JANUS INVESTMENT FUND
497, 2000-02-04
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<PAGE>

                                  [JANUS LOGO]
                            JANUS  HIGH-YIELD  FUND
                                   PROSPECTUS

                                                   JANUARY 31, 2000

             The Securities and Exchange Commission has not
             approved or disapproved of these securities or passed
             on the accuracy or adequacy of this Prospectus. Any
             representation to the contrary is a criminal offense.

<PAGE>

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<PAGE>

TABLE OF CONTENTS
- --------------------------------------------------------------------------------

<TABLE>
                <S>                                               <C>
                RISK/RETURN SUMMARY
                   Janus High-Yield Fund........................    2
                   Fees and expenses............................    5
                INVESTMENT OBJECTIVES, PRINCIPAL INVESTMENT
                STRATEGIES AND RISKS
                   Investment objectives and principal
                   investment strategies........................    6
                   General portfolio policies...................    8
                   Risks........................................   11
                SHAREHOLDER'S MANUAL
                   Minimum investments..........................   17
                   Types of account ownership...................   17
                   To purchase shares...........................   20
                   To exchange shares...........................   21
                   To redeem shares.............................   21
                   Shareholder services and account policies....   25
                MANAGEMENT OF THE FUND
                   Investment adviser...........................   29
                   Portfolio manager............................   30
                OTHER INFORMATION...............................   31
                DISTRIBUTIONS AND TAXES
                   Distributions................................   33
                   Taxes........................................   35
                FINANCIAL HIGHLIGHTS............................   37
                GLOSSARY
                   Glossary of investment terms.................   38
                RATING CATEGORIES
                   Explanation of rating categories.............   45

</TABLE>

                                             Janus High-Yield Fund prospectus  1
<PAGE>

RISK/RETURN SUMMARY
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JANUS HIGH-YIELD FUND

1. WHAT ARE THE INVESTMENT OBJECTIVES OF JANUS HIGH-YIELD FUND?

               The Fund seeks to obtain high current income. Capital
               appreciation is a secondary objective when consistent with its
               primary objective.

               The Fund's Trustees may change these objectives without a
               shareholder vote and the Fund will notify you of any changes that
               are material. If there is a material change in the Fund's
               objectives or policies, you should consider whether the Fund
               remains an appropriate investment for you. There is no guarantee
               that the Fund will meet its objectives.

2. WHAT ARE THE MAIN INVESTMENT STRATEGIES OF JANUS HIGH-YIELD FUND?

               The Fund normally invests at least 65% of its assets in high-
               yield/high-risk fixed-income securities, and may at times invest
               all of its assets in these securities.

               The Fund may invest without limit in foreign equity and debt
               securities.

               In addition to considering economic factors such as the effect of
               interest rates on the Fund's investments, the portfolio manager
               applies a "bottom up" approach in choosing investments. In other
               words, he looks mostly for income-producing securities that meet
               his investment criteria one at a time. If the portfolio manager
               is unable to find such investments, the Fund's assets may be in
               cash or similar investments.

3. WHAT ARE THE MAIN RISKS OF INVESTING IN JANUS HIGH-YIELD FUND?

               Although the Fund may be less volatile than funds that invest
               most of their assets in common stocks, the Fund's returns and
               yields will vary, and you could lose money.

               The Fund invests in a variety of income-producing securities. A
               fundamental risk is that the value of these securities will fall
               if interest rates rise. Generally, the value of a fixed-income
               portfolio will decrease when interest rates rise, which means the
               Fund's net

 2 Janus High-Yield Fund prospectus
<PAGE>

               asset value (NAV) will likewise decrease. Another fundamental
               risk associated with fixed-income funds is credit risk, which is
               the risk that an issuer will be unable to make principal and
               interest payments when due.

               The Fund may invest an unlimited amount of its assets in high-
               yield/high-risk bonds, also known as "junk" bonds. Junk bonds may
               be sensitive to economic changes, political changes, or adverse
               developments specific to the company that issued the bond. These
               securities generally have a greater credit risk than other types
               of fixed-income securities. Because of these factors, the
               performance and NAV of the Fund may vary significantly, depending
               upon its holdings in junk bonds.

               An investment in the Fund is not a bank deposit and is not
               insured or guaranteed by the Federal Deposit Insurance
               Corporation or any other government agency.

                                             Janus High-Yield Fund prospectus  3
<PAGE>

               The following information illustrates how the Fund's performance
               has varied over time. The bar chart depicts the change in the
               Fund's performance from year-to-year during the periods
               indicated. The table compares the Fund's average annual returns
               for the periods indicated to a broad-based securities market
               index.

                JANUS HIGH-YIELD FUND

                A BAR CHART showing Annual Total Returns for Janus High-Yield
                Fund from 1996 through 1999:

                Annual returns for periods ended 12/31
<TABLE>
                <S>                                <C>      <C>      <C>     <C>
                                                   23.99%   15.47%   0.97%    5.54%
                                                    1996     1997     1998     1999

                Each percentage is represented by a bar of proportionate size
                with the actual total return printed above the bar.

                Best Quarter:  1st-1996   7.34%   Worst Quarter:  3rd-1998  (5.76%)
</TABLE>

                          Average annual total return for periods ended 12/31/99
                          ------------------------------------------------------

<TABLE>
<CAPTION>
                                                                            Since Inception
                                                                  1 year      (12/29/95)
                <S>                                              <C>           <C>

                Janus High-Yield Fund                             5.54%         11.11%
                Lehman Brothers High-Yield Bond Index*            2.39%          6.98%
                                                              -----------------------------
</TABLE>

               * Lehman Brothers High-Yield Bond Index is composed of
                 fixed-rate, publicly issued, noninvestment grade debt.

               The Fund's past performance does not necessarily indicate how it
               will perform in the future.

 4 Janus High-Yield Fund prospectus
<PAGE>

FEES AND EXPENSES

               SHAREHOLDER FEES, such as sales loads, redemption fees or
               exchange fees, are charged directly to an investor's account. All
               Janus funds are no-load investments, so you will not pay any
               shareholder fees when you buy or sell shares of the Fund.

               ANNUAL FUND OPERATING EXPENSES are paid out of the Fund's assets
               and include fees for portfolio management, maintenance of
               shareholder accounts, shareholder servicing, accounting and other
               services. You do not pay these fees directly but, as the example
               below shows, these costs are borne indirectly by all
               shareholders.

               This table describes the fees and expenses that you may pay if
               you buy and hold shares of the Fund. It is based upon gross
               expenses (without the effect of expense offset arrangements) for
               the fiscal year ended October 31, 1999.

<TABLE>
<CAPTION>
                                                          Janus High-Yield Fund
   <S>                                                           <C>
   Management Fee                                                 0.75%
   Other Expenses                                                 0.30%
   Total Annual Fund Operating Expenses Without Waivers*          1.05%
   Total Waivers                                                 (0.03%)
   Total Annual Fund Operating Expenses With Waivers*             1.02%
</TABLE>

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  * All expenses are stated both with and without contractual waivers by
    Janus Capital. Waivers for the Fund are first applied against the
    Management Fee and then against Other Expenses. Janus Capital has
    agreed to continue such waivers until at least the next annual renewal
    of the advisory agreements.
- --------------------------------------------------------------------------------

  EXAMPLE

  This example is intended to help you compare the cost of investing in the
  Fund with the cost of investing in other mutual funds. The example
  assumes that you invest $10,000 in the Fund for the time periods
  indicated then redeem all of your shares at the end of those periods. The
  example also assumes that your investment has a 5% return each year and
  that the Fund's operating expenses remain the same. Although your actual
  costs may be higher or lower, based on these assumptions your costs would
  be:

<TABLE>
<CAPTION>
                                               1 Year     3 Years    5 Years    10 Years
                                               -----------------------------------------
   <S>                                         <C>        <C>        <C>        <C>
   Janus High-Yield Fund                        $107       $334       $579       $1,283
</TABLE>

                                             Janus High-Yield Fund prospectus  5
<PAGE>

INVESTMENT OBJECTIVES, PRINCIPAL INVESTMENT
STRATEGIES AND RISKS
- --------------------------------------------------------------------------------

               This section takes a closer look at the investment objectives of
               the Fund, its principal investment strategies and certain risks
               of investing in the Fund. Strategies and policies that are noted
               as "fundamental" cannot be changed without a shareholder vote.

               Please carefully review the "Risks" section of this Prospectus on
               pages 11-13 for a discussion of risks associated with certain
               investment techniques. We've also included a Glossary with
               descriptions of investment terms used throughout this Prospectus.

INVESTMENT OBJECTIVES AND PRINCIPAL INVESTMENT STRATEGIES

               Janus High-Yield Fund seeks to obtain high current income.
               Capital appreciation is a secondary objective when consistent
               with its primary objective. It pursues its objectives by normally
               investing 65% of its assets in high-yield/high-risk fixed-income
               securities, and may at times invest all of its assets in these
               securities.

               In addition to considering economic factors such as the effect of
               interest rates on the Fund's investments, the portfolio manager
               applies a "bottom up" approach in choosing investments. In other
               words, he looks mostly for income-producing securities that meet
               his investment criteria one at a time. If the portfolio manager
               is unable to find such investments, much of the Fund's assets may
               be in cash or similar investments.

The following questions and answers are designed to help you better understand
the Fund's principal investment strategies.

1. HOW DO INTEREST RATES AFFECT THE VALUE OF MY INVESTMENT?

               Generally, a bond will increase in value when interest rates fall
               and decrease in value when interest rates rise. Longer-term bonds
               are generally more sensitive to interest rate changes than
               shorter-term bonds, but they generally offer higher yields to
               compensate investors for the associated risks. High-yield bond
               prices are generally less directly responsive to interest rate
               changes than investment grade issues and may not always follow
               this pattern. A

 6 Janus High-Yield Fund prospectus
<PAGE>

               bond fund's average-weighted effective maturity and its duration
               are measures of how the fund may react to interest rate changes.

2. HOW DOES THE FUND MANAGE INTEREST RATE RISK?

               The Fund may vary the average-weighted effective maturity of its
               portfolio to reflect its portfolio manager's analysis of interest
               rate trends and other factors. The Fund's average-weighted
               effective maturity will tend to be shorter when the portfolio
               manager expects interest rates to rise and longer when its
               portfolio manager expects interest rates to fall. The Fund may
               also use futures, options and other derivatives to manage
               interest rate risks.

3. WHAT IS MEANT BY THE FUND'S "AVERAGE-WEIGHTED EFFECTIVE MATURITY"?

               The stated maturity of a bond is the date when the issuer must
               repay the bond's entire principal value to an investor. Some
               types of bonds may also have an "effective maturity" that is
               shorter than the stated date due to prepayment or call
               provisions. Securities without prepayment or call provisions
               generally have an effective maturity equal to their stated
               maturity. Dollar-weighted effective maturity is calculated by
               averaging the effective maturity of bonds held by the Fund with
               each effective maturity "weighted" according to the percentage of
               net assets that it represents.

4. WHAT IS MEANT BY THE FUND'S "DURATION"?

               A bond's duration indicates the time it will take an investor to
               recoup his investment. Unlike average maturity, duration reflects
               both principal and interest payments. Generally, the higher the
               coupon rate on a bond, the lower its duration will be. The
               duration of a bond fund is calculated by averaging the duration
               of bonds held by a fund with each duration "weighted" according
               to the percentage of net assets that it represents. Because
               duration accounts for interest payments, the Fund's duration is
               usually shorter than its average maturity.

5. WHAT IS A HIGH-YIELD/HIGH-RISK BOND?

               A high-yield/high-risk bond (also called a "junk" bond) is a bond
               rated below investment grade by major rating agencies (i.e., BB
               or

                                             Janus High-Yield Fund prospectus  7
<PAGE>

               lower by Standard & Poor's or Ba or lower by Moody's) or an
               unrated bond of similar quality. It presents greater risk of
               default (the failure to make timely interest and principal
               payments) than higher quality bonds.

GENERAL PORTFOLIO POLICIES

               In investing its portfolio assets, the Fund will follow the
               general policies listed below. The percentage limitations
               included in these policies and elsewhere in this Prospectus apply
               only at the time of purchase of the security. So, for example, if
               the Fund exceeds a limit as a result of market fluctuations or
               the sale of securities, it will not be required to dispose of any
               securities.

               CASH POSITION
               When the Fund's portfolio manager believes that market conditions
               are unfavorable for profitable investing, or when he is otherwise
               unable to locate attractive investment opportunities, the Fund's
               cash or similar investments may increase. In other words, the
               Fund does not always stay fully invested in bonds. Cash or
               similar investments generally are a residual - they represent the
               assets that remain after the portfolio manager has committed
               available assets to desirable investment opportunities. However,
               the portfolio manager may also temporarily increase the Fund's
               cash position to protect its assets or maintain liquidity. When
               the Fund's investments in cash or similar investments increase,
               it may not participate in market advances or declines to the same
               extent that it would if the Fund remained more fully invested in
               bonds.

               OTHER TYPES OF INVESTMENTS
               The Fund invests primarily in fixed-income securities, which may
               include corporate bonds and notes, government securities,
               preferred stock, high-yield/high-risk bonds and municipal
               obligations. The Fund may also invest to a lesser degree in other
               types of

 8 Janus High-Yield Fund prospectus
<PAGE>

               securities. These securities (which are described in the
               Glossary) may include:

               - common stocks

               - mortgage- and asset-backed securities (without limit)

               - zero coupon, pay-in-kind and step coupon securities (without
                 limit)

               - options, futures, forwards, swaps and other types of
                 derivatives for hedging purposes or for non-hedging purposes
                 such as seeking to enhance return

               - securities purchased on a when-issued, delayed delivery or
                 forward commitment basis

               ILLIQUID INVESTMENTS
               The Fund may invest up to 15% of its net assets in illiquid
               investments. An illiquid investment is a security or other
               position that cannot be disposed of quickly in the normal course
               of business. For example, some securities are not registered
               under the U.S. securities laws and cannot be sold to the U.S.
               public because of SEC regulations (these are known as "restricted
               securities"). Under procedures adopted by the Fund's Trustees,
               certain restricted securities may be deemed liquid, and will not
               be counted toward this 15% limit.

               FOREIGN SECURITIES
               The Fund may invest without limit in foreign equity and debt
               securities. The Fund may invest directly in foreign securities
               denominated in a foreign currency and not publicly traded in the
               United States. Other ways of investing in foreign securities
               include depositary receipts or shares, and passive foreign
               investment companies.

               SPECIAL SITUATIONS
               The Fund may invest in special situations. A special situation
               arises when, in the opinion of the Fund's portfolio manager, the

                                             Janus High-Yield Fund prospectus  9
<PAGE>

               securities of a particular issuer will be recognized and
               appreciate in value due to a specific development with respect to
               that issuer. Developments creating a special situation might
               include, among others, a new product or process, a technological
               breakthrough, a management change or other extraordinary
               corporate event, or differences in market supply of and demand
               for the security. The Fund's performance could suffer if the
               anticipated development in a "special situation" investment does
               not occur or does not attract the expected attention.

               PORTFOLIO TURNOVER
               The Fund generally intends to purchase securities for long-term
               investment although, to a limited extent, the Fund may purchase
               securities in anticipation of relatively short-term price gains.
               Short-term transactions may also result from liquidity needs,
               securities having reached a price or yield objective, changes in
               interest rates or the credit standing of an issuer, or by reason
               of economic or other developments not foreseen at the time of the
               investment decision. The Fund may also sell one security and
               simultaneously purchase the same or a comparable security to take
               advantage of short-term differentials in bond yields or
               securities prices. Changes are made in the Fund's portfolio
               whenever its portfolio manager believes such changes are
               desirable. Portfolio turnover rates are generally not a factor in
               making buy and sell decisions.

               Increased portfolio turnover may result in higher costs for
               brokerage commissions, dealer mark-ups and other transaction
               costs and may also result in taxable capital gains. Higher costs
               associated with increased portfolio turnover may offset gains in
               the Fund's performance.

 10 Janus High-Yield Fund prospectus
<PAGE>

RISKS

               Because the Fund invests substantially all of its assets in
               fixed-income securities, it is subject to risks such as credit or
               default risks, and decreased value due to interest rate
               increases. The Fund's performance may also be affected by risks
               to certain types of investments, such as foreign securities and
               derivative instruments.

The following questions and answers are designed to help you better understand
some of the risks of investing in the Fund.

1. WHAT IS MEANT BY "CREDIT QUALITY" AND WHAT ARE THE RISKS ASSOCIATED WITH IT?

               Credit quality measures the likelihood that the issuer will meet
               its obligations on a bond. One of the fundamental risks
               associated with all fixed-income funds is credit risk, which is
               the risk that an issuer will be unable to make principal and
               interest payments when due. U.S. government securities are
               generally considered to be the safest type of investment in terms
               of credit risk. Municipal obligations generally rank between U.S.
               government securities and corporate debt securities in terms of
               credit safety. Corporate debt securities, particularly those
               rated below investment grade, present the highest credit risk.

2. HOW IS CREDIT QUALITY MEASURED?

               Ratings published by nationally recognized statistical rating
               agencies such as Standard & Poor's and Moody's are widely
               accepted measures of credit risk. The lower a bond issue is rated
               by an agency, the more credit risk it is considered to represent.
               Lower rated bonds generally pay higher yields to compensate
               investors for the associated risk. Please refer to "Explanation
               of Rating Categories" on page 45 for a description of rating
               categories.

3. ARE THERE SPECIAL RISKS ASSOCIATED WITH INVESTMENTS IN HIGH-YIELD/HIGH-RISK
   BONDS?

   High-yield/high-risk bonds (or "junk" bonds) are bonds rated below investment
   grade by the primary rating agencies such as

                                            Janus High-Yield Fund prospectus  11
<PAGE>

   Standard & Poor's and Moody's. The value of lower quality bonds generally is
   more dependent on credit risk, or the ability of the issuer to meet interest
   and principal payments, than investment grade bonds. Issuers of
   high-yield/high-risk bonds may not be as strong financially as those issuing
   bonds with higher credit ratings and are more vulnerable to real or perceived
   economic changes, political changes or adverse developments specific to the
   issuer.

   The junk bond market can experience sudden and sharp price swings. Because
   the Fund may invest a significant portion of its portfolio in
   high-yield/high-risk bonds, investors should be willing to tolerate a
   corresponding increase in the risk of significant and sudden changes in NAV.
   Please refer to the "Explanation of Rating Categories" on page 45 for a
   description of rating categories.

4. HOW DOES THE FUND TRY TO REDUCE RISK?

               The Fund may use futures, options, swaps and other derivative
               instruments to "hedge" or protect its portfolio from adverse
               movements in securities prices and interest rates. The Fund may
               also use a variety of currency hedging techniques, including
               forward currency contracts, to manage exchange rate risk. The
               portfolio manager believes the use of these instruments will
               benefit the Fund. However, the Fund's performance could be worse
               than if the Fund had not used such instruments if the portfolio
               manager's judgement proves incorrect. Risks associated with the
               use of derivative instruments are described in the SAI.

5. I'VE HEARD A LOT ABOUT HOW THE CHANGE TO THE YEAR 2000 COULD AFFECT COMPUTER
   SYSTEMS. DOES THIS CREATE ANY SPECIAL RISKS?

               The portfolio manager carefully researches each potential
               investment before making an investment decision and, among other
               things, considers what impact, if any, the year 2000 transition
               has had on the company's operations when selecting portfolio
               holdings. However, there is no guarantee that the information the
               portfolio manager receives regarding a company's Year 2000

 12 Janus High-Yield Fund prospectus
<PAGE>

               transition status is completely accurate. If a company has not
               satisfactorily addressed Year 2000 issues, the Fund's performance
               could suffer.

6. HOW COULD THE FUND'S INVESTMENTS IN FOREIGN SECURITIES AFFECT ITS
   PERFORMANCE?

               The Fund may invest without limit in foreign securities either
               indirectly (e.g., depositary receipts) or directly in foreign
               markets. Investments in foreign securities, including those of
               foreign governments, may involve greater risks than investing in
               domestic securities because the Fund's performance may depend on
               issues other than the performance of a particular company. These
               issues include:

               - currency risk

               - political and economic risk

               - regulatory risk

               - market risk

               - transaction costs

               These risks are described in the SAI.

                                            Janus High-Yield Fund prospectus  13
<PAGE>

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<PAGE>

                                  [JANUS LOGO]
                            Janus  High-Yield  Fund
                              SHAREHOLDER'S MANUAL

                                           This section will help you
                                           become familiar with the
                                           different types of accounts
                                           you can establish with Janus.
                                           It also explains in detail the
                                           wide array of services and
                                           features you can establish on
                                           your account, as well as
                                           account policies and fees that
                                           may apply to your account.
                                           Account policies (including
                                           fees), services and features
                                           may be modified or
                                           discontinued without
                                           shareholder approval or prior
                                           notice.

                                           [JANUS LOGO]

<PAGE>

HOW TO GET IN TOUCH WITH JANUS

INVESTOR SERVICE CENTERS
100 Fillmore Street, Suite 100
Denver, CO 80206

3773 Cherry Creek North Drive, Suite 101
Denver, CO 80209

(Hours: Monday-Friday 7:00 a.m.-6:00 p.m., and Saturday 9:00 a.m.-1:00 p.m.,
Mountain time.)

MAILING ADDRESS
Janus
P.O. Box 173375
Denver, CO 80217-3375

FOR OVERNIGHT CARRIER
Janus
Suite 101
3773 Cherry Creek Drive North
Denver, CO 80209-3821

INVESTOR SERVICE REPRESENTATIVES
If you have any questions while reading this Prospectus, please call one of our
Investor Service Representatives at 1-800-525-3713 Monday-Friday: 8:00 a.m.-8:00
p.m., and Saturday: 10:00 a.m.-4:00 p.m., New York time.

JANUS XPRESSLINE(TM)
1-888-979-7737

JANUS INTERNET ADDRESS
JANUS.COM

For 24-hour access to account and fund information, exchanges, purchases and
redemptions, automated daily quotes on fund share prices, yields and total
returns.

JANUS.COM SPECIALISTS
1-800-975-9932

TDD
1-800-525-0056
A telecommunications device for our hearing- and speech-impaired shareholders.

JANUS LITERATURE LINE
1-800-525-8983
To request a prospectus, shareholder reports or marketing materials 24 hours a
day.

 16 Shareholder's manual
<PAGE>

MINIMUM INVESTMENTS*

<TABLE>
<S>                      <C>
To open a new regular
account                  $2,500
To open a new
retirement account,
education account or
UGMA/UTMA                $  500
To open a new regular
account with an
Automatic Investment
Program                  $  500**
To add to any type of
an account               $  100+
</TABLE>

 * The Fund reserves the right to change the amount of these minimums from time
   to time or to waive them in whole or in part for certain types of accounts.

** An Automatic Investment Program requires a $100 minimum automatic investment
   per month until the account balance reaches $2,500.

 + The minimum subsequent investment for a retirement account or UGMA/UTMA is
   $50.

TYPES OF ACCOUNT OWNERSHIP

               If you are investing in the Fund for the first time, you will
               need to establish an account. You can establish the following
               types of accounts by completing a New Account Application.

               INDIVIDUAL OR JOINT OWNERSHIP
               Individual accounts are owned by one person. Joint accounts have
               two or more owners.

               A GIFT OR TRANSFER TO MINOR (UGMA OR UTMA)
               An UGMA/UTMA is a custodial account managed for the benefit of a
               minor. To open an UGMA or UTMA, you must include the minor's
               Social Security number on the application.

               TRUST
               An established trust can open an account. The names of each
               trustee, the name of the trust and the date of the trust
               agreement must be included on the application.

                                                        Shareholder's manual  17
<PAGE>

               BUSINESS ACCOUNTS
               Corporations and partnerships may also open an account. The
               application must be signed by an authorized officer of the
               corporation or a general partner of the partnership.

TAX-DEFERRED ACCOUNTS

               If you are eligible, you may set up one or more tax-deferred
               accounts. A tax-deferred account allows you to shelter your
               investment income and capital gains from current income taxes. A
               contribution to certain of these plans may also be tax
               deductible. Tax-deferred accounts include retirement plans
               described below and the Education IRA. Please refer to the Janus
               retirement guide for more complete information regarding the
               different types of IRAs, including the Education IRA.
               Distributions from these plans are generally subject to income
               tax and may be subject to an additional tax if withdrawn prior to
               age 59 1/2 or used for a nonqualifying purpose. Investors should
               consult their tax adviser or legal counsel before selecting a
               tax-deferred account.

               Investors Fiduciary Trust Company serves as custodian for the
               tax-deferred accounts offered by the Fund. You will be charged an
               annual account maintenance fee of $12 for each taxpayer
               identification number no matter how many tax-deferred accounts
               you have with Janus. You may pay the fee by check or have it
               automatically deducted from your account (usually in December).
               The custodian reserves the right to change the amount of this fee
               or to waive it in whole or in part for certain types of accounts.

               TRADITIONAL AND ROTH INDIVIDUAL RETIREMENT ACCOUNTS
               Both types of IRAs allow most individuals with earned income to
               contribute up to the lesser of $2,000 ($4,000 for most married
               couples) or 100% of compensation annually.

               EDUCATION IRA
               This plan allows individuals, subject to certain income
               limitations, to contribute up to $500 annually on behalf of any
               child under the age of 18.

 18 Shareholder's manual
<PAGE>

               SIMPLIFIED EMPLOYEE PENSION PLAN
               This plan allows small business owners (including sole
               proprietors) to make tax-deductible contributions for themselves
               and any eligible employee(s). A SEP requires an IRA (a SEP-IRA)
               to be set up for each SEP participant.

               PROFIT SHARING OR MONEY PURCHASE PENSION PLAN
               These plans are open to corporations, partnerships and sole
               proprietors to benefit their employees and themselves.

               SECTION 403(B)(7) PLAN
               Employees of educational organizations or other qualifying, tax-
               exempt organizations may be eligible to participate in a Section
               403(b)(7) Plan.

               PLEASE REFER TO THE CHART ON THE FOLLOWING PAGES FOR INFORMATION
               ON OPENING AN ACCOUNT AND CONDUCTING BUSINESS WITH JANUS. WITH
               CERTAIN LIMITED EXCEPTIONS, THE FUND IS AVAILABLE ONLY TO U.S.
               CITIZENS OR RESIDENTS. WHEN YOU PURCHASE, EXCHANGE, OR REDEEM
               SHARES, YOUR REQUEST WILL BE PROCESSED AT THE NEXT NAV CALCULATED
               AFTER YOUR ORDER IS RECEIVED AND ACCEPTED.

                                                        Shareholder's manual  19
<PAGE>

 TO PURCHASE SHARES

 BY MAIL/IN WRITING
 ------------------------------------------------------------------------------

 - To open your account, complete and sign the appropriate application and make
   your check payable to Janus.

 - To purchase additional shares, complete the remittance slip attached at the
   bottom of your confirmation statement. If you are making a purchase into a
   retirement account, please indicate whether the purchase is a rollover or a
   current or prior year contribution. Send your check and remittance slip or
   written instructions to the address listed on the slip.

 BY TELEPHONE
 ------------------------------------------------------------------------------

 - The "Telephone Purchase of Shares Option" allows you to purchase additional
   shares quickly and conveniently through an electronic transfer of money.
   After establishing this option on your account, call an Investor Service
   Representative during normal business hours or the Janus XpressLine for
   access to this option 24 hours a day. Janus will automatically debit your
   predesignated bank account.

 - Purchases may also be made by wiring money from your bank account to your
   Janus account. Call an Investor Service Representative for wiring
   instructions.

 BY INTERNET
 ------------------------------------------------------------------------------

 - The "Telephone Purchase of Shares Option" allows you to make a purchase into
   an existing account on our Web site at janus.com.

 BY AUTOMATIC INVESTMENT
 ------------------------------------------------------------------------------

 - Automatic Monthly Investment Program - You select the day each month that
   your money ($100 minimum) will be electronically transferred from your bank
   account to your Fund account.

 - Payroll Deduction - If your employer can initiate an automatic payroll
   deduction, you may have all or a portion of your paycheck ($100 minimum)
   invested directly into your Fund account.

 20 Shareholder's manual
<PAGE>

<TABLE>
<S>                                            <C>
    TO EXCHANGE SHARES                           TO REDEEM SHARES
- ---------------------------------------        ---------------------------------------
    - To request an exchange in writing,         - To request a redemption in writ-
      please follow the instructions for           ing, please follow the instructions
      written requests on page 24. Also            for written requests on page 24.
      refer to the exchange policies             - Please see page 23 for information
      listed on page 22 for more infor-            about payment of redemption
      mation.                                      proceeds.

- ---------------------------------------        ---------------------------------------
    - All accounts are automatically eli-        - The telephone redemption option
      gible to exchange shares by tele-            enables you to request redemp-
      phone. To exchange all or a portion          tions daily from your account by
      of your shares into any other                calling an Investor Service Repre-
      available Janus fund, call an                sentative by the close of the
      Investor Service Representative or           regular trading session of the
      the Janus XpressLine.                        NYSE, normally 4:00 p.m. New York
                                                   time. You may also use Janus
                                                   XpressLine for access to this
                                                   option 24 hours a day.

- ---------------------------------------        ---------------------------------------
    - Exchanges may be made on our Web           - Redemptions may be made on our Web
      site at janus.com.                           site at janus.com.
- ---------------------------------------        ---------------------------------------
    - Systematic Exchange - You deter-           - Systematic Redemption - This option
      mine the amount of money you would           allows you to redeem a specific
      like automatically exchanged from            dollar amount from your account on
      one Janus account to another on any          a regular basis.
      day of the month. You may establish
      this program for as little as $100
      per month on existing accounts. You
      may establish a new account with a
      $500 initial purchase and subse-
      quent $100 systematic exchanges.
</TABLE>

                                                        Shareholder's manual  21
<PAGE>

PAYING FOR SHARES

Please note the following when purchasing shares:

- - Cash, credit cards, third party checks, travelers cheques, credit card checks
  or money orders will not be accepted.

- - All purchases must be made in U.S. dollars and checks must be drawn on U.S.
  banks.

- - We may make additional attempts to debit the bank account for ACH purchases.

- - The Fund reserves the right to reject any specific purchase request.

- - If all or a portion of a check is received for investment without a specific
  fund designation, the undesignated amount will be invested in the Janus Money
  Market Fund -- Investor Shares. Shares that are subsequently exchanged from
  Janus Money Market Fund -- Investor Shares into the selected Fund will receive
  the NAV next calculated after your order is received and accepted by the Fund.

- - If your purchase is cancelled, you will be responsible for any losses or fees
  imposed by your bank and losses that may be incurred as a result of any
  decline in the value of the cancelled purchase.

EXCHANGE POLICIES

The exchange privilege is not intended as a vehicle for short-term or excessive
trading. The Fund does not permit excessive trading or market timing. Excessive
purchases, redemptions, or exchanges of Fund shares disrupt portfolio management
and drive Fund expenses higher.

Please note the following when exchanging shares:

- - Except for Systematic Exchanges, new accounts established by exchange must be
  opened with $2,500 or the total account value if the value of the account you
  are exchanging from is less than $2,500.

- - Exchanges between existing accounts must meet the $100 subsequent investment
  requirement.

- - You may make four exchanges out of the Fund during a calendar year (exclusive
  of Systematic Exchange). Exchanges in excess of this limit are considered
  excessive trading and may be subject to an exchange fee or may result in
  termination of the exchange privilege or the right to make future purchases of
  Fund shares.

 22 Shareholder's manual
<PAGE>

- - The Fund reserves the right to reject any purchase order or exchange request
  and to modify or terminate the exchange privilege at any time. For example,
  the Fund may reject exchanges from accounts engaged in or known to engage in
  trading in excess of the limit above (including market timing transactions) or
  whose trading has been or may be disruptive to the Fund.

- - Exchanges between accounts will be accepted only if the registrations are
  identical.

- - If the shares you are exchanging are held in certificate form, you must return
  the certificate to Janus prior to making any exchanges. Effective June 4,
  1999, shares are no longer available in certificate form.

- - An exchange represents the sale of shares from one fund and the purchase of
  shares of another fund, which may produce a taxable gain or loss in a
  non-retirement account.

- - If the balance in the account you are exchanging from falls below the
  systematic exchange amount, all remaining shares will be exchanged
  and the program will be discontinued.

PAYMENT OF REDEMPTION PROCEEDS

- - BY CHECK - Redemption proceeds will be sent to the shareholder(s) of record at
  the address of record within seven days after receipt of a valid redemption
  request. During the 10 days following an address change, checks sent to a new
  address require a signature guarantee.

- - BY ELECTRONIC TRANSFER - If you have established the electronic redemption
  option, your redemption proceeds can be electronically transferred to your
  predesignated bank account on the next bank business day after receipt of your
  redemption request (wire transfer) or the second bank business day after
  receipt of your redemption request (ACH transfer).

Wire transfers will be charged an $8 fee per wire and your bank may charge an
additional fee to receive the wire. Wire redemptions are not available for
retirement accounts.

IF THE SHARES BEING REDEEMED WERE PURCHASED BY CHECK, TELEPHONE, ON OUR WEB
SITE, OR THROUGH THE AUTOMATIC MONTHLY INVESTMENT PROGRAM, THE FUND MAY DELAY
THE PAYMENT OF YOUR REDEMPTION PROCEEDS FOR UP TO 15 DAYS FROM THE DAY OF
PURCHASE TO ALLOW THE PURCHASE TO CLEAR. Unless you provide alternate
instructions, your proceeds will be invested in Janus Money Market
Fund - Investor Shares during the 15 day hold period.

                                                        Shareholder's manual  23
<PAGE>

WRITTEN INSTRUCTIONS

               To redeem or exchange all or part of your shares in writing, your
               request should be sent to one of the addresses listed on page 16
               and must include the following information:

               - the name of the Fund(s)

               - the account number(s)

               - the amount of money or number of shares being redeemed or
                 exchanged

               - the name(s) on the account

               - the signature(s) of all registered account owners (see account
                 application for signature requirements)

               - your daytime telephone number

SIGNATURE GUARANTEE

               A SIGNATURE GUARANTEE IS REQUIRED if any of the following is
               applicable:

               - You request a redemption by check that exceeds $100,000.

               - You would like a check made payable to anyone other than the
                 shareholder(s) of record.

               - You would like a check mailed to an address which has been
                 changed within 10 days of the redemption request.

               - You would like a check mailed to an address other than the
                 address of record.

               THE FUND RESERVES THE RIGHT TO REQUIRE A SIGNATURE GUARANTEE
               UNDER OTHER CIRCUMSTANCES OR TO REJECT OR DELAY A REDEMPTION ON
               CERTAIN LEGAL GROUNDS.

               HOW TO OBTAIN A SIGNATURE GUARANTEE

               A signature guarantee assures that a signature is genuine. The
               signature guarantee protects shareholders from unauthorized
               account transfers. The following financial institutions may
               guaran-

 24 Shareholder's manual
<PAGE>

               tee signatures: banks, savings and loan associations, trust
               companies, credit unions, broker-dealers, and member firms of a
               national securities exchange. Call your financial institution to
               see if they have the ability to guarantee a signature. A
               signature guarantee cannot be provided by a notary public.

               If you live outside the United States, a foreign bank properly
               authorized to do business in your country of residence or a U.S.
               consulate may be able to authenticate your signature.

PRICING OF FUND SHARES

               All purchases, redemptions and exchanges will be processed at the
               NAV next calculated after your request is received and accepted
               by the Fund (or the Fund's agent or authorized designee). The
               Fund's NAV is calculated at the close of the regular trading
               session of the NYSE (normally 4:00 p.m. New York time) each day
               that the NYSE is open. The NAV of Fund shares is not determined
               on days the NYSE is closed (generally New Year's Day, Martin
               Luther King Day, Presidents' Day, Good Friday, Memorial Day,
               Independence Day, Labor Day, Thanksgiving and Christmas). In
               order to receive a day's price, your order must be received by
               the close of the regular trading session of the NYSE. Securities
               are valued at market value or, if a market quotation is not
               readily available, at their fair value determined in good faith
               under procedures established by and under the supervision of the
               Trustees. Short-term instruments maturing within 60 days are
               valued at amortized cost, which approximates market value. See
               the SAI for more detailed information.

SHAREHOLDER SERVICES AND ACCOUNT POLICIES

               ACCOUNT MINIMUMS

               Due to the proportionately higher costs of maintaining small
               accounts, Janus reserves the right to deduct a $10 minimum
               balance fee (or the value of the account if less than $10) from
               accounts with values below the minimums described on page 17 or
               to close such accounts. This policy will apply to accounts

                                                        Shareholder's manual  25
<PAGE>

               participating in the Automatic Monthly Investment Program only if
               your account balance does not reach the required minimum initial
               investment or falls below such minimum and you have discontinued
               monthly investments. This policy does not apply to accounts that
               fall below the minimums solely as a result of market value
               fluctuations. It is expected that, for purposes of this policy,
               accounts will be valued in September, and the $10 fee will be
               assessed on the second Friday of September of each year. You will
               receive notice before we charge the $10 fee or close your account
               so that you may increase your account balance to the required
               minimum.

               TRANSACTIONS THROUGH PROCESSING ORGANIZATIONS

               You may purchase or sell Fund shares through a broker-dealer,
               bank or other financial institution, or an organization that
               provides recordkeeping and consulting services to 401(k) plans or
               other employee benefit plans (a "Processing Organization").
               Processing Organizations may charge you a fee for this service
               and may require different minimum initial and subsequent
               investments than the Fund. Processing Organizations may also
               impose other charges or restrictions different from those
               applicable to shareholders who invest in the Fund directly. A
               Processing Organization, rather than its customers, may be the
               shareholder of record of your shares. The Fund is not responsible
               for the failure of any Processing Organization to carry out its
               obligations to its customers. Certain Processing Organizations
               may receive compensation from Janus Capital or its affiliates and
               certain Processing Organizations may receive compensation from
               the Fund for shareholder recordkeeping and similar services.

               TAXPAYER IDENTIFICATION NUMBER

               On the application or other appropriate form, you will be asked
               to certify that your Social Security or taxpayer identification
               number is correct and that you are not subject to backup
               withholding for failing to report income to the IRS. If you are
               subject to the 31% backup withholding or you did not certify

 26 Shareholder's manual
<PAGE>

               your taxpayer identification number, the IRS requires the Fund to
               withhold 31% of any dividends paid and redemption or exchange
               proceeds. In addition to the 31% backup withholding, you may be
               subject to a $50 fee to reimburse the Fund for any penalty that
               the IRS may impose.

               INVOLUNTARY REDEMPTIONS

               The Fund reserves the right to close an account if the
               shareholder is deemed to engage in activities which are illegal
               or otherwise believed to be detrimental to the Fund.

               TELEPHONE TRANSACTIONS

               You may initiate many transactions by telephone. The Fund and its
               agents will not be responsible for any losses resulting from
               unauthorized transactions when procedures designed to verify the
               identity of the caller are followed.

               It may be difficult to reach an Investor Service Representative
               by telephone during periods of unusual market activity. If you
               are unable to reach a representative by telephone, please
               consider sending written instructions, stopping by a Service
               Center, calling the Janus XpressLine or visiting our Web site.

               TEMPORARY SUSPENSION OF SERVICES

               The Fund or its agents may, in case of emergency, temporarily
               suspend telephone transactions and other shareholder services.

               ADDRESS CHANGES

               To change the address on your account, call 1-800-525-3713 or
               send a written request signed by the shareholder(s) of record.
               Include the name of your Fund, the account number(s), the name(s)
               on the account and both the old and new addresses. Certain
               options may be suspended for 10 days following an address change
               unless a signature guarantee is provided.

                                                        Shareholder's manual  27
<PAGE>

               REGISTRATION CHANGES

               To change the name on an account, the shares are generally
               transferred to a new account. In some cases, legal documentation
               may be required. For further instructions, please call an
               Investor Service Representative.

               STATEMENTS AND REPORTS

               Investors will receive quarterly confirmations of all
               transactions. Quarterly statements for all investors are
               available on our Web site. You may make an election on our Web
               site to discontinue delivery of your paper statements. Dividend
               information will be confirmed quarterly. In addition, the Fund
               will send you an immediate transaction confirmation statement
               after every non-systematic transaction.

