part II -- For Payees exempt from backup
 Taxpayer                    withholding, see Instruction 9 above and the
Identification Number        "Instructions for Certification of Taxpayer
 (TIN) and Certifications    Identification Number on Substitute Form W-9"
                             enclosed herewith and complete as Instructed
                             therein.
 
 
 
 
Certifications -- Under penalties of perjury, I certify that:

(1)   The number shown on this form is my correct Taxpayer Identification 
      Number (or a Taxpayer Identification Number has not been issued to me and
      either (a) I have mailed or delivered an application to receive a Taxpayer
      Identification Number to the appropriate Internal Revenue Service Center
      or Social Security Administration office or (b) I intend to mail or
      deliver an application in the near future). I understand that if I do not
      provide a Taxpayer Identification Number to the payer, 31% of all
      reportable payments made to me thereafter will be withheld until I provide
      a number to the payer and that, if I do not provide my Taxpayer
      Identification Number within sixty (60) days, such retained amounts shall
      be remitted to the Internal Revenue Service ("IRS") as backup withholding.

(2)   I am not subject to backup withholding either because I have not been 
      notified by the IRS that I am subject to backup withholding as a result of
      a failure to report all interest or dividends or the IRS has notified me
      that I am no longer subject to backup withholding.

      Certification Instruction -- You must cross out Item (2) above if you have
      been notified by the IRS that you are currently subject to backup
      withholding because of underreporting interest or dividends on your tax
      return. However, if after being notified by the IRS that you were subject
      to withholding you received another notification form the IRS that you are
      no longer subject to backup withholding, do not cross out Item (2).

Name
    ___________________________________________________________________________

_______________________________________________________________________________
                                  (Please Print)

Address________________________________________________________________________
 ______________________________________________________________________________

 ______________________________________________________________________________
                                 (Include Zip Code)
Signature___________________________________________________Date_______________
 
 
NOTE:  FAILURE TO COMPLETE AND RETURN THIS FORM MAY RESULT IN BACKUP 
       WITHHOLDING OF 31% OF ANY PAYMENTS MADE TO YOU PURSUANT TO THE EXCHANGE
       OFFER AND RELATED CONSENT SOLICITATION. PLEASE REVIEW INSTRUCTION 9 AND
       THE "INSTRUCTIONS FOR CERTIFICATION OF TAXPAYER IDENTIFICATION NUMBER ON
       SUBSTITUTE FORM W-9" FOR ADDITIONAL DETAILS.
 
 
 

                                       11
<PAGE>
 
     Any questions concerning the terms of the Exchange Offers and Consent
          Solicitations may be directed to the Joint Dealer Managers,


                              Salomon Brothers Inc
                            Seven World Trade Center
                            New York, New York 10006
                     Telephone:  (800) 558-3745 (toll free)
                   Telephone:  (212) 783-3738 (call collect)
                     Attention:  Liability Management Group

                                      and

                              Goldman, Sachs & Co.
                                85 Broad Street
                           New York, New York  10004
                     Telephone:  (800) 828-3182 (toll free)
                   Telephone:  (212) 902-8200 (call collect)
                     Attention:  Liability Management Group


 Any questions concerning the completion of this form, or tender procedures or
requests for additional copies of the Prospectus or this Letter of Transmittal
  may be directed to the Information Agent for the Exchange Offer and Related
                            Consent  Solicitation,


                            MacKenzie Partners, Inc.
                                156 Fifth Avenue
                           New York, New York  10010
                     Telephone:  (800) 322-2885 (toll free)
                   Telephone:  (212) 929-5500 (call collect)



                  MFS 2006 Notes tendered, together with this
                  Letter of Transmittal and any other required
               documents, must be delivered to the Exchange Agent
               at its address set forth on the front page hereof.

                                       12

<PAGE>
 
                                                                EXHIBIT 99.3


                         NOTICE OF GUARANTEED DELIVERY

                                 For Tender of

               9-3/8% Senior Discount Notes Due January 15, 2004

                             CUSIP No. 55272T-AA-9

                                       of

                        MFS COMMUNICATIONS COMPANY, INC.

                                In Exchange for

                    9-3/8% Senior Notes Due January 15, 2004

                                       of

                                 WORLDCOM, INC.

                        and Related Consent Solicitation

- -------------------------------------------------------------------------------
THE EXCHANGE OFFER (AS DEFINED BELOW) WILL EXPIRE AT 11:59 P.M., NEW YORK CITY
TIME, ON ___________, 1997, UNLESS EXTENDED (SUCH TIME AND DATE AS EXTENDED, THE
"EXPIRATION DATE"). TENDERS OF MFS 2004 NOTES MAY NOT BE WITHDRAWN (AND THE
RELATED CONSENTS THEREBY REVOKED) AT ANY TIME AFTER 11:59 P.M., NEW YORK CITY
TIME, ON ______________, 1997, UNLESS THE EXCHANGE OFFER IS EXTENDED AND
CONTAINS NEW TERMS MATERIALLY ADVERSE TO THE TENDERING HOLDERS THEREOF.
- -------------------------------------------------------------------------------

     This form, or one substantially equivalent hereto, must be used by a Holder
of 9-3/8% Senior Discount Notes due January 15, 2004 ("MFS 2004 Notes") of MFS
Communications Company, Inc. ("MFS") who wishes to tender MFS 2004 Notes, and
thereby consent to certain proposed amendments to the indenture under which such
notes were issued (the "Proposed Amendments") as described in the Prospectus and
Consent Solicitation, dated ____________, 1997 (the "Prospectus"), pursuant to
the guaranteed delivery procedures described in the Prospectus under the heading
"The Exchange Offers -- Procedures for Tendering -- Guaranteed Delivery
Procedures," relating to the offer (the "Exchange Offer") by WorldCom, Inc.
("WorldCom") to exchange its 9-3/8% Senior Notes due January 15, 2004, for MFS
2004 Notes and in Instruction 2 to the related Letter of Transmittal and Consent
(the "Letter of Transmittal").  Any Holder who wishes to tender MFS 2004 Notes
pursuant to such guaranteed delivery procedures must ensure that Harris Trust
and Savings Bank, as Exchange Agent (the "Exchange Agent"), receives such form,
and any other required documents, on or prior to the Expiration Date.  Such form
may be sent to the Exchange Agent by facsimile transmission, mail or hand
delivery, and must include a guarantee by an Eligible Institution (as defined
below) in the form set forth at the end of this Notice of Guaranteed Delivery.
All capitalized terms used and not defined herein have the meanings ascribed to
them in the Prospectus.

