<PAGE>
NOTICE OF GUARANTEED DELIVERY
This form or one substantially equivalent hereto must be used to accept the
offer for all outstanding 14% Senior Notes due 2010 (the "Old Notes") of Rhythms
NetConnections Inc. (the "Company") in exchange for the Company's 14% Senior
Notes due 2010 made pursuant to the prospectus, dated February 16, 1999 (the
"Prospectus"), and the related letter of transmittal (the "Letter of
Transmittal"), if (i) certificates for Old Notes are not immediately available,
(ii) the Old Notes, the Letter of Transmittal and all other required documents
cannot be delivered or transmitted by facsimile transmission, mail or hand
delivery to The State Street Bank and Trust Company of California, N.A. (the
"Exchange Agent") as set forth below on or prior to 5:00 P.M., New York City
time, on the Expiration Date, or (iii) the procedures for delivery of the Old
Notes through book-entry transfer into the Exchange Agent's account at The
Depository Trust Company ("DTC") in accordance with DTC's Automated Tender Offer
Program cannot be completed on a timely basis. See "The Exchange Offer--Terms of
the Exchange Offer" section in the Prospectus. Capitalized terms not defined
herein are defined in the Prospectus.
UNITED STATES TRUST COMPANY OF NEW YORK
<TABLE>
<S> <C> <C>
BY REGISTERED OR CERTIFIED MAIL: BY HAND DELIVERY TO 4:30 PM: BY HAND DELIVERY AFTER 4:30 PM ON
EXPIRATION DATE:
State Street Bank and Trust Company State Street Bank and Trust Company State Street Bank and Trust Company
of California, N.A. of California, N.A. of California, N.A.
c/o State Street Bank and Trust c/o State Street Bank and Trust c/o State Street Bank and Trust
Company Company Company
2 Avenue de Lafayette, Fifth Floor 2 Avenue de Lafayette, Fifth Floor 2 Avenue de Lafayette, Fifth Floor
Boston, MA 02111-1724 Boston, MA 02111-1724 Boston, MA 02111-1724
Attn: Ralph Jones Attn: Ralph Jones Attn: Ralph Jones
</TABLE>
(Above information to be provided.)
DELIVERY OF THIS INSTRUMENT TO AN ADDRESS OTHER THAN AS SET FORTH ABOVE, OR
TRANSMISSION OF INSTRUCTIONS VIA FACSIMILE OTHER THAN AS SET FORTH ABOVE, WILL
NOT CONSTITUTE A VALID DELIVERY.
<PAGE>
Ladies and Gentlemen:
Upon the terms and conditions set forth in the Prospectus and the Letter of
Transmittal, the undersigned hereby tenders to the Company the principal amount
of Old Notes set forth below, pursuant to the guaranteed delivery procedures
described in "The Exchange Offer, Guaranteed Delivery Procedures" section of the
Prospectus.
<TABLE>
<S> <C>
Principal Amount of Old Notes Tendered: (1) PLEASE SIGN HERE
$ X
X
Signature(s) of Owner(s) or Date
Authorized Signatory
Certificate Nos. (if available): Area Code and Telephone Number:
Total Principal Amount Represented by Old Must be signed by the holder(s) of the Old
Notes Certificate(s): Notes as their name(s) appear(s) on
certificates for Old Notes or on a security
$ position listing, or by person(s) authorized
to become registered holder(s) by endorsement
and documents transmitted with this Notice of
Guaranteed Delivery. If signature is by a
trustee, executor, administrator, guardian,
attorney-in-fact, officer or other person
acting in a fiduciary or representative
capacity, such person must set forth his or
her full title below.
If Old Notes will be delivered by book-entry Please print name(s) and address(es)
transfer into Exchange Agent's account with Name(s):
The Depository Trust Company, provide account
number:
Capacity:
Account Number: Address(es):
</TABLE>
All authority herein conferred or agreed to be conferred shall survive the death
or incapacity of the undersigned and every obligation of the undersigned
hereunder shall be binding upon the heirs, personal representatives, successors
and assigns of the undersigned.
------------------------
(1) Must be in denominations of principal amount of $1,000 and any integral
multiple thereof.
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<PAGE>
GUARANTEE
The undersigned, an Eligible Institution within the meaning of Rule
17(A)(d)-15 under the Securities Exchange Act of 1934, as amended, hereby
guarantees that (i) the certificates representing the principal amount of Old
Notes tendered hereby, in proper form for transfer, together with a properly
completed and duly executed Letter of Transmittal (or a manually signed
facsimile thereof), any required signature guarantee and any other documents
required by the Letter of Transmittal, or (ii) timely confirmation of the
book-entry transfer of such Old Notes into the Exchange Agent's account at DTC
pursuant to the procedures set forth in "The Exchange Offer, Book-Entry
Transfer; Delivery and Form" section of the Prospectus, will be received by the
Exchange Agent at the address set forth above, no later than three New York
Stock Exchange trading days after the date of execution hereof.
________________________________________________________________________________
NAME OF FIRM
________________________________________________________________________________
ADDRESS
________________________________________________________________________________
________________________________________________________________________________
ZIP CODE
________________________________________________________________________________
Area Code & Telephone No.
________________________________________________________________________________
AUTHORIZED SIGNATURE
________________________________________________________________________________
TITLE
________________________________________________________________________________
Name: (PLEASE TYPE OR PRINT)
________________________________________________________________________________
Dated:
________________________________________________________________________________
NOTE: DO NOT SEND CERTIFICATES FOR OLD NOTES WITH THIS FORM. CERTIFICATES FOR
OLD NOTES SHOULD ONLY BE SENT WITH YOUR LETTER OF TRANSMITTAL.
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