               The Fund produces financial reports, which include a list of the
               Fund's portfolio holdings, semiannually and updates its
               prospectus annually. To reduce expenses, the Fund may choose to
               mail only one report or prospectus to your household, even if
               more than one person in the household has a Fund account. Please
               call 1-800-525-3713 if you would like to receive additional
               reports or prospectuses. The Fund reserves the right to charge a
               fee for additional statement requests.

 28 Shareholder's manual
<PAGE>

MANAGEMENT OF THE FUND
- --------------------------------------------------------------------------------
INVESTMENT ADVISER

               Janus Capital Corporation, 100 Fillmore Street, Denver, Colorado
               80206-4928, is the investment adviser to the Fund and is
               responsible for the day-to-day management of its investment
               portfolio and other business affairs.

               Janus Capital began serving as investment adviser to Janus Fund
               in 1970 and currently serves as investment adviser to all of the
               Janus funds, acts as sub-adviser for a number of private-label
               mutual funds and provides separate account advisory services for
               institutional accounts.

               Janus Capital furnishes continuous advice and recommendations
               concerning the Fund's investments. Janus Capital also furnishes
               certain administrative, compliance and accounting services for
               the Fund, and may be reimbursed by the Fund for its costs in
               providing those services. In addition, Janus Capital employees
               serve as officers of the Trust and Janus Capital provides office
               space for the Fund and pays the salaries, fees and expenses of
               all Fund officers and those Trustees who are affiliated with
               Janus Capital. The Fund pays all of its expenses not assumed by
               Janus Capital, including auditing fees and independent Trustees'
               fees and expenses.

               The Fund pays Janus Capital a management fee which is calculated
               daily and paid monthly. The advisory agreement with the Fund
               spells out the management fee and other expenses that the Fund
               must pay.

               The Fund incurs expenses not assumed by Janus Capital, including
               transfer agent and custodian fees and expenses, legal and
               auditing fees, printing and mailing costs of sending reports and
               other information to existing shareholders, and independent
               Trustees' fees and expenses. For the most recent fiscal year, the
               Fund paid Janus Capital a management fee (net of any fee waivers)
               equal to 0.72% of average daily net assets. Without such waivers,
               the management fee would have been 0.75% of average daily net
               assets. Janus Capital has agreed to continue such waivers

                                            Janus High-Yield Fund prospectus  29
<PAGE>

               until at least the next annual renewal of the advisory agreement.
               You will be notified of any change in this limit.

PORTFOLIO MANAGER

SANDY R. RUFENACHT
- --------------------------------------------------------------------------------
                   is Executive Vice President and portfolio manager of the
                   Fund and Janus Short-Term Bond Fund. He has served as
                   manager or co-manager of the Fund since June 1996 and has
                   served as manager of Janus Short-Term Bond Fund since
                   January 1996. He previously served as Executive Vice
                   President and co-manager of Janus Flexible Income Fund.
                   Mr. Rufenacht joined Janus Capital in 1990. He holds a
                   Bachelor of Arts in Business from the University of
                   Northern Colorado.

 30 Janus High-Yield Fund prospectus
<PAGE>

OTHER INFORMATION
- --------------------------------------------------------------------------------

               SIZE OF THE FUND

               Although there is no present intention to do so, the Fund may
               discontinue sales of its shares if management and the Trustees
               believe that continued sales may adversely affect the Fund's
               ability to achieve its investment objectives. If sales of the
               Fund are discontinued, it is expected that existing shareholders
               of the Fund will be permitted to continue to purchase shares and
               to reinvest any dividends or capital gains distributions, absent
               highly unusual circumstances.

               YEAR 2000

               Preparing for Year 2000 has been a high priority for Janus
               Capital. A dedicated group was established to address this issue.
               Janus Capital devoted considerable internal resources and engaged
               one of the foremost experts in the field to achieve Year 2000
               readiness. Janus Capital successfully completed all five steps of
               its Year 2000 preparedness plans including the upgrade and
               replacement of all systems, as well as full-scale testing and
               implementation of those systems. Janus Capital's detailed
               contingency plans were also thoroughly tested. As of the date of
               this Prospectus, Janus Capital has not seen any adverse impact as
               a result of the Year 2000 transition on any of its systems or
               those of its vendors, or on the companies in which the Funds
               invest or worldwide markets and economies. Nonetheless, Janus
               Capital will continue to monitor the effect of the Year 2000
               transition, and there can be no absolute assurance that Year 2000
               issues will not in the future adversely affect the Funds' or
               Janus Capital's operations.

                                            Janus High-Yield Fund prospectus  31
<PAGE>

               DISTRIBUTION OF THE FUND

               The Funds are distributed by Janus Distributors, Inc., a member
               of the National Association of Securities Dealers, Inc. ("NASD").
               To obtain information about NASD member firms and their
               associated persons, you may contact NASD Regulation, Inc. at
               www.nasdr.com or the Public Disclosure Hotline at 800-289-9999.
               An investor brochure containing information describing the Public
               Disclosure Program is available from NASD Regulation, Inc.

 32 Janus High-Yield Fund prospectus
<PAGE>

DISTRIBUTIONS AND TAXES
- --------------------------------------------------------------------------------

DISTRIBUTIONS

               To avoid taxation of the Fund, the Internal Revenue Code requires
               the Fund to distribute net income and any net capital gains
               realized on its investments annually. The Fund's income from
               dividends and interest and any net realized short-term gains are
               paid to shareholders as ordinary income dividends. Net realized
               long-term gains are paid to shareholders as capital gains
               distributions.

               Income dividends are declared daily, Saturdays, Sundays and
               holidays are included, and are generally paid as of the last
               business day of each month. If a month begins on a Saturday,
               Sunday or holiday, dividends for those days are paid at the end
               of the preceding month. You will begin accruing income dividends
               the day after a purchase is effective. If shares are redeemed,
               you will receive all dividends accrued through the day of the
               redemption. Capital gains, if any, are declared and paid in
               December.

               HOW DISTRIBUTIONS AFFECT THE FUND'S NAV

               Distributions, other than daily income dividends, are paid to
               shareholders as of the record date of the distribution of the
               Fund, regardless of how long the shares have been held.
               Undistributed income and realized gains are included in the
               Fund's daily NAV. The share price of the Fund drops by the amount
               of the distribution, net of any subsequent market fluctuations.
               As an example, assume that on December 31, the Fund declared a
               dividend in the amount of $0.25 per share. If the Fund's share
               price was $10.00 on December 30, the Fund's share price on
               December 31 would be $9.75, barring market fluctuations.
               Shareholders should be aware that distributions from a taxable
               mutual fund are not value-enhancing and may create income tax
               obligations.

               "BUYING A DIVIDEND"

               If you purchase shares of the Fund just before the distribution,
               you will pay the full price for the shares and receive a portion
               of the purchase price back as a taxable distribution. This is
               referred

                                            Janus High-Yield Fund prospectus  33
<PAGE>

               to as "buying a dividend." In the above example, if you bought
               shares on December 30, you would have paid $10.00 per share. On
               December 31, the Fund would pay you $0.25 per share as a dividend
               and your shares would now be worth $9.75 per share. Unless your
               account is set up as a tax-deferred account, dividends paid to
               you would be included in your gross income for tax purposes, even
               though you may not have participated in the increase in NAV of
               the Fund, whether or not you reinvested the dividends.

DISTRIBUTION OPTIONS

               When you open an account, you must specify on your application
               how you want to receive your distributions. You may change your
               distribution option at any time by writing the Fund at one of the
               addresses on page 16 or calling 1-800-525-3713. The Fund offers
               the following options:

               1. REINVESTMENT OPTION. You may reinvest your income dividends
                  and capital gains distributions in additional shares. This
                  option is assigned automatically if no other choice is made.

               2. CASH OPTION. You may receive your income dividends and capital
                  gains distributions in cash.

               3. REINVEST AND CASH OPTION. You may receive either your income
                  dividends or capital gains distributions in cash and reinvest
                  the other in additional shares.

               4. REDIRECT OPTION. You may direct your dividends or capital
                  gains to purchase shares of another Janus fund.

               The Fund reserves the right to reinvest into your account
               undeliverable and uncashed dividend and distribution checks that
               remain outstanding for six months in shares of the Fund at the
               NAV next computed after the check is cancelled. Subsequent
               distributions may also be reinvested.

 34 Janus High-Yield Fund prospectus
<PAGE>

TAXES

               As with any investment, you should consider the tax consequences
               of investing in the Fund. Any time you sell or exchange shares of
               a Fund in a taxable account, it is considered a taxable event.
               Depending on the purchase price and the sale price, you may have
               a gain or loss on the transaction. Any tax liabilities generated
               by your transactions are your responsibility.

               The following discussion does not apply to tax-deferred accounts,
               nor is it a complete analysis of the federal tax implications of
               investing in the Fund. You may wish to consult your own tax
               adviser. Additionally, state or local taxes may apply to your
               investment, depending upon the laws of your state of residence.

               TAXES ON DISTRIBUTIONS
               Dividends and distributions by the Fund are subject to federal
               income tax, regardless of whether the distribution is made in
               cash or reinvested in additional shares of the Fund.
               Distributions may be taxable at different rates depending on the
               length of time the Fund holds a security. In certain states, a
               portion of the dividends and distributions (depending on the
               source of the Fund's income) may be exempt from state and local
               taxes. Information regarding the tax status of income dividends
               and capital gains distributions will be mailed to shareholders on
               or before January 31st of each year. Account tax information will
               also be sent to the IRS.

               TAXATION OF THE FUND
               Dividends, interest, and some capital gains received by the Fund
               on foreign securities may be subject to tax withholding or other
               foreign taxes. The Fund may from year to year make the election
               permitted under section 853 of the Internal Revenue Code to pass
               through such taxes to shareholders as a foreign tax credit. If
               such an election is not made, any foreign taxes paid or accrued
               will represent an expense to the Fund.

                                            Janus High-Yield Fund prospectus  35
<PAGE>

               The Fund does not expect to pay federal income or excise taxes
               because it intends to meet certain requirements of the Internal
               Revenue Code. It is important that the Fund meet these
               requirements so that any earnings on your investment will not be
               taxed twice.

 36 Janus High-Yield Fund prospectus
<PAGE>

FINANCIAL HIGHLIGHTS
- --------------------------------------------------------------------------------

               The financial highlights table is intended to help you understand
               the Fund's financial performance through October 31st of each
               fiscal period shown. Items 1 through 8 reflect financial results
               for a single Fund share. The total returns in the table represent
               the rate that an investor would have earned (or lost) on an
               investment in the Fund (assuming reinvestment of all dividends
               and distributions). This information has been audited by
               PricewaterhouseCoopers LLP, whose report, along with the Fund's
               financial statements, are included in the Annual Report, which is
               available upon request and incorporated by reference into the
               SAI.

JANUS HIGH-YIELD FUND
<TABLE>
<CAPTION>
- ---------------------------------------------------------------------------------------------
                                                          Periods ending October 31st
                                                     1999       1998       1997     1996(1)
<S>                                                <C>        <C>        <C>        <C>
  1. NET ASSET VALUE, BEGINNING OF PERIOD           $10.25     $11.83     $11.12     $10.00
     INCOME FROM INVESTMENT OPERATIONS:
  2. Net investment income                            0.89       0.90       0.97       0.80
  3. Net gains or (losses) on securities (both
     realized and unrealized)                       (0.22)     (1.02)       0.82       1.12
  4. Total from investment operations                 0.67     (0.12)       1.79       1.92
     LESS DISTRIBUTIONS:
  5. Dividends (from net investment income)         (0.89)     (0.90)     (0.97)     (0.80)
  6. Distributions (from capital gains)                 --     (0.56)     (0.11)         --
  7. Total distributions                            (0.89)     (1.46)     (1.08)     (0.80)
  8. NET ASSET VALUE, END OF PERIOD                 $10.03     $10.25     $11.83     $11.12
  9. Total return*                                   6.34%     (1.45%)    16.94%     19.71%
 10. Net assets, end of period (in millions)          $264       $268       $301       $211
 11. Average net assets for the period (in
     millions)                                        $297       $381       $266        $88
 12. Ratio of gross expenses to average net
     assets**                                        1.02%(2)   0.99%(2)   1.03%(2)   1.01%(2)
 13. Ratio of net expenses to average net
     assets**                                        1.00%      0.96%      1.00%      1.00%
 14. Ratio of net investment income to average
     net assets**                                    8.48%      7.85%      8.45%      9.00%
 15. Portfolio turnover rate**                        310%       336%       404%       324%
- ----------------------------------------------------------------------------------------------
</TABLE>

(1) Fiscal period from December 29, 1995 (inception) to October 31, 1996.
(2) The ratio was 1.05% in 1999, N/A in 1998, 1.04% in 1997 and 1.18% in 1996
    before waiver of certain Fund expenses.
  * Total return is not annualized for periods of less than one full year.
 ** Annualized for periods of less than one full year.

                                            Janus High-Yield Fund prospectus  37
<PAGE>

GLOSSARY OF INVESTMENT TERMS
- --------------------------------------------------------------------------------

               This glossary provides a more detailed description of some of the
               types of securities and other instruments in which the Fund may
               invest. The Fund may invest in these instruments to the extent
               permitted by its investment objectives and policies. The Fund is
               not limited by this discussion and may invest in any other types
               of instruments not precluded by the policies discussed elsewhere
               in this Prospectus. Please refer to the SAI for a more detailed
               discussion of certain instruments.

I. EQUITY AND DEBT SECURITIES

               BONDS are debt securities issued by a company, municipality,
               government or government agency. The issuer of a bond is required
               to pay the holder the amount of the loan (or par value of the
               bond) at a specified maturity and to make scheduled interest
               payments.

               CERTIFICATES OF PARTICIPATION ("COPS") are certificates
               representing an interest in a pool of securities. Holders are
               entitled to a proportionate interest in the underlying
               securities. Municipal lease obligations are often sold in the
               form of COPs. See "Municipal lease obligations" below.

               COMMERCIAL PAPER is a short-term debt obligation with a maturity
               ranging from 1 to 270 days issued by banks, corporations and
               other borrowers to investors seeking to invest idle cash. The
               Fund may purchase commercial paper issued in private placements
               under Section 4(2) of the Securities Act of 1933.

               COMMON STOCKS are equity securities representing shares of
               ownership in a company, and usually carry voting rights and earns
               dividends. Unlike preferred stock, dividends on common stocks are
               not fixed but are declared at the discretion of the issuer's
               board of directors.

               CONVERTIBLE SECURITIES are preferred stocks or bonds that pay a
               fixed dividend or interest payment and are convertible into
               common stock at a specified price or conversion ratio.

               DEBT SECURITIES are securities representing money borrowed that
               must be repaid at a later date. Such securities have specific

 38 Janus High-Yield Fund prospectus
<PAGE>

               maturities and usually a specific rate of interest or an original
               purchase discount.

               DEPOSITARY RECEIPTS are receipts for shares of a foreign-based
               corporation that entitle the holder to dividends and capital
               gains on the underlying security. Receipts include those issued
               by domestic banks (American Depositary Receipts), foreign banks
               (Global or European Depositary Receipts) and broker-dealers
               (depositary shares).

               FIXED-INCOME SECURITIES are securities that pay a specified rate
               of return. The term generally includes short- and long-term
               government, corporate and municipal obligations that pay a
               specified rate of interest or coupons for a specified period of
               time, and preferred stock, which pays fixed dividends. Coupon and
               dividend rates may be fixed for the life of the issue or, in the
               case of adjustable and floating rate securities, for a shorter
               period.

               HIGH-YIELD/HIGH-RISK BONDS are bonds that are rated below
               investment grade by the primary rating agencies (e.g., BB or
               lower by Standard & Poor's and Ba or lower by Moody's). Other
               terms commonly used to describe such bonds include "lower rated
               bonds," "noninvestment grade bonds" and "junk bonds."

               INDUSTRIAL DEVELOPMENT BONDS are revenue bonds that are issued by
               a public authority but which may be backed only by the credit and
               security of a private issuer and may involve greater credit risk.
               See "Municipal securities" below.

               MORTGAGE- AND ASSET-BACKED SECURITIES are shares in a pool of
               mortgages or other debt. These securities are generally pass-
               through securities, which means that principal and interest
               payments on the underlying securities (less servicing fees) are
               passed through to shareholders on a pro rata basis. These
               securities involve prepayment risk, which is the risk that the
               underlying mortgages or other debt may be refinanced or paid off
               prior to their maturities during periods of declining interest
               rates. In that case, the portfolio managers may have to reinvest
               the proceeds from the securities at a lower rate. Potential
               market gains

                                            Janus High-Yield Fund prospectus  39
<PAGE>

               on a security subject to prepayment risk may be more limited than
               potential market gains on a comparable security that is not
               subject to prepayment risk.

               MUNICIPAL LEASE OBLIGATIONS are revenue bonds backed by leases or
               installment purchase contracts for property or equipment. Lease
               obligations may not be backed by the issuing municipality's
               credit and may involve risks not normally associated with general
               obligation bonds and other revenue bonds. For example, their
               interest may become taxable if the lease is assigned and the
               holders may incur losses if the issuer does not appropriate funds
               for the lease payments on an annual basis, which may result in
               termination of the lease and possible default.

               MUNICIPAL SECURITIES are bonds or notes issued by a U.S. state or
               political subdivision. A municipal security may be a general
               obligation backed by the full faith and credit (i.e., the
               borrowing and taxing power) of a municipality or a revenue
               obligation paid out of the revenues of a designated project,
               facility or revenue source.

               PASSIVE FOREIGN INVESTMENT COMPANIES (PFICS) are any foreign
               corporations which generate certain amounts of passive income or
               hold certain amounts of assets for the production of passive
               income. Passive income includes dividends, interest, royalties,
               rents and annuities. To avoid taxes and interest that the Fund
               must pay if these investments are profitable, the Fund may make
               various elections permitted by the tax laws. These elections
               could require that the Fund recognize taxable income, which in
               turn must be distributed, before the securities are sold and
               before cash is received to pay the distributions.

               PREFERRED STOCKS are equity securities that generally pay
               dividends at a specified rate and have preference over common
               stock in the payment of dividends and liquidation. Preferred
               stock generally does not carry voting rights.

               PAY-IN-KIND BONDS are debt securities that normally give the
               issuer an option to pay cash at a coupon payment date or give the
               holder of the security a similar bond with the same coupon rate

 40 Janus High-Yield Fund prospectus
<PAGE>

               and a face value equal to the amount of the coupon payment that
               would have been made.

               REPURCHASE AGREEMENTS involve the purchase of a security by the
               Fund and a simultaneous agreement by the seller (generally a bank
               or dealer) to repurchase the security from the Fund at a
               specified date or upon demand. This technique offers a method of
               earning income on idle cash. These securities involve the risk
               that the seller will fail to repurchase the security, as agreed.
               In that case, the Fund will bear the risk of market value
               fluctuations until the security can be sold and may encounter
               delays and incur costs in liquidating the security.

               REVERSE REPURCHASE AGREEMENTS involve the sale of a security by
               the Fund to another party (generally a bank or dealer) in return
               for cash and an agreement by the Fund to buy the security back at
               a specified price and time. This technique will be used primarily
               to provide cash to satisfy unusually heavy redemption requests,
               or for other temporary or emergency purposes.

               RULE 144A SECURITIES are securities that are not registered for
               sale to the general public under the Securities Act of 1933, but
               that may be resold to certain institutional investors.

               STANDBY COMMITMENTS are obligations purchased by the Fund from a
               dealer that give the Fund the option to sell a security to the
               dealer at a specified price.

               STEP COUPON BONDS are debt securities that trade at a discount
               from their face value and pay coupon interest. The discount from
               the face value depends on the time remaining until cash payments
               begin, prevailing interest rates, liquidity of the security and
               the perceived credit quality of the issuer.

               STRIP BONDS are debt securities that are stripped of their
               interest (usually by a financial intermediary) after the
               securities are issued. The market value of these securities
               generally fluctuates more in response to changes in interest
               rates than interest-paying securities of comparable maturity.

                                            Janus High-Yield Fund prospectus  41
<PAGE>

               TENDER OPTION BONDS are generally long-term securities that are
               coupled with an option to tender the securities to a bank,
               broker-dealer or other financial institution at periodic
               intervals and receive the face value of the bond. This type of
               security is commonly used as a means of enhancing the security's
               liquidity.

               U.S. GOVERNMENT SECURITIES include direct obligations of the U.S.
               government that are supported by its full faith and credit.
               Treasury bills have initial maturities of less than one year,
               Treasury notes have initial maturities of one to ten years and
               Treasury bonds may be issued with any maturity but generally have
               maturities of at least ten years. U.S. government securities also
               include indirect obligations of the U.S. government that are
               issued by federal agencies and government sponsored entities.
               Unlike Treasury securities, agency securities generally are not
               backed by the full faith and credit of the U.S. government. Some
               agency securities are supported by the right of the issuer to
               borrow from the Treasury, others are supported by the
               discretionary authority of the U.S. government to purchase the
               agency's obligations and others are supported only by the credit
               of the sponsoring agency.

               VARIABLE AND FLOATING RATE SECURITIES have variable or floating
               rates of interest and, under certain limited circumstances, may
               have varying principal amounts. These securities pay interest at
               rates that are adjusted periodically according to a specified
               formula, usually with reference to some interest rate index or
               market interest rate. The floating rate tends to decrease the
               security's price sensitivity to changes in interest rates.

               WARRANTS are securities, typically issued with preferred stocks
               or bonds, that give the holder the right to buy a proportionate
               amount of common stock at a specified price, usually at a price
               that is higher than the market price at the time of issuance of
               the warrant. The right may last for a period of years or
               indefinitely.

               WHEN-ISSUED, DELAYED DELIVERY AND FORWARD TRANSACTIONS generally
               involve the purchase of a security with payment and delivery at
               some time in the future - i.e., beyond normal settlement. The
               Fund does not earn interest on such securities until settlement
               and bears the risk of market value fluctuations in between the

 42 Janus High-Yield Fund prospectus
<PAGE>

               purchase and settlement dates. New issues of stocks and bonds,
               private placements and U.S. government securities may be sold in
               this manner.

               ZERO COUPON BONDS are debt securities that do not pay regular
               interest at regular intervals, but are issued at a discount from
               face value. The discount approximates the total amount of
               interest the security will accrue from the date of issuance to
               maturity. The market value of these securities generally
               fluctuates more in response to changes in interest rates than
               interest-paying securities.

II. FUTURES, OPTIONS AND OTHER DERIVATIVES

               FORWARD CONTRACTS are contracts to purchase or sell a specified
               amount of a financial instrument for an agreed upon price at a
               specified time. Forward contracts are not currently exchange
               traded and are typically negotiated on an individual basis. The
               Fund may enter into forward currency contracts to hedge against
               declines in the value of securities denominated in, or whose
               value is tied to, a currency other than the U.S. dollar or to
               reduce the impact of currency appreciation on purchases of such
               securities. It may also enter into forward contracts to purchase
               or sell securities or other financial indices.

               FUTURES CONTRACTS are contracts that obligate the buyer to
               receive and the seller to deliver an instrument or money at a
               specified price on a specified date. The Fund may buy and sell
               futures contracts on foreign currencies, securities and financial
               indices including interest rates or an index of U.S. government,
               foreign government, equity or fixed-income securities. The Fund
               may also buy options on futures contracts. An option on a futures
               contract gives the buyer the right, but not the obligation, to
               buy or sell a futures contract at a specified price on or before
               a specified date. Futures contracts and options on futures are
               standardized and traded on designated exchanges.

               INDEXED/STRUCTURED SECURITIES are typically short- to
               intermediate-term debt securities whose value at maturity or
               interest rate is

                                            Janus High-Yield Fund prospectus  43
<PAGE>

               linked to currencies, interest rates, equity securities, indices,
               commodity prices or other financial indicators. Such securities
               may be positively or negatively indexed (i.e., their value may
               increase or decrease if the reference index or instrument
               appreciates). Indexed/structured securities may have return
               characteristics similar to direct investments in the underlying
               instrument and may be more volatile than the underlying
               instrument. The Fund bears the market risk of an investment in
               the underlying instrument, as well as the credit risk of the
               issuer.

               INTEREST RATE SWAPS involve the exchange by two parties of their
               respective commitments to pay or receive interest (e.g., an
               exchange of floating rate payments for fixed rate payments).

               INVERSE FLOATERS are debt instruments whose interest rate bears
               an inverse relationship to the interest rate on another
               instrument or index. For example, upon reset the interest rate
               payable on a security may go down when the underlying index has
               risen. Certain inverse floaters may have an interest rate reset
               mechanism that multiplies the effects of change in the underlying
               index. Such mechanism may increase the volatility of the
               security's market value.

               OPTIONS are the right, but not the obligation, to buy or sell a
               specified amount of securities or other assets on or before a
               fixed date at a predetermined price. The Fund may purchase and
               write put and call options on securities, securities indices and
               foreign currencies.

 44 Janus High-Yield Fund prospectus
<PAGE>

EXPLANATION OF RATING CATEGORIES
- --------------------------------------------------------------------------------

               The following is a description of credit ratings issued by two of
               the major credit ratings agencies. Credit ratings evaluate only
               the safety of principal and interest payments, not the market
               value risk of lower quality bonds. Credit rating agencies may
               fail to change credit ratings to reflect subsequent events on a
               timely basis. Although Janus Capital considers ratings when
               making investment decisions, it also performs its own investment
               analysis and does not rely solely on the ratings assigned by
               credit agencies.

                                            Janus High-Yield Fund prospectus  45
<PAGE>

STANDARD & POOR'S
RATINGS SERVICES

<TABLE>
                <S>                          <C>
                BOND RATING                  EXPLANATION
                ----------------------------------------------------------------
                Investment Grade
                AAA......................... Highest rating; extremely strong
                                             capacity to pay principal and
                                             interest.
                AA.......................... High quality; very strong capacity
                                             to pay principal and interest.
                A........................... Strong capacity to pay principal
                                             and interest; somewhat more
                                             susceptible to the adverse effects
                                             of changing circumstances and
                                             economic conditions.
                BBB......................... Adequate capacity to pay principal
                                             and interest; normally exhibit
                                             adequate protection parameters, but
                                             adverse economic conditions or
                                             changing circumstances more likely
                                             to lead to a weakened capacity to
                                             pay principal and interest than for
                                             higher rated bonds.
                Non-Investment Grade
                BB, B,                       Predominantly speculative with
                CCC, CC, C.................. respect to the issuer's capacity to
                                             meet required interest and
                                             principal payments. BB - lowest
                                             degree of speculation; C - the
                                             highest degree of speculation.
                                             Quality and protective
                                             characteristics outweighed by large
                                             uncertainties or major risk
                                             exposure to adverse conditions.
                D........................... In default.
</TABLE>

 46 Janus High-Yield Fund prospectus
<PAGE>

MOODY'S INVESTORS SERVICE, INC.

<TABLE>
                <S>                          <C>
                BOND RATING                  EXPLANATION
                ----------------------------------------------------------------
                Investment Grade
                Aaa......................... Highest quality, smallest degree of
                                             investment risk.
                Aa.......................... High quality; together with Aaa
                                             bonds, they compose the high-grade
                                             bond group.
                A........................... Upper-medium grade obligations;
                                             many favorable investment
                                             attributes.
                Baa......................... Medium-grade obligations; neither
                                             highly protected nor poorly
                                             secured. Interest and principal
                                             appear adequate for the present but
                                             certain protective elements may be
                                             lacking or may be unreliable over
                                             any great length of time.
                Non-Investment Grade
                Ba.......................... More uncertain, with speculative
                                             elements. Protection of interest
                                             and principal payments not well
                                             safeguarded during good and bad
                                             times.
                B........................... Lack characteristics of desirable
                                             investment; potentially low
                                             assurance of timely interest and
                                             principal payments or maintenance
                                             of other contract terms over time.
                Caa......................... Poor standing, may be in default;
                                             elements of danger with respect to
                                             principal or interest payments.
                Ca.......................... Speculative in a high degree; could
                                             be in default or have other marked
                                             shortcomings.
                C........................... Lowest-rated; extremely poor
                                             prospects of ever attaining
                                             investment standing.
</TABLE>

                                            Janus High-Yield Fund prospectus  47
<PAGE>

               Unrated securities will be treated as noninvestment grade
               securities unless a portfolio manager determines that such
               securities are the equivalent of investment grade securities.
               Securities that have received ratings from more than one agency
               are considered investment grade if at least one agency has rated
               the security investment grade.

SECURITIES HOLDINGS BY RATING CATEGORY

               During the fiscal period ended October 31, 1999, the percentage
               of securities holdings for the Fund by rating category based upon
               a weighted monthly average was:

<TABLE>
<CAPTION>
                JANUS HIGH-YIELD FUND
                ------------------------------------------------------------------
                <S>                                             <C>
                BONDS-S&P RATING:
                 AAA                                                          0%
                 AA                                                           0%
                 A                                                            0%
                 BBB                                                          0%
                 BB                                                           6%
                 B                                                           65%
                 CCC                                                          7%
                 CC                                                           0%
                 C                                                            0%
                 Not Rated                                                   11%
                 Preferred Stock                                              1%
                 Cash and Options                                            10%
                 TOTAL                                                      100%
                ------------------------------------------------------------------
</TABLE>

 48 Janus High-Yield Fund prospectus
<PAGE>

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<PAGE>

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 50
<PAGE>

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<PAGE>

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 52
<PAGE>

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<PAGE>

                                  [JANUS LOGO]

        You can request other information, including a Statement of
        Additional Information, Annual Report or Semiannual Report, free
        of charge, by contacting Janus at 1-800-525-3713 or visiting our
        Web site at janus.com. In the Fund's Annual Report, you will
        find a discussion of the market conditions and investment
        strategies that significantly affected the Fund's performance
        during its last fiscal year. Other information is also available
        from financial intermediaries that sell shares of the Fund.

        The Statement of Additional Information provides detailed
        information about the Fund and is incorporated into this
        Prospectus by reference. You may review the Fund's Statement of
        Additional Information at the Public Reference Room of the SEC
        or get text only copies for a fee, by writing to or calling the
        Public Reference Room, Washington, D.C. 20549-6009
        (1-800-SEC-0330). You may obtain the Statement of Additional
        Information for free from the SEC's Web site at
        http://www.sec.gov.

                    Investment Company Act File No. 811-1879

                                 1-800-525-3713
                     PO Box 173375  Denver, CO  80217-3375
                                   janus.com
4265


<PAGE>

                                  [JANUS LOGO]
                                JANUS  FLEXIBLE
                                  INCOME  FUND
                                   PROSPECTUS

                                                   JANUARY 31, 2000

             The Securities and Exchange Commission has not
             approved or disapproved of these securities or passed
             on the accuracy or adequacy of this Prospectus. Any
             representation to the contrary is a criminal offense.

<PAGE>

- --------------------------------------------------------------------------------
<PAGE>

TABLE OF CONTENTS
- --------------------------------------------------------------------------------

<TABLE>
                <S>                                               <C>
                RISK/RETURN SUMMARY
                   Janus Flexible Income Fund...................    2
                   Fees and expenses............................    5
                INVESTMENT OBJECTIVE, PRINCIPAL INVESTMENT
                STRATEGIES AND RISKS
                   Investment objective and principal investment
                   strategies...................................    6
                   General portfolio policies...................    8
                   Risks........................................   11
                SHAREHOLDER'S MANUAL
                   Minimum investments..........................   17
                   Types of account ownership...................   17
                   To purchase shares...........................   20
                   To exchange shares...........................   21
                   To redeem shares.............................   21
                   Shareholder services and account policies....   25
                MANAGEMENT OF THE FUND
                   Investment adviser...........................   29
                   Portfolio manager............................   30
                OTHER INFORMATION............... ...............   31
                DISTRIBUTIONS AND TAXES
                   Distributions................................   33
                   Taxes........................................   35
                FINANCIAL HIGHLIGHTS.............. .............   37
                GLOSSARY
                   Glossary of investment terms.................   38
                RATING CATEGORIES
                   Explanation of rating categories.............   45

</TABLE>

                                        Janus Flexible Income Fund prospectus  1
<PAGE>

RISK/RETURN SUMMARY
- --------------------------------------------------------------------------------

JANUS FLEXIBLE INCOME FUND

1. WHAT IS THE INVESTMENT OBJECTIVE OF JANUS FLEXIBLE INCOME FUND?

               The Fund seeks to obtain maximum total return, consistent with
               preservation of capital.

               The Fund's Trustees may change this objective without a
               shareholder vote and the Fund will notify you of any changes that
               are material. If there is a material change in the Fund's
               objective or policies, you should consider whether the Fund
               remains an appropriate investment for you. There is no guarantee
               that the Fund will meet its objective.

2. WHAT ARE THE MAIN INVESTMENT STRATEGIES OF JANUS FLEXIBLE INCOME FUND?

               The Fund invests primarily in a wide variety of income-producing
               securities such as corporate bonds and notes, government
               securities and preferred stock. As a fundamental policy, the Fund
               will invest at least 80% of its assets in income-producing
               securities. The Fund may own an unlimited amount of high-yield/
               high-risk bonds, and these securities may be a big part of the
               portfolio.

               The Fund may invest without limit in foreign equity and debt
               securities.

               In addition to considering economic factors such as the effect of
               interest rates on the Fund's investments, the portfolio manager
               applies a "bottom up" approach in choosing investments. In other
               words, he looks mostly for income-producing securities that meet
               his investment criteria one at a time. If the portfolio manager
               is unable to find such investments, the Fund's assets may be in
               cash or similar investments.

3. WHAT ARE THE MAIN RISKS OF INVESTING IN JANUS FLEXIBLE INCOME FUND?

               Although the Fund may be less volatile than funds that invest
               most of their assets in common stocks, the Fund's returns and
               yields will vary, and you could lose money.

 2 Janus Flexible Income Fund prospectus
<PAGE>

               The Fund invests in a variety of income-producing securities. A
               fundamental risk is that the value of these securities will fall
               if interest rates rise. Generally, the value of a fixed-income
               portfolio will decrease when interest rates rise, which means the
               Fund's net asset value (NAV) will likewise decrease. Another
               fundamental risk associated with fixed-income funds is credit
               risk, which is the risk that an issuer will be unable to make
               principal and interest payments when due.

               The Fund may invest an unlimited amount of its assets in high-
               yield/high-risk bonds, also known as "junk" bonds. Junk bonds may
               be sensitive to economic changes, political changes, or adverse
               developments specific to the company that issued the bond. These
               bonds generally have a greater credit risk than other types of
               fixed-income securities. Because of these factors, the
               performance and NAV of the Fund may vary significantly, depending
               upon its holdings in junk bonds.

               An investment in the Fund is not a bank deposit and is not
               insured or guaranteed by the Federal Deposit Insurance
               Corporation or any other government agency.

                                        Janus Flexible Income Fund prospectus  3
<PAGE>

               The following information illustrates how the Fund's performance
               has varied over time. The bar chart depicts the change in the
               Fund's performance from year-to-year during the periods
               indicated. The table compares the Fund's average annual returns
               for the periods indicated to a broad-based securities market
               index.

               JANUS FLEXIBLE INCOME FUND

               A BAR CHART showing Annual Total Returns for Janus Flexible
               Income Fund from 1990 through 1999:

                Annual returns for periods ended 12/31
<TABLE>
               <S>       <C>      <C>      <C>     <C>      <C>      <C>      <C>      <C>      <C>
               (4.62%)  25.96%   11.85%    15.70%  (2.92%)   21.15%   6.88%   11.43%   8.84%    0.46%
                1990     1991     1992      1993    1994      1995    1996     1997     1998     1999

                Each percentage is represented by a bar of proportionate size
                with the actual total return printed above the bar.

                Best Quarter:  1st-1991   8.17%   Worst Quarter:  1st-1990  (8.37%)
</TABLE>

                          Average annual total return for periods ended 12/31/99
                          ------------------------------------------------------

<TABLE>
<CAPTION>
                                                                                  Since Inception
                                                    1 year   5 years   10 years      (7/7/87)
                <S>                                 <C>      <C>       <C>        <C>
                Janus Flexible Income Fund           0.46%    9.53%      9.06%          8.65%
                Lehman Brothers Gov't/Corp
                  Bond Index*                       (2.15)%   7.61%      7.65%          8.08%
                                                     ---------------------------------------------
</TABLE>

                * Lehman Brothers Gov't/Corp Bond Index is composed of all bonds
                  that are of investment grade with at least one year until
                  maturity.

               The Fund's past performance does not necessarily indicate how it
               will perform in the future.

 4 Janus Flexible Income Fund prospectus
<PAGE>

FEES AND EXPENSES

               SHAREHOLDER FEES, such as sales loads, redemption fees or
               exchange fees, are charged directly to an investor's account. All
               Janus funds are no-load investments, so you will not pay any
               shareholder fees when you buy or sell shares of the Fund.

               ANNUAL FUND OPERATING EXPENSES are paid out of the Fund's assets
               and include fees for portfolio management, maintenance of
               shareholder accounts, shareholder servicing, accounting and other
               services. You do not pay these fees directly but, as the example
               below shows, these costs are borne indirectly by all
               shareholders.

               This table describes the fees and expenses that you may pay if
               you buy and hold shares of the Fund. It is based upon gross
               expenses (without the effect of expense offset arrangements) for
               the fiscal year ended October 31, 1999.

<TABLE>
<CAPTION>
                                                       Janus Flexible Income Fund
   <S>                                                           <C>
   Management Fee                                                 0.57%
   Other Expenses                                                 0.25%
   Total Annual Fund Operating Expenses                           0.82%
</TABLE>

- --------------------------------------------------------------------------------
  EXAMPLE:
  This example is intended to help you compare the cost of investing in the
  Fund with the cost of investing in other mutual funds. The example
  assumes that you invest $10,000 in the Fund for the time periods
  indicated then redeem all of your shares at the end of those periods. The
  example also assumes that your investment has a 5% return each year, and
  that the Fund's operating expenses remain the same. Although your actual
  costs may be higher or lower, based on these assumptions your costs would
  be:

<TABLE>
<CAPTION>
                                             1 Year    3 Years    5 Years    10 Years
                                             ----------------------------------------
   <S>                                       <C>       <C>        <C>        <C>
   Janus Flexible Income Fund                 $84       $262       $455       $1,014
</TABLE>

                                        Janus Flexible Income Fund prospectus  5
<PAGE>

INVESTMENT OBJECTIVE, PRINCIPAL INVESTMENT
STRATEGIES AND RISKS
- --------------------------------------------------------------------------------

               This section takes a closer look at the investment objective of
               the Fund, its principal investment strategies and certain risks
               of investing in the Fund. Strategies and policies that are noted
               as "fundamental" cannot be changed without a shareholder vote.

               Please carefully review the "Risks" section of this Prospectus on
               pages 11-13 for a discussion of risks associated with certain
               investment techniques. We've also included a Glossary with
               descriptions of investment terms used throughout this Prospectus.

INVESTMENT OBJECTIVE AND PRINCIPAL INVESTMENT STRATEGIES

               Janus Flexible Income Fund seeks to obtain maximum total return,
               consistent with preservation of capital. It pursues its objective
               by primarily investing in a wide variety of income-producing
               securities such as corporate bonds and notes, government
               securities and preferred stock. As a fundamental policy, the Fund
               will invest at least 80% of its assets in income-producing
               securities. The Fund may own an unlimited amount of high-yield/
               high-risk bonds, and these may be a big part of the portfolio.
               This Fund generates total return from a combination of current
               income and capital appreciation, but income is usually the
               dominant portion.

               In addition to considering economic factors such as the effect of
               interest rates on the Fund's investments, the portfolio manager
               applies a "bottom up" approach in choosing investments. In other
               words, he looks mostly for income-producing securities that meet
               his investment criteria one at a time. If the portfolio manager
               is unable to find such investments, much of the Fund's assets may
               be in cash or similar investments.

The following questions and answers are designed to help you better understand
the Fund's principal investment strategies.

1. HOW DO INTEREST RATES AFFECT THE VALUE OF MY INVESTMENT?

               Generally, a fixed-income security will increase in value when
               interest rates fall and decrease in value when interest rates
               rise. Longer-term securities are generally more sensitive to
               interest rate

 6 Janus Flexible Income Fund prospectus
<PAGE>

               changes than shorter-term securities, but they generally offer
               higher yields to compensate investors for the associated risks.
               High-yield bond prices are generally less directly responsive to
               interest rate changes than investment grade issues and may not
               always follow this pattern. A bond fund's average-weighted
               effective maturity and its duration are measures of how the fund
               may react to interest rate changes.