        Delivery To:      Harris Trust and Savings Bank, Exchange Agent

<TABLE>
<CAPTION>
By Registered or Certified   By Overnight or Hand     By Facsimile Transmission:
       Mail:                       Delivery:
<S>                          <C>                      <C>
   Harris Trust and             Harris Trust and      (212) 701-7636 
     Savings Bank                 Savings Bank     
c/o Harris Trust Company     c/o Harris Trust Company
     of New York                  of New York
    P.O. Box 1010               77 Water Street       Confirm by Telephone:
 Wall Street Station               4th Floor
  New York, NY 10268           New York, NY 10004     (212) 701-7624
</TABLE>

          Questions regarding the Exchange Offer or completion of this Notice of
Guaranteed Delivery should be directed to MacKenzie Partners, Inc., the
Information Agent for the Exchange Offer, at (800) 322-2885 (toll free).

          DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY TO AN ADDRESS OTHER
THAN AS SET FORTH ABOVE OR TRANSMISSION VIA A FACSIMILE NUMBER OTHER THAN AS SET
FORTH ABOVE WILL NOT CONSTITUTE A VALID DELIVERY.
<PAGE>
 
              PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY

          Ladies and Gentlemen:

     Upon the terms and subject to the conditions set forth in the Prospectus
and the related Letter of Transmittal, receipt of which is hereby acknowledged,
the undersigned hereby tenders to WorldCom and consents to the Proposed
Amendments with respect to the principal amount at stated maturity of MFS 2004
Notes specified below pursuant to the guaranteed delivery procedures set forth
in the Prospectus and in Instruction 2 of the related Letter of Transmittal.

     Listed below are the MFS 2004 Notes to which this Notice of Guaranteed
Delivery relates.  If the space provided below is inadequate, the certificate
numbers and principal amount at stated maturity of MFS 2004 Notes are listed on
a separate signed schedule affixed hereto.

<TABLE>
<CAPTION>
- ------------------------------------------------------------------------------------------------------
DESCRIPTION OF MFS 2004 NOTES                              (1)                          (2)
- ------------------------------------------------------------------------------------------------------
                                                                                     Aggregate
                                                                                      Principal
          Name(s) and Address(es) of Holder(s)           Certificate              Amount at Stated
              (Please fill in, if blank)                  Number(s)*                Maturity of 
                                                                                  MFS 2004 Note(s)
                                                                                    Tendered by
                                                                                Guaranteed Delivery
                                                                                    Procedures 
- ------------------------------------------------------------------------------------------------------
<S>                                                      <C>                    <C>
                                                         --------------------------------------------- 

                                                         --------------------------------------------- 

                                                         --------------------------------------------- 

                                                         --------------------------------------------- 
                                                         Total
- ------------------------------------------------------------------------------------------------------
</TABLE>
 *  Need not be completed if MFS 2004 Notes will be tendered by book-entry
    transfer in accordance with the instructions contained in the Letter of
    Transmittal.




  If MFS Notes will be tendered by book-entry transfer through The Depository
  Trust Company, the Depository Trust Company Account Participant shall be:
  _________________


- -------------------------------------------------------------------------------
     All authority herein conferred or deemed to be conferred hereby shall  not
be affected by and shall survive the death or incapacity of the undersigned and
every obligation of the undersigned hereunder shall be binding upon the heirs,
personal representatives, executors, administrators, successors, assigns,
trustees in bankruptcy and other legal representatives  of the undersigned.
- -------------------------------------------------------------------------------

                                       2
<PAGE>
 
                            PLEASE SIGN AND COMPLETE

Name of Holder: _______________________________________________________________

Signature(s): _________________________________________________________________

            : _________________________________________________________________ 


Name(s) (please print): _______________________________________________________

Address: ______________________________________________________________________

         ______________________________________________________________________

         ______________________________________________________________________


Area Code and Telephone Number: _______________________________________________

Date: _________________________________________________________________________


                                   GUARANTEE

                    (Not to be used for signature guarantee)

     The undersigned, a firm that is a member firm of a registered national
securities exchange or of the National Association of Securities Dealers, Inc.,
a commercial bank or trust company having an office correspondent in the United
States or any "eligible guarantor" institution within the meaning of Rule 17Ad-
15 of the Securities Exchange Act of 1934, as amended, hereby guarantees to
deposit with the Exchange Agent, at one of its addresses set forth above, a
properly completed and duly executed Letter of Transmittal (or a manually signed
facsimile thereof), with any required signature guarantees, together with
certificates evidencing the MFS 2004 Notes tendered hereby or timely
confirmation of the book-entry transfer of the MFS 2004 Notes into the Exchange
Agent's account at the book-entry transfer facility described in the Prospectus
under the caption "The Exchange Offers -- Procedures for Tendering" and in the
Letter of Transmittal, and any other documents required by the Letter of
Transmittal, all by 11:59 p.m., New York City time, within two New York Stock
Exchange, Inc. trading days after the Expiration Date.