2. HOW DOES THE FUND MANAGE INTEREST RATE RISK?

               The Fund may vary the average-weighted effective maturity of its
               portfolio to reflect its portfolio manager's analysis of interest
               rate trends and other factors. The Fund's average-weighted
               effective maturity will tend to be shorter when the portfolio
               manager expects interest rates to rise and longer when its
               portfolio manager expects interest rates to fall. The Fund may
               also use futures, options and other derivatives to manage
               interest rate risks.

3. WHAT IS MEANT BY THE FUND'S "AVERAGE-WEIGHTED EFFECTIVE MATURITY"?

               The stated maturity of a bond is the date when the issuer must
               repay the bond's entire principal value to an investor. Some
               types of bonds may also have an "effective maturity" that is
               shorter than the stated date due to prepayment or call
               provisions. Securities without prepayment or call provisions
               generally have an effective maturity equal to their stated
               maturity. Dollar-weighted effective maturity is calculated by
               averaging the effective maturity of bonds held by the Fund with
               each effective maturity "weighted" according to the percentage of
               net assets that it represents.

4. WHAT IS MEANT BY THE FUND'S "DURATION"?

               A bond's duration indicates the time it will take an investor to
               recoup his investment. Unlike average maturity, duration reflects
               both principal and interest payments. Generally, the higher the
               coupon rate on a bond, the lower its duration will be. The
               duration of a bond fund is calculated by averaging the duration
               of bonds held by a fund with each duration "weighted" according
               to the percentage of net assets that it represents. Because
               duration

                                        Janus Flexible Income Fund prospectus  7
<PAGE>

               accounts for interest payments, the Fund's duration is usually
               shorter than its average maturity.

5. WHAT IS A HIGH-YIELD/HIGH-RISK BOND?

               A high-yield/high-risk bond (also called a "junk" bond) is a bond
               rated below investment grade by major rating agencies (i.e., BB
               or lower by Standard & Poor's or Ba or lower by Moody's) or an
               unrated bond of similar quality. It presents greater risk of
               default (the failure to make timely interest and principal
               payments) than higher quality bonds.

GENERAL PORTFOLIO POLICIES

               In investing its portfolio assets, the Fund will follow the
               general policies listed below. The percentage limitations
               included in these policies and elsewhere in this Prospectus apply
               only at the time of purchase of the security. So, for example, if
               the Fund exceeds a limit as a result of market fluctuations or
               the sale of securities, it will not be required to dispose of any
               securities.

               CASH POSITION
               When the Fund's portfolio manager believes that market conditions
               are unfavorable for profitable investing, or when he is otherwise
               unable to locate attractive investment opportunities, the Fund's
               cash or similar investments may increase. In other words, the
               Fund does not always stay fully invested in bonds. Cash or
               similar investments generally are a residual - they represent the
               assets that remain after the portfolio manager has committed
               available assets to desirable investment opportunities. However,
               the portfolio manager may also temporarily increase the Fund's
               cash position to protect its assets or maintain liquidity. When
               the Fund's investments in cash or similar investments increase,
               it may not participate in market advances or declines to the same
               extent that it would if the Fund remained more fully invested in
               bonds.

               OTHER TYPES OF INVESTMENTS
               The Fund invests primarily in fixed-income securities, which may
               include corporate bonds and notes, government securities, pre-

 8 Janus Flexible Income Fund prospectus
<PAGE>

               ferred stock, high-yield/high-risk bonds and municipal
               obligations. The Fund may also invest to a lesser degree in other
               types of securities. These securities (which are described in the
               Glossary) may include:

               - common stocks

               - mortgage- and asset-backed securities

               - zero coupon, pay-in-kind and step coupon securities

               - options, futures, forwards, swaps and other types of
                 derivatives for hedging purposes or for non-hedging purposes
                 such as seeking to enhance return

               - securities purchased on a when-issued, delayed delivery or
                 forward commitment basis

               ILLIQUID INVESTMENTS
               The Fund may invest up to 15% of its net assets in illiquid
               investments. An illiquid investment is a security or other
               position that cannot be disposed of quickly in the normal course
               of business. For example, some securities are not registered
               under the U.S. securities laws and cannot be sold to the U.S.
               public because of SEC regulations (these are known as "restricted
               securities"). Under procedures adopted by the Fund's Trustees,
               certain restricted securities may be deemed liquid, and will not
               be counted toward this 15% limit.

               FOREIGN SECURITIES
               The Fund may invest without limit in foreign equity and debt
               securities. The Fund may invest directly in foreign securities
               denominated in a foreign currency and not publicly traded in the
               United States. Other ways of investing in foreign securities
               include depositary receipts or shares, and passive foreign
               investment companies.

                                        Janus Flexible Income Fund prospectus  9
<PAGE>

               SPECIAL SITUATIONS
               The Fund may invest in special situations. A special situation
               arises when, in the opinion of the Fund's portfolio manager, the
               securities of a particular issuer will be recognized and
               appreciate in value due to a specific development with respect to
               that issuer. Developments creating a special situation might
               include, among others, a new product or process, a technological
               breakthrough, a management change or other extraordinary
               corporate event, or differences in market supply of and demand
               for the security. The Fund's performance could suffer if the
               anticipated development in a "special situation" investment does
               not occur or does not attract the expected attention.

               PORTFOLIO TURNOVER
               The Fund generally intends to purchase securities for long-term
               investment although, to a limited extent, the Fund may purchase
               securities in anticipation of relatively short-term price gains.
               Short-term transactions may also result from liquidity needs,
               securities having reached a price or yield objective, changes in
               interest rates or the credit standing of an issuer, or by reason
               of economic or other developments not foreseen at the time of the
               investment decision. The Fund may also sell one security and
               simultaneously purchase the same or a comparable security to take
               advantage of short-term differentials in bond yields or
               securities prices. Changes are made in the Fund's portfolio
               whenever its portfolio manager believes such changes are
               desirable. Portfolio turnover rates are generally not a factor in
               making buy and sell decisions.

               Increased portfolio turnover may result in higher costs for
               brokerage commissions, dealer mark-ups and other transaction
               costs and may also result in taxable capital gains. Higher costs
               associated with increased portfolio turnover may offset gains in
               the Fund's performance.

 10 Janus Flexible Income Fund prospectus
<PAGE>

RISKS

               Because the Fund invests substantially all of its assets in
               fixed-income securities, it is subject to risks such as credit or
               default risks, and decreased value due to interest rate
               increases. The Fund's performance may also be affected by risks
               to certain types of investments, such as foreign securities and
               derivative instruments.

The following questions and answers are designed to help you better understand
some of the risks of investing in the Fund.

1. WHAT IS MEANT BY "CREDIT QUALITY" AND WHAT ARE THE RISKS ASSOCIATED WITH IT?

               Credit quality measures the likelihood that the issuer will meet
               its obligations on a bond. One of the fundamental risks
               associated with all fixed-income funds is credit risk, which is
               the risk that an issuer will be unable to make principal and
               interest payments when due. U.S. government securities are
               generally considered to be the safest type of investment in terms
               of credit risk. Municipal obligations generally rank between U.S.
               government securities and corporate debt securities in terms of
               credit safety. Corporate debt securities, particularly those
               rated below investment grade, present the highest credit risk.

2. HOW IS CREDIT QUALITY MEASURED?

               Ratings published by nationally recognized statistical rating
               agencies such as Standard & Poor's and Moody's are widely
               accepted measures of credit risk. The lower a bond issue is rated
               by an agency, the more credit risk it is considered to represent.
               Lower rated bonds generally pay higher yields to compensate
               investors for the associated risk. Please refer to "Explanation
               of Rating Categories" on page 45 for description of rating
               categories.

3. ARE THERE SPECIAL RISKS ASSOCIATED WITH INVESTMENTS IN HIGH-YIELD/HIGH-RISK
   BONDS?

               High-yield/high-risk bonds (or "junk" bonds) are bonds rated
               below investment grade by the primary rating agencies such as
               Standard & Poor's and Moody's. The value of lower quality

                                       Janus Flexible Income Fund prospectus  11
<PAGE>

               bonds generally is more dependent on credit risk, or the ability
               of the issuer to meet interest and principal payments, than
               investment grade bonds. Issuers of high-yield/high-risk bonds may
               not be as strong financially as those issuing bonds with higher
               credit ratings and are more vulnerable to real or perceived
               economic changes, political changes or adverse developments
               specific to the issuer.

               The junk bond market can experience sudden and sharp price
               swings. Because the Fund may invest a significant portion of its
               portfolio in high-yield/high-risk bonds, investors should be
               willing to tolerate a corresponding increase in the risk of
               significant and sudden changes in NAV. Please refer to
               "Explanation of Rating Categories" on page 45 for a description
               of rating categories.

4. HOW DOES THE FUND TRY TO REDUCE RISK?

               The Fund may use futures, options, swaps and other derivative
               instruments to "hedge" or protect its portfolio from adverse
               movements in securities prices and interest rates. The Fund may
               also use a variety of currency hedging techniques, including
               forward currency contracts, to manage exchange rate risk. The
               portfolio manager believes the use of these instruments will
               benefit the Fund. However, the Fund's performance could be worse
               than if the Fund had not used such instruments if the portfolio
               manager's judgement proves incorrect. Risks associated with the
               use of derivative instruments are described in the SAI.

5. I'VE HEARD A LOT ABOUT HOW THE CHANGE TO THE YEAR 2000 COULD AFFECT COMPUTER
   SYSTEMS. DOES THIS CREATE ANY SPECIAL RISKS?

               The portfolio manager carefully researches each potential
               investment before making an investment decision and, among other
               things considers what impact, if any, the Year 2000 transition
               has had on the company's operations when selecting portfolio
               holdings. However, there is no guarantee that the information the
               portfolio manager receives regarding a company's Year 2000
               transition status is completely accurate. If a company has not

 12 Janus Flexible Income Fund prospectus
<PAGE>

               satisfactorily addressed Year 2000 issues, the Fund's performance
               could suffer.

6. HOW COULD THE FUND'S INVESTMENTS IN FOREIGN SECURITIES AFFECT ITS
   PERFORMANCE?

               The Fund may invest without limit in foreign securities either
               indirectly (e.g., depositary receipts) or directly in foreign
               markets. Investments in foreign securities, including those of
               foreign governments, may involve greater risks than investing in
               domestic securities because the Fund's performance may depend on
               issues other than the performance of a particular company. These
               issues include:

               - currency risk

               - political and economic risk

               - regulatory risk

               - market risk

               - transaction costs

               These risks are described in the SAI.

                                       Janus Flexible Income Fund prospectus  13
<PAGE>

- --------------------------------------------------------------------------------
<PAGE>

                                  [JANUS LOGO]
                                JANUS  FLEXIBLE
                                  INCOME  FUND
                              SHAREHOLDER'S MANUAL

                                           This section will help you
                                           become familiar with the
                                           different types of accounts
                                           you can establish with Janus.
                                           It also explains in detail the
                                           wide array of services and
                                           features you can establish on
                                           your account, as well as
                                           account policies and fees that
                                           may apply to your account.
                                           Account policies (including
                                           fees), services and features
                                           may be modified or
                                           discontinued without
                                           shareholder approval or prior
                                           notice.

                                           [JANUS LOGO]

<PAGE>

HOW TO GET IN TOUCH WITH JANUS

INVESTOR SERVICE CENTERS
100 Fillmore Street, Suite 100
Denver, CO 80206

3773 Cherry Creek North Drive, Suite 101
Denver, CO 80209

(Hours: Monday-Friday 7:00 a.m.-6:00 p.m., and Saturday 9:00 a.m.-1:00 p.m.,
Mountain time.)

MAILING ADDRESS
Janus
P.O. Box 173375
Denver, CO 80217-3375

FOR OVERNIGHT CARRIER
Janus
Suite 101
3773 Cherry Creek Drive North
Denver, CO 80209-3821

INVESTOR SERVICE REPRESENTATIVES
If you have any questions while reading this Prospectus, please call one of our
Investor Service Representatives at 1-800-525-3713 Monday-Friday: 8:00 a.m.-8:00
p.m., and Saturday: 10:00 a.m.-4:00 p.m., New York time.

JANUS XPRESSLINE(TM)
1-888-979-7737

JANUS INTERNET ADDRESS
JANUS.COM

For 24-hour access to account and fund information, exchanges, purchases and
redemptions, automated daily quotes on fund share prices, yields and total
returns.

JANUS.COM SPECIALISTS
1-800-975-9932

TDD
1-800-525-0056
A telecommunications device for our hearing- and speech-impaired shareholders.

JANUS LITERATURE LINE
1-800-525-8983
To request a prospectus, shareholder reports or marketing materials 24 hours a
day.

 16 Shareholder's manual
<PAGE>

MINIMUM INVESTMENTS*

<TABLE>
<S>                      <C>
To open a new regular
account                  $2,500
To open a new
retirement account,
education account or
UGMA/UTMA                $  500
To open a new regular
account with an
Automatic Investment
Program                  $  500**
To add to any type of
an account               $  100+
</TABLE>

 * The Fund reserves the right to change the amount of these minimums from time
   to time or to waive them in whole or in part for certain types of accounts.

** An Automatic Investment Program requires a $100 minimum automatic investment
   per month until the account balance reaches $2,500.

 + The minimum subsequent investment for a retirement account or UGMA/UTMA is
   $50.

TYPES OF ACCOUNT OWNERSHIP

               If you are investing in the Fund for the first time, you will
               need to establish an account. You can establish the following
               types of accounts by completing a New Account Application.

               INDIVIDUAL OR JOINT OWNERSHIP
               Individual accounts are owned by one person. Joint accounts have
               two or more owners.

               A GIFT OR TRANSFER TO MINOR (UGMA OR UTMA)
               An UGMA/UTMA is a custodial account managed for the benefit of a
               minor. To open an UGMA or UTMA, you must include the minor's
               Social Security number on the application.

               TRUST
               An established trust can open an account. The names of each
               trustee, the name of the trust and the date of the trust
               agreement must be included on the application.

                                                        Shareholder's manual  17
<PAGE>

               BUSINESS ACCOUNTS
               Corporations and partnerships may also open an account. The
               application must be signed by an authorized officer of the
               corporation or a general partner of the partnership.

TAX-DEFERRED ACCOUNTS

               If you are eligible, you may set up one or more tax-deferred
               accounts. A tax-deferred account allows you to shelter your
               investment income and capital gains from current income taxes. A
               contribution to certain of these plans may also be tax
               deductible. Tax-deferred accounts include retirement plans
               described below and the Education IRA. Please refer to the Janus
               retirement guide for more complete information regarding the
               different types of IRAs, including the Education IRA.
               Distributions from these plans are generally subject to income
               tax and may be subject to an additional tax if withdrawn prior to
               age 59 1/2 or used for a nonqualifying purpose. Investors should
               consult their tax adviser or legal counsel before selecting a
               tax-deferred account.

               Investors Fiduciary Trust Company serves as custodian for the
               tax-deferred accounts offered by the Fund. You will be charged an
               annual account maintenance fee of $12 for each taxpayer
               identification number no matter how many tax-deferred accounts
               you have with Janus. You may pay the fee by check or have it
               automatically deducted from your account (usually in December).
               The custodian reserves the right to change the amount of this fee
               or to waive it in whole or in part for certain types of accounts.

               TRADITIONAL AND ROTH INDIVIDUAL RETIREMENT ACCOUNTS
               Both types of IRAs allow most individuals with earned income to
               contribute up to the lesser of $2,000 ($4,000 for most married
               couples) or 100% of compensation annually.

               EDUCATION IRA
               This plan allows individuals, subject to certain income
               limitations, to contribute up to $500 annually on behalf of any
               child under the age of 18.

 18 Shareholder's manual
<PAGE>

               SIMPLIFIED EMPLOYEE PENSION PLAN
               This plan allows small business owners (including sole
               proprietors) to make tax-deductible contributions for themselves
               and any eligible employee(s). A SEP requires an IRA (a SEP-IRA)
               to be set up for each SEP participant.

               PROFIT SHARING OR MONEY PURCHASE PENSION PLAN
               These plans are open to corporations, partnerships and sole
               proprietors to benefit their employees and themselves.

               SECTION 403(B)(7) PLAN
               Employees of educational organizations or other qualifying, tax-
               exempt organizations may be eligible to participate in a Section
               403(b)(7) Plan.

               PLEASE REFER TO THE CHART ON THE FOLLOWING PAGES FOR INFORMATION
               ON OPENING AN ACCOUNT AND CONDUCTING BUSINESS WITH JANUS. WITH
               CERTAIN LIMITED EXCEPTIONS, THE FUND IS AVAILABLE ONLY TO U.S.
               CITIZENS OR RESIDENTS. WHEN YOU PURCHASE, EXCHANGE, OR REDEEM
               SHARES, YOUR REQUEST WILL BE PROCESSED AT THE NEXT NAV CALCULATED
               AFTER YOUR ORDER IS RECEIVED AND ACCEPTED.

                                                        Shareholder's manual  19
<PAGE>

 TO PURCHASE SHARES

 BY MAIL/IN WRITING
 ------------------------------------------------------------------------------

 - To open your account, complete and sign the appropriate application and make
   your check payable to Janus.

 - To purchase additional shares, complete the remittance slip attached at the
   bottom of your confirmation statement. If you are making a purchase into a
   retirement account, please indicate whether the purchase is a rollover or a
   current or prior year contribution. Send your check and remittance slip or
   written instructions to the address listed on the slip.

 BY TELEPHONE
 ------------------------------------------------------------------------------

 - The "Telephone Purchase of Shares Option" allows you to purchase additional
   shares quickly and conveniently through an electronic transfer of money.
   After establishing this option on your account, call an Investor Service
   Representative during normal business hours or the Janus XpressLine for
   access to this option 24 hours a day. Janus will automatically debit your
   predesignated bank account.

 - Purchases may also be made by wiring money from your bank account to your
   Janus account. Call an Investor Service Representative for wiring
   instructions.

 BY INTERNET
 ------------------------------------------------------------------------------

 - The "Telephone Purchase of Shares Option" allows you to make a purchase into
   an existing account on our Web site at janus.com.

 BY AUTOMATIC INVESTMENT
 ------------------------------------------------------------------------------

 - Automatic Monthly Investment Program - You select the day each month that
   your money ($100 minimum) will be electronically transferred from your bank
   account to your Fund account.

 - Payroll Deduction - If your employer can initiate an automatic payroll
   deduction, you may have all or a portion of your paycheck ($100 minimum)
   invested directly into your Fund account.

 20 Shareholder's manual
<PAGE>

<TABLE>
<S>                                            <C>

    TO EXCHANGE SHARES                           TO REDEEM SHARES
- ---------------------------------------        ---------------------------------------
    - To request an exchange in writing,         - To request a redemption in writ-
      please follow the instructions for           ing, please follow the instructions
      written requests on page 24. Also            for written requests on page 24.
      refer to the exchange policies             - Please see page 23 for information
      listed on page 22 for more infor-            about payment of redemption
      mation.                                      proceeds.

- ---------------------------------------        ---------------------------------------
    - All accounts are automatically eli-        - The telephone redemption option
      gible to exchange shares by tele-            enables you to request redemp-
      phone. To exchange all or a portion          tions daily from your account by
      of your shares into any other                calling an Investor Service Repre-
      available Janus fund, call an                sentative by the close of the
      Investor Service Representative or           regular trading session of the
      the Janus XpressLine.                        NYSE, normally 4:00 p.m. New York
                                                   time. You may also use Janus
                                                   XpressLine for access to this
                                                   option 24 hours a day.

- ---------------------------------------        ---------------------------------------
    - Exchanges may be made on our Web           - Redemptions may be made on our Web
      site at janus.com.                           site at janus.com.
- ---------------------------------------        ---------------------------------------
    - Systematic Exchange - You deter-           - Systematic Redemption - This option
      mine the amount of money you would           allows you to redeem a specific
      like automatically exchanged from            dollar amount from your account on
      one Janus account to another on any          a regular basis.
      day of the month. You may establish
      this program for as little as $100
      per month on existing accounts. You
      may establish a new account with a
      $500 initial purchase and subse-
      quent $100 systematic exchanges.
</TABLE>

                                                        Shareholder's manual  21
<PAGE>

PAYING FOR SHARES

Please note the following when purchasing shares:

- - Cash, credit cards, third party checks, travelers cheques, credit card checks
  or money orders will not be accepted.

- - All purchases must be made in U.S. dollars and checks must be drawn on U.S.
  banks.

- - We may make additional attempts to debit the bank account for ACH purchases.

- - The Fund reserves the right to reject any specific purchase request.

- - If all or a portion of a check is received for investment without a specific
  fund designation, the undesignated amount will be invested in the Janus Money
  Market Fund -- Investor Shares. Shares that are subsequently exchanged from
  Janus Money Market Fund -- Investor Shares into the selected Fund will receive
  the NAV next calculated after your order is received and accepted by the Fund.

- - If your purchase is cancelled, you will be responsible for any losses or fees
  imposed by your bank and losses that may be incurred as a result of any
  decline in the value of the cancelled purchase.

EXCHANGE POLICIES

The exchange privilege is not intended as a vehicle for short-term or excessive
trading. The Fund does not permit excessive trading or market timing. Excessive
purchases, redemptions, or exchanges of Fund shares disrupt portfolio management
and drive Fund expenses higher.

Please note the following when exchanging shares:

- - Except for Systematic Exchanges, new accounts established by exchange must be
  opened with $2,500 or the total account value if the value of the account you
  are exchanging from is less than $2,500.

- - Exchanges between existing accounts must meet the $100 subsequent investment
  requirement.

- - You may make four exchanges out of the Fund during a calendar year (exclusive
  of Systematic Exchange). Exchanges in excess of this limit are considered
  excessive trading and may be subject to an exchange fee or may result in
  termination of the exchange privilege or the right to make future purchases of
  Fund shares.

 22 Shareholder's manual
<PAGE>

- - The Fund reserves the right to reject any purchase order or exchange request
  and to modify or terminate the exchange privilege at any time. For example,
  the Fund may reject exchanges from accounts engaged in or known to engage in
  trading in excess of the limit above (including market timing transactions) or
  whose trading has been or may be disruptive to the Fund.

- - Exchanges between accounts will be accepted only if the registrations are
  identical.

- - If the shares you are exchanging are held in certificate form, you must return
  the certificate to Janus prior to making any exchanges. Effective June 4,
  1999, shares are no longer available in certificate form.

- - An exchange represents the sale of shares from one fund and the purchase of
  shares of another fund, which may produce a taxable gain or loss in a
  non-retirement account.

- - If the balance in the account you are exchanging from falls below the
  systematic exchange amount, all remaining shares will be exchanged
  and the program will be discontinued.

PAYMENT OF REDEMPTION PROCEEDS

- - BY CHECK - Redemption proceeds will be sent to the shareholder(s) of record at
  the address of record within seven days after receipt of a valid redemption
  request. During the 10 days following an address change, checks sent to a new
  address require a signature guarantee.

- - BY ELECTRONIC TRANSFER - If you have established the electronic redemption
  option, your redemption proceeds can be electronically transferred to your
  predesignated bank account on the next bank business day after receipt of your
  redemption request (wire transfer) or the second bank business day after
  receipt of your redemption request (ACH transfer).

Wire transfers will be charged an $8 fee per wire and your bank may charge an
additional fee to receive the wire. Wire redemptions are not available for
retirement accounts.

IF THE SHARES BEING REDEEMED WERE PURCHASED BY CHECK, TELEPHONE, ON OUR WEB
SITE, OR THROUGH THE AUTOMATIC MONTHLY INVESTMENT PROGRAM, THE FUND MAY DELAY
THE PAYMENT OF YOUR REDEMPTION PROCEEDS FOR UP TO 15 DAYS FROM THE DAY OF
PURCHASE TO ALLOW THE PURCHASE TO CLEAR. Unless you provide alternate
instructions, your proceeds will be invested in Janus Money Market
Fund - Investor Shares during the 15 day hold period.

                                                        Shareholder's manual  23
<PAGE>

WRITTEN INSTRUCTIONS

               To redeem or exchange all or part of your shares in writing, your
               request should be sent to one of the addresses listed on page 16
               and must include the following information:

               - the name of the Fund(s)

               - the account number(s)

               - the amount of money or number of shares being redeemed or
                 exchanged

               - the name(s) on the account

               - the signature(s) of all registered account owners (see account
                 application for signature requirements)

               - your daytime telephone number

SIGNATURE GUARANTEE

               A SIGNATURE GUARANTEE IS REQUIRED if any of the following is
               applicable:

               - You request a redemption by check that exceeds $100,000.

               - You would like a check made payable to anyone other than the
                 shareholder(s) of record.

               - You would like a check mailed to an address which has been
                 changed within 10 days of the redemption request.

               - You would like a check mailed to an address other than the
                 address of record.

               THE FUND RESERVES THE RIGHT TO REQUIRE A SIGNATURE GUARANTEE
               UNDER OTHER CIRCUMSTANCES OR TO REJECT OR DELAY A REDEMPTION ON
               CERTAIN LEGAL GROUNDS.

               HOW TO OBTAIN A SIGNATURE GUARANTEE

               A signature guarantee assures that a signature is genuine. The
               signature guarantee protects shareholders from unauthorized
               account transfers. The following financial institutions may
               guaran-

 24 Shareholder's manual
<PAGE>

               tee signatures: banks, savings and loan associations, trust
               companies, credit unions, broker-dealers, and member firms of a
               national securities exchange. Call your financial institution to
               see if they have the ability to guarantee a signature. A
               signature guarantee cannot be provided by a notary public.

               If you live outside the United States, a foreign bank properly
               authorized to do business in your country of residence or a U.S.
               consulate may be able to authenticate your signature.

PRICING OF FUND SHARES

               All purchases, redemptions and exchanges will be processed at the
               NAV next calculated after your request is received and accepted
               by the Fund (or the Fund's agent or authorized designee). The
               Fund's NAV is calculated at the close of the regular trading
               session of the NYSE (normally 4:00 p.m. New York time) each day
               that the NYSE is open. The NAV of Fund shares is not determined
               on days the NYSE is closed (generally New Year's Day, Martin
               Luther King Day, Presidents' Day, Good Friday, Memorial Day,
               Independence Day, Labor Day, Thanksgiving and Christmas). In
               order to receive a day's price, your order must be received by
               the close of the regular trading session of the NYSE. Securities
               are valued at market value or, if a market quotation is not
               readily available, at their fair value determined in good faith
               under procedures established by and under the supervision of the
               Trustees. Short-term instruments maturing within 60 days are
               valued at amortized cost, which approximates market value. See
               the SAI for more detailed information.

SHAREHOLDER SERVICES AND ACCOUNT POLICIES

               ACCOUNT MINIMUMS

               Due to the proportionately higher costs of maintaining small
               accounts, Janus reserves the right to deduct a $10 minimum
               balance fee (or the value of the account if less than $10) from
               accounts with values below the minimums described on page 17 or
               to close such accounts. This policy will apply to accounts

                                                        Shareholder's manual  25
<PAGE>

               participating in the Automatic Monthly Investment Program only if
               your account balance does not reach the required minimum initial
               investment or falls below such minimum and you have discontinued
               monthly investments. This policy does not apply to accounts that
               fall below the minimums solely as a result of market value
               fluctuations. It is expected that, for purposes of this policy,
               accounts will be valued in September, and the $10 fee will be
               assessed on the second Friday of September of each year. You will
               receive notice before we charge the $10 fee or close your account
               so that you may increase your account balance to the required
               minimum.

               TRANSACTIONS THROUGH PROCESSING ORGANIZATIONS

               You may purchase or sell Fund shares through a broker-dealer,
               bank or other financial institution, or an organization that
               provides recordkeeping and consulting services to 401(k) plans or
               other employee benefit plans (a "Processing Organization").
               Processing Organizations may charge you a fee for this service
               and may require different minimum initial and subsequent
               investments than the Fund. Processing Organizations may also
               impose other charges or restrictions different from those
               applicable to shareholders who invest in the Fund directly. A
               Processing Organization, rather than its customers, may be the
               shareholder of record of your shares. The Fund is not responsible
               for the failure of any Processing Organization to carry out its
               obligations to its customers. Certain Processing Organizations
               may receive compensation from Janus Capital or its affiliates and
               certain Processing Organizations may receive compensation from
               the Fund for shareholder recordkeeping and similar services.

               TAXPAYER IDENTIFICATION NUMBER

               On the application or other appropriate form, you will be asked
               to certify that your Social Security or taxpayer identification
               number is correct and that you are not subject to backup
               withholding for failing to report income to the IRS. If you are
               subject to the 31% backup withholding or you did not certify

 26 Shareholder's manual
<PAGE>

               your taxpayer identification number, the IRS requires the Fund to
               withhold 31% of any dividends paid and redemption or exchange
               proceeds. In addition to the 31% backup withholding, you may be
               subject to a $50 fee to reimburse the Fund for any penalty that
               the IRS may impose.

               INVOLUNTARY REDEMPTIONS

               The Fund reserves the right to close an account if the
               shareholder is deemed to engage in activities which are illegal
               or otherwise believed to be detrimental to the Fund.

               TELEPHONE TRANSACTIONS

               You may initiate many transactions by telephone. The Fund and its
               agents will not be responsible for any losses resulting from
               unauthorized transactions when procedures designed to verify the
               identity of the caller are followed.

               It may be difficult to reach an Investor Service Representative
               by telephone during periods of unusual market activity. If you
               are unable to reach a representative by telephone, please
               consider sending written instructions, stopping by a Service
               Center, calling the Janus XpressLine or visiting our Web site.

               TEMPORARY SUSPENSION OF SERVICES

               The Fund or its agents may, in case of emergency, temporarily
               suspend telephone transactions and other shareholder services.

               ADDRESS CHANGES

               To change the address on your account, call 1-800-525-3713 or
               send a written request signed by the shareholder(s) of record.
               Include the name of your Fund, the account number(s), the name(s)
               on the account and both the old and new addresses. Certain
               options may be suspended for 10 days following an address change
               unless a signature guarantee is provided.

                                                        Shareholder's manual  27
<PAGE>

               REGISTRATION CHANGES

               To change the name on an account, the shares are generally
               transferred to a new account. In some cases, legal documentation
               may be required. For further instructions, please call an
               Investor Service Representative.

               STATEMENTS AND REPORTS

               Investors will receive quarterly confirmations of all
               transactions. Quarterly statements for all investors are
               available on our Web site. You may make an election on our Web
               site to discontinue delivery of your paper statements. Dividend
               information will be confirmed quarterly. In addition, the Fund
               will send you an immediate transaction confirmation statement
               after every non-systematic transaction.

               The Fund produces financial reports, which include a list of the
               Fund's portfolio holdings, semiannually and updates its
               prospectus annually. To reduce expenses, the Fund may choose to
               mail only one report or prospectus to your household, even if
               more than one person in the household has a Fund account. Please
               call 1-800-525-3713 if you would like to receive additional
               reports or prospectuses. The Fund reserves the right to charge a
               fee for additional statement requests.

 28 Shareholder's manual
<PAGE>

MANAGEMENT OF THE FUND
- --------------------------------------------------------------------------------

INVESTMENT ADVISER

               Janus Capital Corporation, 100 Fillmore Street, Denver, Colorado
               80206-4928, is the investment adviser to the Fund and is
               responsible for the day-to-day management of its investment
               portfolio and other business affairs.

               Janus Capital began serving as investment adviser to Janus Fund
               in 1970 and currently serves as investment adviser to all of the
               Janus funds, acts as sub-adviser for a number of private-label
               mutual funds and provides separate account advisory services for
               institutional accounts.

               Janus Capital furnishes continuous advice and recommendations
               concerning the Fund's investments. Janus Capital also furnishes
               certain administrative, compliance and accounting services for
               the Fund, and may be reimbursed by the Fund for its costs in
               providing those services. In addition, Janus Capital employees
               serve as officers of the Trust and Janus Capital provides office
               space for the Fund and pays the salaries, fees and expenses of
               all Fund officers and those Trustees who are affiliated with
               Janus Capital. The Fund pays all of its expenses not assumed by
               Janus Capital, including auditing fees and independent Trustees'
               fees and expenses.

               The Fund pays Janus Capital a management fee which is calculated
               daily and paid monthly. The advisory agreement with the Fund
               spells out the management fee and other expenses that the Fund
               must pay.

               The Fund incurs expenses not assumed by Janus Capital, including
               transfer agent and custodian fees and expenses, legal and
               auditing fees, printing and mailing costs of sending reports and
               other information to existing shareholders, and independent
               Trustees' fees and expenses. For the most recent fiscal year, the
               Fund paid Janus Capital a management fee equal to 0.57% of
               average daily net assets.

                                       Janus Flexible Income Fund prospectus  29
<PAGE>

PORTFOLIO MANAGER

RONALD V. SPEAKER
- --------------------------------------------------------------------------------
                   is Executive Vice President and portfolio manager of the
                   Fund, which he has managed or co-managed since December
                   1991. He previously served as co-manager of Janus
                   High-Yield Fund from its inception to February 1998 and
                   manager of Janus Short-Term Bond Fund and Janus Federal
                   Tax-Exempt Fund from their inceptions through December
                   1995. He holds a Bachelor of Arts in Finance from the
                   University of Colorado and is a Chartered Financial
                   Analyst.

                   In January 1997, Mr. Speaker settled an administrative
                   action involving two personal trades made by him in
                   January of 1993. Without admitting or denying the
                   allegations, Mr. Speaker agreed to civil money penalty,
                   disgorgement, and interest payments totaling $37,199 and
                   to a 90-day suspension which ended on April 25, 1997.

 30 Janus Flexible Income Fund prospectus
<PAGE>

OTHER INFORMATION
- --------------------------------------------------------------------------------

               SIZE OF THE FUND

               Although there is no present intention to do so, the Fund may
               discontinue sales of its shares if management and the Trustees
               believe that continued sales may adversely affect the Fund's
               ability to achieve its investment objective. If sales of the Fund
               are discontinued, it is expected that existing shareholders of
               the Fund will be permitted to continue to purchase shares and to
               reinvest any dividends or capital gains distributions, absent
               highly unusual circumstances.

               YEAR 2000

               Preparing for Year 2000 has been a high priority for Janus
               Capital. A dedicated group was established to address this issue.
               Janus Capital devoted considerable internal resources and engaged
               one of the foremost experts in the field to achieve Year 2000
               readiness. Janus Capital successfully completed all five steps of
               its Year 2000 preparedness plans including the upgrade and
               replacement of all systems, as well as full-scale testing and
               implementation of those systems. Janus Capital's detailed
               contingency plans were also thoroughly tested. As of the date of
               this Prospectus, Janus Capital has not seen any adverse impact as
               a result of the Year 2000 transition on any of its systems or
               those of its vendors, or on the companies in which the Funds
               invest or worldwide markets and economies. Nonetheless, Janus
               Capital will continue to monitor the effect of the Year 2000
               transition, and there can be no absolute assurance that Year 2000
               issues will not in the future adversely affect the Funds' or
               Janus Capital's operations.

                                       Janus Flexible Income Fund prospectus  31
<PAGE>

               DISTRIBUTION OF THE FUND

               The Fund is distributed by Janus Distributors, Inc., a member of
               the National Association of Securities Dealers, Inc. ("NASD"). To
               obtain information about NASD member firms and their associated
               persons, you may contact NASD Regulation, Inc. at www.nasdr.com
               or the Public Disclosure Hotline at 800-289-9999. An investor
               brochure containing information describing the Public Disclosure
               Program is available from NASD Regulation, Inc.

 32 Janus Flexible Income Fund prospectus
<PAGE>

DISTRIBUTIONS AND TAXES
- --------------------------------------------------------------------------------

DISTRIBUTIONS

               To avoid taxation of the Fund, the Internal Revenue Code requires
               the Fund to distribute net income and any net capital gains
               realized on its investments annually. The Fund's income from
               dividends and interest and any net realized short-term gains are
               paid to shareholders as ordinary income dividends. Net realized
               long-term gains are paid to shareholders as capital gains
               distributions.

               Income dividends are declared daily, Saturdays, Sundays and
               holidays included, and are generally paid as of the last business
               day of each month. If a month begins on a Saturday, Sunday or
               holiday, dividends for those days are paid at the end of the
               preceding month. You will begin accruing income dividends the day
               after a purchase is effective. If shares are redeemed, you will
               receive all dividends accrued through the day of the redemption.
               Capital gains, if any, are declared and paid in December.

               HOW DISTRIBUTIONS AFFECT THE FUND'S NAV

               Distributions, other than daily income dividends, are paid to
               shareholders as of the record date of the distribution of the
               Fund, regardless of how long the shares have been held.
               Undistributed income and realized gains are included in the
               Fund's daily NAV. The share price of the Fund drops by the amount
               of the distribution, net of any subsequent market fluctuations.
               As an example, assume that on December 31, the Fund declared a
               dividend in the amount of $0.25 per share. If the Fund's share
               price was $10.00 on December 30, the Fund's share price on
               December 31 would be $9.75, barring market fluctuations.
               Shareholders should be aware that distributions from a taxable
               mutual fund are not value-enhancing and may create income tax
               obligations.

               "BUYING A DIVIDEND"

               If you purchase shares of the Fund just before the distribution,
               you will pay the full price for the shares and receive a portion
               of the purchase price back as a taxable distribution. This is
               referred

                                       Janus Flexible Income Fund prospectus  33
<PAGE>

               to as "buying a dividend." In the above example, if you bought
               shares on December 30, you would have paid $10.00 per share. On
               December 31, the Fund would pay you $0.25 per share as a dividend
               and your shares would now be worth $9.75 per share. Unless your
               account is set up as a tax-deferred account, dividends paid to
               you would be included in your gross income for tax purposes, even
               though you may not have participated in the increase in NAV of
               the Fund, whether or not you reinvested the dividends.

DISTRIBUTION OPTIONS

               When you open an account, you must specify on your application
               how you want to receive your distributions. You may change your
               distribution option at any time by writing the Fund at one of the
               addresses on page 16 or calling 1-800-525-3713. The Fund offers
               the following options:

               1. REINVESTMENT OPTION. You may reinvest your income dividends
                  and capital gains distributions in additional shares. This
                  option is assigned automatically if no other choice is made.

               2. CASH OPTION. You may receive your income dividends and capital
                  gains distributions in cash.

               3. REINVEST AND CASH OPTION. You may receive either your income
                  dividends or capital gains distributions in cash and reinvest
                  the other in additional shares.

               4. REDIRECT OPTION. You may direct your dividends or capital
                  gains to purchase shares of another Janus fund.

               The Fund reserves the right to reinvest into your account
               undeliverable and uncashed dividend and distribution checks that
               remain outstanding for six months in shares of the Fund at the
               NAV next computed after the check is cancelled. Subsequent
               distributions may also be reinvested.

 34 Janus Flexible Income Fund prospectus
<PAGE>

TAXES

               As with any investment, you should consider the tax consequences
               of investing in the Fund. Any time you sell or exchange shares of
               a Fund in a taxable account, it is considered a taxable event.
               Depending on the purchase price and the sale price, you may have
               a gain or loss on the transaction. Any tax liabilities generated
               by your transactions are your responsibility.

               The following discussion does not apply to tax-deferred accounts,
               nor is it a complete analysis of the federal tax implications of
               investing in the Fund. You may wish to consult your own tax
               adviser. Additionally, state or local taxes may apply to your
               investment, depending upon the laws of your state of residence.

               TAXES ON DISTRIBUTIONS

               Dividends and distributions by the Fund are subject to federal
               income tax, regardless of whether the distribution is made in
               cash or reinvested in additional shares of the Fund.
               Distributions may be taxable at different rates depending on the
               length of time the Fund holds a security. In certain states, a
               portion of the dividends and distributions (depending on the
               source of the Fund's income) may be exempt from state and local
               taxes. Information regarding the tax status of income dividends
               and capital gains distributions will be mailed to shareholders on
               or before January 31st of each year. Account tax information will
               also be sent to the IRS.

                                       Janus Flexible Income Fund prospectus  35
<PAGE>

               TAXATION OF THE FUND

               Dividends, interest, and some capital gains received by the Fund
               on foreign securities may be subject to tax withholding or other
               foreign taxes. The Fund may from year to year make the election
               permitted under section 853 of the Internal Revenue Code to pass
               through such taxes to shareholders as a foreign tax credit. If
               such an election is not made, any foreign taxes paid or accrued
               will represent an expense to the Fund.

               The Fund does not expect to pay federal income or excise taxes
               because it intends to meet certain requirements of the Internal
               Revenue Code. It is important that the Fund meet these
               requirements so that any earnings on your investment will not be
               taxed twice.

 36 Janus Flexible Income Fund prospectus
<PAGE>

FINANCIAL HIGHLIGHTS
- --------------------------------------------------------------------------------

               The financial highlights table is intended to help you understand
               the Fund's financial performance for the past 5 years through
               October 31st of each fiscal year shown. Items 1 through 8 reflect
               financial results for a single Fund share. The total returns in
               the table represent the rate that an investor would have earned
               (or lost) on an investment in the Fund (assuming reinvestment of
               all dividends and distributions). This information has been
               audited by PricewaterhouseCoopers LLP, whose report, along with
               the Fund's financial statements, are included in the Annual
               Report, which is available upon request and incorporated by
               reference into the SAI.

JANUS FLEXIBLE INCOME FUND

<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------
                                                      Periods ending October 31st
                                                 1999     1998    1997    1996     1995
<S>                                             <C>      <C>      <C>     <C>      <C>
  1. NET ASSET VALUE, BEGINNING OF PERIOD        $9.91   $10.00   $9.65   $9.55    $8.96
     INCOME FROM INVESTMENT OPERATIONS:
  2. Net investment income                        0.63     0.67    0.69    0.73     0.72
  3. Net gains or (losses) on securities (both
     realized and unrealized)                   (0.45)     0.12    0.37    0.10     0.59
  4. Total from investment operations             0.18     0.79    1.06    0.83     1.31
     LESS DISTRIBUTIONS:
  5. Dividends (from net investment income)     (0.63)   (0.67)   (0.69) (0.73)   (0.72)
  6. Distributions (from capital gains)         (0.11)   (0.21)   (0.02)     --       --
  7. Total distributions                        (0.74)   (0.88)   (0.71) (0.73)   (0.72)
  8. NET ASSET VALUE, END OF PERIOD              $9.35    $9.91   $10.00  $9.65    $9.55
  9. Total return                                1.75%    8.14%   11.48%  9.01%   15.35%
 10. Net assets, end of period (in millions)    $1,279   $1,104     $727   $604     $580
 11. Average net assets for the period (in
     millions)                                  $1,266     $893     $656   $604     $450
 12. Ratio of gross expenses to average net
     assets                                      0.82%    0.84%    0.87%  0.88%    0.96%
 13. Ratio of net expenses to average net
     assets                                      0.81%    0.82%    0.86%  0.87%    0.96%
 14. Ratio of net investment income to average
     net assets                                  6.54%    6.68%    7.10%  7.60%    7.91%
 15. Portfolio turnover rate                      119%     148%     207%   214%     250%
- ------------------------------------------------------------------------------------------
</TABLE>

                                       Janus Flexible Income Fund prospectus  37
<PAGE>

GLOSSARY OF INVESTMENT TERMS
- --------------------------------------------------------------------------------

               This glossary provides a more detailed description of some of the
               types of securities and other instruments in which the Fund may
               invest. The Fund may invest in these instruments to the extent
               permitted by its investment objective and policies. The Fund is
               not limited by this discussion and may invest in any other types
               of instruments not precluded by the policies discussed elsewhere
               in this Prospectus. Please refer to the SAI for a more detailed
               discussion of certain instruments.

I. EQUITY AND DEBT SECURITIES

               BONDS are debt securities issued by a company, municipality,
               government or government agency. The issuer of a bond is required
               to pay the holder the amount of the loan (or par value of the
               bond) at a specified maturity and to make scheduled interest
               payments.

               CERTIFICATES OF PARTICIPATION ("COPS") are certificates
               representing an interest in a pool of securities. Holders are
               entitled to a proportionate interest in the underlying
               securities. Municipal lease obligations are often sold in the
               form of COPs. See "Municipal lease obligations" below.

               COMMERCIAL PAPER is a short-term debt obligation with a maturity
               ranging from 1 to 270 days issued by banks, corporations and
               other borrowers to investors seeking to invest idle cash. The
               Fund may purchase commercial paper issued in private placements
               under Section 4(2) of the Securities Act of 1933.

               COMMON STOCKS are equity securities representing shares of
               ownership in a company, and usually carry voting rights and earns
               dividends. Unlike preferred stock, dividends on common stocks are
               not fixed but are declared at the discretion of the issuer's
               board of directors.

               CONVERTIBLE SECURITIES are preferred stocks or bonds that pay a
               fixed dividend or interest payment and are convertible into
               common stock at a specified price or conversion ratio.

 38 Janus Flexible Income Fund prospectus
<PAGE>

               DEBT SECURITIES are securities representing money borrowed that
               must be repaid at a later date. Such securities have specific
               maturities and usually a specific rate of interest or an original
               purchase discount.

               DEPOSITARY RECEIPTS are receipts for shares of a foreign-based
               corporation that entitle the holder to dividends and capital
               gains on the underlying security. Receipts include those issued
               by domestic banks (American Depositary Receipts), foreign banks
               (Global or European Depositary Receipts) and broker-dealers
               (depositary shares).

               FIXED-INCOME SECURITIES are securities that pay a specified rate
               of return. The term generally includes short- and long-term
               government, corporate and municipal obligations that pay a
               specified rate of interest or coupons for a specified period of
               time, and preferred stock, which pays fixed dividends. Coupon and
               dividend rates may be fixed for the life of the issue or, in the
               case of adjustable and floating rate securities, for a shorter
               period.

               HIGH-YIELD/HIGH-RISK BONDS are bonds that are rated below
               investment grade by the primary rating agencies (e.g., BB or
               lower by Standard & Poor's and Ba or lower by Moody's). Other
               terms commonly used to describe such bonds include "lower rated
               bonds," "noninvestment grade bonds" and "junk bonds."

               INDUSTRIAL DEVELOPMENT BONDS are revenue bonds that are issued by
               a public authority but which may be backed only by the credit and
               security of a private issuer and may involve greater credit risk.
               See "Municipal securities" below.

               MORTGAGE- AND ASSET-BACKED SECURITIES are shares in a pool of
               mortgages or other debt. These securities are generally pass-
               through securities, which means that principal and interest
               payments on the underlying securities (less servicing fees) are
               passed through to shareholders on a pro rata basis. These
               securities involve prepayment risk, which is the risk that the
               underlying mortgages or other debt may be refinanced or paid off
               prior to their maturities during periods of declining interest
               rates.

                                       Janus Flexible Income Fund prospectus  39
<PAGE>

               In that case, the portfolio managers may have to reinvest the
               proceeds from the securities at a lower rate. Potential market
               gains on a security subject to prepayment risk may be more
               limited than potential market gains on a comparable security that
               is not subject to prepayment risk.

               MUNICIPAL LEASE OBLIGATIONS are revenue bonds backed by leases or
               installment purchase contracts for property or equipment. Lease
               obligations may not be backed by the issuing municipality's
               credit and may involve risks not normally associated with general
               obligation bonds and other revenue bonds. For example, their
               interest may become taxable if the lease is assigned and the
               holders may incur losses if the issuer does not appropriate funds
               for the lease payments on an annual basis, which may result in
               termination of the lease and possible default.

               MUNICIPAL SECURITIES are bonds or notes issued by a U.S. state or
               political subdivision. A municipal security may be a general
               obligation backed by the full faith and credit (i.e., the
               borrowing and taxing power) of a municipality or a revenue
               obligation paid out of the revenues of a designated project,
               facility or revenue source.

               PASSIVE FOREIGN INVESTMENT COMPANIES (PFICS) are any foreign
               corporations which generate certain amounts of passive income or
               hold certain amounts of assets for the production of passive
               income. Passive income includes dividends, interest, royalties,
               rents and annuities. To avoid taxes and interest that the Fund
               must pay if these investments are profitable, the Fund may make
               various elections permitted by the tax laws. These elections
               could require that the Fund recognize taxable income, which in
               turn must be distributed, before the securities are sold and
               before cash is received to pay the distributions.

               PAY-IN-KIND BONDS are debt securities that normally give the
               issuer an option to pay cash at a coupon payment date or give the
               holder of the security a similar bond with the same coupon rate
               and a face value equal to the amount of the coupon payment that
               would have been made.

 40 Janus Flexible Income Fund prospectus
<PAGE>

               PREFERRED STOCKS are equity securities that generally pay
               dividends at a specified rate and have preference over common
               stock in the payment of dividends and liquidation. Preferred
               stock generally does not carry voting rights.

               REPURCHASE AGREEMENTS involve the purchase of a security by the
               Fund and a simultaneous agreement by the seller (generally a bank
               or dealer) to repurchase the security from the Fund at a
               specified date or upon demand. This technique offers a method of
               earning income on idle cash. These securities involve the risk
               that the seller will fail to repurchase the security, as agreed.
               In that case, the Fund will bear the risk of market value
               fluctuations until the security can be sold and may encounter
               delays and incur costs in liquidating the security.

               REVERSE REPURCHASE AGREEMENTS involve the sale of a security by
               the Fund to another party (generally a bank or dealer) in return
               for cash and an agreement by the Fund to buy the security back at
               a specified price and time. This technique will be used primarily
               to provide cash to satisfy unusually heavy redemption requests,
               or for other temporary or emergency purposes.

               RULE 144A SECURITIES are securities that are not registered for
               sale to the general public under the Securities Act of 1933, but
               that may be resold to certain institutional investors.

               STANDBY COMMITMENTS are obligations purchased by the Fund from a
               dealer that give the Fund the option to sell a security to the
               dealer at a specified price.

               STEP COUPON BONDS are debt securities that trade at a discount
               from their face value and pay coupon interest. The discount from
               the face value depends on the time remaining until cash payments
               begin, prevailing interest rates, liquidity of the security and
               the perceived credit quality of the issuer.

               STRIP BONDS are debt securities that are stripped of their
               interest (usually by a financial intermediary) after the
               securities are issued. The market value of these securities
               generally fluctuates more in

                                       Janus Flexible Income Fund prospectus  41
<PAGE>

               response to changes in interest rates than interest-paying
               securities of comparable maturity.

               TENDER OPTION BONDS are generally long-term securities that are
               coupled with an option to tender the securities to a bank,
               broker-dealer or other financial institution at periodic
               intervals and receive the face value of the bond. This type of
               security is commonly used as a means of enhancing the security's
               liquidity.

               U.S. GOVERNMENT SECURITIES include direct obligations of the U.S.
               government that are supported by its full faith and credit.
               Treasury bills have initial maturities of less than one year,
               Treasury notes have initial maturities of one to ten years and
               Treasury bonds may be issued with any maturity but generally have
               maturities of at least ten years. U.S. government securities also
               include indirect obligations of the U.S. government that are
               issued by federal agencies and government sponsored entities.
               Unlike Treasury securities, agency securities generally are not
               backed by the full faith and credit of the U.S. government. Some
               agency securities are supported by the right of the issuer to
               borrow from the Treasury, others are supported by the
               discretionary authority of the U.S. government to purchase the
               agency's obligations and others are supported only by the credit
               of the sponsoring agency.

               VARIABLE AND FLOATING RATE SECURITIES have variable or floating
               rates of interest and, under certain limited circumstances, may
               have varying principal amounts. These securities pay interest at
               rates that are adjusted periodically according to a specified
               formula, usually with reference to some interest rate index or
               market interest rate. The floating rate tends to decrease the
               security's price sensitivity to changes in interest rates.

               WARRANTS are securities, typically issued with preferred stocks
               or bonds, that give the holder the right to buy a proportionate
               amount of common stock at a specified price, usually at a price
               that is higher than the market price at the time of issuance of
               the warrant. The right may last for a period of years or
               indefinitely.

 42 Janus Flexible Income Fund prospectus
<PAGE>

               WHEN-ISSUED, DELAYED DELIVERY AND FORWARD TRANSACTIONS generally
               involve the purchase of a security with payment and delivery at
               some time in the future - i.e., beyond normal settlement. The
               Fund does not earn interest on such securities until settlement
               and bears the risk of market value fluctuations in between the
               purchase and settlement dates. New issues of stocks and bonds,
               private placements and U.S. government securities may be sold in
               this manner.

               ZERO COUPON BONDS are debt securities that do not pay regular
               interest at regular intervals, but are issued at a discount from
               face value. The discount approximates the total amount of
               interest the security will accrue from the date of issuance to
               maturity. The market value of these securities generally
               fluctuates more in response to changes in interest rates than
               interest-paying securities.

II. FUTURES, OPTIONS AND OTHER DERIVATIVES

               FORWARD CONTRACTS are contracts to purchase or sell a specified
               amount of a financial instrument for an agreed upon price at a
               specified time. Forward contracts are not currently exchange
               traded and are typically negotiated on an individual basis. The
               Fund may enter into forward currency contracts to hedge against
               declines in the value of securities denominated in, or whose
               value is tied to, a currency other than the U.S. dollar or to
               reduce the impact of currency appreciation on purchases of such
               securities. It may also enter into forward contracts to purchase
               or sell securities or other financial indices.

               FUTURES CONTRACTS are contracts that obligate the buyer to
               receive and the seller to deliver an instrument or money at a
               specified price on a specified date. The Fund may buy and sell
               futures contracts on foreign currencies, securities and financial
               indices including interest rates or an index of U.S. government,
               foreign government, equity or fixed-income securities. The Fund
               may also buy options on futures contracts. An option on a futures
               contract gives the buyer the right, but not the obligation, to
               buy or sell a futures contract at a specified price on or before
               a specified date.

                                       Janus Flexible Income Fund prospectus  43
<PAGE>

               Futures contracts and options on futures are standardized and
               traded on designated exchanges.

               INDEXED/STRUCTURED SECURITIES are typically short- to
               intermediate-term debt securities whose value at maturity or
               interest rate is linked to currencies, interest rates, equity
               securities, indices, commodity prices or other financial
               indicators. Such securities may be positively or negatively
               indexed (i.e., their value may increase or decrease if the
               reference index or instrument appreciates). Indexed/structured
               securities may have return characteristics similar to direct
               investments in the underlying instrument and may be more volatile
               than the underlying instrument. The Fund bears the market risk of
               an investment in the underlying instrument, as well as the credit
               risk of the issuer.

               INTEREST RATE SWAPS involve the exchange by two parties of their
               respective commitments to pay or receive interest (e.g., an
               exchange of floating rate payments for fixed rate payments).

               INVERSE FLOATERS are debt instruments whose interest rate bears
               an inverse relationship to the interest rate on another
               instrument or index. For example, upon reset the interest rate
               payable on a security may go down when the underlying index has
               risen. Certain inverse floaters may have an interest rate reset
               mechanism that multiplies the effects of change in the underlying
               index. Such mechanism may increase the volatility of the
               security's market value.

               OPTIONS are the right, but not the obligation, to buy or sell a
               specified amount of securities or other assets on or before a
               fixed date at a predetermined price. The Fund may purchase and
               write put and call options on securities, securities indices and
               foreign currencies.

 44 Janus Flexible Income Fund prospectus
<PAGE>

EXPLANATION OF RATING CATEGORIES
- --------------------------------------------------------------------------------

               The following is a description of credit ratings issued by two of
               the major credit ratings agencies. Credit ratings evaluate only
               the safety of principal and interest payments, not the market
               value risk of lower quality securities. Credit rating agencies
               may fail to change credit ratings to reflect subsequent events on
               a timely basis. Although Janus Capital considers security ratings
               when making investment decisions, it also performs its own
               investment analysis and does not rely solely on the ratings
               assigned by credit agencies.

                                       Janus Flexible Income Fund prospectus  45
<PAGE>

STANDARD & POOR'S
RATINGS SERVICES

<TABLE>
                <S>                          <C>
                BOND RATING                  EXPLANATION
                ----------------------------------------------------------------
                Investment Grade
                AAA......................... Highest rating; extremely strong
                                             capacity to pay principal and
                                             interest.
                AA.......................... High quality; very strong capacity
                                             to pay principal and interest.
                A........................... Strong capacity to pay principal
                                             and interest; somewhat more
                                             susceptible to the adverse effects
                                             of changing circumstances and
                                             economic conditions.
                BBB......................... Adequate capacity to pay principal
                                             and interest; normally exhibit
                                             adequate protection parameters, but
                                             adverse economic conditions or
                                             changing circumstances more likely
                                             to lead to a weakened capacity to
                                             pay principal and interest than for
                                             higher rated bonds.
                Non-Investment Grade
                BB, B, CCC, CC, C........... Predominantly speculative with
                                             respect to the issuer's capacity to
                                             meet required interest and
                                             principal payments. BB - lowest
                                             degree of speculation; C - the
                                             highest degree of speculation.
                                             Quality and protective
                                             characteristics outweighed by large
                                             uncertainties or major risk
                                             exposure to adverse conditions.
                D........................... In default.
</TABLE>

 46 Janus Flexible Income Fund prospectus
<PAGE>

MOODY'S INVESTORS SERVICE, INC.

<TABLE>
                <S>                          <C>
                BOND RATING                  EXPLANATION
                ----------------------------------------------------------------
                Investment Grade
                Aaa......................... Highest quality, smallest degree of
                                             investment risk.
                Aa.......................... High quality; together with Aaa
                                             bonds, they compose the high-grade
                                             bond group.
                A........................... Upper-medium grade obligations;
                                             many favorable investment
                                             attributes.
                Baa......................... Medium-grade obligations; neither
                                             highly protected nor poorly
                                             secured. Interest and principal
                                             appear adequate for the present but
                                             certain protective elements may be
                                             lacking or may be unreliable over
                                             any great length of time.
                Non-Investment Grade
                Ba.......................... More uncertain, with speculative
                                             elements. Protection of interest
                                             and principal payments not well
                                             safeguarded during good and bad
                                             times.
                B........................... Lack characteristics of desirable
                                             investment; potentially low
                                             assurance of timely interest and
                                             principal payments or maintenance
                                             of other contract terms over time.
                Caa......................... Poor standing, may be in default;
                                             elements of danger with respect to
                                             principal or interest payments.
                Ca.......................... Speculative in a high degree; could
                                             be in default or have other marked
                                             shortcomings.
                C........................... Lowest-rated; extremely poor
                                             prospects of ever attaining
                                             investment standing.
</TABLE>

                                       Janus Flexible Income Fund prospectus  47
<PAGE>

               Unrated securities will be treated as noninvestment grade
               securities unless a portfolio manager determines that such
               securities are the equivalent of investment grade securities.
               Securities that have received ratings from more than one agency
               are considered investment grade if at least one agency has rated
               the security investment grade.

SECURITIES HOLDINGS BY RATING CATEGORY

               During the fiscal period ended October 31, 1999, the percentage
               of securities holdings for the Fund by rating category based upon
               a weighted monthly average was:

<TABLE>
<CAPTION>
                JANUS FLEXIBLE INCOME FUND
                ------------------------------------------------------------------
                <S>                                                       <C>
                BONDS-S&P RATING:
                 AAA                                                         10%
                 AA                                                           8%
                 A                                                           13%
                 BBB                                                         27%
                 BB                                                           7%
                 B                                                           19%
                 CCC                                                          1%
                 CC                                                           0%
                 C                                                            0%
                 Not Rated                                                  4.0%
                 Preferred Stock                                              2%
                 Cash and Options                                             9%
                 TOTAL                                                      100%
                ------------------------------------------------------------------
</TABLE>

 48 Janus Flexible Income Fund prospectus
<PAGE>

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<PAGE>

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<PAGE>

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<PAGE>

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 52
<PAGE>

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<PAGE>

                                  [JANUS LOGO]

        You can request other information, including a Statement of
        Additional Information, Annual Report or Semiannual Report, free
        of charge, by contacting Janus at 1-800-525-3713 or visiting our
        Web site at janus.com. In the Fund's Annual Report, you will
        find a discussion of the market conditions and investment
        strategies that significantly affected the Fund's performance
        during its last fiscal year. Other information is also available
        from financial intermediaries that sell shares of the Fund.

        The Statement of Additional Information provides detailed
        information about the Fund and is incorporated into this
        Prospectus by reference. You may review the Fund's Statement of
        Additional Information at the Public Reference Room of the SEC
        or get text only copies for a fee, by writing to or calling the
        Public Reference Room, Washington, D.C. 20549-6009
        (1-800-SEC-0330). You may obtain the Statement of Additional
        Information for free from the SEC's Web site at
        http://www.sec.gov.

                    Investment Company Act File No. 811-1879

                                 1-800-525-3713
                     PO Box 173375  Denver, CO  80217-3375
                                   janus.com

4266

<PAGE>

                              JANUS  GLOBAL  LIFE
                                 SCIENCES  FUND
                                   PROSPECTUS

                                                   JANUARY 31, 2000

             The Securities and Exchange Commission has not
             approved or disapproved of these securities or passed
             on the accuracy or adequacy of this Prospectus. Any
             representation to the contrary is a criminal offense.

                                  [JANUS LOGO]
<PAGE>

- --------------------------------------------------------------------------------
<PAGE>

TABLE OF CONTENTS
- --------------------------------------------------------------------------------

<TABLE>
                <S>                                               <C>
                RISK/RETURN SUMMARY
                   Janus Global Life Sciences Fund..............    2
                   Fees and expenses............................    5
                INVESTMENT OBJECTIVE, PRINCIPAL INVESTMENT
                STRATEGIES AND RISKS
                   Investment objective and principal investment
                   strategies...................................    6
                   General portfolio policies...................    7
                   Risks........................................   10
                SHAREHOLDER'S MANUAL
                   Minimum investments..........................   19
                   Type of account ownership....................   19
                   To purchase shares...........................   22
                   To exchange shares...........................   23
                   To redeem shares.............................   23
                   Shareholder services and account policies....   27
                MANAGEMENT OF THE FUND
                   Investment adviser...........................   31
                   Portfolio manager............................   32
                OTHER INFORMATION............... ...............   33
                DISTRIBUTIONS AND TAXES
                   Distributions................................   35
                   Taxes........................................   36
                FINANCIAL HIGHLIGHTS.............. .............   38
                GLOSSARY
                   Glossary of investment terms.................   40
</TABLE>

                                   Janus Global Life Sciences Fund prospectus  1
<PAGE>

RISK/RETURN SUMMARY
- --------------------------------------------------------------------------------

JANUS GLOBAL LIFE SCIENCES FUND

1. WHAT IS THE INVESTMENT OBJECTIVE OF JANUS GLOBAL LIFE SCIENCES FUND?

               The Fund seeks long-term growth of capital.

               The Fund's Trustees may change this objective without a
               shareholder vote and the Fund will notify you of any changes that
               are material. If there is a material change in the Fund's
               objective or policies, you should consider whether the Fund
               remains an appropriate investment for you. There is no guarantee
               that the Fund will meet its objective.

2. WHAT ARE THE MAIN INVESTMENT STRATEGIES OF JANUS GLOBAL LIFE SCIENCES FUND?

               The Fund invests primarily in equity securities of U.S. and
               foreign companies selected for their growth potential. Normally,
               it invests at least 65% of its total assets in securities of
               companies that the portfolio manager believes have a life science
               orientation. Generally speaking, the "life sciences" relate to
               maintaining or improving quality of life. So, for example,
               companies with a "life science orientation" include companies
               engaged in research, development, production or distribution of
               products or services related to health and personal care,
               medicine or pharmaceuticals. As a fundamental policy, the Fund
               normally invests at least 25% of its total assets, in the
               aggregate, in the following industry groups: health care;
               pharmaceuticals; agriculture; cosmetics/personal care; and
               biotechnology.

               The Fund may invest without limit in foreign equity and debt
               securities and less than 35% of its net assets in
               high-yield/high-risk bonds.

               The portfolio manager applies a "bottom up" approach in choosing
               investments. In other words, he looks for companies with earnings
               growth potential one at a time. If the portfolio manager is
               unable to find such investments, a significant portion of the
               Fund's assets may be in cash or similar investments.

 2 Janus Global Life Sciences Fund prospectus
<PAGE>

3. WHAT ARE THE MAIN RISKS OF INVESTING IN JANUS GLOBAL LIFE SCIENCES FUND?

               The biggest risk of investing in this Fund is that its returns
               may vary and you could lose money. If you are considering
               investing in the Fund, remember that it is designed for long-term
               investors who can accept the risks of investing in a portfolio
               with significant common stock holdings. Common stocks tend to be
               more volatile than other investment choices.

               The value of the Fund's portfolio may decrease if the value of an
               individual company in the portfolio decreases. The value of the
               Fund's portfolio could also decrease if the stock market goes
               down. If the value of the Fund's portfolio decreases, the Fund's
               net asset value (NAV) will also decrease which means if you sell
               your shares in the Fund you would get back less money.

               The Fund concentrates its investments in related industry groups.
               Because of this, companies in its portfolio may share common
               characteristics and react similarly to market developments. For
               example, many companies with a life science orientation are
               highly regulated and may be dependent upon certain types of
               technology. As a result, changes in government funding or
               subsidies, new or anticipated legislative changes, or
               technological advances could affect the value of such companies
               and, therefore, the Fund's NAV. The Fund's returns may be more
               volatile than those of a less concentrated portfolio.

               The Fund may have significant exposure to foreign markets. As a
               result, its returns and NAV may be affected to a large degree by
               fluctuations in currency exchange rates or political or economic
               conditions in a particular country.

               The Fund is nondiversified. In other words, it may hold larger
               positions in a smaller number of securities than a diversified
               fund. As a result, a single security's increase or decrease in
               value may have a greater impact on the Fund's NAV and total
               return.

               An investment in the Fund is not a bank deposit and is not
               insured or guaranteed by the Federal Deposit Insurance
               Corporation or any other government agency.

                                   Janus Global Life Sciences Fund prospectus  3
<PAGE>

               The following information illustrates how the Fund's performance
               has varied over time. The bar chart depicts the change in
               performance from year-to-year during the period indicated. The
               table compares the Fund's average annual returns for the periods
               indicated to a broad-based securities market index.

                JANUS GLOBAL LIFE SCIENCES FUND

                A BAR CHART showing the Annual Total Return for Janus Global
                Life Sciences Fund for 1999:

                Annual returns for periods ended 12/31
<TABLE>
                <S>                                                          <C>
                                                                              61.00%
                                                                               1999

                The percentage is represented by a bar of proportionate size
                with the actual total return printed above the bar.

                Best Quarter:  4th-1999   31.32%   Worst Quarter:  1st-1999  4.20%
</TABLE>

                          Average annual total return for periods ended 12/31/99
                          ------------------------------------------------------

<TABLE>
<CAPTION>
                                                                 1 year and Since Inception
                                                                         (12/31/98)
                <S>                                              <C>
                Janus Global Life Sciences Fund                            61.00%
                S&P 500 Index*                                             21.03%
                                                                 ---------------------------
</TABLE>

               * The S&P 500 is the Standard & Poor's Composite Index of 500
                 Stocks, a widely recognized, unmanaged index of common stock
                 prices.

               The Fund's past performance does not necessarily indicate how
               they will perform in the future.

 4 Janus Global Life Sciences Fund prospectus
<PAGE>

FEES AND EXPENSES

               SHAREHOLDER FEES, such as sales loads, redemption fees or
               exchange fees, are charged directly to an investor's account. All
               Janus funds are no-load investments, so you will not pay any
               shareholder fees when you buy or sell shares of the Fund.

               ANNUAL FUND OPERATING EXPENSES are paid out of the Fund's assets
               and include fees for portfolio management, maintenance of
               shareholder accounts, shareholder servicing, accounting and other
               services. You do not pay these fees directly but, as the example
               below shows, these costs are borne indirectly by all
               shareholders.

               This table describes the fees and expenses that you may pay if
               you buy and hold shares of the Fund. It is based upon gross
               expenses (without the effect of expense offset arrangements). All
               of the fees and expenses shown were determined based on net
               assets as of the fiscal year ended October 31, 1999.

<TABLE>
<CAPTION>
                                                  Janus Global Life Sciences Fund
   <S>                                                         <C>
   Management Fee(1)                                            0.65%
   Other Expenses                                               0.46%(2)
   Total Annual Fund Operating Expenses                         1.11%
</TABLE>

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

  (1) "Management Fee" information has been restated to reflect a new fee
      schedule effective January 31, 2000.

  (2) For the fiscal period from December 31, 1998 (inception) to October
      31, 1999.
- --------------------------------------------------------------------------------

  EXAMPLE:
  This example is intended to help you compare the cost of investing in the
  Fund with the cost of investing in other mutual funds. The example
  assumes that you invest $10,000 in the Fund for the time periods
  indicated then redeem all of your shares at the end of those periods. The
  example also assumes that your investment has a 5% return each year and
  that the Fund's operating expenses remain the same. Although your actual
  costs may be higher or lower, based on these assumptions your costs would
  be:

<TABLE>
<CAPTION>
                                             1 Year     3 Years    5 Years    10 Years
                                             -----------------------------------------
   <S>                                       <C>        <C>        <C>        <C>
   Janus Global Life Sciences Fund            $113       $353       $612       $1,352
</TABLE>

                                   Janus Global Life Sciences Fund prospectus  5
<PAGE>

INVESTMENT OBJECTIVE, PRINCIPAL INVESTMENT
STRATEGIES AND RISKS
- --------------------------------------------------------------------------------

               This section takes a closer look at the investment objective of
               the Fund, its principal investment strategies and certain risks
               of investing in the Fund. Strategies and policies that are noted
               as "fundamental" cannot be changed without a shareholder vote.

               Please carefully review the "Risks" section of this Prospectus on
               pages 10-14 for a discussion of risks associated with certain
               investment techniques. We've also included a Glossary with
               descriptions of investment terms used throughout this Prospectus.

INVESTMENT OBJECTIVE AND PRINCIPAL INVESTMENT STRATEGIES

               Janus Global Life Sciences Fund seeks long-term growth of
               capital. It pursues its objective by investing primarily in
               equity securities of U.S. and foreign companies selected for
               their growth potential. Normally, it invests at least 65% of its
               total assets in securities of companies that the portfolio
               manager believes have a life science orientation. As a
               fundamental policy, the Fund normally invests at least 25% of its
               total assets, in the aggregate, in the following industry groups:
               healthcare; pharmaceuticals; agriculture; cosmetics/personal
               care; and biotechnology.

The following questions and answers are designed to help you better understand
the Fund's principal investment strategies.

1. HOW ARE COMMON STOCKS SELECTED?

               The Fund may invest substantially all of its assets in common
               stocks if its portfolio manager believes that common stocks will
               appreciate in value. The portfolio manager generally takes a
               "bottom up" approach to selecting companies. In other words, he
               seeks to identify individual companies with earnings growth
               potential that may not be recognized by the market at large. He
               makes this assessment by looking at companies one at a time,
               regardless of size, country of organization, place of principal
               business activity, or other similar selection criteria.
               Realization of income is not a significant consideration when
               choosing investments for the Fund. Income realized on the Fund's
               investments will be incidental to its objective.

 6 Janus Global Life Sciences Fund prospectus
<PAGE>

2. ARE THE SAME CRITERIA USED TO SELECT FOREIGN SECURITIES?

               Generally, yes. The portfolio manager seeks companies that meet
               his selection criteria, regardless of where a company is located.
               Foreign securities are generally selected on a stock-by-stock
               basis without regard to any defined allocation among countries or
               geographic regions. However, certain factors such as expected
               levels of inflation, government policies influencing business
               conditions, the outlook for currency relationships, and prospects
               for economic growth among countries, regions or geographic areas
               may warrant greater consideration in selecting foreign
               securities. There are no limitations on the countries in which
               the Fund may invest and the Fund may at times have significant
               foreign exposure.

3. WHAT DOES "LIFE SCIENCE ORIENTATION" MEAN IN RELATION TO THE FUND?

               Generally speaking, the "life sciences" relate to maintaining or
               improving quality of life. So, for example, companies with a
               "life science orientation" include companies engaged in research,
               development, production or distribution of products or services
               related to health and personal care, medicine or pharmaceuticals.
               Life science oriented companies also include companies that the
               portfolio manager believes have growth potential primarily as a
               result of particular products, technology, patents or other
               market advantages in the life sciences. Life sciences encompass a
               variety of industries, including health care, nutrition,
               agriculture, medical diagnostics, nuclear and biochemical
               research and development and health care facilities ownership and
               operation.

GENERAL PORTFOLIO POLICIES

               In investing its portfolio assets, the Fund will follow the
               general policies listed below. The percentage limitations
               included in these policies and elsewhere in this Prospectus apply
               at the time of purchase of the security. So, for example, if the
               Fund exceeds a limit as a result of market fluctuations or the
               sale of securities, it will not be required to dispose of any
               securities.

                                   Janus Global Life Sciences Fund prospectus  7
<PAGE>

               CASH POSITION
               When the Fund's portfolio manager believes that market conditions
               are unfavorable for profitable investing, or when he is otherwise
               unable to locate attractive investment opportunities, the Fund's
               cash or similar investments may increase. In other words, the
               Fund does not always stay fully invested in stocks. Cash or
               similar investments generally are a residual - they represent the
               assets that remain after the portfolio manager has committed
               available assets to desirable investment opportunities. However,
               the portfolio manager may also temporarily increase the Fund's
               cash position to protect its assets or maintain liquidity. When
               the Fund's investments in cash or similar investments increase,
               it may not participate in market advances or declines to the same
               extent that it would if the Fund remained more fully invested in
               stocks.

               OTHER TYPES OF INVESTMENTS
               The Fund invests primarily in domestic and foreign equity
               securities, which may include preferred stocks, common stocks,
               warrants and securities convertible into common or preferred
               stocks, but it may also invest to a lesser degree in other types
               of securities. These securities (which are described in the
               Glossary) may include:

               - debt securities

               - indexed/structured securities

               - high-yield/high-risk bonds (less than 35% of the Fund's assets)

               - options, futures, forwards, swaps and other types of
                 derivatives for hedging purposes or for non-hedging purposes
                 such as seeking to enhance return

               - securities purchased on a when-issued, delayed delivery or
                 forward commitment basis

               ILLIQUID INVESTMENTS
               The Fund may invest up to 15% of its net assets in illiquid
               investments. An illiquid investment is a security or other
               position

 8 Janus Global Life Sciences Fund prospectus
<PAGE>

               that cannot be disposed of quickly in the normal course of
               business. For example, some securities are not registered under
               the U.S. securities laws and cannot be sold to the U.S. public
               because of SEC regulations (these are known as "restricted
               securities"). Under procedures adopted by the Fund's Trustees,
               certain restricted securities may be deemed liquid, and will not
               be counted toward this 15% limit.

               FOREIGN SECURITIES
               The Fund may invest without limit in foreign equity and debt
               securities. The Fund may invest directly in foreign securities
               denominated in a foreign currency and not publicly traded in the
               United States. Other ways of investing in foreign securities
               include depositary receipts or shares, and passive foreign
               investment companies.

               SPECIAL SITUATIONS
               The Fund may invest in special situations. A special situation
               arises when, in the opinion of the Fund's portfolio manager, the
               securities of a particular issuer will be recognized and
               appreciate in value due to a specific development with respect to
               that issuer. Developments creating a special situation might
               include, among others, a new product or process, a technological
               breakthrough, a management change or other extraordinary
               corporate event, or differences in market supply of and demand
               for the security. The Fund's performance could suffer if the
               anticipated development in a "special situation" investment does
               not occur or does not attract the expected attention.

               PORTFOLIO TURNOVER
               The Fund generally intends to purchase securities for long-term
               investment although, to a limited extent, the Fund may purchase
               securities in anticipation of relatively short-term price gains.
               Short-term transactions may also result from liquidity needs,
               securities having reached a price or yield objective, changes in
               interest rates or the credit standing of an issuer, or by reason
               of economic or

                                   Janus Global Life Sciences Fund prospectus  9
<PAGE>

               other developments not foreseen at the time of the investment
               decision. The Fund may also sell one security and simultaneously
               purchase the same or a comparable security to take advantage of
               short-term differentials in bond yields or securities prices.
               Changes are made in the Fund's portfolio whenever its portfolio
               manager believes such changes are desirable. Portfolio turnover
               rates are generally not a factor in making buy and sell
               decisions.

               Increased portfolio turnover may result in higher costs for
               brokerage commissions, dealer mark-ups and other transaction
               costs and may also result in taxable capital gains. Higher costs
               associated with increased portfolio turnover may offset gains in
               the Fund's performance.

RISKS

               Because the Fund may invest substantially all of its assets in
               common stocks, the main risk is the risk that the value of the
               stocks it holds might decrease in response to the activities of
               an individual company or in response to general market and/or
               economic conditions. If this occurs, the Fund's share price may
               also decrease. The Fund's performance may also be affected by
               risks specific to certain types of investments, such as foreign
               securities, derivative investments, non-investment grade bonds,
               initial public offerings (IPOs) or companies with relatively
               small market capitalizations. IPOs and other investment
               techniques may have a magnified performance impact on a fund with
               a small asset base. A fund may not experience similar performance
               as its assets grow. The Fund's performance may also be affected
               by industry risk.

The following questions and answers are designed to help you better understand
some of the risks of investing in the Fund.

1. THE FUND MAY INVEST IN SMALLER OR NEWER COMPANIES. DOES THIS CREATE ANY
   SPECIAL RISKS?

               Many attractive investment opportunities may be smaller, start-up
               companies offering emerging products or services. Smaller or
               newer companies may suffer more significant losses as well as

 10 Janus Global Life Sciences Fund prospectus
<PAGE>

               realize more substantial growth than larger or more established
               issuers because they may lack depth of management, be unable to
               generate funds necessary for growth or potential development, or
               be developing or marketing new products or services for which
               markets are not yet established and may never become established.
               In addition, such companies may be insignificant factors in their
               industries and may become subject to intense competition from
               larger or more established companies. Securities of smaller or
               newer companies may have more limited trading markets than the
               markets for securities of larger or more established issuers, and
               may be subject to wide price fluctuations. Investments in such
               companies tend to be more volatile and somewhat more speculative.

2. HOW COULD THE FUND'S INVESTMENTS IN FOREIGN SECURITIES AFFECT ITS
   PERFORMANCE?

               The Fund may invest without limit in foreign securities either
               indirectly (e.g., depositary receipts) or directly in foreign
               markets. Investments in foreign securities, including those of
               foreign governments, may involve greater risks than investing in
               domestic securities because the Fund's performance may depend on
               issues other than the performance of a particular company. These
               issues include:

               - CURRENCY RISK As long as the Fund holds a foreign security, its
                 value will be affected by the value of the local currency
                 relative to the U.S. dollar. When the Fund sells a foreign
                 denominated security, its value may be worth less in U.S.
                 dollars even if the security increases in value in its home
                 country. U.S. dollar denominated securities of foreign issuers
                 may also be affected by currency risk.

               - POLITICAL AND ECONOMIC RISK Foreign investments may be subject
                 to heightened political and economic risks, particularly in
                 emerging markets which may have relatively unstable
                 governments, immature economic structures, national policies
                 restricting investments by foreigners, different legal systems,
                 and economies based on only a few industries. In some
                 countries,

                                  Janus Global Life Sciences Fund prospectus  11
<PAGE>

                 there is the risk that the government may take over the assets
                 or operations of a company or that the government may impose
                 taxes or limits on the removal of the Fund's assets from that
                 country.

               - REGULATORY RISK There may be less government supervision of
                 foreign markets. As a result, foreign issuers may not be
                 subject to the uniform accounting, auditing and financial
                 reporting standards and practices applicable to domestic
                 issuers and there may be less publicly available information
                 about foreign issuers.

               - MARKET RISK Foreign securities markets, particularly those of
                 emerging market countries, may be less liquid and more volatile
                 than domestic markets. Certain markets may require payment for
                 securities before delivery and delays may be encountered in
                 settling securities transactions. In some foreign markets,
                 there may not be protection against failure by other parties to
                 complete transactions.

               - TRANSACTION COSTS Costs of buying, selling and holding foreign
                 securities, including brokerage, tax and custody costs, may be
                 higher than those involved in domestic transactions.

3. HOW DOES THE NONDIVERSIFIED STATUS OF THE FUND AFFECT ITS RISK?

               Diversification is a way to reduce risk by investing in a broad
               range of stocks or other securities. A "nondiversified" fund has
               the ability to take larger positions in a smaller number of
               issuers. Because the appreciation or depreciation of a single
               stock may have a greater impact on the NAV of a nondiversified
               fund, its share price can be expected to fluctuate more than a
               comparable diversified fund. This fluctuation, if significant,
               may affect the performance of the Fund.