- -------------------------------------------------------------------------------
                                   SIGN HERE
Name of Firm: _________________________________________________________________

Authorized Signature: _________________________________________________________

Name (please print): __________________________________________________________

Title:_________________________________________________________________________

Address: ______________________________________________________________________
 
         ______________________________________________________________________

         ______________________________________________________________________

Area Code and Telephone Number: _______________________________________________

Date:__________________________________________________________________________

- -------------------------------------------------------------------------------

          DO NOT SEND MFS NOTES WITH THIS FORM.  ACTUAL SURRENDER OF MFS NOTES
MUST BE MADE PURSUANT TO, AND ACCOMPANIED BY, A PROPERLY COMPLETED AND DULY
EXECUTED LETTER OF TRANSMITTAL AND ANY OTHER REQUIRED DOCUMENTS.

                                       3
<PAGE>
 
                 INSTRUCTIONS FOR NOTICE OF GUARANTEED DELIVERY

          1. DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY. A properly
completed and duly executed copy of this Notice of Guaranteed Delivery (or
facsimile thereof) and any other documents required by this Notice of Guaranteed
Delivery must be received by the Exchange Agent at its address set forth herein
on or prior to the Expiration Date. The method of delivery of this Notice of
Guaranteed Delivery and any other required documents to the Exchange Agent is at
the election and risk of the holder, and the delivery will be deemed made only
when actually received by the Exchange Agent. If delivery is by mail, registered
mail with return receipt requested, properly insured, is recommended. Instead of
delivery by mail, it is recommended that the holder use an overnight or hand
delivery service, properly insured. In all cases sufficient time should be
allowed to assure timely delivery.

          2.  SIGNATURES ON THIS NOTICE OF GUARANTEED DELIVERY.  If this Notice
of Guaranteed Delivery is signed by the Holder(s) of the MFS 2004 Notes
specified herein, the signature(s) must correspond with the name(s) as written
on the face of the MFS 2004 Notes or on a security position listing with respect
thereto without any alteration, enlargement or change whatsoever. If any of the
tendered MFS 2004 Notes are held by two or more Holders, all such persons must
sign this Notice of Guaranteed Delivery. If any of the tendered MFS 2004 Notes
are registered in different names, it will be necessary to complete, sign and
submit as many separate Notices of Guaranteed Delivery as there are different
registrations.

          If this Notice of Guaranteed Delivery is signed by a person other than
the Holder(s) of any MFS 2004 Notes specified herein or a participant of the
book-entry transfer facility, this Notice of Guaranteed Delivery must be
accompanied by appropriate bond powers, signed as the name of the Holder(s)
appears on the MFS 2004 Notes or signed as the name of the participant shown on
the DTC's security position listing.

     If this Notice of Guaranteed Delivery or any bond powers or other
instruments of transfer are signed by a trustee, executor, administrator,
guardian, attorney-in-fact, officer of a corporation, agent or other person(s)
acting in a fiduciary or representative capacity, such person(s) should so
indicate when signing and, unless waived by the Company, the Company or
Exchange Agent must submit proper evidence satisfactory to the Company of
their authority so to act.

     3.  REQUESTS FOR ASSISTANCE OR ADDITIONAL COPIES.  Requests for assistance
or additional copies of the Prospectus or the applicable Letter of Transmittal
or Notice of Guaranteed Delivery should be directed to the Information Agent at
the telephone number set forth on the cover hereof or at the address and
telephone number set forth on the back cover page of the Letter of Transmittal
and on the back cover page of the Prospectus.

                                       4

<PAGE>
 
                                                                EXHIBIT 99.4


                         NOTICE OF GUARANTEED DELIVERY

                                 For Tender of

               8-7/8% Senior Discount Notes Due January 15, 2006

                             CUSIP No. 55272T-AB-7

                                       of

                        MFS COMMUNICATIONS COMPANY, INC.

                                In Exchange for

                    8-7/8% Senior Notes Due January 15, 2006

                                       of

                                 WORLDCOM, INC.

                        and Related Consent Solicitation

- -------------------------------------------------------------------------------
THE EXCHANGE OFFER (AS DEFINED BELOW) WILL EXPIRE AT 11:59 P.M., NEW YORK CITY
TIME, ON ___________, 1997, UNLESS EXTENDED (SUCH TIME AND DATE AS EXTENDED, THE
"EXPIRATION DATE"). TENDERS OF MFS 2006 NOTES MAY NOT BE WITHDRAWN (AND THE
RELATED CONSENTS THEREBY REVOKED) AT ANY TIME AFTER 11:59 P.M., NEW YORK CITY
TIME, ON ______________, 1997, UNLESS THE EXCHANGE OFFER IS EXTENDED AND
CONTAINS NEW TERMS MATERIALLY ADVERSE TO THE TENDERING HOLDERS THEREOF.
- -------------------------------------------------------------------------------

     This form, or one substantially equivalent hereto, must be used by a Holder
of 8-7/8% Senior Discount Notes due January 15, 2006 ("MFS 2006 Notes") of MFS
Communications Company, Inc. ("MFS") who wishes to tender MFS 2006 Notes, and
thereby consent to certain proposed amendments to the indenture under which such
notes were issued (the "Proposed Amendments") as described in the Prospectus and
Consent Solicitation, dated ____________, 1997 (the "Prospectus"), pursuant to
the guaranteed delivery procedures described in the Prospectus under the heading
"The Exchange Offers -- Procedures for Tendering -- Guaranteed Delivery
Procedures," relating to the offer (the "Exchange Offer") by WorldCom, Inc.
("WorldCom") to exchange its 8-7/8% Senior Notes due January 15, 2006, for MFS
2006 Notes and in Instruction 2 to the related Letter of Transmittal and Consent
(the "Letter of Transmittal").  Any Holder who wishes to tender MFS 2006 Notes
pursuant to such guaranteed delivery procedures must ensure that Harris Trust
and Savings Bank, as Exchange Agent (the "Exchange Agent"), receives such form,
and any other required documents, on or prior to the Expiration Date.  Such form
may be sent to the Exchange Agent by facsimile transmission, mail or hand
delivery, and must include a guarantee by an Eligible Institution (as defined
below) in the form set forth at the end of this Notice of Guaranteed Delivery.
All capitalized terms used and not defined herein have the meanings ascribed to
them in the Prospectus.