4. WHAT IS "INDUSTRY RISK"?

               Industry risk is the possibility that a group of related stocks
               will decline in price due to industry-specific developments.
               Companies in the same or similar industries may share common
               characteristics and are more likely to react similarly to
               industry-specific

 12 Janus Global Life Sciences Fund prospectus
<PAGE>

               market or economic developments. In the life sciences, for
               example, many companies are subject to government regulation and
               approval of their products and services, which may affect their
               price or availability. In addition, the products and services
               offered by these companies may quickly become obsolete in the
               face of scientific or technological developments. The economic
               outlook of such companies may fluctuate dramatically due to
               changes in regulatory or competitive environments.

               The Fund invests in a concentrated portfolio, which may result in
               greater exposure to related industries. As a result, the Fund may
               be more volatile than a less concentrated portfolio.

5. I'VE HEARD A LOT ABOUT HOW THE CHANGE TO THE YEAR 2000 COULD AFFECT COMPUTER
   SYSTEMS. DOES THIS CREATE ANY SPECIAL RISKS?

               The portfolio manager carefully researches each potential
               investment before making an investment decision and, among other
               things, considers what impact, if any, the Year 2000 transition
               has had on the company's operations when selecting portfolio
               holdings. However, there is no guarantee that the information the
               portfolio manager receives regarding a company's Year 2000
               transition status is completely accurate. If a company has not
               satisfactorily addressed Year 2000 issues, the Fund's performance
               could suffer.

6. ARE THERE SPECIAL RISKS ASSOCIATED WITH INVESTMENTS IN HIGH-YIELD/HIGH-RISK
   BONDS?

               High-yield/high-risk bonds (or "junk" bonds) are bonds rated
               below investment grade by the primary rating agencies such as
               Standard & Poor's and Moody's. The value of lower quality bonds
               generally is more dependent on credit risk, or the ability of the
               issuer to meet interest and principal payments, than investment
               grade bonds. Issuers of high-yield bonds may not be as strong
               financially as those issuing bonds with higher credit ratings and
               are more vulnerable to real or perceived economic changes,
               political changes or adverse developments specific to the issuer.

                                  Janus Global Life Sciences Fund prospectus  13
<PAGE>

               Please refer to the SAI for a description of bond rating
               categories.

7. HOW DOES THE FUND TRY TO REDUCE RISK?

               The Fund may use futures, options, swaps and other derivative
               instruments to "hedge" or protect its portfolio from adverse
               movements in securities prices and interest rates. The Fund may
               also use a variety of currency hedging techniques, including
               forward currency contracts, to manage exchange rate risk. The
               Fund believes the use of these instruments will benefit the Fund.
               However, the Fund's performance could be worse than if the Fund
               had not used such instruments if the portfolio manager's
               judgement proves incorrect. Risks associated with the use of
               derivative instruments are described in the SAI.

 14 Janus Global Life Sciences Fund prospectus
<PAGE>

                       This page intentionally left blank

                                  Janus Global Life Sciences Fund prospectus  15
<PAGE>

- --------------------------------------------------------------------------------
<PAGE>

                                  [JANUS LOGO]
                              JANUS  GLOBAL  LIFE
                                 SCIENCES  FUND
                              SHAREHOLDER'S MANUAL

                                           This section will help you
                                           become familiar with the
                                           different types of accounts
                                           you can establish with Janus.
                                           It also explains in detail the
                                           wide array of services and
                                           features you can establish on
                                           your account, as well as
                                           account policies and fees that
                                           may apply to your account.
                                           Account policies (including
                                           fees), services and features
                                           may be modified or
                                           discontinued without
                                           shareholder approval or prior
                                           notice.

                                           [JANUS LOGO]

<PAGE>

HOW TO GET IN TOUCH WITH JANUS

INVESTOR SERVICE CENTERS
100 Fillmore Street, Suite 100
Denver, CO 80206

3773 Cherry Creek North Drive, Suite 101
Denver, CO 80209

(Hours: Monday-Friday 7:00 a.m.-6:00 p.m., and Saturday 9:00 a.m.-1:00 p.m.,
Mountain time.)

MAILING ADDRESS
Janus
P.O. Box 173375
Denver, CO 80217-3375

FOR OVERNIGHT CARRIER
Janus
Suite 101
3773 Cherry Creek Drive North
Denver, CO 80209-3821

INVESTOR SERVICE REPRESENTATIVES
If you have any questions while reading this Prospectus, please call one of our
Investor Service Representatives at 1-800-525-3713 Monday-Friday: 8:00 a.m.-8:00
p.m., and Saturday: 10:00 a.m.-4:00 p.m., New York time.

JANUS XPRESSLINE(TM)
1-888-979-7737

JANUS INTERNET ADDRESS
JANUS.COM

For 24-hour access to account and fund information, exchanges, purchases and
redemptions, automated daily quotes on fund share prices, yields and total
returns.

JANUS.COM SPECIALISTS
1-800-975-9932

TDD
1-800-525-0056
A telecommunications device for our hearing- and speech-impaired shareholders.

JANUS LITERATURE LINE
1-800-525-8983
To request a prospectus, shareholder reports or marketing materials 24 hours a
day.

 18 Shareholder's manual
<PAGE>

MINIMUM INVESTMENTS*

<TABLE>
<S>                      <C>
To open a new regular
account                  $2,500
To open a new
retirement account,
education account or
UGMA/UTMA                $  500
To open a new regular
account with an
Automatic Investment
Program                  $  500**
To add to any type of
an account               $  100+
</TABLE>

 * The Fund reserves the right to change the amount of these minimums from time
   to time or to waive them in whole or in part for certain types of accounts.

** An Automatic Investment Program requires a $100 minimum automatic investment
   per month until the account balance reaches $2,500.

 + The minimum subsequent investment for a retirement account or UGMA/UTMA is
   $50.

TYPES OF ACCOUNT OWNERSHIP

               If you are investing in the Fund for the first time, you will
               need to establish an account. You can establish the following
               types of accounts by completing a New Account Application.

               INDIVIDUAL OR JOINT OWNERSHIP
               Individual accounts are owned by one person. Joint accounts have
               two or more owners.

               A GIFT OR TRANSFER TO MINOR (UGMA OR UTMA)
               An UGMA/UTMA is a custodial account managed for the benefit of a
               minor. To open an UGMA or UTMA, you must include the minor's
               Social Security number on the application.

               TRUST
               An established trust can open an account. The names of each
               trustee, the name of the trust and the date of the trust
               agreement must be included on the application.

                                                        Shareholder's manual  19
<PAGE>

               BUSINESS ACCOUNTS
               Corporations and partnerships may also open an account. The
               application must be signed by an authorized officer of the
               corporation or a general partner of the partnership.

TAX-DEFERRED ACCOUNTS

               If you are eligible, you may set up one or more tax-deferred
               accounts. A tax-deferred account allows you to shelter your
               investment income and capital gains from current income taxes. A
               contribution to certain of these plans may also be tax
               deductible. Tax-deferred accounts include retirement plans
               described below and the Education IRA. Please refer to the Janus
               retirement guide for more complete information regarding the
               different types of IRAs, including the Education IRA.
               Distributions from these plans are generally subject to income
               tax and may be subject to an additional tax if withdrawn prior to
               age 59 1/2 or used for a nonqualifying purpose. Investors should
               consult their tax adviser or legal counsel before selecting a
               tax-deferred account.

               Investors Fiduciary Trust Company serves as custodian for the
               tax-deferred accounts offered by the Fund. You will be charged an
               annual account maintenance fee of $12 for each taxpayer
               identification number no matter how many tax-deferred accounts
               you have with Janus. You may pay the fee by check or have it
               automatically deducted from your account (usually in December).
               The custodian reserves the right to change the amount of this fee
               or to waive it in whole or in part for certain types of accounts.

               TRADITIONAL AND ROTH INDIVIDUAL RETIREMENT ACCOUNTS
               Both types of IRAs allow most individuals with earned income to
               contribute up to the lesser of $2,000 ($4,000 for most married
               couples) or 100% of compensation annually.

               EDUCATION IRA
               This plan allows individuals, subject to certain income
               limitations, to contribute up to $500 annually on behalf of any
               child under the age of 18.

 20 Shareholder's manual
<PAGE>

               SIMPLIFIED EMPLOYEE PENSION PLAN
               This plan allows small business owners (including sole
               proprietors) to make tax-deductible contributions for themselves
               and any eligible employee(s). A SEP requires an IRA (a SEP-IRA)
               to be set up for each SEP participant.

               PROFIT SHARING OR MONEY PURCHASE PENSION PLAN
               These plans are open to corporations, partnerships and sole
               proprietors to benefit their employees and themselves.

               SECTION 403(B)(7) PLAN
               Employees of educational organizations or other qualifying, tax-
               exempt organizations may be eligible to participate in a Section
               403(b)(7) Plan.

               PLEASE REFER TO THE CHART ON THE FOLLOWING PAGES FOR INFORMATION
               ON OPENING AN ACCOUNT AND CONDUCTING BUSINESS WITH JANUS. WITH
               CERTAIN LIMITED EXCEPTIONS, THE FUND IS AVAILABLE ONLY TO U.S.
               CITIZENS OR RESIDENTS. WHEN YOU PURCHASE, EXCHANGE, OR REDEEM
               SHARES, YOUR REQUEST WILL BE PROCESSED AT THE NEXT NAV CALCULATED
               AFTER YOUR ORDER IS RECEIVED AND ACCEPTED.

                                                        Shareholder's manual  21
<PAGE>

 TO PURCHASE SHARES

 BY MAIL/IN WRITING
 ------------------------------------------------------------------------------

 - To open your account, complete and sign the appropriate application and make
   your check payable to Janus.

 - To purchase additional shares, complete the remittance slip attached at the
   bottom of your confirmation statement. If you are making a purchase into a
   retirement account, please indicate whether the purchase is a rollover or a
   current or prior year contribution. Send your check and remittance slip or
   written instructions to the address listed on the slip.

 BY TELEPHONE
 ------------------------------------------------------------------------------

 - The "Telephone Purchase of Shares Option" allows you to purchase additional
   shares quickly and conveniently through an electronic transfer of money.
   After establishing this option on your account, call an Investor Service
   Representative during normal business hours or the Janus XpressLine for
   access to this option 24 hours a day. Janus will automatically debit your
   predesignated bank account.

 - Purchases may also be made by wiring money from your bank account to your
   Janus account. Call an Investor Service Representative for wiring
   instructions.

 BY INTERNET
 ------------------------------------------------------------------------------

 - The "Telephone Purchase of Shares Option" allows you to make a purchase into
   an existing account on our Web site at janus.com.

 BY AUTOMATIC INVESTMENT
 ------------------------------------------------------------------------------

 - Automatic Monthly Investment Program - You select the day each month that
   your money ($100 minimum) will be electronically transferred from your bank
   account to your Fund account.

 - Payroll Deduction - If your employer can initiate an automatic payroll
   deduction, you may have all or a portion of your paycheck ($100 minimum)
   invested directly into your Fund account.

 22 Shareholder's manual
<PAGE>

<TABLE>
<S>                                            <C>
    TO EXCHANGE SHARES                           TO REDEEM SHARES
- ---------------------------------------        ---------------------------------------
    - To request an exchange in writing,         - To request a redemption in writ-
      please follow the instructions for           ing, please follow the instructions
      written requests on page 26. Also            for written requests on page 26.
      refer to the exchange policies             - Please see page 25 for information
      listed on page 24 for more infor-            about payment of redemption
      mation.                                      proceeds.

- ---------------------------------------        ---------------------------------------
    - All accounts are automatically eli-        - The telephone redemption option
      gible to exchange shares by tele-            enables you to request redemp-
      phone. To exchange all or a portion          tions daily from your account by
      of your shares into any other                calling an Investor Service Repre-
      available Janus fund, call an                sentative by the close of the
      Investor Service Representative or           regular trading session of the
      the Janus XpressLine.                        NYSE, normally 4:00 p.m. New York
                                                   time. You may also use Janus
                                                   XpressLine for access to this
                                                   option 24 hours a day.

- ---------------------------------------        ---------------------------------------
    - Exchanges may be made on our Web           - Redemptions may be made on our Web
      site at janus.com.                           site at janus.com.
- ---------------------------------------        ---------------------------------------
    - Systematic Exchange - You deter-           - Systematic Redemption - This option
      mine the amount of money you would           allows you to redeem a specific
      like automatically exchanged from            dollar amount from your account on
      one Janus account to another on any          a regular basis.
      day of the month. You may establish
      this program for as little as $100
      per month on existing accounts. You
      may establish a new account with a
      $500 initial purchase and subse-
      quent $100 systematic exchanges.
</TABLE>

                                                        Shareholder's manual  23
<PAGE>

PAYING FOR SHARES

Please note the following when purchasing shares:

- - Cash, credit cards, third party checks, travelers cheques, credit card checks
  or money orders will not be accepted.

- - All purchases must be made in U.S. dollars and checks must be drawn on U.S.
  banks.

- - We may make additional attempts to debit the bank account for ACH purchases.

- - The Fund reserves the right to reject any specific purchase request.

- - If all or a portion of a check is received for investment without a specific
  fund designation, the undesignated amount will be invested in the Janus Money
  Market Fund -- Investor Shares. Shares that are subsequently exchanged from
  Janus Money Market Fund -- Investor Shares into the selected Fund will receive
  the NAV next calculated after your order is received and accepted by the Fund.

- - If your purchase is cancelled, you will be responsible for any losses or fees
  imposed by your bank and losses that may be incurred as a result of any
  decline in the value of the cancelled purchase.

EXCHANGE POLICIES

The exchange privilege is not intended as a vehicle for short-term or excessive
trading. The Fund does not permit excessive trading or market timing. Excessive
purchases, redemptions, or exchanges of Fund shares disrupt portfolio management
and drive Fund expenses higher.

Please note the following when exchanging shares:

- - Except for Systematic Exchanges, new accounts established by exchange must be
  opened with $2,500 or the total account value if the value of the account you
  are exchanging from is less than $2,500.

- - Exchanges between existing accounts must meet the $100 subsequent investment
  requirement.

- - You may make four exchanges out of the Fund during a calendar year (exclusive
  of Systematic Exchange). Exchanges in excess of this limit are considered
  excessive trading and may be subject to an exchange fee or may result in
  termination of the exchange privilege or the right to make future purchases of
  Fund shares.

 24 Shareholder's manual
<PAGE>

- - The Fund reserves the right to reject any purchase order or exchange request
  and to modify or terminate the exchange privilege at any time. For example,
  the Fund may reject exchanges from accounts engaged in or known to engage in
  trading in excess of the limit above (including market timing transactions) or
  whose trading has been or may be disruptive to the Fund.

- - Exchanges between accounts will be accepted only if the registrations are
  identical.

- - If the shares you are exchanging are held in certificate form, you must return
  the certificate to Janus prior to making any exchanges. Effective June 4,
  1999, shares are no longer available in certificate form.

- - An exchange represents the sale of shares from one fund and the purchase of
  shares of another fund, which may produce a taxable gain or loss in a
  non-retirement account.

- - If the balance in the account you are exchanging from falls below the
  systematic exchange amount, all remaining shares will be exchanged
  and the program will be discontinued.

PAYMENT OF REDEMPTION PROCEEDS

- - BY CHECK - Redemption proceeds will be sent to the shareholder(s) of record at
  the address of record within seven days after receipt of a valid redemption
  request. During the 10 days following an address change, checks sent to a new
  address require a signature guarantee.

- - BY ELECTRONIC TRANSFER - If you have established the electronic redemption
  option, your redemption proceeds can be electronically transferred to your
  predesignated bank account on the next bank business day after receipt of your
  redemption request (wire transfer) or the second bank business day after
  receipt of your redemption request (ACH transfer).

Wire transfers will be charged an $8 fee per wire and your bank may charge an
additional fee to receive the wire. Wire redemptions are not available for
retirement accounts.

IF THE SHARES BEING REDEEMED WERE PURCHASED BY CHECK, TELEPHONE, ON OUR WEB
SITE, OR THROUGH THE AUTOMATIC MONTHLY INVESTMENT PROGRAM, THE FUND MAY DELAY
THE PAYMENT OF YOUR REDEMPTION PROCEEDS FOR UP TO 15 DAYS FROM THE DAY OF
PURCHASE TO ALLOW THE PURCHASE TO CLEAR. Unless you provide alternate
instructions, your proceeds will be invested in Janus Money Market
Fund - Investor Shares during the 15 day hold period.

                                                        Shareholder's manual  25
<PAGE>

WRITTEN INSTRUCTIONS

               To redeem or exchange all or part of your shares in writing, your
               request should be sent to one of the addresses listed on page 18
               and must include the following information:

               - the name of the Fund(s)

               - the account number(s)

               - the amount of money or number of shares being redeemed or
                 exchanged

               - the name(s) on the account

               - the signature(s) of all registered account owners (see account
                 application for signature requirements)

               - your daytime telephone number

SIGNATURE GUARANTEE

               A SIGNATURE GUARANTEE IS REQUIRED if any of the following is
               applicable:

               - You request a redemption by check that exceeds $100,000.

               - You would like a check made payable to anyone other than the
                 shareholder(s) of record.

               - You would like a check mailed to an address which has been
                 changed within 10 days of the redemption request.

               - You would like a check mailed to an address other than the
                 address of record.

               THE FUND RESERVES THE RIGHT TO REQUIRE A SIGNATURE GUARANTEE
               UNDER OTHER CIRCUMSTANCES OR TO REJECT OR DELAY A REDEMPTION ON
               CERTAIN LEGAL GROUNDS.

               HOW TO OBTAIN A SIGNATURE GUARANTEE

               A signature guarantee assures that a signature is genuine. The
               signature guarantee protects shareholders from unauthorized
               account transfers. The following financial institutions may
               guaran-

 26 Shareholder's manual
<PAGE>

               tee signatures: banks, savings and loan associations, trust
               companies, credit unions, broker-dealers, and member firms of a
               national securities exchange. Call your financial institution to
               see if they have the ability to guarantee a signature. A
               signature guarantee cannot be provided by a notary public.

               If you live outside the United States, a foreign bank properly
               authorized to do business in your country of residence or a U.S.
               consulate may be able to authenticate your signature.

PRICING OF FUND SHARES

               All purchases, redemptions and exchanges will be processed at the
               NAV next calculated after your request is received and accepted
               by the Fund (or the Fund's agent or authorized designee). The
               Fund's NAV is calculated at the close of the regular trading
               session of the NYSE (normally 4:00 p.m. New York time) each day
               that the NYSE is open. The NAV of Fund shares is not determined
               on days the NYSE is closed (generally New Year's Day, Martin
               Luther King Day, Presidents' Day, Good Friday, Memorial Day,
               Independence Day, Labor Day, Thanksgiving and Christmas). In
               order to receive a day's price, your order must be received by
               the close of the regular trading session of the NYSE. Securities
               are valued at market value or, if a market quotation is not
               readily available, at their fair value determined in good faith
               under procedures established by and under the supervision of the
               Trustees. Short-term instruments maturing within 60 days are
               valued at amortized cost, which approximates market value. See
               the SAI for more detailed information.

SHAREHOLDER SERVICES AND ACCOUNT POLICIES

               ACCOUNT MINIMUMS

               Due to the proportionately higher costs of maintaining small
               accounts, Janus reserves the right to deduct a $10 minimum
               balance fee (or the value of the account if less than $10) from
               accounts with values below the minimums described on page 19 or
               to close such accounts. This policy will apply to accounts

                                                        Shareholder's manual  27
<PAGE>

               participating in the Automatic Monthly Investment Program only if
               your account balance does not reach the required minimum initial
               investment or falls below such minimum and you have discontinued
               monthly investments. This policy does not apply to accounts that
               fall below the minimums solely as a result of market value
               fluctuations. It is expected that, for purposes of this policy,
               accounts will be valued in September, and the $10 fee will be
               assessed on the second Friday of September of each year. You will
               receive notice before we charge the $10 fee or close your account
               so that you may increase your account balance to the required
               minimum.

               TRANSACTIONS THROUGH PROCESSING ORGANIZATIONS

               You may purchase or sell Fund shares through a broker-dealer,
               bank or other financial institution, or an organization that
               provides recordkeeping and consulting services to 401(k) plans or
               other employee benefit plans (a "Processing Organization").
               Processing Organizations may charge you a fee for this service
               and may require different minimum initial and subsequent
               investments than the Fund. Processing Organizations may also
               impose other charges or restrictions different from those
               applicable to shareholders who invest in the Fund directly. A
               Processing Organization, rather than its customers, may be the
               shareholder of record of your shares. The Fund is not responsible
               for the failure of any Processing Organization to carry out its
               obligations to its customers. Certain Processing Organizations
               may receive compensation from Janus Capital or its affiliates and
               certain Processing Organizations may receive compensation from
               the Fund for shareholder recordkeeping and similar services.

               TAXPAYER IDENTIFICATION NUMBER

               On the application or other appropriate form, you will be asked
               to certify that your Social Security or taxpayer identification
               number is correct and that you are not subject to backup
               withholding for failing to report income to the IRS. If you are
               subject to the 31% backup withholding or you did not certify

 28 Shareholder's manual
<PAGE>

               your taxpayer identification number, the IRS requires the Fund to
               withhold 31% of any dividends paid and redemption or exchange
               proceeds. In addition to the 31% backup withholding, you may be
               subject to a $50 fee to reimburse the Fund for any penalty that
               the IRS may impose.

               INVOLUNTARY REDEMPTIONS

               The Fund reserves the right to close an account if the
               shareholder is deemed to engage in activities which are illegal
               or otherwise believed to be detrimental to the Fund.

               TELEPHONE TRANSACTIONS

               You may initiate many transactions by telephone. The Fund and its
               agents will not be responsible for any losses resulting from
               unauthorized transactions when procedures designed to verify the
               identity of the caller are followed.

               It may be difficult to reach an Investor Service Representative
               by telephone during periods of unusual market activity. If you
               are unable to reach a representative by telephone, please
               consider sending written instructions, stopping by a Service
               Center, calling the Janus XpressLine or visiting our Web site.

               TEMPORARY SUSPENSION OF SERVICES

               The Fund or its agents may, in case of emergency, temporarily
               suspend telephone transactions and other shareholder services.

               ADDRESS CHANGES

               To change the address on your account, call 1-800-525-3713 or
               send a written request signed by the shareholder(s) of record.
               Include the name of your Fund, the account number(s), the name(s)
               on the account and both the old and new addresses. Certain
               options may be suspended for 10 days following an address change
               unless a signature guarantee is provided.

                                                        Shareholder's manual  29
<PAGE>

               REGISTRATION CHANGES

               To change the name on an account, the shares are generally
               transferred to a new account. In some cases, legal documentation
               may be required. For further instructions, please call an
               Investor Service Representative.

               STATEMENTS AND REPORTS

               Investors will receive quarterly confirmations of all
               transactions. Quarterly statements for all investors are
               available on our Web site. You may make an election on our Web
               site to discontinue delivery of your paper statements. Dividend
               information will be distributed annually. In addition, the Fund
               will send you an immediate transaction confirmation statement
               after every non-systematic transaction.

               The Fund produces financial reports, which include a list of the
               Fund's portfolio holdings, semiannually and updates its
               prospectus annually. To reduce expenses, the Fund may choose to
               mail only one report or prospectus to your household, even if
               more than one person in the household has a Fund account. Please
               call 1-800-525-3713 if you would like to receive additional
               reports or prospectuses. The Fund reserves the right to charge a
               fee for additional statement requests.

 30 Shareholder's manual
<PAGE>

MANAGEMENT OF THE FUND
- --------------------------------------------------------------------------------

INVESTMENT ADVISER

               Janus Capital Corporation, 100 Fillmore Street, Denver, Colorado
               80206-4928, is the investment adviser to the Fund and is
               responsible for the day-to-day management of its investment
               portfolio and other business affairs.

               Janus Capital began serving as investment adviser to Janus Fund
               in 1970 and currently serves as investment adviser to all of the
               Janus funds, acts as sub-adviser for a number of private-label
               mutual funds and provides separate account advisory services for
               institutional accounts.

               Janus Capital furnishes continuous advice and recommendations
               concerning the Fund's investments. Janus Capital also furnishes
               certain administrative, compliance and accounting services for
               the Fund, and may be reimbursed by the Fund for its costs in
               providing those services. In addition, Janus Capital employees
               serve as officers of the Trust and Janus Capital provides office
               space for the Fund and pays the salaries, fees and expenses of
               all Fund officers and those Trustees who are affiliated with
               Janus Capital.

               The Fund pays Janus Capital a management fee which is calculated
               daily and paid monthly. The advisory agreement with the Fund
               spells out the management fee and other expenses that the Fund
               must pay.

               The Fund incurs expenses not assumed by Janus Capital, including
               transfer agent and custodian fees and expenses, legal and
               auditing fees, printing and mailing costs of sending reports and
               other information to existing shareholders, and independent
               Trustees' fees and expenses. For the most recent fiscal year, the
               Fund paid Janus Capital a management fee equal to 0.75% of
               average daily net assets.

                                  Janus Global Life Sciences Fund prospectus  31
<PAGE>

PORTFOLIO MANAGER

THOMAS R. MALLEY
- --------------------------------------------------------------------------------
                   is Executive Vice President and portfolio manager of the
                   Fund, which he has managed since inception. He joined
                   Janus Capital in 1991 as a research analyst and has
                   focused on companies in the health care, pharmaceutical
                   and biotechnology industries. Mr. Malley has a Bachelor of
                   Science in Biology from Stanford University. Mr. Malley is
                   a Chartered Financial Analyst.

 32 Janus Global Life Sciences Fund prospectus
<PAGE>

OTHER INFORMATION
- --------------------------------------------------------------------------------

               SIZE OF THE FUND

               The Fund may discontinue sales of its shares if management and
               the Trustees believe that continued sales may adversely affect
               the Fund's ability to achieve its investment objective. If sales
               of the Fund are discontinued, it is expected that existing
               shareholders of the Fund would be permitted to continue to
               purchase shares and to reinvest any dividends or capital gains
               distributions, absent highly unusual circumstances.

               YEAR 2000

               Preparing for Year 2000 has been a high priority for Janus
               Capital. A dedicated group was established to address this issue.
               Janus Capital devoted considerable internal resources and engaged
               one of the foremost experts in the field to achieve Year 2000
               readiness. Janus Capital successfully completed all five steps of
               its Year 2000 preparedness plans including the upgrade and
               replacement of all systems, as well as full-scale testing and
               implementation of those systems. Janus Capital's detailed
               contingency plans were also thoroughly tested. As of the date of
               this Prospectus, Janus Capital has not seen any adverse impact as
               a result of the Year 2000 transition on any of its systems or
               those of its vendors, or on the companies in which the Funds
               invest or worldwide markets and economies. Nonetheless, Janus
               Capital will continue to monitor the effect of the Year 2000
               transition, and there can be no absolute assurance that Year 2000
               issues will not in the future adversely affect the Funds' or
               Janus Capital's operations.

                                  Janus Global Life Sciences Fund prospectus  33
<PAGE>

               DISTRIBUTION OF THE FUND

               The Fund is distributed by Janus Distributors, Inc., a member of
               the National Association of Securities Dealers, Inc. ("NASD"). To
               obtain information about NASD member firms and their associated
               persons, you may contact NASD Regulation, Inc. at www.nasdr.com;
               or the Public Disclosure Hotline at 800-289-9999. An investor
               brochure containing information describing the Public Disclosure
               Program is available from NASD Regulation, Inc.

 34 Janus Global Life Sciences Fund prospectus
<PAGE>

DISTRIBUTIONS AND TAXES
- --------------------------------------------------------------------------------

DISTRIBUTIONS

               To avoid taxation of the Fund, the Internal Revenue Code requires
               the Fund to distribute net income and any net gains realized on
               its investments annually. The Fund's income from dividends and
               interest and any net realized short-term gains are paid to
               shareholders as ordinary income dividends. Net realized long-term
               gains are paid to shareholders as capital gains distributions.
               Dividends and capital gains distributions are normally declared
               and paid in December.

               HOW DISTRIBUTIONS AFFECT A FUND'S NAV

               Distributions are paid to shareholders as of the record date of
               the distribution of the Fund, regardless of how long the shares
               have been held. Dividends and capital gains awaiting distribution
               are included in the Fund's daily NAV. The share price of the Fund
               drops by the amount of the distribution, net of any subsequent
               market fluctuations. As an example, assume that on December 31,
               the Fund declared a dividend in the amount of $0.25 per share. If
               the Fund's share price was $10.00 on December 30, the Fund's
               share price on December 31 would be $9.75, barring market
               fluctuations. Shareholders should be aware that distributions
               from a taxable mutual fund are not value-enhancing and may create
               income tax obligations.

               "BUYING A DIVIDEND"

               If you purchase shares of the Fund just before the distribution,
               you will pay the full price for the shares and receive a portion
               of the purchase price back as a taxable distribution. This is
               referred to as "buying a dividend." In the above example, if you
               bought shares on December 30, you would have paid $10.00 per
               share. On December 31, the Fund would pay you $0.25 per share as
               a dividend and your shares would now be worth $9.75 per share.
               Unless your account is set up as a tax-deferred account,
               dividends paid to you would be included in your gross income for
               tax purposes, even though you may not have participated in the

                                  Janus Global Life Sciences Fund prospectus  35
<PAGE>

               increase in NAV of the Fund, whether or not you reinvested the
               dividends.

DISTRIBUTION OPTIONS

               When you open an account, you must specify on your application
               how you want to receive your distributions. You may change your
               distribution option at any time by writing the Fund at one of the
               addresses listed on page 18 or calling 1-800-525-3713. The Fund
               offers the following options:

               1. REINVESTMENT OPTION. You may reinvest your income dividends
                  and capital gains distributions in additional shares. This
                  option is assigned automatically if no other choice is made.

               2. CASH OPTION. You may receive your income dividends and capital
                  gains distributions in cash.

               3. REINVEST AND CASH OPTION. You may receive either your income
                  dividends or capital gains distributions in cash and reinvest
                  the other in additional shares.

               4. REDIRECT OPTION. You may direct your dividends or capital
                  gains to purchase shares of another Janus fund.

               The Fund reserves the right to reinvest into your account
               undeliverable and uncashed dividend and distribution checks that
               remain outstanding for six months in shares of the Fund at the
               NAV next computed after the check is cancelled. Subsequent
               distributions may also be reinvested.

TAXES

               As with any investment, you should consider the tax consequences
               of investing in the Fund. Any time you sell or exchange shares of
               a Fund in a taxable account, it is considered a taxable event.
               Depending on the purchase price and the sale price, you may have
               a gain or loss on the transaction. Any tax liabilities generated
               by your transactions are your responsibility.

               The following discussion does not apply to tax-deferred accounts,
               nor is it a complete analysis of the federal tax implications of

 36 Janus Global Life Sciences Fund prospectus
<PAGE>

               investing in the Fund. You may wish to consult your own tax
               adviser. Additionally, state or local taxes may apply to your
               investment, depending upon the laws of your state of residence.

               TAXES ON DISTRIBUTIONS

               Dividends and distributions by the Fund are subject to federal
               income tax, regardless of whether the distribution is made in
               cash or reinvested in additional shares of the Fund.
               Distributions may be taxable at different rates depending on the
               length of time the Fund holds a security. In certain states, a
               portion of the dividends and distributions (depending on the
               source of the Fund's income) may be exempt from state and local
               taxes. Information regarding the tax status of income dividends
               and capital gains distributions will be mailed to shareholders on
               or before January 31st of each year.

               TAXATION OF THE FUND

               Dividends, interest and some capital gains received by the Fund
               on foreign securities may be subject to tax withholding or other
               foreign taxes. The Fund may from year to year make the election
               permitted under Section 853 of the Internal Revenue Code to pass
               through such taxes to shareholders as a foreign tax credit. If
               such an election is not made, any foreign taxes paid or accrued
               will represent an expense to the Fund.

               The Fund does not expect to pay federal income or excise taxes
               because it intends to meet certain requirements of the Internal
               Revenue Code. It is important that the Fund meets these
               requirements so that any earnings on your investment will not be
               taxed twice.

                                  Janus Global Life Sciences Fund prospectus  37
<PAGE>

FINANCIAL HIGHLIGHTS
- --------------------------------------------------------------------------------

               The financial highlights table is intended to help you understand
               the Fund's financial performance through October 31st of each
               fiscal period shown. Items 1 through 9 reflect financial results
               for a single Fund share. The total returns in the table represent
               the rate that an investor would have earned (or lost) on an
               investment in the Fund (assuming reinvestment of all dividends
               and distributions). This information has been audited by
               PricewaterhouseCoopers LLP, whose report, along with the Fund's
               financial statements, are included in the Annual Reports, which
               are available upon request and incorporated by reference into the
               SAI.

 38 Janus Global Life Sciences Fund prospectus
<PAGE>

<TABLE>
<CAPTION>
JANUS GLOBAL LIFE SCIENCES FUND
- -----------------------------------------------------------------------------
                                                                Period ending
                                                                October 31st
                                                                   1999(1)
<S>                                                             <C>
  1. NET ASSET VALUE, BEGINNING OF PERIOD                           $10.00
     INCOME FROM INVESTMENT OPERATIONS:
  2. Net investment income                                              --
  3. Net gains or (losses) on securities (both realized and
     unrealized)                                                      1.97
  4. Total from investment operations                                 1.97
     LESS DISTRIBUTIONS:
  5. Dividends (from net investment income)                             --
  6. Dividends (in excess of net investment income)                     --
  7. Distributions (from capital gains)                                 --
  8. Total distributions                                                --
  9. NET ASSET VALUE, END OF PERIOD                                 $11.97
 10. Total return*                                                  19.70%
 11. Net assets, end of period (in millions)                          $344
 12. Average net assets for the period (in millions)                  $228
 13. Ratio of gross expenses to average net assets**                 1.21%
 14. Ratio of net expenses to average net assets**                   1.19%
 15. Ratio of net investment income/(loss) to average net
     assets**                                                      (0.41%)
 16. Portfolio turnover rate**                                        235%
- -----------------------------------------------------------------------------
</TABLE>

(1) Fiscal period from December 31, 1998 (inception) to October 31, 1999.
  * Total return is not annualized for periods of less than one full year.
 ** Annualized for periods of less than one full year.

                                  Janus Global Life Sciences Fund prospectus  39
<PAGE>

GLOSSARY OF INVESTMENT TERMS
- --------------------------------------------------------------------------------

               This glossary provides a more detailed description of some of the
               types of securities and other instruments in which the Fund may
               invest. The Fund may invest in these instruments to the extent
               permitted by its investment objective and policies. The Fund is
               not limited by this discussion and may invest in any other types
               of instruments not precluded by the policies discussed elsewhere
               in this Prospectus. Please refer to the SAI for a more detailed
               discussion of certain instruments.

I. EQUITY AND DEBT SECURITIES

               BONDS are debt securities issued by a company, municipality,
               government or government agency. The issuer of a bond is required
               to pay the holder the amount of the loan (or par value of the
               bond) at a specified maturity and to make scheduled interest
               payments.

               COMMERCIAL PAPER is a short-term debt obligation with a maturity
               ranging from 1 to 270 days issued by banks, corporations and
               other borrowers to investors seeking to invest idle cash. The
               Fund may purchase commercial paper issued in private placements
               under Section 4(2) of the Securities Act of 1933.

               COMMON STOCKS are equity securities representing shares of
               ownership in a company, and usually carry voting rights and earns
               dividends. Unlike preferred stock, dividends on common stock are
               not fixed but are declared at the discretion of the issuer's
               board of directors.

               CONVERTIBLE SECURITIES are preferred stocks or bonds that pay a
               fixed dividend or interest payment and are convertible into
               common stock at a specified price or conversion ratio.

               DEBT SECURITIES are securities representing money borrowed that
               must be repaid at a later date. Such securities have specific
               maturities and usually a specific rate of interest or an original
               purchase discount.

               DEPOSITARY RECEIPTS are receipts for shares of a foreign-based
               corporation that entitle the holder to dividends and capital
               gains

 40 Janus Global Life Sciences Fund prospectus
<PAGE>

               on the underlying security. Receipts include those issued by
               domestic banks (American Depositary Receipts), foreign banks
               (Global or European Depositary Receipts) and broker-dealers
               (depositary shares).

               FIXED-INCOME SECURITIES are securities that pay a specified rate
               of return. The term generally includes short- and long-term
               government, corporate and municipal obligations that pay a
               specified rate of interest or coupons for a specified period of
               time and preferred stock, which pays fixed dividends. Coupon and
               dividend rates may be fixed for the life of the issue or, in the
               case of adjustable and floating rate securities, for a shorter
               period.

               HIGH-YIELD/HIGH-RISK BONDS are bonds that are rated below
               investment grade by the primary rating agencies (e.g., BB or
               lower by Standard & Poor's and Ba or lower by Moody's). Other
               terms commonly used to describe such bonds include "lower rated
               bonds," "noninvestment grade bonds" and "junk bonds."

               MORTGAGE- AND ASSET-BACKED SECURITIES are shares in a pool of
               mortgages or other debt. These securities are generally pass-
               through securities, which means that principal and interest
               payments on the underlying securities (less servicing fees) are
               passed through to shareholders on a pro rata basis. These
               securities involve prepayment risk, which is the risk that the
               underlying mortgages or other debt may be refinanced or paid off
               prior to their maturities during periods of declining interest
               rates. In that case, the portfolio manager may have to reinvest
               the proceeds from the securities at a lower rate. Potential
               market gains on a security subject to prepayment risk may be more
               limited than potential market gains on a comparable security that
               is not subject to prepayment risk.

               PASSIVE FOREIGN INVESTMENT COMPANIES ("PFICS") are any foreign
               corporations which generate amounts of passive income or hold
               certain amounts of assets for the production of passive income.
               Passive income includes dividends, interest, royalties, rents and
               annuities. To avoid taxes and interest that the Fund must pay if
               these investments are profitable, the Fund may make various

                                  Janus Global Life Sciences Fund prospectus  41
<PAGE>

               elections permitted by the tax laws. These elections could
               require that the Fund recognize taxable income, which in turn
               must be distributed, before the securities are sold and before
               cash is received to pay the distributions.

               PREFERRED STOCKS are equity securities that generally pay
               dividends at a specified rate and have preference over common
               stock in the payment of dividends and liquidation. Preferred
               stock generally does not carry voting rights.

               REPURCHASE AGREEMENTS involve the purchase of a security by the
               Fund and a simultaneous agreement by the seller (generally a bank
               or dealer) to repurchase the security from the Fund at a
               specified date or upon demand. This technique offers a method of
               earning income on idle cash. These securities involve the risk
               that the seller will fail to repurchase the security, as agreed.
               In that case, the Fund will bear the risk of market value
               fluctuations until the security can be sold and may encounter
               delays and incur costs in liquidating the security.

               REVERSE REPURCHASE AGREEMENTS involve the sale of a security by
               the Fund to another party (generally a bank or dealer) in return
               for cash and an agreement by the Fund to buy the security back at
               a specified price and time. This technique will be used primarily
               to provide cash to satisfy unusually heavy redemption requests,
               or for other temporary or emergency purposes.

               U.S. GOVERNMENT SECURITIES include direct obligations of the U.S.
               government that are supported by its full faith and credit.
               Treasury bills have initial maturities of less than one year,
               Treasury notes have initial maturities of one to ten years and
               Treasury bonds may be issued with any maturity but generally have
               maturities of at least ten years. U.S. government securities also
               include indirect obligations of the U.S. government that are
               issued by federal agencies and government sponsored entities.
               Unlike Treasury securities, agency securities generally are not
               backed by the full faith and credit of the U.S. government. Some
               agency securities are supported by the right of the issuer to
               borrow from the Treasury, others are supported by the
               discretionary authority

 42 Janus Global Life Sciences Fund prospectus
<PAGE>

               of the U.S. government to purchase the agency's obligations and
               others are supported only by the credit of the sponsoring agency.

               VARIABLE AND FLOATING RATE SECURITIES have variable or floating
               rates of interest and, under certain limited circumstances, may
               have varying principal amounts. These securities pay interest at
               rates that are adjusted periodically according to a specified
               formula, usually with reference to some interest rate index or
               market interest rate. The floating rate tends to decrease the
               security's price sensitivity to changes in interest rates.