        Delivery To:      Harris Trust and Savings Bank, Exchange Agent

<TABLE>
<CAPTION>
By Registered or Certified   By Overnight or Hand     By Facsimile Transmission:
       Mail:                       Delivery:
<S>                          <C>                      <C>
   Harris Trust and             Harris Trust and      (212) 701-7636 
     Savings Bank                 Savings Bank     
c/o Harris Trust Company     c/o Harris Trust Company
     of New York                  of New York
    P.O. Box 1010               77 Water Street       Confirm by Telephone:
 Wall Street Station               4th Floor
  New York, NY 10268           New York, NY 10004     (212) 701-7624
</TABLE>


          Questions regarding the Exchange Offer or completion of this Notice of
Guaranteed Delivery should be directed to MacKenzie Partners, Inc., the
Information Agent for the Exchange Offer, at (800) 322-2885 (toll free).

          DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY TO AN ADDRESS OTHER
THAN AS SET FORTH ABOVE OR TRANSMISSION VIA A FACSIMILE NUMBER OTHER THAN AS SET
FORTH ABOVE WILL NOT CONSTITUTE A VALID DELIVERY.
<PAGE>
 
              PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY

Ladies and Gentlemen:

     Upon the terms and subject to the conditions set forth in the Prospectus
and the related Letter of Transmittal, receipt of which is hereby acknowledged,
the undersigned hereby tenders to WorldCom and consents to the Proposed
Amendments with respect to the principal amount at stated maturity of MFS 2006
Notes specified below pursuant to the guaranteed delivery procedures set forth
in the Prospectus and in Instruction 2 of the related Letter of Transmittal.

     Listed below are the MFS 2006 Notes to which this Notice of Guaranteed
Delivery relates.  If the space provided below is inadequate, the certificate
numbers and principal amount at stated maturity of MFS 2006 Notes are listed on
a separate signed schedule affixed hereto.

<TABLE>
<CAPTION>
- ------------------------------------------------------------------------------------------------------
DESCRIPTION OF MFS 2004 NOTES                              (1)                          (2)
- ------------------------------------------------------------------------------------------------------
                                                                                     Aggregate
                                                                                      Principal
          Name(s) and Address(es) of Holder(s)           Certificate              Amount at Stated
              (Please fill in, if blank)                  Number(s)*                Maturity of 
                                                                                  MFS 2006 Note(s)
                                                                                    Tendered by
                                                                                Guaranteed Delivery
                                                                                    Procedures 
- ------------------------------------------------------------------------------------------------------
<S>                                                      <C>                    <C>
                                                         --------------------------------------------- 

                                                         --------------------------------------------- 

                                                         --------------------------------------------- 

                                                         --------------------------------------------- 
                                                         Total
- ------------------------------------------------------------------------------------------------------
</TABLE>
   *  Need not be completed if MFS 2006 Notes will be tendered by book-entry
      transfer in accordance with the instructions contained in the Letter of
      Transmittal.


   If MFS Notes will be tendered by book-entry transfer through The Depository
   Trust Company, the Depository Trust Company Account Number shall be:
   _________________


- -------------------------------------------------------------------------------
     All authority herein conferred or deemed to be conferred hereby shall  not
be affected by and shall survive the death or incapacity of the undersigned and
every obligation of the undersigned hereunder shall be binding upon the heirs,
personal representatives, executors, administrators, successors, assigns,
trustees in bankruptcy and other legal representatives  of the undersigned.
- -------------------------------------------------------------------------------

                                       2
<PAGE>
 
                            PLEASE SIGN AND COMPLETE

Name of Holder: _______________________________________________________________

Signature(s): _________________________________________________________________

            : _________________________________________________________________ 


Name(s) (please print): _______________________________________________________

Address: ______________________________________________________________________

         ______________________________________________________________________

         ______________________________________________________________________


Area Code and Telephone Number: _______________________________________________

Date: _________________________________________________________________________


                                   GUARANTEE

                    (Not to be used for signature guarantee)

     The undersigned, a firm that is a member firm of a registered national
securities exchange or of the National Association of Securities Dealers, Inc.,
a commercial bank or trust company having an office correspondent in the United
States or any "eligible guarantor" institution within the meaning of Rule 17Ad-
15 of the Securities Exchange Act of 1934, as amended, hereby guarantees to
deposit with the Exchange Agent, at one of its addresses set forth above, a
properly completed and duly executed Letter of Transmittal (or a manually signed
facsimile thereof), with any required signature guarantees, together with
certificates evidencing the MFS 2006 Notes tendered hereby or timely
confirmation of the book-entry transfer of the MFS 2006 Notes into the Exchange
Agent's account at the book-entry transfer facility described in the Prospectus
under the caption "The Exchange Offers -- Procedures for Tendering" and in the
Letter of Transmittal, and any other documents required by the Letter of
Transmittal, all by 11:59 p.m., New York City time, within two New York Stock
Exchange, Inc. trading days after the Expiration Date.



- -------------------------------------------------------------------------------
                                   SIGN HERE
Name of Firm: _________________________________________________________________

Authorized Signature: _________________________________________________________

Name (please print): __________________________________________________________

Title:_________________________________________________________________________

Address: ______________________________________________________________________
 
         ______________________________________________________________________

         ______________________________________________________________________

Area Code and Telephone Number: _______________________________________________

Date:__________________________________________________________________________

- -------------------------------------------------------------------------------

DO NOT SEND MFS NOTES WITH THIS FORM. ACTUAL SURRENDER OF MFS NOTES MUST BE MADE
PURSUANT TO, AND ACCOMPANIED BY, A PROPERLY COMPLETED AND DULY EXECUTED LETTER
OF TRANSMITTAL AND ANY OTHER REQUIRED DOCUMENTS.

                                       3
<PAGE>
 
                 INSTRUCTIONS FOR NOTICE OF GUARANTEED DELIVERY

          1. DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY. A properly
completed and duly executed copy of this Notice of Guaranteed Delivery (or
facsimile thereof) and any other documents required by this Notice of Guaranteed
Delivery must be received by the Exchange Agent at its address set forth herein
on or prior to the Expiration Date. The method of delivery of this Notice of
Guaranteed Delivery and any other required documents to the Exchange Agent is at
the election and risk of the holder, and the delivery will be deemed made only
when actually received by the Exchange Agent. If delivery is by mail, registered
mail with return receipt requested, properly insured, is recommended. Instead of
delivery by mail, it is recommended that the holder use an overnight or hand
delivery service, properly insured. In all cases sufficient time should be
allowed to assure timely delivery.

          2.  SIGNATURES ON THIS NOTICE OF GUARANTEED DELIVERY.  If this Notice
of Guaranteed Delivery is signed by the Holder(s) of the MFS 2006 Notes
specified herein, the signature(s) must correspond with the name(s) as written
on the face of the MFS 2006 Notes or on a security position listing with respect
thereto without any alteration, enlargement or change whatsoever. If any of the
tendered MFS 2006 Notes are held by two or more Holders, all such persons must
sign this Notice of Guaranteed Delivery. If any of the tendered MFS 2006 Notes
are registered in different names, it will be necessary to complete, sign and
submit as many separate Notices of Guaranteed Delivery as there are different
registrations.

          If this Notice of Guaranteed Delivery is signed by a person other than
the Holder(s) of any MFS 2006 Notes specified herein or a participant of the
book-entry transfer facility, this Notice of Guaranteed Delivery must be
accompanied by appropriate bond powers, signed as the name of the Holder(s)
appears on the MFS 2006 Notes or signed as the name of the participant shown on
the DTC's security position listing.

          If this Notice of Guaranteed Delivery or any bond powers or other
instruments of transfer are signed by a trustee, executor, administrator,
guardian, attorney-in-fact, officer of a corporation, agent or other person(s)
acting in a fiduciary or representative capacity, such person(s) should so
indicate when signing and, unless waived by the Company, the Company or Exchange
Agent must submit proper evidence satisfactory to the Company of their authority
so to act.

          3. REQUESTS FOR ASSISTANCE OR ADDITIONAL COPIES. Requests for
assistance or additional copies of the Prospectus or the applicable Letter of
Transmittal or Notice of Guaranteed Delivery should be directed to the
Information Agent at the telephone number set forth on the cover hereof or at
the address and telephone number set forth on the back cover page of the Letter
of Transmittal and on the back cover page of the Prospectus.

                                       4

<PAGE>
 
                                                                EXHIBIT 99.5


                                 WORLDCOM, INC.

                               OFFER TO EXCHANGE

    $686,398,000 9 3/8% Senior Notes of WorldCom, Inc. due January 15, 2004

                          For Any and All Outstanding

9 3/8% Senior Discount Notes of MFS Communications Company, Inc. due January 15,
                                      2004
                             CUSIP No. 55272T-AA-9

                                      And

    $671,850,000 8 7/8% Senior Notes of WorldCom, Inc. due January 15, 2006

                          For Any and All Outstanding

8 7/8% Senior Discount Notes of MFS Communications Company, Inc. due January 15,
                                      2006
                             CUSIP No. 55272T-AB-7

                                      And

                             CONSENT SOLICITATIONS


- --------------------------------------------------------------------------------
EACH EXCHANGE OFFER WILL EXPIRE AT 11:59 P.M., NEW YORK CITY TIME, ON          ,
1997, UNLESS EXTENDED (SUCH TIME AND DATE, AS EXTENDED, THE "EXPIRATION DATE"
WITH RESPECT TO SUCH EXCHANGE OFFER).  TENDERS OF MFS NOTES MAY NOT BE WITHDRAWN
(AND THE RELATED CONSENTS THEREBY REVOKED) AT ANY TIME AFTER 11:59 P.M., NEW
YORK CITY TIME, ON          , 1997, UNLESS THE APPLICABLE EXCHANGE OFFER IS
EXTENDED AND CONTAINS NEW TERMS MATERIALLY ADVERSE TO THE TENDERING HOLDERS
THEREOF.
- --------------------------------------------------------------------------------


To:  Brokers, Dealers, Commercial Banks,                        July ____, 1997
     Trust Companies and Other Nominees:

          Salomon Brothers Inc and Goldman, Sachs & Co. are acting as Dealer
Managers for WorldCom, Inc. (the "Company") in connection with the Company's
offers to exchange (i) $871.597 principal amount of its 9-3/8% Senior Notes due
January 15, 2004 ("WorldCom 2004 Notes") for each $1,000 principal amount at
stated maturity of outstanding 9-3/8% Senior Discount Notes due January 15, 2004
("MFS 2004 Notes") of MFS Communications Company, Inc. ("MFS") and (ii) $737.912
principal amount of its 8-7/8% Senior Notes due January 15, 2006 ("WorldCom 2006
Notes" and together with the WorldCom 2004 Notes, "WorldCom Notes") for each
$1,000 principal amount at stated maturity of outstanding 8-7/8% Senior Discount
Notes due January 15, 2006 ("MFS 2006 Notes") and together with the MFS 2004
Notes, "MFS Notes") of MFS (each such offer, an "Exchange Offer," and
collectively the "Exchange Offers"). If the aggregate principal amount of
WorldCom Notes that otherwise would be issued in exchange for the MFS Notes of a
series tendered by a holder and accepted by the Company pursuant to the Exchange
Offers is not an integral multiple of $1,000, such principal amount will be
reduced to the nearest such multiple and the Company will pay to such holder an
amount in cash equal to the reduction of such principal amount.
 