               WARRANTS are securities, typically issued with preferred stocks
               or bonds, that give the holder the right to buy a proportionate
               amount of common stock at a specified price, usually at a price
               that is higher than the market price at the time of issuance of
               the warrant. The right may last for a period of years or
               indefinitely.

               WHEN-ISSUED, DELAYED DELIVERY AND FORWARD TRANSACTIONS generally
               involve the purchase of a security with payment and delivery at
               some time in the future - i.e., beyond normal settlement. The
               Fund does not earn interest on such securities until settlement
               and bears the risk of market value fluctuations in between the
               purchase and settlement dates. New issues of stocks and bonds,
               private placements and U.S. government securities may be sold in
               this manner.

II. FUTURES, OPTIONS AND OTHER DERIVATIVES

               FORWARD CONTRACTS are contracts to purchase or sell a specified
               amount of a financial instrument for an agreed upon price at a
               specified time. Forward contracts are not currently exchange
               traded and are typically negotiated on an individual basis. The
               Fund may enter into forward currency contracts to hedge against
               declines on the value of securities denominated in, or whose
               value is tied to, a currency other than the U.S. dollar or to
               reduce the impact of currency appreciation on purchases of such
               securities. It may also enter into forward contracts to purchase
               or sell securities or other financial indices.

                                  Janus Global Life Sciences Fund prospectus  43
<PAGE>

               FUTURES CONTRACTS are contracts that obligate the buyer to
               receive and the seller to deliver an instrument or money at a
               specified price on a specified date. The Fund may buy and sell
               futures contracts on foreign currencies, securities and financial
               indices including interest rates or an index of U.S. government,
               foreign government, equity or fixed-income securities. The Fund
               may also buy options on futures contracts. An option on a futures
               contract gives the buyer the right, but not the obligation, to
               buy or sell a futures contract at a specified price on or before
               a specified date. Futures contracts and options on futures are
               standardized and traded on designated exchanges.

               INDEXED/STRUCTURED SECURITIES are typically short- to
               intermediate-term debt securities whose value at maturity or
               interest rate is linked to currencies, interest rates, equity
               securities, indices, commodity prices or other financial
               indicators. Such securities may be positively or negatively
               indexed (i.e., their value may increase or decrease if the
               reference index or instrument appreciates). Indexed/structured
               securities may have return characteristics similar to direct
               investments in the underlying instruments and may be more
               volatile than the underlying instruments. The Fund bears the
               market risk of an investment in the underlying instruments, as
               well as the credit risk of the issuer.

               OPTIONS are the right, but not the obligation, to buy or sell a
               specified amount of securities or other assets on or before a
               fixed date at a predetermined price. The Fund may purchase and
               write put and call options on securities, securities indices and
               foreign currencies.

 44 Janus Global Life Sciences Fund prospectus
<PAGE>

                       This page intentionally left blank
<PAGE>

                                  [JANUS LOGO]

        You can request other information, including a Statement of
        Additional Information, Annual Report or Semiannual Report free
        of charge, by contacting Janus at 1-800-525-3713 or visiting our
        Web site at janus.com. In the Fund's Annual Report, you will
        find a discussion of the market conditions and investment
        strategies that significantly affected the Fund's performance
        during its last fiscal year. Other information is also available
        from financial intermediaries that sell shares of the Fund.

        The Statement of Additional Information provides detailed
        information about the Fund and is incorporated into this
        Prospectus by reference. You may review the Fund's Statement of
        Additional Information at the Public Reference Room of the SEC
        or get text only copies for a fee, by writing to or calling the
        Public Reference Room, Washington, D.C. 20549-6009
        (1-800-SEC-0330). You may obtain the Statement of Additional
        Information for free from the SEC's Web site at
        http://www.sec.gov.

                    Investment Company Act File No. 811-1879

                                 1-800-525-3713
                     PO Box 173375  Denver, CO  80217-3375
                                   janus.com
4237


<PAGE>

                                  [JANUS LOGO]
                                 JANUS  SPECIAL
                                SITUATIONS  FUND
                                   PROSPECTUS

                                                   JANUARY 31, 2000

             The Securities and Exchange Commission has not
             approved or disapproved of these securities or passed
             on the accuracy or adequacy of this Prospectus. Any
             representation to the contrary is a criminal offense.

<PAGE>

- --------------------------------------------------------------------------------
<PAGE>

TABLE OF CONTENTS
- --------------------------------------------------------------------------------

<TABLE>
                <S>                                               <C>
                RISK/RETURN SUMMARY
                   Janus Special Situations Fund................    2
                   Fees and expenses............................    5
                INVESTMENT OBJECTIVE, PRINCIPAL INVESTMENT
                STRATEGIES AND RISKS
                   Investment objective and principal investment
                   strategies...................................    6
                   General portfolio policies...................    8
                   Risks........................................   10
                SHAREHOLDER'S MANUAL
                   Minimum investments..........................   17
                   Types of account ownership...................   17
                   To purchase shares...........................   20
                   To exchange shares...........................   21
                   To redeem shares.............................   21
                   Shareholder services and account policies....   25
                MANAGEMENT OF THE FUND
                   Investment adviser...........................   29
                   Portfolio manager............................   30
                OTHER INFORMATION............... ...............   31
                DISTRIBUTIONS AND TAXES
                   Distributions................................   33
                   Taxes........................................   34
                FINANCIAL HIGHLIGHTS.............. .............   36
                GLOSSARY
                   Glossary of investment terms.................   37

</TABLE>

                                     Janus Special Situations Fund prospectus  1
<PAGE>

RISK/RETURN SUMMARY
- --------------------------------------------------------------------------------

JANUS SPECIAL SITUATIONS FUND

1. WHAT IS THE INVESTMENT OBJECTIVE OF JANUS SPECIAL SITUATIONS FUND?

               The Fund seeks capital appreciation.

               The Fund's Trustees may change this objective without a
               shareholder vote and the Fund will notify you of any changes that
               are material. If there is a material change in the Fund's
               objective or policies, you should consider whether the Fund
               remains an appropriate investment for you. There is no guarantee
               that the Fund will meet its objective.

2. WHAT ARE THE MAIN INVESTMENT STRATEGIES OF JANUS SPECIAL SITUATIONS FUND?

               The Fund invests primarily in common stocks selected for their
               capital appreciation potential. The Fund emphasizes stocks of
               "special situation" companies that the portfolio manager believes
               have been overlooked or undervalued by other investors. A
               "special situation" arises when, in the portfolio manager's
               opinion, securities of a particular company will appreciate in
               value due to a specific development. The portfolio manager pays
               particular attention to companies that he thinks have high free
               cash flows.

               The Fund may invest without limit in foreign equity and debt
               securities and less than 35% of its net assets in
               high-yield/high-risk bonds.

               The portfolio manager applies a "bottom up" approach in choosing
               investments. In other words, he looks for companies with earnings
               growth potential one at a time. If the portfolio manager is
               unable to find such investments, a significant portion of the
               Fund's assets may be in cash or similar investments.

3. WHAT ARE THE MAIN RISKS OF INVESTING IN JANUS SPECIAL SITUATIONS FUND?

               The biggest risk of investing in this Fund is that its returns
               may vary and you could lose money. If you are considering
               investing in the Fund, remember that it is designed for long-term
               investors who can accept the risks of investing in a portfolio
               with

 2 Janus Special Situations Fund prospectus
<PAGE>

               significant common stock holdings. Common stocks tend to be more
               volatile than other investment choices.

               The value of the Fund's portfolio may decrease if the value of an
               individual company in the portfolio decreases. The value of the
               Fund's portfolio could also decrease if the stock market goes
               down. If the value of the Fund's portfolio decreases, the Fund's
               net asset value (NAV) will also decrease which means if you sell
               your shares in the Fund you would get back less money.

               The Fund emphasizes investments in special situation companies
               which may not appreciate if an anticipated development does not
               occur or attract the anticipated attention. See "What is a
               'special situation'?" on page 7 for an explanation of what the
               portfolio manager may consider a special situation.

               The Fund is nondiversified. In other words, it may hold larger
               positions in a smaller number of securities than a diversified
               fund. As a result, a single security's increase or decrease in
               value may have a greater impact on the Fund's NAV and total
               return.

               An investment in the Fund is not a bank deposit and is not
               insured or guaranteed by the Federal Deposit Insurance
               Corporation or any other government agency.

                                     Janus Special Situations Fund prospectus  3
<PAGE>

               The following information illustrates how the Fund's performance
               has varied over time. The bar chart depicts the change in the
               Fund's performance from year-to-year during the periods
               indicated. The table compares the Fund's average annual returns
               for the periods indicated to a broad-based securities market
               index.

                JANUS SPECIAL SITUATIONS FUND

                A BAR CHART showing Annual Total Returns for Janus Special
                Situations Fund from 1997 through 1999:

                Annual returns for periods ended 12/31
<TABLE>
                <S>                                         <C>      <C>     <C>
                                                            46.04%   25.31%   52.46%
                                                             1997     1998     1999

                Each percentage is represented by a bar of proportionate size
                with the actual total return printed above the bar.

                Best Quarter:  4th-1998   28.53%   Worst Quarter:  3rd-1998  (19.55%)
</TABLE>

                          Average annual total return for periods ended 12/31/99
                          ------------------------------------------------------

<TABLE>
<CAPTION>
                                                                            Since Inception
                                                                   1 year     (12/31/96)
                <S>                                               <C>          <C>
                Janus Special Situations Fund                      52.46%       40.78%
                S&P 500 Index*                                     21.03%       27.56%
                                                               ----------------------------
</TABLE>

                * The S&P 500 is the Standard & Poor's Composite Index of 500
                  Stocks, a widely recognized, unmanaged index of common stock
                  prices.

               The Fund's past performance does not necessarily indicate how it
               will perform in the future.

 4 Janus Special Situations Fund prospectus
<PAGE>

FEES AND EXPENSES

               SHAREHOLDER FEES, such as sales loads, redemption fees or
               exchange fees, are charged directly to an investor's account. All
               Janus funds are no-load investments, so you will not pay any
               shareholder fees when you buy or sell shares of the Fund.

               ANNUAL FUND OPERATING EXPENSES are paid out of the Fund's assets
               and include fees for portfolio management, maintenance of
               shareholder accounts, shareholder servicing, accounting and other
               services. You do not pay these fees directly but, as the example
               below shows, these costs are borne indirectly by all
               shareholders.

               This table describes the fees and expenses that you may pay if
               you buy and hold shares of the Fund. It is based upon gross
               expenses (without the effect of expense offset arrangements). All
               of the fees and expenses shown were determined based on net
               assets as of the fiscal year ended October 31, 1999.

<TABLE>
<CAPTION>
                                                     Janus Special Situations Fund
   <S>                                                           <C>
   Management Fee(1)                                              0.65%
   Other Expenses                                                 0.31%
   Total Annual Fund Operating Expenses                           0.96%
</TABLE>

- --------------------------------------------------------------------------------
  (1) "Management Fee" information has been restated to reflect a new fee
      schedule effective January 31, 2000.
- --------------------------------------------------------------------------------
  EXAMPLE:
  This example is intended to help you compare the cost of investing in the
  Fund with the cost of investing in other mutual funds. The example
  assumes that you invest $10,000 in the Fund for the time periods
  indicated then redeem all of your shares at the end of those periods. The
  example also assumes that your investment has a 5% return each year and
  that the Fund's operating expenses remain the same. Although your actual
  costs may be higher or lower, based on these assumptions your costs would
  be:

<TABLE>
<CAPTION>
                                             1 Year    3 Years    5 Years    10 Years
                                             ----------------------------------------
   <S>                                       <C>       <C>        <C>        <C>
   Janus Special Situations Fund              $98       $306       $531       $1,178
</TABLE>

                                     Janus Special Situations Fund prospectus  5
<PAGE>

INVESTMENT OBJECTIVE, PRINCIPAL INVESTMENT
STRATEGIES AND RISKS
- --------------------------------------------------------------------------------

               This section takes a closer look at the investment objective of
               the Fund, its principal investment strategies and certain risks
               of investing in the Fund. Strategies and policies that are noted
               as "fundamental" cannot be changed without a shareholder vote.

               Please carefully review the "Risks" section of this Prospectus on
               pages 10-13 for a discussion of risks associated with certain
               investment techniques. We've also included a Glossary with
               descriptions of investment terms used throughout this Prospectus.

INVESTMENT OBJECTIVE AND PRINCIPAL INVESTMENT STRATEGIES

               Janus Special Situations Fund seeks capital appreciation. It
               pursues its objective by investing primarily in common stocks
               selected for their capital appreciation potential. The Fund
               emphasizes stocks of "special situation" companies that the
               portfolio manager believes have been overlooked or undervalued by
               other investors. A "special situation" arises when, in the
               portfolio manager's opinion, securities of a particular company
               will appreciate in value due to a specific development. The
               portfolio manager pays particular attention to companies that he
               thinks may have high free cash flows.

The following questions and answers are designed to help you better understand
the Fund's principal investment strategies.

1. HOW ARE COMMON STOCKS SELECTED?

               The Fund may invest substantially all of its assets in common
               stocks if its portfolio manager believes that common stocks will
               appreciate in value. The portfolio manager generally takes a
               "bottom up" approach to selecting companies. In other words, he
               seeks to identify individual companies with earnings growth
               potential that may not be recognized by the market at large. He
               makes this assessment by looking at companies one at a time,
               regardless of size, country of organization, place of principal
               business activity, or other similar selection criteria.
               Realization of income is not a significant consideration when
               choosing invest-

 6 Janus Special Situations Fund prospectus
<PAGE>

               ments for the Fund. Income realized on the Fund's investments
               will be incidental to its objective.

2. ARE THE SAME CRITERIA USED TO SELECT FOREIGN SECURITIES?

               Generally, yes. The portfolio manager seeks companies that meet
               his selection criteria regardless of where a company is located.
               Foreign securities are generally selected on a stock-by-stock
               basis without regard to any defined allocation among countries or
               geographic regions. However, certain factors such as expected
               levels of inflation, government policies influencing business
               conditions, the outlook for currency relationships, and prospects
               for economic growth among countries, regions or geographic areas
               may warrant greater consideration in selecting foreign
               securities. There are no limitations on the countries in which
               the Fund may invest and the Fund may at times have significant
               foreign exposure.

3. WHAT IS A "SPECIAL SITUATION"?

               The Fund emphasizes investments in special situations. A special
               situation arises when the portfolio manager believes that the
               securities of an issuer will be recognized and appreciate in
               value due to a specific development with respect to that issuer.
               Special situations may include significant changes in a company's
               allocation of its existing capital, a restructuring of assets, or
               a redirection of free cash flows. For example, issuers undergoing
               significant capital changes may include companies involved in
               spin-offs, sales of divisions, mergers or acquisitions, companies
               emerging from bankruptcy, or companies initiating large changes
               in their debt to equity ratio. Companies that are redirecting
               cash flows may be reducing debt, repurchasing shares or paying
               dividends. Special situations may also result from (i)
               significant changes in industry structure through regulatory
               developments or shifts in competition; (ii) a new or improved
               product, service, operation or technological advance; (iii)
               changes in senior management; and (iv) significant changes in
               cost structure. The Fund's performance could suffer if the
               anticipated development in

                                     Janus Special Situations Fund prospectus  7
<PAGE>

               a "special situation" investment does not occur or does not
               attract the expected attention.

GENERAL PORTFOLIO POLICIES

               In investing its portfolio assets, the Fund will follow the
               general policies listed below. The percentage limitations
               included in these policies and elsewhere in this Prospectus apply
               only at the time of purchase of the security. So, for example, if
               the Fund exceeds a limit as a result of market fluctuations or
               the sale of securities, it will not be required to dispose of any
               securities.

               CASH POSITION
               When the Fund's portfolio manager believes that market conditions
               are unfavorable for profitable investing, or when he is otherwise
               unable to locate attractive investment opportunities, the Fund's
               cash or similar investments may increase. In other words, the
               Fund does not always stay fully invested in stocks. Cash or
               similar investments generally are a residual - they represent the
               assets that remain after the portfolio manager has committed
               available assets to desirable investment opportunities. However,
               the portfolio manager may also temporarily increase the Fund's
               cash position to protect its assets or maintain liquidity. When
               the Fund's investments in cash or similar investments increase,
               it may not participate in market advances or declines to the same
               extent that it would if the Fund remained more fully invested in
               stocks.

               OTHER TYPES OF INVESTMENTS
               The Fund invests primarily in domestic and foreign equity
               securities, which may include preferred stocks, common stocks,
               warrants and securities convertible into common or preferred
               stocks, but it may also invest to a lesser degree in other types
               of securities. These securities (which are described in the
               Glossary) may include:

               - debt securities

               - indexed/structured securities

               - high-yield/high-risk bonds (less than 35% of the Fund's assets)

 8 Janus Special Situations Fund prospectus
<PAGE>

               - options, futures, forwards, swaps and other types of
                 derivatives for hedging purposes or for non-hedging purposes
                 such as seeking to enhance return

               - securities purchased on a when-issued, delayed delivery or
                 forward commitment basis

               ILLIQUID INVESTMENTS
               The Fund may invest up to 15% of its net assets in illiquid
               investments. An illiquid investment is a security or other
               position that cannot be disposed of quickly in the normal course
               of business. For example, some securities are not registered
               under the U.S. securities laws and cannot be sold to the U.S.
               public because of SEC regulations (these are known as "restricted
               securities"). Under procedures adopted by the Fund's Trustees,
               certain restricted securities may be deemed liquid, and will not
               be counted toward this 15% limit.

               FOREIGN SECURITIES
               The Fund may invest without limit in foreign equity and debt
               securities. The Fund may invest directly in foreign securities
               denominated in a foreign currency and not publicly traded in the
               United States. Other ways of investing in foreign securities
               include depositary receipts or shares, and passive foreign
               investment companies.

               PORTFOLIO TURNOVER
               The Fund generally intends to purchase securities for long-term
               investment although, to a limited extent, the Fund may purchase
               securities in anticipation of relatively short-term price gains.
               Short-term transactions may also result from liquidity needs,
               securities having reached a price or yield objective, changes in
               interest rates or the credit standing of an issuer, or by reason
               of economic or other developments not foreseen at the time of the
               investment decision. The Fund may also sell one security and
               simultaneously purchase the same or a comparable security to take
               advantage of short-term differentials in bond yields or
               securities prices. Changes

                                     Janus Special Situations Fund prospectus  9
<PAGE>

               are made in the Fund's portfolio whenever its portfolio manager
               believes such changes are desirable. Portfolio turnover rates are
               generally not a factor in making buy and sell decisions.

               Increased portfolio turnover may result in higher costs for
               brokerage commissions, dealer mark-ups and other transaction
               costs and may also result in taxable capital gains. Higher costs
               associated with increased portfolio turnover may offset gains in
               the Fund's performance.

RISKS

               Because the Fund may invest substantially all of its assets in
               common stocks, the main risk is the risk that the value of the
               stocks it holds might decrease in response to the activities of
               an individual company or in response to general market and/or
               economic conditions. If this occurs, the Fund's share price may
               also decrease. The Fund's performance may also be affected by
               risks specific to certain types of investments, such as foreign
               securities, derivative investments, non-investment grade bonds,
               initial public offerings (IPOs) or companies with relatively
               small market capitalizations. IPOs and other investment
               techniques may have a magnified performance impact on a fund with
               a small asset base. A fund may not experience similar performance
               as its assets grow.

 10 Janus Special Situations Fund prospectus
<PAGE>

The following questions and answers are designed to help you better understand
some of the risks of investing in the Fund.

1. THE FUND MAY INVEST IN SMALLER OR NEWER COMPANIES. DOES THIS CREATE ANY
   SPECIAL RISKS?

               Many attractive investment opportunities may be smaller, start-up
               companies offering emerging products or services. Smaller or
               newer companies may suffer more significant losses as well as
               realize more substantial growth than larger or more established
               issuers because they may lack depth of management, be unable to
               generate funds necessary for growth or potential development, or
               be developing or marketing new products or services for which
               markets are not yet established and may never become established.
               In addition, such companies may be insignificant factors in their
               industries and may become subject to intense competition from
               larger or more established companies. Securities of smaller or
               newer companies may have more limited trading markets than the
               markets for securities of larger or more established issuers, and
               may be subject to wide price fluctuations. Investments in such
               companies tend to be more volatile and somewhat more speculative.

2. HOW DOES THE NONDIVERSIFIED STATUS OF THE FUND AFFECT ITS RISK?

               Diversification is a way to reduce risk by investing in a broad
               range of stocks or other securities. A "nondiversified" fund has
               the ability to take larger positions in a smaller number of
               issuers. Because the appreciation or depreciation of a single
               stock may have a greater impact on the NAV of a nondiversified
               fund, its share price can be expected to fluctuate more than a
               comparable diversified fund. This fluctuation, if significant,
               may affect the performance of the Fund.

3. I'VE HEARD A LOT ABOUT HOW THE CHANGE TO THE YEAR 2000 COULD AFFECT COMPUTER
   SYSTEMS. DOES THIS CREATE ANY SPECIAL RISKS?

               The portfolio manager carefully researches each potential
               investment before making an investment decision and, among other
               things considers what impact, if any, the Year 2000

                                    Janus Special Situations Fund prospectus  11
<PAGE>

               transition has had on the company's operations when selecting
               portfolio holdings. However, there is no guarantee that the
               information the portfolio manager receives regarding a company's
               Year 2000 transition status is completely accurate. If a company
               has not satisfactorily addressed Year 2000 issues, the Fund's
               performance could suffer.

4. HOW COULD THE FUND'S INVESTMENTS IN FOREIGN SECURITIES AFFECT ITS
   PERFORMANCE?

               The Fund may invest without limit in foreign securities either
               indirectly (e.g., depositary receipts) or directly in foreign
               markets. Investments in foreign securities, including those of
               foreign governments, may involve greater risks than investing in
               domestic securities because the Fund's performance may depend on
               issues other than the performance of a particular company. These
               issues include:

               - currency risk

               - political and economic risk

               - regulatory risk

               - market risk

               - transaction costs

               These risks are described in the SAI.

5. ARE THERE SPECIAL RISKS ASSOCIATED WITH INVESTMENTS IN HIGH-YIELD/HIGH-RISK
   BONDS?

               High-yield/high-risk bonds (or "junk" bonds) are bonds rated
               below investment grade by the primary rating agencies such as
               Standard & Poor's and Moody's. The value of lower quality bonds
               generally is more dependent on credit risk, or the ability of the
               issuer to meet interest and principal payments, than investment
               grade bonds. Issuers of high-yield bonds may not be as strong
               financially as those issuing bonds with higher credit ratings and
               are more vulnerable to real or perceived economic changes,
               political changes or adverse developments specific to the issuer.

 12 Janus Special Situations Fund prospectus
<PAGE>

               Please refer to the SAI for a description of bond rating
               categories.

6. HOW DOES THE FUND TRY TO REDUCE RISK?

               The Fund may use futures, options, swaps and other derivative
               instruments to "hedge" or protect its portfolio from adverse
               movements in securities prices and interest rates. The Fund may
               also use a variety of currency hedging techniques, including
               forward currency contracts, to manage exchange rate risk. The
               portfolio manager believes the use of these instruments will
               benefit the Fund. However, the Fund's performance could be worse
               than if the Fund had not used such instruments if the portfolio
               manager's judgement proves incorrect. Risks associated with the
               use of derivative instruments are described in the SAI.

                                    Janus Special Situations Fund prospectus  13
<PAGE>

- --------------------------------------------------------------------------------
<PAGE>

                                  [JANUS LOGO]
                                 JANUS  SPECIAL
                                SITUATIONS  FUND
                              SHAREHOLDER'S MANUAL

                                           This section will help you
                                           become familiar with the
                                           different types of accounts
                                           you can establish with Janus.
                                           It also explains in detail the
                                           wide array of services and
                                           features you can establish on
                                           your account, as well as
                                           account policies and fees that
                                           may apply to your account.
                                           Account policies (including
                                           fees), services and features
                                           may be modified or
                                           discontinued without
                                           shareholder approval or prior
                                           notice.

                                           [JANUS LOGO]

<PAGE>

HOW TO GET IN TOUCH WITH JANUS

INVESTOR SERVICE CENTERS
100 Fillmore Street, Suite 100
Denver, CO 80206

3773 Cherry Creek North Drive, Suite 101
Denver, CO 80209

(Hours: Monday-Friday 7:00 a.m.-6:00 p.m., and Saturday 9:00 a.m.-1:00 p.m.,
Mountain time.)

MAILING ADDRESS
Janus
P.O. Box 173375
Denver, CO 80217-3375

FOR OVERNIGHT CARRIER
Janus
Suite 101
3773 Cherry Creek Drive North
Denver, CO 80209-3821

INVESTOR SERVICE REPRESENTATIVES
If you have any questions while reading this Prospectus, please call one of our
Investor Service Representatives at 1-800-525-3713 Monday-Friday: 8:00 a.m.-8:00
p.m., and Saturday: 10:00 a.m.-4:00 p.m., New York time.

JANUS XPRESSLINE(TM)
1-888-979-7737

JANUS INTERNET ADDRESS
JANUS.COM

For 24-hour access to account and fund information, exchanges, purchases and
redemptions, automated daily quotes on fund share prices, yields and total
returns.

JANUS.COM SPECIALISTS
1-800-975-9932

TDD
1-800-525-0056
A telecommunications device for our hearing- and speech-impaired shareholders.

JANUS LITERATURE LINE
1-800-525-8983
To request a prospectus, shareholder reports or marketing materials 24 hours a
day.

 16 Shareholder's manual
<PAGE>

MINIMUM INVESTMENTS*

<TABLE>
<S>                      <C>
To open a new regular
account                  $2,500
To open a new
retirement account,
education account or
UGMA/UTMA                $  500
To open a new regular
account with an
Automatic Investment
Program                  $  500**
To add to any type of
an account               $  100+
</TABLE>

 * The Fund reserves the right to change the amount of these minimums from time
   to time or to waive them in whole or in part for certain types of accounts.

** An Automatic Investment Program requires a $100 minimum automatic investment
   per month until the account balance reaches $2,500.

 + The minimum subsequent investment for a retirement account or UGMA/UTMA is
   $50.

TYPES OF ACCOUNT OWNERSHIP

               If you are investing in the Fund for the first time, you will
               need to establish an account. You can establish the following
               types of accounts by completing a New Account Application.

               INDIVIDUAL OR JOINT OWNERSHIP
               Individual accounts are owned by one person. Joint accounts have
               two or more owners.

               A GIFT OR TRANSFER TO MINOR (UGMA OR UTMA)
               An UGMA/UTMA is a custodial account managed for the benefit of a
               minor. To open an UGMA or UTMA, you must include the minor's
               Social Security number on the application.

               TRUST
               An established trust can open an account. The names of each
               trustee, the name of the trust and the date of the trust
               agreement must be included on the application.

                                                        Shareholder's manual  17
<PAGE>

               BUSINESS ACCOUNTS
               Corporations and partnerships may also open an account. The
               application must be signed by an authorized officer of the
               corporation or a general partner of the partnership.

TAX-DEFERRED ACCOUNTS

               If you are eligible, you may set up one or more tax-deferred
               accounts. A tax-deferred account allows you to shelter your
               investment income and capital gains from current income taxes. A
               contribution to certain of these plans may also be tax
               deductible. Tax-deferred accounts include retirement plans
               described below and the Education IRA. Please refer to the Janus
               retirement guide for more complete information regarding the
               different types of IRAs, including the Education IRA.
               Distributions from these plans are generally subject to income
               tax and may be subject to an additional tax if withdrawn prior to
               age 59 1/2 or used for a nonqualifying purpose. Investors should
               consult their tax adviser or legal counsel before selecting a
               tax-deferred account.

               Investors Fiduciary Trust Company serves as custodian for the
               tax-deferred accounts offered by the Fund. You will be charged an
               annual account maintenance fee of $12 for each taxpayer
               identification number no matter how many tax-deferred accounts
               you have with Janus. You may pay the fee by check or have it
               automatically deducted from your account (usually in December).
               The custodian reserves the right to change the amount of this fee
               or to waive it in whole or in part for certain types of accounts.

               TRADITIONAL AND ROTH INDIVIDUAL RETIREMENT ACCOUNTS
               Both types of IRAs allow most individuals with earned income to
               contribute up to the lesser of $2,000 ($4,000 for most married
               couples) or 100% of compensation annually.

               EDUCATION IRA
               This plan allows individuals, subject to certain income
               limitations, to contribute up to $500 annually on behalf of any
               child under the age of 18.

 18 Shareholder's manual
<PAGE>

               SIMPLIFIED EMPLOYEE PENSION PLAN
               This plan allows small business owners (including sole
               proprietors) to make tax-deductible contributions for themselves
               and any eligible employee(s). A SEP requires an IRA (a SEP-IRA)
               to be set up for each SEP participant.

               PROFIT SHARING OR MONEY PURCHASE PENSION PLAN
               These plans are open to corporations, partnerships and sole
               proprietors to benefit their employees and themselves.

               SECTION 403(B)(7) PLAN
               Employees of educational organizations or other qualifying, tax-
               exempt organizations may be eligible to participate in a Section
               403(b)(7) Plan.

               PLEASE REFER TO THE CHART ON THE FOLLOWING PAGES FOR INFORMATION
               ON OPENING AN ACCOUNT AND CONDUCTING BUSINESS WITH JANUS. WITH
               CERTAIN LIMITED EXCEPTIONS, THE FUND IS AVAILABLE ONLY TO U.S.
               CITIZENS OR RESIDENTS. WHEN YOU PURCHASE, EXCHANGE, OR REDEEM
               SHARES, YOUR REQUEST WILL BE PROCESSED AT THE NEXT NAV CALCULATED
               AFTER YOUR ORDER IS RECEIVED AND ACCEPTED.

                                                        Shareholder's manual  19
<PAGE>

 TO PURCHASE SHARES

 BY MAIL/IN WRITING
 ------------------------------------------------------------------------------

 - To open your account, complete and sign the appropriate application and make
   your check payable to Janus.

 - To purchase additional shares, complete the remittance slip attached at the
   bottom of your confirmation statement. If you are making a purchase into a
   retirement account, please indicate whether the purchase is a rollover or a
   current or prior year contribution. Send your check and remittance slip or
   written instructions to the address listed on the slip.

 BY TELEPHONE
 ------------------------------------------------------------------------------

 - The "Telephone Purchase of Shares Option" allows you to purchase additional
   shares quickly and conveniently through an electronic transfer of money.
   After establishing this option on your account, call an Investor Service
   Representative during normal business hours or the Janus XpressLine for
   access to this option 24 hours a day. Janus will automatically debit your
   predesignated bank account.

 - Purchases may also be made by wiring money from your bank account to your
   Janus account. Call an Investor Service Representative for wiring
   instructions.

 BY INTERNET
 ------------------------------------------------------------------------------

 - The "Telephone Purchase of Shares Option" allows you to make a purchase into
   an existing account on our Web site at janus.com.

 BY AUTOMATIC INVESTMENT
 ------------------------------------------------------------------------------

 - Automatic Monthly Investment Program - You select the day each month that
   your money ($100 minimum) will be electronically transferred from your bank
   account to your Fund account.

 - Payroll Deduction - If your employer can initiate an automatic payroll
   deduction, you may have all or a portion of your paycheck ($100 minimum)
   invested directly into your Fund account.

 20 Shareholder's manual
<PAGE>

<TABLE>
<S>                                            <C>
    TO EXCHANGE SHARES                           TO REDEEM SHARES
- ---------------------------------------        ---------------------------------------
    - To request an exchange in writing,         - To request a redemption in writ-
      please follow the instructions for           ing, please follow the instructions
      written requests on page 24. Also            for written requests on page 24.
      refer to the exchange policies             - Please see page 23 for information
      listed on page 22 for more infor-            about payment of redemption
      mation.                                      proceeds.

- ---------------------------------------        ---------------------------------------
    - All accounts are automatically eli-        - The telephone redemption option
      gible to exchange shares by tele-            enables you to request redemp-
      phone. To exchange all or a portion          tions daily from your account by
      of your shares into any other                calling an Investor Service Repre-
      available Janus fund, call an                sentative by the close of the
      Investor Service Representative or           regular trading session of the
      the Janus XpressLine.                        NYSE, normally 4:00 p.m. New York
                                                   time. You may also use Janus
                                                   XpressLine for access to this
                                                   option 24 hours a day.

- ---------------------------------------        ---------------------------------------
    - Exchanges may be made on our Web           - Redemptions may be made on our Web
      site at janus.com.                           site at janus.com.
- ---------------------------------------        ---------------------------------------
    - Systematic Exchange - You deter-           - Systematic Redemption - This option
      mine the amount of money you would           allows you to redeem a specific
      like automatically exchanged from            dollar amount from your account on
      one Janus account to another on any          a regular basis.
      day of the month. You may establish
      this program for as little as $100
      per month on existing accounts. You
      may establish a new account with a
      $500 initial purchase and subse-
      quent $100 systematic exchanges.
</TABLE>

                                                        Shareholder's manual  21
<PAGE>

PAYING FOR SHARES

Please note the following when purchasing shares:

- - Cash, credit cards, third party checks, travelers cheques, credit card checks
  or money orders will not be accepted.

- - All purchases must be made in U.S. dollars and checks must be drawn on U.S.
  banks.

- - We may make additional attempts to debit the bank account for ACH purchases.

- - The Fund reserves the right to reject any specific purchase request.

- - If all or a portion of a check is received for investment without a specific
  fund designation, the undesignated amount will be invested in the Janus Money
  Market Fund -- Investor Shares. Shares that are subsequently exchanged from
  Janus Money Market Fund -- Investor Shares into the selected Fund will receive
  the NAV next calculated after your order is received and accepted by the Fund.

- - If your purchase is cancelled, you will be responsible for any losses or fees
  imposed by your bank and losses that may be incurred as a result of any
  decline in the value of the cancelled purchase.

EXCHANGE POLICIES

The exchange privilege is not intended as a vehicle for short-term or excessive
trading. The Fund does not permit excessive trading or market timing. Excessive
purchases, redemptions, or exchanges of Fund shares disrupt portfolio management
and drive Fund expenses higher.

Please note the following when exchanging shares:

- - Except for Systematic Exchanges, new accounts established by exchange must be
  opened with $2,500 or the total account value if the value of the account you
  are exchanging from is less than $2,500.

- - Exchanges between existing accounts must meet the $100 subsequent investment
  requirement.

- - You may make four exchanges out of the Fund during a calendar year (exclusive
  of Systematic Exchange). Exchanges in excess of this limit are considered
  excessive trading and may be subject to an exchange fee or may result in
  termination of the exchange privilege or the right to make future purchases of
  Fund shares.

 22 Shareholder's manual
<PAGE>

- - The Fund reserves the right to reject any purchase order or exchange request
  and to modify or terminate the exchange privilege at any time. For example,
  the Fund may reject exchanges from accounts engaged in or known to engage in
  trading in excess of the limit above (including market timing transactions) or
  whose trading has been or may be disruptive to the Fund.

- - Exchanges between accounts will be accepted only if the registrations are
  identical.

- - If the shares you are exchanging are held in certificate form, you must return
  the certificate to Janus prior to making any exchanges. Effective June 4,
  1999, shares are no longer available in certificate form.

- - An exchange represents the sale of shares from one fund and the purchase of
  shares of another fund, which may produce a taxable gain or loss in a
  non-retirement account.

- - If the balance in the account you are exchanging from falls below the
  systematic exchange amount, all remaining shares will be exchanged
  and the program will be discontinued.

PAYMENT OF REDEMPTION PROCEEDS

- - BY CHECK - Redemption proceeds will be sent to the shareholder(s) of record at
  the address of record within seven days after receipt of a valid redemption
  request. During the 10 days following an address change, checks sent to a new
  address require a signature guarantee.

- - BY ELECTRONIC TRANSFER - If you have established the electronic redemption
  option, your redemption proceeds can be electronically transferred to your
  predesignated bank account on the next bank business day after receipt of your
  redemption request (wire transfer) or the second bank business day after
  receipt of your redemption request (ACH transfer).

Wire transfers will be charged an $8 fee per wire and your bank may charge an
additional fee to receive the wire. Wire redemptions are not available for
retirement accounts.

IF THE SHARES BEING REDEEMED WERE PURCHASED BY CHECK, TELEPHONE, ON OUR WEB
SITE, OR THROUGH THE AUTOMATIC MONTHLY INVESTMENT PROGRAM, THE FUND MAY DELAY
THE PAYMENT OF YOUR REDEMPTION PROCEEDS FOR UP TO 15 DAYS FROM THE DAY OF
PURCHASE TO ALLOW THE PURCHASE TO CLEAR. Unless you provide alternate
instructions, your proceeds will be invested in Janus Money Market
Fund - Investor Shares during the 15 day hold period.

                                                        Shareholder's manual  23
<PAGE>

WRITTEN INSTRUCTIONS

               To redeem or exchange all or part of your shares in writing, your
               request should be sent to one of the addresses listed on page 16
               and must include the following information:

               - the name of the Fund(s)

               - the account number(s)

               - the amount of money or number of shares being redeemed or
                 exchanged

               - the name(s) on the account

               - the signature(s) of all registered account owners (see account
                 application for signature requirements)

               - your daytime telephone number

SIGNATURE GUARANTEE

               A SIGNATURE GUARANTEE IS REQUIRED if any of the following is
               applicable:

               - You request a redemption by check that exceeds $100,000.

               - You would like a check made payable to anyone other than the
                 shareholder(s) of record.

               - You would like a check mailed to an address which has been
                 changed within 10 days of the redemption request.

               - You would like a check mailed to an address other than the
                 address of record.

               THE FUND RESERVES THE RIGHT TO REQUIRE A SIGNATURE GUARANTEE
               UNDER OTHER CIRCUMSTANCES OR TO REJECT OR DELAY A REDEMPTION ON
               CERTAIN LEGAL GROUNDS.

               HOW TO OBTAIN A SIGNATURE GUARANTEE

               A signature guarantee assures that a signature is genuine. The
               signature guarantee protects shareholders from unauthorized
               account transfers. The following financial institutions may
               guaran-

 24 Shareholder's manual
<PAGE>

               tee signatures: banks, savings and loan associations, trust
               companies, credit unions, broker-dealers, and member firms of a
               national securities exchange. Call your financial institution to
               see if they have the ability to guarantee a signature. A
               signature guarantee cannot be provided by a notary public.

               If you live outside the United States, a foreign bank properly
               authorized to do business in your country of residence or a U.S.
               consulate may be able to authenticate your signature.

PRICING OF FUND SHARES

               All purchases, redemptions and exchanges will be processed at the
               NAV next calculated after your request is received and accepted
               by the Fund (or the Fund's agent or authorized designee). The
               Fund's NAV is calculated at the close of the regular trading
               session of the NYSE (normally 4:00 p.m. New York time) each day
               that the NYSE is open. The NAV of Fund shares is not determined
               on days the NYSE is closed (generally New Year's Day, Martin
               Luther King Day, Presidents' Day, Good Friday, Memorial Day,
               Independence Day, Labor Day, Thanksgiving and Christmas). In
               order to receive a day's price, your order must be received by
               the close of the regular trading session of the NYSE. Securities
               are valued at market value or, if a market quotation is not
               readily available, at their fair value determined in good faith
               under procedures established by and under the supervision of the
               Trustees. Short-term instruments maturing within 60 days are
               valued at amortized cost, which approximates market value. See
               the SAI for more detailed information.

SHAREHOLDER SERVICES AND ACCOUNT POLICIES

               ACCOUNT MINIMUMS

               Due to the proportionately higher costs of maintaining small
               accounts, Janus reserves the right to deduct a $10 minimum
               balance fee (or the value of the account if less than $10) from
               accounts with values below the minimums described on page 17 or
               to close such accounts. This policy will apply to accounts

                                                        Shareholder's manual  25
<PAGE>

               participating in the Automatic Monthly Investment Program only if
               your account balance does not reach the required minimum initial
               investment or falls below such minimum and you have discontinued
               monthly investments. This policy does not apply to accounts that
               fall below the minimums solely as a result of market value
               fluctuations. It is expected that, for purposes of this policy,
               accounts will be valued in September, and the $10 fee will be
               assessed on the second Friday of September of each year. You will
               receive notice before we charge the $10 fee or close your account
               so that you may increase your account balance to the required
               minimum.