          Concurrently with the Exchange Offers, the Company is soliciting
consents from holders of each series of MFS Notes to certain amendments (the
"Proposed Amendments") to the indenture governing such series of MFS Notes, as
described in the Prospectus (as defined below). Holders of MFS Notes of either
series may give their consent to the Proposed Amendments applicable to that
series only by tendering such MFS Notes in the applicable Exchange Offer, will
be required to so consent as a condition to a valid tender and will be deemed to
have given such consent by so tendering. Each holder who gives a valid consent
will receive a Consent Payment fee in an amount equal to (i) with respect to
such holder's MFS 2004 Notes, 0. % of the Accreted Value, as of July 15, 1997
(the "Interest Accrual Date"), of such MFS 2004 Notes and (ii) with respect to
such holder's MFS 2006 Notes, 0. % of the Accreted Value, as of the Interest
Accrual Date, of such MFS 2006 Notes, in either case, with respect to which such
consent has been given. All capitalized terms used and not defined herein have
the meanings ascribed to them in the Prospectus.

          The Company's obligation to consummate either Exchange Offer, and to
make Consent Payments, is conditioned on, among other things, receipt of
consents from holders of a majority in aggregate principal amount outstanding of
both series of MFS Notes. The Company may, in its sole discretion, waive any
condition with respect to an Exchange Offer and accept for exchange any MFS
Notes tendered. Notwithstanding the foregoing, the Company will not consummate
the Exchange Offer with respect to the MFS 2004 Notes if less than $ of
principal amount of WorldCom 2004 Notes would be issued in such Exchange Offer
and will not consummate the Exchange Offer with respect to the MFS 2006 Notes if
less than $ of principal amount of WorldCom 2006 Notes would be issued in such
Exchange Offer.
<PAGE>
 
          We are requesting that you promptly contact your clients for whom you
hold MFS Notes regarding the Exchange Offers. For your information and for
forwarding to your clients, we are enclosing the following documents:


          1.   The Prospectus and Consent Solicitation dated July ____, 1997
               (the "Prospectus");
          2.   The YELLOW Letter of Transmittal to be used to tender MFS 2004
               Notes and consent to the Proposed Amendments with respect to such
               Notes;
          3.   The BLUE Letter of Transmittal to be used to tender MFS 2006
               Notes and consent to the Proposed Amendments with respect to such
               Notes;
          4.   The Notice of Guaranteed Delivery to be used, if necessary, in
               connection with the Exchange Offer for the MFS 2004 Notes;
          5.   The Notice of Guaranteed Delivery to be used, if necessary, in
               connection with the Exchange Offer for the MFS 2006 Notes;
          6.   A form of letter which may be sent to your clients for whose
               accounts you hold MFS Notes, with space provided for obtaining
               such clients' instructions with regard to the Exchange Offers;
          7.   Guidelines for Certification of Taxpayer Identification Number on
               Substitute Form W-9; and
          8.   Return envelopes addressed to Harris Trust and Savings Bank, as
               Exchange Agent (the "Exchange Agent") for the Exchange Offers.

          To tender MFS Notes in an Exchange Offer, and thereby deliver a
consent in the related Consent Solicitation, certificates for the MFS Notes to
be tendered (or confirmation of a book-entry transfer of such MFS Notes to the
Exchange Agent's account at The Depository Trust Company ("DTC")), a completed
and signed copy of the relevant Letter of Transmittal and any other required
documents, must be received by the Exchange Agent on or prior to 11:59 p.m., New
York City time, on the Expiration Date, in accordance with the instructions set
forth in the Prospectus and the relevant Letter of Transmittal.  The completion,
execution and delivery of the applicable Letter of Transmittal with respect to
particular MFS Notes will constitute the delivery of a consent with respect to
such MFS Notes.

          Holders whose MFS Notes are not immediately available or who cannot
deliver their MFS Notes and all other required documents to the Exchange Agent
on or prior to the Expiration Date may nevertheless tender their MFS Notes (and
thereby consent to the applicable Proposed Amendments) by delivering the
applicable Notice of Guaranteed Delivery and any other required documents
pursuant to the guaranteed delivery procedures described in the Prospectus.

          Subject to satisfaction or waiver of the conditions to an Exchange
Offer, the Company will exchange (and thereby purchase) any and all MFS Notes
that are properly tendered in such Exchange Offer and not withdrawn. WorldCom
Notes will be delivered only in book-entry form through DTC. Accordingly, if you
anticipate tendering MFS Notes you must either have in place, or arrange for,
facilities to receive WorldCom Notes through DTC. WorldCom Notes will be
delivered and Consent Payments and other cash payments, if any, will be made by
check (in New York next day funds) on the third business day following the
Expiration Date or as soon as possible thereafter.

          Tendering holders of MFS Notes will not be required to pay any
fee or commission to the Dealer Managers. However, if a tendering holder handles
the transaction through its broker, dealer, commercial bank, trust company or
other institution, such holder may be required to pay brokerage fees or
commissions. The Company will pay or cause to be paid all transfer taxes
applicable to the exchange of MFS Notes pursuant to the Exchange Offers, except
as set forth in the Prospectus and Instruction 6 of the Letters of Transmittal.

          Any inquiries you may have with respect to the terms of the Exchange
Offers may be directed to Salomon Brothers Inc or Goldman Sachs & Co., as the
Dealer Managers, at their respective address and telephone number set forth in
the Prospectus. Any inquiries with respect to tender procedures, or requests for
additional copies of the enclosed materials, should be directed to MacKenzie
Partners, Inc., the Information Agent for the Exchange Offers, at its address
and telephone number set forth in the Prospectus.

                              Very truly yours,




                              SALOMON BROTHERS INC
                              GOLDMAN, SACHS & CO.

          NOTHING CONTAINED HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL CONSTITUTE
YOU OR ANY OTHER PERSON AS AN AGENT OF THE COMPANY, THE DEALER MANAGERS, THE
EXCHANGE AGENT, THE INFORMATION AGENT OR ANY OF THEIR AFFILIATES OR AUTHORIZE
YOU OR ANY OTHER PERSON TO USE ANY DOCUMENT OR MAKE ANY STATEMENTS ON THEIR
BEHALF WITH RESPECT TO THE EXCHANGE OFFERS, EXCEPT FOR STATEMENTS EXPRESSLY MADE
IN THE PROSPECTUS OR THE LETTERS OF TRANSMITTAL.


Enclosures

                                       2

<PAGE>
 
                                                                EXHIBIT 99.6

                                 WORLDCOM, INC.

                               OFFER TO EXCHANGE

    $686,398,000  9 3/8% Senior Notes of WorldCom, Inc. due January 15, 2004

                          For Any and All Outstanding

9 3/8% Senior Discount Notes of MFS Communications Company, Inc. due January 15,
                                      2004
                             CUSIP No. 55272T-AA-9

                                      And

    $671,850,000 8 7/8% Senior Notes of WorldCom, Inc. due January 15, 2006

                          For Any and All Outstanding

8 7/8% Senior Discount Notes of MFS Communications Company, Inc. due January 15,
                                      2006
                             CUSIP No. 55272T-AB-7

                                      And

                             CONSENT SOLICITATIONS
- --------------------------------------------------------------------------------
EACH EXCHANGE OFFER WILL EXPIRE AT 11:59 P.M., NEW YORK CITY TIME, ON          ,
1997, UNLESS EXTENDED (SUCH TIME AND DATE, AS EXTENDED, THE "EXPIRATION DATE"
WITH RESPECT TO SUCH EXCHANGE OFFER).  TENDERS OF MFS NOTES MAY NOT BE WITHDRAWN
(AND THE RELATED CONSENTS THEREBY REVOKED) AT ANY TIME AFTER 11:59 P.M., NEW
YORK CITY TIME, ON          , 1997, UNLESS THE APPLICABLE EXCHANGE OFFER IS
EXTENDED AND CONTAINS NEW TERMS MATERIALLY ADVERSE TO THE TENDERING HOLDERS
THEREOF.
- --------------------------------------------------------------------------------


To Our Clients:

          Enclosed for your consideration is a Prospectus and Consent
Solicitation dated __________, 1997 (together the "Prospectus") and the Letters
of Transmittal pursuant to which WorldCom, Inc., a Georgia corporation (the
"Company"), is offering to exchange (i) $871.597 principal amount of its 9-3/8%
Senior Notes due January 15, 2004 ("WorldCom 2004 Notes") for each $1,000
principal amount at stated maturity of outstanding 9-3/8% Senior Discount Notes
due January 15, 2004 ("MFS 2004 Notes") of MFS Communications Company, Inc.
("MFS") and (ii) $737.912 principal amount of its 8-7/8% Senior Notes due
January 15, 2006 ("WorldCom 2006 Notes" and together with WorldCom 2004 Notes,
"WorldCom Notes") for each $1,000 principal amount at stated maturity of
outstanding 8-7/8% Senior Discount Notes due January 15, 2006 ("MFS 2006 Notes"
and together with MFS 2004 Notes, "MFS Notes") of MFS (each such offer, an
"Exchange Offer," and collectively the "Exchange Offers"). If the aggregate
principal amount of WorldCom Notes that otherwise would be issued in exchange
for the MFS Notes of a series tendered by a holder and accepted by the Company
pursuant to the Exchange Offers is not an integral multiple of $1,000, such
principal amount will be reduced to the nearest such multiple and the Company
will pay to such holder an amount in cash equal to the reduction of such
principal amount.

          Concurrently with the Exchange Offers, the Company is soliciting
consents from holders of each series of MFS Notes to certain amendments (the
"Proposed Amendments") to the indenture governing such series of MFS Notes, as
described in the Prospectus. Holders of MFS Notes of either series may give
their consent to the Proposed Amendments applicable to that series only by
tendering such MFS Notes in the applicable Exchange Offer, will be required to
so consent as a condition to a valid tender and will be deemed to have given
such consent by so tendering. Each holder who gives a valid consent will receive
a cash fee in an amount equal to (i) with respect to such holder's MFS 2004
Notes, 0. % of the Accreted Value, as of July 15, 1997 (the "Interest Accrual
Date"), of such MFS 2004 Notes and (ii) with respect to such holder's MFS 2006
Notes, 0. % of the Accreted Value, as of the Interest Accrual Date, of such MFS
2006 Notes, in either case, with respect to which such consent has been given.
All capitalized terms used and not defined herein have the meanings ascribed to
them in the Prospectus.
<PAGE>
 
          This material is being forwarded to you as the beneficial owner of
either MFS 2004 Notes or MFS 2006 Notes (or both) held by us for your account or
benefit. A tender of any of your MFS Notes, and delivery of a consent with
respect thereto, may be made only by us as the registered holder thereof and
only pursuant to your instructions. Therefore, the Company urges beneficial
owners of MFS Notes held by a broker, dealer, commercial bank, trust company or
other nominee to contact such nominee promptly if they wish to tender their MFS
Notes, and thereby deliver a consent with respect thereto, in an Exchange Offer.