               TRANSACTIONS THROUGH PROCESSING ORGANIZATIONS

               You may purchase or sell Fund shares through a broker-dealer,
               bank or other financial institution, or an organization that
               provides recordkeeping and consulting services to 401(k) plans or
               other employee benefit plans (a "Processing Organization").
               Processing Organizations may charge you a fee for this service
               and may require different minimum initial and subsequent
               investments than the Fund. Processing Organizations may also
               impose other charges or restrictions different from those
               applicable to shareholders who invest in the Fund directly. A
               Processing Organization, rather than its customers, may be the
               shareholder of record of your shares. The Fund is not responsible
               for the failure of any Processing Organization to carry out its
               obligations to its customers. Certain Processing Organizations
               may receive compensation from Janus Capital or its affiliates and
               certain Processing Organizations may receive compensation from
               the Fund for shareholder recordkeeping and similar services.

               TAXPAYER IDENTIFICATION NUMBER

               On the application or other appropriate form, you will be asked
               to certify that your Social Security or taxpayer identification
               number is correct and that you are not subject to backup
               withholding for failing to report income to the IRS. If you are
               subject to the 31% backup withholding or you did not certify

 26 Shareholder's manual
<PAGE>

               your taxpayer identification number, the IRS requires the Fund to
               withhold 31% of any dividends paid and redemption or exchange
               proceeds. In addition to the 31% backup withholding, you may be
               subject to a $50 fee to reimburse the Fund for any penalty that
               the IRS may impose.

               INVOLUNTARY REDEMPTIONS

               The Fund reserves the right to close an account if the
               shareholder is deemed to engage in activities which are illegal
               or otherwise believed to be detrimental to the Fund.

               TELEPHONE TRANSACTIONS

               You may initiate many transactions by telephone. The Fund and its
               agents will not be responsible for any losses resulting from
               unauthorized transactions when procedures designed to verify the
               identity of the caller are followed.

               It may be difficult to reach an Investor Service Representative
               by telephone during periods of unusual market activity. If you
               are unable to reach a representative by telephone, please
               consider sending written instructions, stopping by a Service
               Center, calling the Janus XpressLine or visiting our Web site.

               TEMPORARY SUSPENSION OF SERVICES

               The Fund or its agents may, in case of emergency, temporarily
               suspend telephone transactions and other shareholder services.

               ADDRESS CHANGES

               To change the address on your account, call 1-800-525-3713 or
               send a written request signed by the shareholder(s) of record.
               Include the name of your Fund, the account number(s), the name(s)
               on the account and both the old and new addresses. Certain
               options may be suspended for 10 days following an address change
               unless a signature guarantee is provided.

                                                        Shareholder's manual  27
<PAGE>

               REGISTRATION CHANGES

               To change the name on an account, the shares are generally
               transferred to a new account. In some cases, legal documentation
               may be required. For further instructions, please call an
               Investor Service Representative.

               STATEMENTS AND REPORTS

               Investors will receive quarterly confirmations of all
               transactions. Quarterly statements for all investors are
               available on our Web site. You may make an election on our Web
               site to discontinue delivery of your paper statements. Dividend
               information will be distributed annually. In addition, the Fund
               will send you an immediate transaction confirmation statement
               after every non-systematic transaction.

               The Fund produces financial reports, which include a list of the
               Fund's portfolio holdings, semiannually and updates its
               prospectus annually. To reduce expenses, the Fund may choose to
               mail only one report or prospectus to your household, even if
               more than one person in the household has a Fund account. Please
               call 1-800-525-3713 if you would like to receive additional
               reports or prospectuses. The Fund reserves the right to charge a
               fee for additional statement requests.

 28 Shareholder's manual
<PAGE>

MANAGEMENT OF THE FUND
- --------------------------------------------------------------------------------

INVESTMENT ADVISER

               Janus Capital Corporation, 100 Fillmore Street, Denver, Colorado
               80206-4928, is the investment adviser to the Fund and is
               responsible for the day-to-day management of its investment
               portfolio and other business affairs.

               Janus Capital began serving as investment adviser to Janus Fund
               in 1970 and currently serves as investment adviser to all of the
               Janus funds, acts as sub-adviser for a number of private-label
               mutual funds and provides separate account advisory services for
               institutional accounts.

               Janus Capital furnishes continuous advice and recommendations
               concerning the Fund's investments. Janus Capital also furnishes
               certain administrative, compliance and accounting services for
               the Fund, and may be reimbursed by the Fund for its costs in
               providing those services. In addition, Janus Capital employees
               serve as officers of the Trust and Janus Capital provides office
               space for the Fund and pays the salaries, fees and expenses of
               all Fund officers and those Trustees who are affiliated with
               Janus Capital.

               The Fund pays Janus Capital a management fee which is calculated
               daily and paid monthly. The advisory agreement with the Fund
               spells out the management fee and other expenses that the Fund
               must pay.

               The Fund incurs expenses not assumed by Janus Capital, including
               transfer agent and custodian fees and expenses, legal and
               auditing fees, printing and mailing costs of sending reports and
               other information to existing shareholders, and independent
               Trustees' fees and expenses. For the most recent fiscal year, the
               Fund paid Janus Capital a management fee equal to 0.69% of
               average daily net assets.

                                    Janus Special Situations Fund prospectus  29
<PAGE>

PORTFOLIO MANAGER

DAVID C. DECKER
- --------------------------------------------------------------------------------
                   is Executive Vice President and portfolio manager of the
                   Fund, which he has managed since inception. Mr. Decker is
                   also the portfolio manager of Janus Strategic Value Fund
                   and is an assistant portfolio manager of Janus Fund. He
                   joined Janus Capital in 1992 as a research analyst and
                   focused on companies in the automotive and defense
                   industries prior to managing the Fund. He obtained his
                   Master of Business Administration in Finance from the
                   Fuqua School of Business at Duke University and a Bachelor
                   of Arts in Economics and Political Science from Tufts
                   University. Mr. Decker is a Chartered Financial Analyst.

 30 Janus Special Situations Fund prospectus
<PAGE>

OTHER INFORMATION
- --------------------------------------------------------------------------------

               SIZE OF THE FUND

               Although there is no present intention to do so, the Fund may
               discontinue sales of its shares if management and the Trustees
               believe that continued sales may adversely affect the Fund's
               ability to achieve its investment objective. If sales of the Fund
               are discontinued, it is expected that existing shareholders of
               the Fund would be permitted to continue to purchase shares and to
               reinvest any dividends or capital gains distributions, absent
               highly unusual circumstances.

               YEAR 2000

               Preparing for Year 2000 has been a high priority for Janus
               Capital. A dedicated group was established to address this issue.
               Janus Capital devoted considerable internal resources and engaged
               one of the foremost experts in the field to achieve Year 2000
               readiness. Janus Capital successfully completed all five steps of
               its Year 2000 preparedness plans including the upgrade and
               replacement of all systems, as well as full-scale testing and
               implementation of those systems. Janus Capital's detailed
               contingency plans were also thoroughly tested. As of the date of
               this Prospectus, Janus Capital has not seen any adverse impact as
               a result of the Year 2000 transition on any of its systems or
               those of its vendors, or on the companies in which the Funds
               invest or worldwide markets and economies. Nonetheless, Janus
               Capital will continue to monitor the effect of the Year 2000
               transition, and there can be no absolute assurance that Year 2000
               issues will not in the future adversely affect the Funds' or
               Janus Capital's operations.

                                    Janus Special Situations Fund prospectus  31
<PAGE>

               DISTRIBUTION OF THE FUND

               The Fund is distributed by Janus Distributors, Inc., a member of
               the National Association of Securities Dealers, Inc. ("NASD"). To
               obtain information about NASD member firms and their associated
               persons, you may contact NASD Regulation, Inc. at www.nasdr.com
               or the Public Disclosure Hotline at 800-289-9999. An investor
               brochure containing information describing the Public Disclosure
               Program is available from NASD Regulation, Inc.

 32 Janus Special Situations Fund prospectus
<PAGE>

DISTRIBUTIONS AND TAXES
- --------------------------------------------------------------------------------

DISTRIBUTIONS

               To avoid taxation of the Fund, the Internal Revenue Code requires
               the Fund to distribute net income and any net capital gains
               realized on its investments annually. The Fund's income from
               dividends and interest and any net realized short-term gains are
               paid to shareholders as ordinary income dividends. Net realized
               long-term gains are paid to shareholders as capital gains
               distributions. Dividends and capital gains distributions are
               normally declared and paid in December.

               HOW DISTRIBUTIONS AFFECT THE FUND'S NAV

               Distributions are paid to shareholders as of the record date of
               the distribution of the Fund, regardless of how long the shares
               have been held. Dividends and capital gains awaiting distribution
               are included in the Fund's daily NAV. The share price of the Fund
               drops by the amount of the distribution, net of any subsequent
               market fluctuations. As an example, assume that on December 31,
               the Fund declared a dividend in the amount of $0.25 per share. If
               the Fund's share price was $10.00 on December 30, the Fund's
               share price on December 31 would be $9.75, barring market
               fluctuations. Shareholders should be aware that distributions
               from a taxable mutual fund are not value-enhancing and may create
               income tax obligations.

               "BUYING A DIVIDEND"

               If you purchase shares of the Fund just before the distribution,
               you will pay the full price for the shares and receive a portion
               of the purchase price back as a taxable distribution. This is
               referred to as "buying a dividend." In the above example, if you
               bought shares on December 30, you would have paid $10.00 per
               share. On December 31, the Fund would pay you $0.25 per share as
               a dividend and your shares would now be worth $9.75 per share.
               Unless your account is set up as a tax-deferred account,
               dividends paid to you would be included in your gross income for
               tax purposes, even though you may not have participated in the

                                    Janus Special Situations Fund prospectus  33
<PAGE>

               increase in NAV of the Fund, whether or not you reinvested the
               dividends.

DISTRIBUTION OPTIONS

               When you open an account, you must specify on your application
               how you want to receive your distributions. You may change your
               distribution option at any time by writing the Fund at one of the
               addresses on page 16 or calling 1-800-525-3713. The Fund offers
               the following options:

               1. REINVESTMENT OPTION. You may reinvest your income dividends
                  and capital gains distributions in additional shares. This
                  option is assigned automatically if no other choice is made.

               2. CASH OPTION. You may receive your income dividends and capital
                  gains distributions in cash.

               3. REINVEST AND CASH OPTION. You may receive either your income
                  dividends or capital gains distributions in cash and reinvest
                  the other in additional shares.

               4. REDIRECT OPTION. You may direct your dividends or capital
                  gains to purchase shares of another Janus fund.

               The Fund reserves the right to reinvest into your account
               undeliverable and uncashed dividend and distribution checks that
               remain outstanding for six months in shares of the Fund at the
               NAV next computed after the check is cancelled. Subsequent
               distributions may also be reinvested.

TAXES

               As with any investment, you should consider the tax consequences
               of investing in the Fund. Any time you sell or exchange shares of
               a Fund in a taxable account, it is considered a taxable event.
               Depending on the purchase price and the sale price, you may have
               a gain or loss on the transaction. Any tax liabilities generated
               by your transactions are your responsibility.

               The following discussion does not apply to tax-deferred accounts,
               nor is it a complete analysis of the federal tax implications of

 34 Janus Special Situations Fund prospectus
<PAGE>

               investing in the Fund. You may wish to consult your own tax
               adviser. Additionally, state or local taxes may apply to your
               investment, depending upon the laws of your state of residence.

               TAXES ON DISTRIBUTIONS

               Dividends and distributions by the Fund are subject to federal
               income tax, regardless of whether the distribution is made in
               cash or reinvested in additional shares of the Fund.
               Distributions may be taxable at different rates depending on the
               length of time the Fund holds a security. In certain states, a
               portion of the dividends and distributions (depending on the
               source of the Fund's income) may be exempt from state and local
               taxes. Information regarding the tax status of income dividends
               and capital gains distributions will be mailed to shareholders on
               or before January 31st of each year. Account tax information will
               also be sent to the IRS.

               TAXATION OF THE FUND

               Dividends, interest, and some capital gains received by the Fund
               on foreign securities may be subject to tax withholding or other
               foreign taxes. The Fund may from year to year make the election
               permitted under section 853 of the Internal Revenue Code to pass
               through such taxes to shareholders as a foreign tax credit. If
               such an election is not made, any foreign taxes paid or accrued
               will represent an expense to the Fund.

               The Fund does not expect to pay federal income or excise taxes
               because it intends to meet certain requirements of the Internal
               Revenue Code. It is important that the Fund meet these
               requirements so that any earnings on your investment will not be
               taxed twice.

                                    Janus Special Situations Fund prospectus  35
<PAGE>

FINANCIAL HIGHLIGHTS
- --------------------------------------------------------------------------------

               The financial highlights table is intended to help you understand
               the Fund's financial performance through October 31st of each
               fiscal period shown. Items 1 through 9 reflect financial results
               for a single Fund share. The total returns in the table represent
               the rate that an investor would have earned (or lost) on an
               investment in the Fund (assuming reinvestment of all dividends
               and distributions). This information has been audited by
               PricewaterhouseCoopers LLP, whose report, along with the Fund's
               financial statements, are included in the Annual Report, which is
               available upon request and incorporated by reference into the
               SAI.

JANUS SPECIAL SITUATIONS FUND

<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------
                                                        Periods ending October 31st
                                                         1999      1998     1997(1)
<S>                                                     <C>       <C>       <C>
  1. NET ASSET VALUE, BEGINNING OF PERIOD                $14.57    $14.08    $10.00
     INCOME FROM INVESTMENT OPERATIONS:
  2. Net investment income                                   --        --        --
  3. Net gains or (losses) on securities (both
     realized and unrealized)                              8.22      1.15      4.08
  4. Total from investment operations                      8.22      1.15      4.08
     LESS DISTRIBUTIONS:
  5. Dividends (from net investment income)                  --        --        --
  6. Dividends (in excess of net investment income)          --        --        --
  7. Distributions (from capital gains)                  (0.04)    (0.66)        --
  8. Total distributions                                 (0.04)    (0.66)        --
  9. NET ASSET VALUE, END OF PERIOD                      $22.75    $14.57    $14.08
 10. Total return*                                       56.54%     8.49%    40.80%
 11. Net assets, end of period (in millions)             $1,197      $786      $334
 12. Average net assets for the period (in millions)     $1,001      $716      $168
 13. Ratio of gross expenses to average net assets**      1.00%     1.08%     1.20%
 14. Ratio of net expenses to average net assets**        0.98%     1.05%     1.18%
 15. Ratio of net investment income/(loss) to average
     net assets**                                       (0.76%)   (0.49%)    (0.08%)
 16. Portfolio turnover rate**                             104%      117%      146%
- -----------------------------------------------------------------------------------
</TABLE>

(1) Fiscal period from December 31, 1996 (inception) to October 31, 1997.
  * Total return is not annualized for periods of less than one full year.
 ** Annualized for periods of less than one full year.

 36 Janus Special Situations Fund prospectus

<PAGE>


GLOSSARY OF INVESTMENT TERMS
- --------------------------------------------------------------------------------

               This glossary provides a more detailed description of some of the
               types of securities and other instruments in which the Fund may
               invest. The Fund may invest in these instruments to the extent
               permitted by its investment objective and policies. The Fund is
               not limited by this discussion and may invest in any other types
               of instruments not precluded by the policies discussed elsewhere
               in this Prospectus. Please refer to the SAI for a more detailed
               discussion of certain instruments.

I. EQUITY AND DEBT SECURITIES

               BONDS are debt securities issued by a company, municipality,
               government or government agency. The issuer of a bond is required
               to pay the holder the amount of the loan (or par value of the
               bond) at a specified maturity and to make scheduled interest
               payments.

               COMMERCIAL PAPER is a short-term debt obligation with a maturity
               ranging from 1 to 270 days issued by banks, corporations and
               other borrowers to investors seeking to invest idle cash. The
               Fund may purchase commercial paper issued in private placements
               under Section 4(2) of the Securities Act of 1933.

               COMMON STOCKS are equity securities representing shares of
               ownership in a company, and usually carry voting rights and earns
               dividends. Unlike preferred stock, dividends on common stocks are
               not fixed but are declared at the discretion of the issuer's
               board of directors.

               CONVERTIBLE SECURITIES are preferred stocks or bonds that pay a
               fixed dividend or interest payment and are convertible into
               common stock at a specified price or conversion ratio.

               DEBT SECURITIES are securities representing money borrowed that
               must be repaid at a later date. Such securities have specific
               maturities and usually a specific rate of interest or an original
               purchase discount.

               DEPOSITARY RECEIPTS are receipts for shares of a foreign-based
               corporation that entitle the holder to dividends and capital
               gains

                                    Janus Special Situations Fund prospectus  37
<PAGE>

               on the underlying security. Receipts include those issued by
               domestic banks (American Depositary Receipts), foreign banks
               (Global or European Depositary Receipts) and broker-dealers
               (depositary shares).

               FIXED-INCOME SECURITIES are securities that pay a specified rate
               of return. The term generally includes short- and long-term
               government, corporate and municipal obligations that pay a
               specified rate of interest or coupons for a specified period of
               time, and preferred stock, which pays fixed dividends. Coupon and
               dividend rates may be fixed for the life of the issue or, in the
               case of adjustable and floating rate securities, for a shorter
               period.

               HIGH-YIELD/HIGH-RISK BONDS are bonds that are rated below
               investment grade by the primary rating agencies (e.g., BB or
               lower by Standard & Poor's and Ba or lower by Moody's). Other
               terms commonly used to describe such bonds include "lower rated
               bonds," "noninvestment grade bonds" and "junk bonds."

               MORTGAGE- AND ASSET-BACKED SECURITIES are shares in a pool of
               mortgages or other debt. These securities are generally pass-
               through securities, which means that principal and interest
               payments on the underlying securities (less servicing fees) are
               passed through to shareholders on a pro rata basis. These
               securities involve prepayment risk, which is the risk that the
               underlying mortgages or other debt may be refinanced or paid off
               prior to their maturities during periods of declining interest
               rates. In that case, the portfolio managers may have to reinvest
               the proceeds from the securities at a lower rate. Potential
               market gains on a security subject to prepayment risk may be more
               limited than potential market gains on a comparable security that
               is not subject to prepayment risk.

               PASSIVE FOREIGN INVESTMENT COMPANIES (PFICS) are any foreign
               corporations which generate certain amounts of passive income or
               hold certain amounts of assets for the production of passive
               income. Passive income includes dividends, interest, royalties,
               rents and annuities. To avoid taxes and interest that the Fund
               must pay if these investments are profitable, the Fund may make

 38 Janus Special Situations Fund prospectus
<PAGE>

               various elections permitted by the tax laws. These elections
               could require that the Fund recognize taxable income, which in
               turn must be distributed, before the securities are sold and
               before cash is received to pay the distributions.

               PREFERRED STOCKS are equity securities that generally pay
               dividends at a specified rate and have preference over common
               stock in the payment of dividends and liquidation. Preferred
               stock generally does not carry voting rights.

               REPURCHASE AGREEMENTS involve the purchase of a security by the
               Fund and a simultaneous agreement by the seller (generally a bank
               or dealer) to repurchase the security from the Fund at a
               specified date or upon demand. This technique offers a method of
               earning income on idle cash. These securities involve the risk
               that the seller will fail to repurchase the security, as agreed.
               In that case, the Fund will bear the risk of market value
               fluctuations until the security can be sold and may encounter
               delays and incur costs in liquidating the security.

               REVERSE REPURCHASE AGREEMENTS involve the sale of a security by
               the Fund to another party (generally a bank or dealer) in return
               for cash and an agreement by the Fund to buy the security back at
               a specified price and time. This technique will be used primarily
               to provide cash to satisfy unusually heavy redemption requests,
               or for other temporary or emergency purposes.

               U.S. GOVERNMENT SECURITIES include direct obligations of the U.S.
               government that are supported by its full faith and credit.
               Treasury bills have initial maturities of less than one year,
               Treasury notes have initial maturities of one to ten years and
               Treasury bonds may be issued with any maturity but generally have
               maturities of at least ten years. U.S. government securities also
               include indirect obligations of the U.S. government that are
               issued by federal agencies and government sponsored entities.
               Unlike Treasury securities, agency securities generally are not
               backed by the full faith and credit of the U.S. government. Some
               agency securities are supported by the right of the issuer to
               borrow from the Treasury, others are supported by the
               discretionary authority

                                    Janus Special Situations Fund prospectus  39
<PAGE>

               of the U.S. government to purchase the agency's obligations and
               others are supported only by the credit of the sponsoring agency.

               WARRANTS are securities, typically issued with preferred stocks
               or bonds, that give the holder the right to buy a proportionate
               amount of common stock at a specified price, usually at a price
               that is higher than the market price at the time of issuance of
               the warrant. The right may last for a period of years or
               indefinitely.

               WHEN-ISSUED, DELAYED DELIVERY AND FORWARD TRANSACTIONS generally
               involve the purchase of a security with payment and delivery at
               some time in the future - i.e., beyond normal settlement. The
               Fund does not earn interest on such securities until settlement
               and bears the risk of market value fluctuations in between the
               purchase and settlement dates. New issues of stocks and bonds,
               private placements and U.S. government securities may be sold in
               this manner.

II. FUTURES, OPTIONS AND OTHER DERIVATIVES

               FORWARD CONTRACTS are contracts to purchase or sell a specified
               amount of a financial instrument for an agreed upon price at a
               specified time. Forward contracts are not currently exchange
               traded and are typically negotiated on an individual basis. The
               Fund may enter into forward currency contracts to hedge against
               declines in the value of securities denominated in, or whose
               value is tied to, a currency other than the U.S. dollar or to
               reduce the impact of currency appreciation on purchases of such
               securities. It may also enter into forward contracts to purchase
               or sell securities or other financial indices.

               FUTURES CONTRACTS are contracts that obligate the buyer to
               receive and the seller to deliver an instrument or money at a
               specified price on a specified date. The Fund may buy and sell
               futures contracts on foreign currencies, securities and financial
               indices including interest rates or an index of U.S. government,
               foreign government, equity or fixed-income securities. The Fund
               may also buy options on futures contracts. An option on a futures
               contract gives the buyer the right, but not the obligation, to
               buy or sell a

 40 Janus Special Situations Fund prospectus
<PAGE>

               futures contract at a specified price on or before a specified
               date. Futures contracts and options on futures are standardized
               and traded on designated exchanges.

               INDEXED/STRUCTURED SECURITIES are typically short- to
               intermediate-term debt securities whose value at maturity or
               interest rate is linked to currencies, interest rates, equity
               securities, indices, commodity prices or other financial
               indicators. Such securities may be positively or negatively
               indexed (i.e., their value may increase or decrease if the
               reference index or instrument appreciates). Indexed/structured
               securities may have return characteristics similar to direct
               investments in the underlying instrument and may be more volatile
               than the underlying instrument. The Fund bears the market risk of
               an investment in the underlying instrument, as well as the credit
               risk of the issuer.

               OPTIONS are the right, but not the obligation, to buy or sell a
               specified amount of securities or other assets on or before a
               fixed date at a predetermined price. The Fund may purchase and
               write put and call options on securities, securities indices and
               foreign currencies.

                                    Janus Special Situations Fund prospectus  41
<PAGE>

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 42
<PAGE>

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<PAGE>

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 44
<PAGE>

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<PAGE>

                                  [JANUS LOGO]

        You can request other information, including a Statement of
        Additional Information, Annual Report or Semiannual Report, free
        of charge, by contacting Janus at 1-800-525-3713 or visiting our
        Web site at janus.com. In the Fund's Annual Report, you will
        find a discussion of the market conditions and investment
        strategies that significantly affected the Fund's performance
        during its last fiscal year. Other information is also available
        from financial intermediaries that sell shares of the Fund.

        The Statement of Additional Information provides detailed
        information about the Fund and is incorporated into this
        Prospectus by reference. You may review the Fund's Statement of
        Additional Information at the Public Reference Room of the SEC
        or get text only copies for a fee, by writing to or calling the
        Public Reference Room, Washington, D.C. 20549-6009
        (1-800-SEC-0330). You may obtain the Statement of Additional
        Information for free from the SEC's Web site at
        http://www.sec.gov.

                    Investment Company Act File No. 811-1879

                                 1-800-525-3713
                     PO Box 173375  Denver, CO  80217-3375
                                   janus.com
4238


<PAGE>

                                  [JANUS LOGO]
                             JANUS  WORLDWIDE  FUND
                                   PROSPECTUS

                                                   JANUARY 31, 2000

             The Securities and Exchange Commission has not
             approved or disapproved of these securities or passed
             on the accuracy or adequacy of this Prospectus. Any
             representation to the contrary is a criminal offense.

<PAGE>

- --------------------------------------------------------------------------------
<PAGE>

TABLE OF CONTENTS
- --------------------------------------------------------------------------------

<TABLE>
                <S>                                               <C>
                RISK/RETURN SUMMARY
                   Janus Worldwide Fund.........................    2
                   Fees and expenses............................    5
                INVESTMENT OBJECTIVE, PRINCIPAL INVESTMENT
                STRATEGIES AND RISKS
                   Investment objective and
                   principal investment strategies..............    6
                   General portfolio policies...................    7
                   Risks........................................    9
                SHAREHOLDER'S MANUAL
                   Minimum investments..........................   17
                   Types of account ownership...................   17
                   To purchase shares...........................   20
                   To exchange shares...........................   21
                   To redeem shares.............................   21
                   Shareholder services and account policies....   25
                MANAGEMENT OF THE FUND
                   Investment adviser...........................   29
                   Portfolio manager............................   30
                OTHER INFORMATION............... ...............   31
                DISTRIBUTIONS AND TAXES
                   Distributions................................   33
                   Taxes........................................   34
                FINANCIAL HIGHLIGHTS.............. .............   36
                GLOSSARY
                   Glossary of investment terms.................   37

</TABLE>

                                              Janus Worldwide Fund prospectus  1
<PAGE>

RISK/RETURN SUMMARY
- --------------------------------------------------------------------------------

JANUS WORLDWIDE FUND

1. WHAT IS THE INVESTMENT OBJECTIVE OF JANUS WORLDWIDE FUND?

               The Fund seeks long-term growth of capital in a manner consistent
               with the preservation of capital.

               The Fund's Trustees may change this objective without a
               shareholder vote and the Fund will notify you of any changes that
               are material. If there is a material change in the Fund's
               objective or policies, you should consider whether the Fund
               remains an appropriate investment for you. There is no guarantee
               that the Fund will meet its objective.

2. WHAT ARE THE MAIN INVESTMENT STRATEGIES OF JANUS WORLDWIDE FUND?

               The Fund invests primarily in common stocks of companies of any
               size throughout the world. The Fund normally invests in issuers
               from at least five different countries, including the United
               States. The Fund may at times invest in fewer than five countries
               or even a single country.

               The Fund may invest without limit in foreign equity and debt
               securities and less than 35% of its net assets in
               high-yield/high-risk bonds.

               The portfolio managers apply a "bottom up" approach in choosing
               investments. In other words, they look for companies with
               earnings growth potential one at a time. If the portfolio
               managers are unable to find such investments, a significant
               portion of the Fund's assets may be in cash or similar
               investments.

3. WHAT ARE THE MAIN RISKS OF INVESTING IN JANUS WORLDWIDE FUND?

               The biggest risk of investing in this Fund is that its returns
               may vary and you could lose money. If you are considering
               investing in the Fund, remember that it is designed for long-term
               investors who can accept the risks of investing in a portfolio
               with significant foreign common stock holdings. Common stocks
               tend to be more volatile than other investment choices.

 2 Janus Worldwide Fund prospectus
<PAGE>

               The value of the Fund's portfolio may decrease if the value of an
               individual company in the portfolio decreases. The value of the
               Fund's portfolio could also decrease if the stock market goes
               down. If the value of the Fund's portfolio decreases, the Fund's
               net asset value (NAV) will also decrease which means if you sell
               your shares in the Fund you would get back less money. The Fund
               may have significant exposure to foreign markets. As a result,
               its returns and NAV may be affected to a large degree by
               fluctuations in currency exchange rates or political or economic
               conditions in a particular country.

               An investment in the Fund is not a bank deposit and is not
               insured or guaranteed by the Federal Deposit Insurance
               Corporation or any other government agency.

                                              Janus Worldwide Fund prospectus  3
<PAGE>

               The following information illustrates how the Fund's performance
               has varied over time. The bar chart depicts the change in the
               Fund's performance from year-to-year during the periods
               indicated. The table compares the Fund's average annual returns
               for the periods indicated to a broad-based securities market
               index.

                JANUS WORLDWIDE FUND

                A BAR CHART showing Annual Total Returns for Janus Worldwide
                Fund from 1992 through 1999:

                Annual returns for periods ended 12/31
<TABLE>
                <S>      <C>      <C>     <C>      <C>      <C>      <C>     <C>
                9.01%    28.41%   3.61%    21.90%  26.40%   20.48%   25.87%   64.37%
                 1992     1993    1994      1995    1996     1997     1998     1999

                Each percentage is represented by a bar of proportionate size
                with the actual total return printed above the bar.

                Best Quarter:  4th-1999   42.11%   Worst Quarter:  3rd-1998  (16.10%)
</TABLE>

                          Average annual total return for periods ended 12/31/99
                          ------------------------------------------------------

<TABLE>
<CAPTION>
                                                                                  Since
                                                                                Inception
                                                          1 year   5 years      (5/15/91)
                <S>                                      <C>      <C>           <C>
                Janus Worldwide Fund                      64.37%   30.88%        25.10%
                Morgan Stanley International
                  Worldwide Index*                        24.93%   19.76%        14.51%
                                                      -------------------------------------
</TABLE>

                * The Morgan Stanley International Worldwide Index is a market
                  capitalization weighted index composed of countries
                  representative of the market structure of 47 developed and
                  emerging markets.

               The Fund's past performance does not necessarily indicate how it
               will perform in the future.

 4 Janus Worldwide Fund prospectus
<PAGE>

FEES AND EXPENSES

               SHAREHOLDER FEES, such as sales loads, redemption fees or
               exchange fees, are charged directly to an investor's account. All
               Janus funds are no-load investments, so you will not pay any
               shareholder fees when you buy or sell shares of the Fund.

               ANNUAL FUND OPERATING EXPENSES are paid out of the Fund's assets
               and include fees for portfolio management, maintenance of
               shareholder accounts, shareholder servicing, accounting and other
               services. You do not pay these fees directly but, as the example
               below shows, these costs are borne indirectly by all
               shareholders.

               This table describes the fees and expenses that you may pay if
               you buy and hold shares of the Fund. It is based upon gross
               expenses (without the effect of expense offset arrangements). All
               of the fees and expenses shown were determined based on net
               assets as of the fiscal year ended October 31, 1999.

<TABLE>
<CAPTION>
                                                           Janus Worldwide Fund
   <S>                                                           <C>
   Management Fee(1)                                              0.65%
   Other Expenses                                                 0.24%
   Total Annual Fund Operating Expenses                           0.89%
</TABLE>

- --------------------------------------------------------------------------------
  (1) "Management Fee" information has been restated to reflect a new fee
      schedule effective January 31, 2000.

  EXAMPLE:
  This example is intended to help you compare the cost of investing in the
  Fund with the cost of investing in other mutual funds. The example
  assumes that you invest $10,000 in the Fund for the time periods
  indicated then redeem all of your shares at the end of those periods. The
  example also assumes that your investment has a 5% return each year and
  that the Fund's operating expenses remain the same. Although your actual
  costs may be higher or lower, based on these assumptions your costs would
  be:

<TABLE>
<CAPTION>
                                             1 Year     3 Years    5 Years    10 Years
                                             -----------------------------------------
   <S>                                        <C>        <C>        <C>        <C>
   Janus Worldwide Fund                        $91       $284       $493       $1,096
</TABLE>

                                              Janus Worldwide Fund prospectus  5
<PAGE>

INVESTMENT OBJECTIVE, PRINCIPAL INVESTMENT
STRATEGIES AND RISKS
- --------------------------------------------------------------------------------

               This section takes a closer look at the investment objective of
               the Fund, its principal investment strategies and certain risks
               of investing in the Fund. Strategies and policies that are noted
               as "fundamental" cannot be changed without a shareholder vote.

               Please carefully review the "Risks" section of this Prospectus on
               pages 9-12 for a discussion of risks associated with certain
               investment techniques. We've also included a Glossary with
               descriptions of investment terms used throughout this Prospectus.

INVESTMENT OBJECTIVE AND PRINCIPAL INVESTMENT STRATEGIES

               Janus Worldwide Fund seeks long-term growth of capital in a
               manner consistent with the preservation of capital. It pursues
               its objective by investing primarily in common stocks of
               companies of any size throughout the world. The Fund normally
               invests in issuers from at least five different countries,
               including the United States. The Fund may at times invest in
               fewer than five countries or even a single country.

               The Fund may invest substantially all of its assets in common
               stocks of foreign issuers if its portfolio managers believe that
               common stocks will appreciate in value. The portfolio managers
               generally take a "bottom up" approach to selecting companies. In
               other words, they seek to identify individual companies with
               earnings growth potential that may not be recognized by the
               market at large. They make this assessment by looking at
               companies one at a time, regardless of size, country of
               organization, place of principal business activity, or other
               similar selection criteria. Realization of income is not a
               significant consideration when choosing investments for the Fund.
               Income realized on the Fund's investments will be incidental to
               its objective.

               Foreign securities are generally selected on a stock-by-stock
               basis without regard to any defined allocation among countries or
               geographic regions. However, certain factors such as expected
               levels of inflation, government policies influencing business
               conditions, the outlook for currency relationships, and prospects

 6 Janus Worldwide Fund prospectus
<PAGE>

               for economic growth among countries, regions or geographic areas
               may warrant greater consideration in selecting foreign
               securities.

GENERAL PORTFOLIO POLICIES

               In investing its portfolio assets, the Fund will follow the
               general policies listed below. The percentage limitations
               included in these policies and elsewhere in this Prospectus apply
               at the time of purchase of the security. So, for example, if the
               Fund exceeds a limit as a result of market fluctuations or the
               sale of securities, it will not be required to dispose of any
               securities.

               CASH POSITION
               When the Fund's portfolio managers believe that market conditions
               are unfavorable for profitable investing, or when they are
               otherwise unable to locate attractive investment opportunities,
               the Fund's cash or similar investments may increase. In other
               words, the Fund does not always stay fully invested in stocks.
               Cash or similar investments generally are a residual - they
               represent the assets that remain after the portfolio managers
               have committed available assets to desirable investment
               opportunities. However, the portfolio managers may also
               temporarily increase the Fund's cash position to protect its
               assets or maintain liquidity. When the Fund's investments in cash
               or similar investments increase, it may not participate in market
               advances or declines to the same extent that it would if the Fund
               remained more fully invested in stocks.

               OTHER TYPES OF INVESTMENTS
               The Fund invests primarily in domestic and foreign equity
               securities, which may include preferred stocks, common stocks,
               warrants and securities convertible into common or preferred
               stocks, but it may also invest to a lesser degree in other types
               of securities. These securities (which are described in the
               Glossary) may include:

               - debt securities

               - indexed/structured securities

                                              Janus Worldwide Fund prospectus  7
<PAGE>

               - high-yield/high-risk bonds (less than 35% of the Fund's assets)

               - options, futures, forwards, swaps and other types of
                 derivatives for hedging purposes or for non-hedging purposes
                 such as seeking to enhance return

               - securities purchased on a when-issued, delayed delivery or
                 forward commitment basis

               ILLIQUID INVESTMENTS
               The Fund may invest up to 15% of its net assets in illiquid
               investments. An illiquid investment is a security or other
               position that cannot be disposed of quickly in the normal course
               of business. For example, some securities are not registered
               under the U.S. securities laws and cannot be sold to the U.S.
               public because of SEC regulations (these are known as "restricted
               securities"). Under procedures adopted by the Fund's Trustees,
               certain restricted securities may be deemed liquid, and will not
               be counted toward this 15% limit.

               FOREIGN SECURITIES
               The Fund may invest without limit in foreign equity and debt
               securities. The Fund may invest directly in foreign securities
               denominated in a foreign currency and not publicly traded in the
               United States. Other ways of investing in foreign securities
               include depositary receipts or shares, and passive foreign
               investment companies.

               SPECIAL SITUATIONS
               The Fund may invest in special situations. A special situation
               arises when, in the opinion of the Fund's portfolio managers, the
               securities of a particular issuer will be recognized and
               appreciate in value due to a specific development with respect to
               that issuer. Developments creating a special situation might
               include, among others, a new product or process, a technological
               breakthrough, a management change or other extraordinary
               corporate event, or differences in market supply of and demand
               for the security. The Fund's performance could suffer if the
               anticipated development in

 8 Janus Worldwide Fund prospectus
<PAGE>

               a "special situation" investment does not occur or does not
               attract the expected attention.

               PORTFOLIO TURNOVER
               The Fund generally intends to purchase securities for long-term
               investment although, to a limited extent, the Fund may purchase
               securities in anticipation of relatively short-term price gains.
               Short-term transactions may also result from liquidity needs,
               securities having reached a price or yield objective, changes in
               interest rates or the credit standing of an issuer, or by reason
               of economic or other developments not foreseen at the time of the
               investment decision. The Fund may also sell one security and
               simultaneously purchase the same or a comparable security to take
               advantage of short-term differentials in bond yields or
               securities prices. Changes are made in the Fund's portfolio
               whenever its portfolio managers believe such changes are
               desirable. Portfolio turnover rates are generally not a factor in
               making buy and sell decisions.

               Increased portfolio turnover may result in higher costs for
               brokerage commissions, dealer mark-ups and other transaction
               costs and may also result in taxable capital gains. Higher costs
               associated with increased portfolio turnover may offset gains in
               the Fund's performance.

RISKS

               Because the Fund may invest substantially all of its assets in
               common stocks, the main risk is the risk that the value of the
               stocks it holds might decrease in response to the activities of
               an individual company or in response to general market and/or
               economic conditions. If this occurs, the Fund's share price may
               also decrease. The Fund's performance may also be affected by
               risks specific to certain types of investments, such as foreign
               securities, derivative investments, non-investment grade debt
               securities, initial public offerings (IPOs) or companies with
               relatively small market capitalizations. IPOs and other
               investment techniques may have a magnified performance impact on
               a fund

                                              Janus Worldwide Fund prospectus  9
<PAGE>

               with a small asset base. A fund may not experience similar
               performance as its assets grow.

The following questions and answers are designed to help you better understand
some of the risks of investing in the Fund.

1. HOW COULD THE FUND'S INVESTMENTS IN FOREIGN SECURITIES AFFECT ITS
   PERFORMANCE?

               The Fund may invest without limit in foreign securities either
               indirectly (e.g., depositary receipts) or directly in foreign
               markets. Investments in foreign securities, including those of
               foreign governments, may involve greater risks than investing in
               domestic securities because the Fund's performance may depend on
               issues other than the performance of a particular company. These
               issues include:

               - CURRENCY RISK. As long as the Fund holds a foreign security,
                 its value will be affected by the value of the local currency
                 relative to the U.S. dollar. When the Fund sells a foreign
                 denominated security, its value may be worth less in U.S.
                 dollars even if the security increases in value in its home
                 country. U.S. dollar denominated securities of foreign issuers
                 may also be affected by currency risk.

               - POLITICAL AND ECONOMIC RISK. Foreign investments may be subject
                 to heightened political and economic risks, particularly in
                 emerging markets which may have relatively unstable
                 governments, immature economic structures, national policies
                 restricting investments by foreigners, different legal systems,
                 and economies based on only a few industries. In some
                 countries, there is the risk that the government may take over
                 the assets or operations of a company or that the government
                 may impose taxes or limits on the removal of the Fund's assets
                 from that country.

               - REGULATORY RISK. There may be less government supervision of
                 foreign markets. As a result, foreign issuers may not be
                 subject to the uniform accounting, auditing and financial
                 reporting

 10 Janus Worldwide Fund prospectus
<PAGE>

                 standards and practices applicable to domestic issuers and
                 there may be less publicly available information about foreign
                 issuers.

               - MARKET RISK. Foreign securities markets, particularly those of
                 emerging market countries, may be less liquid and more volatile
                 than domestic markets. Certain markets may require payment for
                 securities before delivery and delays may be encountered in
                 settling securities transactions. In some foreign markets,
                 there may not be protection against failure by other parties to
                 complete transactions.

               - TRANSACTION COSTS. Costs of buying, selling and holding foreign
                 securities, including brokerage, tax and custody costs, may be
                 higher than those involved in domestic transactions.