          The Letters of Transmittal are being furnished to you for your
information only and cannot be used by you to tender MFS Notes held by us for
your account. Accordingly, we request instructions as to whether you wish us to
tender any or all of your MFS Notes held by us for your account, and thereby
deliver a consent with respect thereto, pursuant to the terms and subject to the
conditions set forth in the Prospectus and the relevant Letter of Transmittal.
In the event you choose to have us so tender such MFS Notes, you must provide
instructions to that effect by completing, signing and returning to us the
instruction form below. Your instructions to us should be forwarded as promptly
as possible in order to provide us with sufficient time to permit us to tender
your MFS Notes on your behalf in accordance with the provisions of the Exchange
Offers. An envelope to return your instructions to us is enclosed. Please note
that if you want us to tender some but not all of the MFS Notes held by us for
your account, you must indicate on the instruction form the MFS Notes you want
us to tender identified by series and principal amount. The principal amount
at stated maturity of MFS Notes of any series may be tendered only in
denominations of $1,000.

          The Prospectus contains important information which you are urged to
review carefully before making any decision with respect to an Exchange Offer.

     Your attention is directed to the following:

1.  Each Exchange Offer is for any and all outstanding MFS Notes of the relevant
series of MFS Notes.  The obligation of the Company to consummate either
Exchange Offer, and make Consent Payments, is conditioned on, among other
things, receipt of consents from holders of a majority in aggregate principal
amount outstanding of both series of MFS Notes.  The Company may, in its sole
discretion, waive any condition with respect to an Exchange Offer and accept for
exchange any MFS Notes tendered.  Notwithstanding the foregoing, the Company
will not consummate the Exchange Offer with respect to the MFS 2004 Notes if
less than $            of principal amount of WorldCom 2004 Notes would be
issued in such Exchange Offer and will not consummate the Exchange Offer with
respect to the MFS 2006 Notes if less than $            of principal amount of
WorldCom 2006 Notes would be issued in such Exchange Offer.

2.  The tender of MFS Notes of a series pursuant to the Exchange Offers will
constitute giving a consent to the Proposed Amendments with respect to such
series and, upon acceptance for exchange of such MFS Notes, the holder thereof
will receive a cash fee for so consenting as described previously in this
letter.

3.  Each Exchange Offer will expire at 11:59 p.m., New York City time, on the
Expiration Date.  Tenders of MFS Notes may not be withdrawn (and the related
consents thereby revoked) at any time after 11:59 p.m., New York City time on
_________, 1997, unless the applicable Exchange Offer is extended and contains
new terms materially adverse to the tendering holders thereof.  Withdrawal of
tendered MFS Notes will be deemed a revocation of the consent to which such MFS
Notes relate.  If you wish to withdraw any MFS Notes that you instructed us to
tender you should contact us immediately.

4.  Any transfer taxes incident to the transfer of MFS Notes to the Company will
be paid by the Company pursuant to the Exchange Offers, except as provided in
the Prospectus and Instruction 6 of the Letter of Transmittal.

     Any inquiries you may have with respect to the terms of the Exchange Offers
may be directed to Salomon Brothers Inc. or Goldman Sachs & Co., as Dealer
Managers, at their respective address and telephone number set forth in the
Prospectus.  Any inquiries with respect to tender procedures, or requests for
additional copies of the enclosed materials, should be directed to MacKenzie
Partners, Inc., the Information Agent for the Exchange Offers, at its address
and telephone number set forth in the Prospectus.


                              Very truly yours,




                              _______________________________

                                       2
<PAGE>
 
                                  INSTRUCTIONS


     The undersigned hereby acknowledges receipt of your letter, dated July ___,
1997 and the material referred to therein relating to the Exchange Offers and
the Consent Solicitations made by WorldCom, Inc. with respect to certain Senior
Discount Notes of MFS Communications Company, Inc.  The undersigned further
acknowledges that he or she understands the terms of the Exchange Offers and
Consent Solicitations as set forth in the Prospectus and the relevant Letter(s)
of Transmittal

     The undersigned hereby instructs you to tender (and thereby deliver a
consent with respect to) the MFS Notes indicated below, pursuant to the terms
and subject to the conditions of the relevant Exchange Offer and Consent
Solicitation.

     Check one box:

     Box 1:

     [  ]   Please tender all MFS Notes held by you for the account of the
            undersigned.

     Box 2:

     [  ]   Please tender only those MFS Notes held by you for the account of
            the undersigned as indicated in the box immediately below.



- --------------------------------------------------------------------------------
Please complete this box, if, and only if, you have checked Box 2 above.

Please tender the following MFS Notes held by you for the account of the 
undersigned:

                                                Principal Amount at Stated
                                                Maturity in Integral Multiples
                                                of $1,000.

[ ]  MFS 9 3/8% Senior Discount Notes due 2004  $____________________________


[ ]  MFS 8 7/8% Senior Discount Notes due 2006  $____________________________

- --------------------------------------------------------------------------------


- --------------------------------------------------------------------------------
                               PLEASE SIGN HERE:


                          Date _____________________


Signature: ___________________        Signature: _____________________________
                                                    (if more than one
                                                    beneficial owner)

Name: ________________________        Name: __________________________________
        (please print)                              (if more than one
                                              beneficial owner)(please print)


Address: _____________________________________________________________________

______________________________________________________________________________


Telephone: __________________________________________
                      (include area code)

Employer Identification or Social Security Number: ___________________________


             All beneficial owners of the MFS Notes to be tendered
                    by us must sign this instruction form.

- --------------------------------------------------------------------------------

                                       3


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