2. THE FUND MAY INVEST IN SMALLER OR NEWER COMPANIES. DOES THIS CREATE ANY
   SPECIAL RISKS?

               Many attractive investment opportunities may be smaller, start-up
               companies offering emerging products or services. Smaller or
               newer companies may suffer more significant losses as well as
               realize more substantial growth than larger or more established
               issuers because they may lack depth of management, be unable to
               generate funds necessary for growth or potential development, or
               be developing or marketing new products or services for which
               markets are not yet established and may never become established.
               In addition, such companies may be insignificant factors in their
               industries and may become subject to intense competition from
               larger or more established companies. Securities of smaller or
               newer companies may have more limited trading markets than the
               markets for securities of larger or more established issuers, and
               may be subject to wide price fluctuations. Investments in such
               companies tend to be more volatile and somewhat more speculative.

3. I'VE HEARD A LOT ABOUT HOW THE CHANGE TO THE YEAR 2000 COULD AFFECT COMPUTER
   SYSTEMS. DOES THIS CREATE ANY SPECIAL RISKS?

               The portfolio manager carefully researches each potential
               investment before making an investment decision and, among other

                                             Janus Worldwide Fund prospectus  11
<PAGE>

               things considers what impact, if any, the Year 2000 transition
               has had on the company's operations when selecting portfolio
               holdings. However, there is no guarantee that the information the
               portfolio manager receives regarding a company's Year 2000
               transition status is completely accurate. If a company has not
               satisfactorily addressed Year 2000 issues, the Fund's performance
               could suffer.

4. ARE THERE SPECIAL RISKS ASSOCIATED WITH INVESTMENTS IN HIGH-YIELD/HIGH-RISK
   BONDS?

               High-yield/high-risk bonds (or "junk" bonds) are bonds rated
               below investment grade by the primary rating agencies such as
               Standard & Poor's and Moody's. The value of lower quality bonds
               generally is more dependent on credit risk, or the ability of the
               issuer to meet interest and principal payments, than investment
               grade bonds. Issuers of high-yield bonds may not be as strong
               financially as those issuing bonds with higher credit ratings and
               are more vulnerable to real or perceived economic changes,
               political changes or adverse developments specific to the issuer.

               Please refer to the SAI for a description of bond rating
               categories.

5. HOW DOES THE FUND TRY TO REDUCE RISK?

               The Fund may use futures, options, swaps and other derivative
               instruments to "hedge" or protect its portfolio from adverse
               movements in securities prices and interest rates. The Fund may
               also use a variety of currency hedging techniques, including
               forward currency contracts, to manage exchange rate risk. The
               Fund believes the use of these instruments will benefit the Fund.
               However, the Fund's performance could be worse than if the Fund
               had not used such instruments if the portfolio manager's
               judgement proves incorrect. Risks associated with the use of
               derivative instruments are described in the SAI.

 12 Janus Worldwide Fund prospectus
<PAGE>

                       This page intentionally left blank

                                             Janus Worldwide Fund prospectus  13
<PAGE>

- --------------------------------------------------------------------------------
<PAGE>

                                  [JANUS LOGO]
                             JANUS  WORLDWIDE  FUND
                              SHAREHOLDER'S MANUAL

                                           This section will help you
                                           become familiar with the
                                           different types of accounts
                                           you can establish with Janus.
                                           It also explains in detail the
                                           wide array of services and
                                           features you can establish on
                                           your account, as well as
                                           account policies and fees that
                                           may apply to your account.
                                           Account policies (including
                                           fees), services and features
                                           may be modified or
                                           discontinued without
                                           shareholder approval or prior
                                           notice.

                                           [JANUS LOGO]

<PAGE>

HOW TO GET IN TOUCH WITH JANUS

INVESTOR SERVICE CENTERS
100 Fillmore Street, Suite 100
Denver, CO 80206

3773 Cherry Creek North Drive, Suite 101
Denver, CO 80209

(Hours: Monday-Friday 7:00 a.m.-6:00 p.m., and Saturday 9:00 a.m.-1:00 p.m.,
Mountain time.)

MAILING ADDRESS
Janus
P.O. Box 173375
Denver, CO 80217-3375

FOR OVERNIGHT CARRIER
Janus
Suite 101
3773 Cherry Creek Drive North
Denver, CO 80209-3821

INVESTOR SERVICE REPRESENTATIVES
If you have any questions while reading this Prospectus, please call one of our
Investor Service Representatives at 1-800-525-3713 Monday-Friday: 8:00 a.m.-8:00
p.m., and Saturday: 10:00 a.m.-4:00 p.m., New York time.

JANUS XPRESSLINE(TM)
1-888-979-7737

JANUS INTERNET ADDRESS
JANUS.COM

For 24-hour access to account and fund information, exchanges, purchases and
redemptions, automated daily quotes on fund share prices, yields and total
returns.

JANUS.COM SPECIALISTS
1-800-975-9932

TDD
1-800-525-0056
A telecommunications device for our hearing- and speech-impaired shareholders.

JANUS LITERATURE LINE
1-800-525-8983
To request a prospectus, shareholder reports or marketing materials 24 hours a
day.

 16 Shareholder's manual
<PAGE>

MINIMUM INVESTMENTS*

<TABLE>
<S>                      <C>
To open a new regular
account                  $2,500
To open a new
retirement account,
education account or
UGMA/UTMA                $  500
To open a new regular
account with an
Automatic Investment
Program                  $  500**
To add to any type of
an account               $  100+
</TABLE>

 * The Fund reserves the right to change the amount of these minimums from time
   to time or to waive them in whole or in part for certain types of accounts.

** An Automatic Investment Program requires a $100 minimum automatic investment
   per month until the account balance reaches $2,500.

 + The minimum subsequent investment for a retirement account or UGMA/UTMA is
   $50.

TYPES OF ACCOUNT OWNERSHIP

               If you are investing in the Fund for the first time, you will
               need to establish an account. You can establish the following
               types of accounts by completing a New Account Application.

               INDIVIDUAL OR JOINT OWNERSHIP
               Individual accounts are owned by one person. Joint accounts have
               two or more owners.

               A GIFT OR TRANSFER TO MINOR (UGMA OR UTMA)
               An UGMA/UTMA is a custodial account managed for the benefit of a
               minor. To open an UGMA or UTMA, you must include the minor's
               Social Security number on the application.

               TRUST
               An established trust can open an account. The names of each
               trustee, the name of the trust and the date of the trust
               agreement must be included on the application.

                                                        Shareholder's manual  17
<PAGE>

               BUSINESS ACCOUNTS
               Corporations and partnerships may also open an account. The
               application must be signed by an authorized officer of the
               corporation or a general partner of the partnership.

TAX-DEFERRED ACCOUNTS

               If you are eligible, you may set up one or more tax-deferred
               accounts. A tax-deferred account allows you to shelter your
               investment income and capital gains from current income taxes. A
               contribution to certain of these plans may also be tax
               deductible. Tax-deferred accounts include retirement plans
               described below and the Education IRA. Please refer to the Janus
               retirement guide for more complete information regarding the
               different types of IRAs, including the Education IRA.
               Distributions from these plans are generally subject to income
               tax and may be subject to an additional tax if withdrawn prior to
               age 59 1/2 or used for a nonqualifying purpose. Investors should
               consult their tax adviser or legal counsel before selecting a
               tax-deferred account.

               Investors Fiduciary Trust Company serves as custodian for the
               tax-deferred accounts offered by the Fund. You will be charged an
               annual account maintenance fee of $12 for each taxpayer
               identification number no matter how many tax-deferred accounts
               you have with Janus. You may pay the fee by check or have it
               automatically deducted from your account (usually in December).
               The custodian reserves the right to change the amount of this fee
               or to waive it in whole or in part for certain types of accounts.

               TRADITIONAL AND ROTH INDIVIDUAL RETIREMENT ACCOUNTS
               Both types of IRAs allow most individuals with earned income to
               contribute up to the lesser of $2,000 ($4,000 for most married
               couples) or 100% of compensation annually.

               EDUCATION IRA
               This plan allows individuals, subject to certain income
               limitations, to contribute up to $500 annually on behalf of any
               child under the age of 18.

 18 Shareholder's manual
<PAGE>

               SIMPLIFIED EMPLOYEE PENSION PLAN
               This plan allows small business owners (including sole
               proprietors) to make tax-deductible contributions for themselves
               and any eligible employee(s). A SEP requires an IRA (a SEP-IRA)
               to be set up for each SEP participant.

               PROFIT SHARING OR MONEY PURCHASE PENSION PLAN
               These plans are open to corporations, partnerships and sole
               proprietors to benefit their employees and themselves.

               SECTION 403(B)(7) PLAN
               Employees of educational organizations or other qualifying, tax-
               exempt organizations may be eligible to participate in a Section
               403(b)(7) Plan.

               PLEASE REFER TO THE CHART ON THE FOLLOWING PAGES FOR INFORMATION
               ON OPENING AN ACCOUNT AND CONDUCTING BUSINESS WITH JANUS. WITH
               CERTAIN LIMITED EXCEPTIONS, THE FUND IS AVAILABLE ONLY TO U.S.
               CITIZENS OR RESIDENTS. WHEN YOU PURCHASE, EXCHANGE, OR REDEEM
               SHARES, YOUR REQUEST WILL BE PROCESSED AT THE NEXT NAV CALCULATED
               AFTER YOUR ORDER IS RECEIVED AND ACCEPTED.

                                                        Shareholder's manual  19
<PAGE>

 TO PURCHASE SHARES

 BY MAIL/IN WRITING
 ------------------------------------------------------------------------------

 - To open your account, complete and sign the appropriate application and make
   your check payable to Janus.

 - To purchase additional shares, complete the remittance slip attached at the
   bottom of your confirmation statement. If you are making a purchase into a
   retirement account, please indicate whether the purchase is a rollover or a
   current or prior year contribution. Send your check and remittance slip or
   written instructions to the address listed on the slip.

 BY TELEPHONE
 ------------------------------------------------------------------------------

 - The "Telephone Purchase of Shares Option" allows you to purchase additional
   shares quickly and conveniently through an electronic transfer of money.
   After establishing this option on your account, call an Investor Service
   Representative during normal business hours or the Janus XpressLine for
   access to this option 24 hours a day. Janus will automatically debit your
   predesignated bank account.

 - Purchases may also be made by wiring money from your bank account to your
   Janus account. Call an Investor Service Representative for wiring
   instructions.

 BY INTERNET
 ------------------------------------------------------------------------------

 - The "Telephone Purchase of Shares Option" allows you to make a purchase into
   an existing account on our Web site at janus.com.

 BY AUTOMATIC INVESTMENT
 ------------------------------------------------------------------------------

 - Automatic Monthly Investment Program - You select the day each month that
   your money ($100 minimum) will be electronically transferred from your bank
   account to your Fund account.

 - Payroll Deduction - If your employer can initiate an automatic payroll
   deduction, you may have all or a portion of your paycheck ($100 minimum)
   invested directly into your Fund account.

 20 Shareholder's manual
<PAGE>

<TABLE>
<S>                                            <C>
    TO EXCHANGE SHARES                           TO REDEEM SHARES
- ---------------------------------------        ---------------------------------------
    - To request an exchange in writing,         - To request a redemption in writ-
      please follow the instructions for           ing, please follow the instructions
      written requests on page 24. Also            for written requests on page 24.
      refer to the exchange policies             - Please see page 23 for information
      listed on page 22 for more infor-            about payment of redemption
      mation.                                      proceeds.

- ---------------------------------------        ---------------------------------------
    - All accounts are automatically eli-        - The telephone redemption option
      gible to exchange shares by tele-            enables you to request redemp-
      phone. To exchange all or a portion          tions daily from your account by
      of your shares into any other                calling an Investor Service Repre-
      available Janus fund, call an                sentative by the close of the
      Investor Service Representative or           regular trading session of the
      the Janus XpressLine.                        NYSE, normally 4:00 p.m. New York
                                                   time. You may also use Janus
                                                   XpressLine for access to this
                                                   option 24 hours a day.

- ---------------------------------------        ---------------------------------------
    - Exchanges may be made on our Web           - Redemptions may be made on our Web
      site at janus.com.                           site at janus.com.
- ---------------------------------------        ---------------------------------------
    - Systematic Exchange - You deter-           - Systematic Redemption - This option
      mine the amount of money you would           allows you to redeem a specific
      like automatically exchanged from            dollar amount from your account on
      one Janus account to another on any          a regular basis.
      day of the month. You may establish
      this program for as little as $100
      per month on existing accounts. You
      may establish a new account with a
      $500 initial purchase and subse-
      quent $100 systematic exchanges.
</TABLE>

                                                        Shareholder's manual  21
<PAGE>

PAYING FOR SHARES

Please note the following when purchasing shares:

- - Cash, credit cards, third party checks, travelers cheques, credit card checks
  or money orders will not be accepted.

- - All purchases must be made in U.S. dollars and checks must be drawn on U.S.
  banks.

- - We may make additional attempts to debit the bank account for ACH purchases.

- - The Fund reserves the right to reject any specific purchase request.

- - If all or a portion of a check is received for investment without a specific
  fund designation, the undesignated amount will be invested in the Janus Money
  Market Fund -- Investor Shares. Shares that are subsequently exchanged from
  Janus Money Market Fund -- Investor Shares into the selected Fund will receive
  the NAV next calculated after your order is received and accepted by the Fund.

- - If your purchase is cancelled, you will be responsible for any losses or fees
  imposed by your bank and losses that may be incurred as a result of any
  decline in the value of the cancelled purchase.

EXCHANGE POLICIES

The exchange privilege is not intended as a vehicle for short-term or excessive
trading. The Funds do not permit excessive trading or market timing. Excessive
purchases, redemptions, or exchanges of Fund shares disrupt portfolio management
and drive Fund expenses higher.

Please note the following when exchanging shares:

- - Except for Systematic Exchanges, new accounts established by exchange must be
  opened with $2,500 or the total account value if the value of the account you
  are exchanging from is less than $2,500.

- - Exchanges between existing accounts must meet the $100 subsequent investment
  requirement.

- - You may make four exchanges out of the Fund during a calendar year (exclusive
  of Systematic Exchange). Exchanges in excess of this limit are considered
  excessive trading and may be subject to an exchange fee or may result in
  termination of the exchange privilege or the right to make future purchases of
  Fund shares.

 22 Shareholder's manual
<PAGE>

- - The Fund reserves the right to reject any purchase order or exchange request
  and to modify or terminate the exchange privilege at any time. For example,
  the Fund may reject exchanges from accounts engaged in or known to engage in
  trading in excess of the limit above (including market timing transactions) or
  whose trading has been or may be disruptive to a Fund.

- - Exchanges between accounts will be accepted only if the registrations are
  identical.

- - If the shares you are exchanging are held in certificate form, you must return
  the certificate to Janus prior to making any exchanges. Effective June 4,
  1999, shares are no longer available in certificate form.

- - An exchange represents the sale of shares from one Fund and the purchase of
  shares of another Fund, which may produce a taxable gain or loss in a
  non-retirement account.

- - If the balance in the account you are exchanging from falls below the
  systematic exchange amount, all remaining shares will be exchanged
  and the program will be discontinued.

PAYMENT OF REDEMPTION PROCEEDS

- - BY CHECK - Redemption proceeds will be sent to the shareholder(s) of record at
  the address of record within seven days after receipt of a valid redemption
  request. During the 10 days following an address change, checks sent to a new
  address require a signature guarantee.

- - BY ELECTRONIC TRANSFER - If you have established the electronic redemption
  option, your redemption proceeds can be electronically transferred to your
  predesignated bank account on the next bank business day after receipt of your
  redemption request (wire transfer) or the second bank business day after
  receipt of your redemption request (ACH transfer).

Wire transfers will be charged an $8 fee per wire and your bank may charge an
additional fee to receive the wire. Wire redemptions are not available for
retirement accounts.

IF THE SHARES BEING REDEEMED WERE PURCHASED BY CHECK, TELEPHONE, ON OUR WEB
SITE, OR THROUGH THE AUTOMATIC MONTHLY INVESTMENT PROGRAM, THE FUND MAY DELAY
THE PAYMENT OF YOUR REDEMPTION PROCEEDS FOR UP TO 15 DAYS FROM THE DAY OF
PURCHASE TO ALLOW THE PURCHASE TO CLEAR. Unless you provide alternate
instructions, your proceeds will be invested in Janus Money Market
Fund - Investor Shares during the 15 day hold period.

                                                        Shareholder's manual  23
<PAGE>

WRITTEN INSTRUCTIONS

               To redeem or exchange all or part of your shares in writing, your
               request should be sent to one of the addresses listed on page 16
               and must include the following information:

               - the name of the Fund(s)

               - the account number(s)

               - the amount of money or number of shares being redeemed or
                 exchanged

               - the name(s) on the account

               - the signature(s) of all registered account owners (see account
                 application for signature requirements)

               - your daytime telephone number

SIGNATURE GUARANTEE

               A SIGNATURE GUARANTEE IS REQUIRED if any of the following is
               applicable:

               - You request a redemption by check that exceeds $100,000.

               - You would like a check made payable to anyone other than the
                 shareholder(s) of record.

               - You would like a check mailed to an address which has been
                 changed within 10 days of the redemption request.

               - You would like a check mailed to an address other than the
                 address of record.

               THE FUND RESERVES THE RIGHT TO REQUIRE A SIGNATURE GUARANTEE
               UNDER OTHER CIRCUMSTANCES OR TO REJECT OR DELAY A REDEMPTION ON
               CERTAIN LEGAL GROUNDS.

               HOW TO OBTAIN A SIGNATURE GUARANTEE

               A signature guarantee assures that a signature is genuine. The
               signature guarantee protects shareholders from unauthorized
               account transfers. The following financial institutions may
               guaran-

 24 Shareholder's manual
<PAGE>

               tee signatures: banks, savings and loan associations, trust
               companies, credit unions, broker-dealers, and member firms of a
               national securities exchange. Call your financial institution to
               see if they have the ability to guarantee a signature. A
               signature guarantee cannot be provided by a notary public.

               If you live outside the United States, a foreign bank properly
               authorized to do business in your country of residence or a U.S.
               consulate may be able to authenticate your signature.

PRICING OF FUND SHARES

               All purchases, redemptions and exchanges will be processed at the
               NAV next calculated after your request is received and accepted
               by the Fund (or the Fund's agent or authorized designee). The
               Fund's NAV is calculated at the close of the regular trading
               session of the NYSE (normally 4:00 p.m. New York time) each day
               that the NYSE is open. The NAV of Fund shares is not determined
               on days the NYSE is closed (generally New Year's Day, Martin
               Luther King Day, Presidents' Day, Good Friday, Memorial Day,
               Independence Day, Labor Day, Thanksgiving and Christmas). In
               order to receive a day's price, your order must be received by
               the close of the regular trading session of the NYSE. Securities
               are valued at market value or, if a market quotation is not
               readily available, at their fair value determined in good faith
               under procedures established by and under the supervision of the
               Trustees. Short-term instruments maturing within 60 days are
               valued at amortized cost, which approximates market value. See
               the SAI for more detailed information.

SHAREHOLDER SERVICES AND ACCOUNT POLICIES

               ACCOUNT MINIMUMS

               Due to the proportionately higher costs of maintaining small
               accounts, Janus reserves the right to deduct a $10 minimum
               balance fee (or the value of the account if less than $10) from
               accounts with values below the minimums described on page 17 or
               to close such accounts. This policy will apply to accounts

                                                        Shareholder's manual  25
<PAGE>

               participating in the Automatic Monthly Investment Program only if
               your account balance does not reach the required minimum initial
               investment or falls below such minimum and you have discontinued
               monthly investments. This policy does not apply to accounts that
               fall below the minimums solely as a result of market value
               fluctuations. It is expected that, for purposes of this policy,
               accounts will be valued in September, and the $10 fee will be
               assessed on the second Friday of September of each year. You will
               receive notice before we charge the $10 fee or close your account
               so that you may increase your account balance to the required
               minimum.

               TRANSACTIONS THROUGH PROCESSING ORGANIZATIONS

               You may purchase or sell Fund shares through a broker-dealer,
               bank or other financial institution, or an organization that
               provides recordkeeping and consulting services to 401(k) plans or
               other employee benefit plans (a "Processing Organization").
               Processing Organizations may charge you a fee for this service
               and may require different minimum initial and subsequent
               investments than the Fund. Processing Organizations may also
               impose other charges or restrictions different from those
               applicable to shareholders who invest in the Fund directly. A
               Processing Organization, rather than its customers, may be the
               shareholder of record of your shares. The Fund is not responsible
               for the failure of any Processing Organization to carry out its
               obligations to its customers. Certain Processing Organizations
               may receive compensation from Janus Capital or its affiliates and
               certain Processing Organizations may receive compensation from
               the Fund for shareholder recordkeeping and similar services.

               TAXPAYER IDENTIFICATION NUMBER

               On the application or other appropriate form, you will be asked
               to certify that your Social Security or taxpayer identification
               number is correct and that you are not subject to backup
               withholding for failing to report income to the IRS. If you are
               subject to the 31% backup withholding or you did not certify

 26 Shareholder's manual
<PAGE>

               your taxpayer identification number, the IRS requires the Fund to
               withhold 31% of any dividends paid and redemption or exchange
               proceeds. In addition to the 31% backup withholding, you may be
               subject to a $50 fee to reimburse the Fund for any penalty that
               the IRS may impose.

               INVOLUNTARY REDEMPTIONS

               The Fund reserves the right to close an account if the
               shareholder is deemed to engage in activities which are illegal
               or otherwise believed to be detrimental to the Fund.

               TELEPHONE TRANSACTIONS

               You may initiate many transactions by telephone. The Fund and its
               agents will not be responsible for any losses resulting from
               unauthorized transactions when procedures designed to verify the
               identity of the caller are followed.

               It may be difficult to reach an Investor Service Representative
               by telephone during periods of unusual market activity. If you
               are unable to reach a representative by telephone, please
               consider sending written instructions, stopping by a Service
               Center, calling the Janus XpressLine or visiting our Web site.

               TEMPORARY SUSPENSION OF SERVICES

               The Fund or its agents may, in case of emergency, temporarily
               suspend telephone transactions and other shareholder services.

               ADDRESS CHANGES

               To change the address on your account, call 1-800-525-3713 or
               send a written request signed by the shareholder(s) of record.
               Include the name of your Fund, the account number(s), the name(s)
               on the account and both the old and new addresses. Certain
               options may be suspended for 10 days following an address change
               unless a signature guarantee is provided.

                                                        Shareholder's manual  27
<PAGE>

               REGISTRATION CHANGES

               To change the name on an account, the shares are generally
               transferred to a new account. In some cases, legal documentation
               may be required. For further instructions, please call an
               Investor Service Representative.

               STATEMENTS AND REPORTS

               Investors will receive quarterly confirmations of all
               transactions. Quarterly statements for all investors are
               available on our Web site. You may make an election on our Web
               site to discontinue delivery of your paper statements. Dividend
               information will be distributed annually. In addition, the Fund
               will send you an immediate transaction confirmation statement
               after every non-systematic transaction.

               The Fund produces financial reports, which include a list of the
               Fund's portfolio holdings, semiannually and updates its
               prospectus annually. To reduce expenses, the Fund may choose to
               mail only one report or prospectus to your household, even if
               more than one person in the household has a Fund account. Please
               call 1-800-525-3713 if you would like to receive additional
               reports or prospectuses. The Fund reserves the right to charge a
               fee for additional statement requests.

 28 Shareholder's manual
<PAGE>

MANAGEMENT OF THE FUND
- --------------------------------------------------------------------------------
INVESTMENT ADVISER

               Janus Capital Corporation, 100 Fillmore Street, Denver, Colorado
               80206-4928, is the investment adviser to the Fund and is
               responsible for the day-to-day management of its investment
               portfolio and other business affairs.

               Janus Capital began serving as investment adviser to Janus Fund
               in 1970 and currently serves as investment adviser to all of the
               Janus funds, acts as sub-adviser for a number of private-label
               mutual funds and provides separate account advisory services for
               institutional accounts.

               Janus Capital furnishes continuous advice and recommendations
               concerning the Fund's investments. Janus Capital also furnishes
               certain administrative, compliance and accounting services for
               the Fund, and may be reimbursed by the Fund for its costs in
               providing those services. In addition, Janus Capital employees
               serve as officers of the Trust and Janus Capital provides office
               space for the Fund and pays the salaries, fees and expenses of
               all Fund officers and those Trustees who are affiliated with
               Janus Capital.

               The Fund pays Janus Capital a management fee which is calculated
               daily and paid monthly. The advisory agreement with the Fund
               spells out the management fee and other expenses that the Fund
               must pay.

               The Fund incurs expenses not assumed by Janus Capital, including
               transfer agent and custodian fees and expenses, legal and
               auditing fees, printing and mailing costs of sending reports and
               other information to existing shareholders, and independent
               Trustees' fees and expenses. For the most recent fiscal year, the
               Fund paid Janus Capital a management fee equal to 0.65% of
               average daily net assets.

                                             Janus Worldwide Fund prospectus  29
<PAGE>

PORTFOLIO MANAGER

LAURENCE J. CHANG
- --------------------------------------------------------------------------------
                   is Executive Vice President and co-manager of the Fund
                   which he has co-managed since September 1999. He is also
                   Executive Vice President and co-manager of Janus Overseas
                   Fund which he has co-managed since April 1998. Mr. Chang
                   joined Janus Capital in 1993 as a research analyst. He
                   received an undergraduate degree with honors in Religion
                   with a concentration in Philosophy from Dartmouth College
                   and a Master's Degree in Political Science from Stanford
                   University. Mr. Chang is a Chartered Financial Analyst.

HELEN YOUNG HAYES
- --------------------------------------------------------------------------------
                   is Executive Vice President and co-manager of the Fund.
                   She is also Executive Vice President and co-manager of
                   Janus Overseas Fund. Ms. Hayes joined Janus Capital in
                   1987 and has managed or co-managed the Fund and Janus
                   Overseas Fund since their inceptions. She holds a Bachelor
                   of Arts in Economics from Yale University. Ms. Hayes is a
                   Chartered Financial Analyst.

 30 Janus Worldwide Fund prospectus
<PAGE>

OTHER INFORMATION
- --------------------------------------------------------------------------------

               SIZE OF THE FUND

               The Fund may discontinue sales of its shares if management and
               the Trustees believe that continued sales may adversely affect
               the Fund's ability to achieve its investment objective. If sales
               of the Fund are discontinued, it is expected that existing
               shareholders of the Fund would be permitted to continue to
               purchase shares and to reinvest any dividends or capital gains
               distributions, absent highly unusual circumstances.

               YEAR 2000

               Preparing for Year 2000 has been a high priority for Janus
               Capital. A dedicated group was established to address this issue.
               Janus Capital devoted considerable internal resources and engaged
               one of the foremost experts in the field to achieve Year 2000
               readiness. Janus Capital successfully completed all five steps of
               its Year 2000 preparedness plans including the upgrade and
               replacement of all systems, as well as full-scale testing and
               implementation of those systems. Janus Capital's detailed
               contingency plans were also thoroughly tested. As of the date of
               this prospectus, Janus Capital has not seen any adverse impact as
               a result of the Year 2000 transition on any of its systems or
               those of its vendors, or on the companies in which the Funds
               invest or worldwide markets and economies. Nonetheless, Janus
               Capital will continue to monitor the effect of the Year 2000
               transition, and there can be no absolute assurance that Year 2000
               issues will not in the future adversely affect the Funds' or
               Janus Capital's operations.

                                             Janus Worldwide Fund prospectus  31
<PAGE>

               DISTRIBUTION OF THE FUND

               The Fund is distributed by Janus Distributors, Inc., a member of
               the National Association of Securities Dealers, Inc. ("NASD"). To
               obtain information about NASD member firms and their associated
               persons, you may contact NASD Regulation, Inc. at www. nasdr.
               com, or the Public Disclosure Hotline at 800-289-9999. An
               investor brochure containing information describing the Public
               Disclosure Program is available from NASD Regulation, Inc.

 32 Janus Worldwide Fund prospectus
<PAGE>

DISTRIBUTIONS AND TAXES
- --------------------------------------------------------------------------------

DISTRIBUTIONS

               To avoid taxation of the Fund, the Internal Revenue Code requires
               the Fund to distribute net income and any net gains realized on
               its investments annually. The Fund's income from dividends and
               interest and any net realized short-term gains are paid to
               shareholders as ordinary income dividends. Net realized long-term
               gains are paid to shareholders as capital gains distributions.
               Dividends and capital gains distributions are normally declared
               and paid in December.

               HOW DISTRIBUTIONS AFFECT A FUND'S NAV

               Distributions are paid to shareholders as of the record date of
               the distribution of the Fund, regardless of how long the shares
               have been held. Dividends and capital gains awaiting distribution
               are included in the Fund's daily NAV. The share price of the Fund
               drops by the amount of the distribution, net of any subsequent
               market fluctuations. As an example, assume that on December 31,
               the Fund declared a dividend in the amount of $0.25 per share. If
               the Fund's share price was $10.00 on December 30, the Fund's
               share price on December 31 would be $9.75, barring market
               fluctuations. Shareholders should be aware that distributions
               from a taxable mutual fund are not value-enhancing and may create
               income tax obligations.

               "BUYING A DIVIDEND"

               If you purchase shares of the Fund just before the distribution,
               you will pay the full price for the shares and receive a portion
               of the purchase price back as a taxable distribution. This is
               referred to as "buying a dividend." In the above example, if you
               bought shares on December 30, you would have paid $10.00 per
               share. On December 31, the Fund would pay you $0.25 per share as
               a dividend and your shares would now be worth $9.75 per share.
               Unless your account is set up as a tax-deferred account,
               dividends paid to you would be included in your gross income for
               tax purposes, even though you may not have participated in the

                                             Janus Worldwide Fund prospectus  33
<PAGE>

               increase in NAV of the Fund, whether or not you reinvested the
               dividends.

DISTRIBUTION OPTIONS

               When you open an account, you must specify on your application
               how you want to receive your distributions. You may change your
               distribution option at any time by writing the Fund at one of the
               addresses listed on page 16 or calling 1-800-525-3713. The Fund
               offers the following options:

               1. REINVESTMENT OPTION. You may reinvest your income dividends
                  and capital gains distributions in additional shares. This
                  option is assigned automatically if no other choice is made.

               2. CASH OPTION. You may receive your income dividends and capital
                  gains distributions in cash.

               3. REINVEST AND CASH OPTION. You may receive either your income
                  dividends or capital gains distributions in cash and reinvest
                  the other in additional shares.

               4. REDIRECT OPTION. You may direct your dividends or capital
                  gains to purchase shares of another Janus fund.

               The Fund reserves the right to reinvest into your account
               undeliverable and uncashed dividend and distribution checks that
               remain outstanding for six months in shares of the Fund at the
               NAV next computed after the check is cancelled. Subsequent
               distributions may also be reinvested.

TAXES

               As with any investment, you should consider the tax consequences
               of investing in the Fund. Any time you sell or exchange shares of
               a Fund in a taxable account, it is considered a taxable event.
               Depending on the purchase price and the sale price, you may have
               a gain or loss on the transaction. Any tax liabilities generated
               by your transactions are your responsibility.

               The following discussion does not apply to tax-deferred accounts,
               nor is it a complete analysis of the federal tax implications of

 34 Janus Worldwide Fund prospectus
<PAGE>

               investing in the Fund. You may wish to consult your own tax
               adviser. Additionally, state or local taxes may apply to your
               investment, depending upon the laws of your state of residence.

               TAXES ON DISTRIBUTIONS
               Dividends and distributions by the Fund are subject to federal
               income tax, regardless of whether the distribution is made in
               cash or reinvested in additional shares of the Fund.
               Distributions may be taxable at different rates depending on the
               length of time the Fund holds a security. In certain states, a
               portion of the dividends and distributions (depending on the
               source of the Fund's income) may be exempt from state and local
               taxes. Information regarding the tax status of income dividends
               and capital gains distributions will be mailed to shareholders on
               or before January 31st of each year.

               TAXATION OF THE FUND
               Dividends, interest and some capital gains received by the Fund
               on foreign securities may be subject to tax withholding or other
               foreign taxes. The Fund may from year to year make the election
               permitted under Section 853 of the Internal Revenue Code to pass
               through such taxes to shareholders as a foreign tax credit. If
               such an election is not made, any foreign taxes paid or accrued
               will represent an expense to the Fund.

               The Fund does not expect to pay federal income or excise taxes
               because it intends to meet certain requirements of the Internal
               Revenue Code. It is important that the Fund meets these
               requirements so that any earnings on your investment will not be
               taxed twice.

                                             Janus Worldwide Fund prospectus  35
<PAGE>

FINANCIAL HIGHLIGHTS
- --------------------------------------------------------------------------------

               The financial highlights table is intended to help you understand
               the Fund's financial performance for the past 5 years through
               October 31st of each fiscal year shown. Items 1 through 9 reflect
               financial results for a single Fund share. The total returns in
               the table represent the rate that an investor would have earned
               (or lost) on an investment in the Fund (assuming reinvestment of
               all dividends and distributions). This information has been
               audited by PricewaterhouseCoopers LLP, whose report, along with
               the Fund's financial statements, are included in the Annual
               Report, which is available upon request and incorporated by
               reference into the SAI.

JANUS WORLDWIDE FUND
<TABLE>
<CAPTION>
- ---------------------------------------------------------------------------------------
                                                   Periods ending October 31st
                                            1999      1998      1997     1996     1995
<S>                                        <C>       <C>       <C>      <C>      <C>
  1. NET ASSET VALUE, BEGINNING OF PERIOD   $41.52    $40.05   $34.60   $27.65   $27.00
     INCOME FROM INVESTMENT OPERATIONS:
  2. Net investment income                    0.02      1.26   (0.08)     0.49     0.81
  3. Net gains or (losses) on securities
     (both realized and unrealized)          17.51      3.01     7.73     7.79     1.39
  4. Total from investment operations        17.53      4.27     7.65     8.28     2.20
     LESS DISTRIBUTIONS:
  5. Dividends (from net investment
     income)                                (0.18)    (1.35)   (0.15)   (0.26)   (0.54)
  6. Dividends (in excess of net
     investment income)                         --        --       --       --       --
  7. Distributions (from capital gains)         --    (1.45)   (2.05)   (1.07)   (1.01)
  8. Total distributions                    (0.18)    (2.80)   (2.20)   (1.33)   (1.55)
  9. NET ASSET VALUE, END OF PERIOD         $58.87    $41.52   $40.05   $34.60   $27.65
 10. Total return                           42.33%    11.40%   23.34%   31.00%    8.89%
 11. Net assets, end of period (in
     millions)                             $24,091   $13,932  $10,358   $4,467   $1,804
 12. Average net assets for the period
     (in millions)                         $18,893   $13,078   $7,784   $2,953   $1,622
 13. Ratio of gross expenses to average
     net assets                              0.89%     0.92%    0.97%    1.02%    1.24%
 14. Ratio of net expenses to average net
     assets                                  0.88%     0.90%    0.95%    1.01%    1.23%
 15. Ratio of net investment
     income/(loss) to average net assets     0.07%     0.47%    0.65%    0.73%    0.99%
 16. Portfolio turnover rate                   68%       86%      79%      80%     142%
- ------------------------------------------------------------------------------
</TABLE>

 36 Janus Worldwide Fund prospectus
<PAGE>

GLOSSARY OF INVESTMENT TERMS
- --------------------------------------------------------------------------------

               This glossary provides a more detailed description of some of the
               types of securities and other instruments in which the Fund may
               invest. The Fund may invest in these instruments to the extent
               permitted by its investment objective and policies. The Fund is
               not limited by this discussion and may invest in any other types
               of instruments not precluded by the policies discussed elsewhere
               in this Prospectus. Please refer to the SAI for a more detailed
               discussion of certain instruments.

I. EQUITY AND DEBT SECURITIES

               BONDS are debt securities issued by a company, municipality,
               government or government agency. The issuer of a bond is required
               to pay the holder the amount of the loan (or par value of the
               bond) at a specified maturity and to make scheduled interest
               payments.

               COMMERCIAL PAPER is a short-term debt obligation with a maturity
               ranging from 1 to 270 days issued by banks, corporations and
               other borrowers to investors seeking to invest idle cash. The
               Fund may purchase commercial paper issued in private placements
               under Section 4(2) of the Securities Act of 1933.

               COMMON STOCKS are equity securities representing shares of
               ownership in a company, and usually carry voting rights and earns
               dividends. Unlike preferred stock, dividends on common stock are
               not fixed but are declared at the discretion of the issuer's
               board of directors.

               CONVERTIBLE SECURITIES are preferred stocks or bonds that pay a
               fixed dividend or interest payment and are convertible into
               common stock at a specified price or conversion ratio.

               DEBT SECURITIES are securities representing money borrowed that
               must be repaid at a later date. Such securities have specific

                                             Janus Worldwide Fund prospectus  37
<PAGE>

               maturities and usually a specific rate of interest or an original
               purchase discount.

               DEPOSITARY RECEIPTS are receipts for shares of a foreign-based
               corporation that entitle the holder to dividends and capital
               gains on the underlying security. Receipts include those issued
               by domestic banks (American Depositary Receipts), foreign banks
               (Global or European Depositary Receipts) and broker- dealers
               (depositary shares).

               FIXED-INCOME SECURITIES are securities that pay a specified rate
               of return. The term generally includes short- and long-term
               government, corporate and municipal obligations that pay a
               specified rate of interest or coupons for a specified period of
               time and preferred stock, which pays fixed dividends. Coupon and
               dividend rates may be fixed for the life of the issue or, in the
               case of adjustable and floating rate securities, for a shorter
               period.

               HIGH-YIELD/HIGH-RISK BONDS are bonds that are rated below
               investment grade by the primary rating agencies (e.g., BB or
               lower by Standard & Poor's and Ba or lower by Moody's). Other
               terms commonly used to describe such bonds include "lower rated
               bonds," "noninvestment grade bonds" and "junk bonds."

               MORTGAGE- AND ASSET-BACKED SECURITIES are shares in a pool of
               mortgages or other debt. These securities are generally pass-
               through securities, which means that principal and interest
               payments on the underlying securities (less servicing fees) are
               passed through to shareholders on a pro rata basis. These
               securities involve prepayment risk, which is the risk that the
               underlying mortgages or other debt may be refinanced or paid off
               prior to their maturities during periods of declining interest
               rates. In that case, the portfolio manager may have to reinvest
               the proceeds from the securities at a lower rate. Potential
               market gains on a security subject to prepayment risk may be more
               limited than potential market gains on a comparable security that
               is not subject to prepayment risk.

 38 Janus Worldwide Fund prospectus
<PAGE>

               PASSIVE FOREIGN INVESTMENT COMPANIES ("PFICS") are any foreign
               corporations which generate amounts of passive income or hold
               certain amounts of assets for the production of passive income.
               Passive income includes dividends, interest, royalties, rents and
               annuities. To avoid taxes and interest that the Fund must pay if
               these investments are profitable, the Fund may make various
               elections permitted by the tax laws. These elections could
               require that the Fund recognize taxable income, which in turn
               must be distributed, before the securities are sold and before
               cash is received to pay the distributions.

               PREFERRED STOCKS are equity securities that generally pay
               dividends at a specified rate and have preference over common
               stock in the payment of dividends and liquidation. Preferred
               stock generally does not carry voting rights.

               REPURCHASE AGREEMENTS involve the purchase of a security by the
               Fund and a simultaneous agreement by the seller (generally a bank
               or dealer) to repurchase the security from the Fund at a
               specified date or upon demand. This technique offers a method of
               earning income on idle cash. These securities involve the risk
               that the seller will fail to repurchase the security, as agreed.
               In that case, the Fund will bear the risk of market value
               fluctuations until the security can be sold and may encounter
               delays and incur costs in liquidating the security.

               REVERSE REPURCHASE AGREEMENTS involve the sale of a security by
               the Fund to another party (generally a bank or dealer) in return
               for cash and an agreement by the Fund to buy the security back at
               a specified price and time. This technique will be used primarily
               to provide cash to satisfy unusually heavy redemption requests,
               or for other temporary or emergency purposes.

               U.S. GOVERNMENT SECURITIES include direct obligations of the U.S.
               government that are supported by its full faith and credit.
               Treasury bills have initial maturities of less than one year,
               Treasury notes have initial maturities of one to ten years and
               Treasury

                                             Janus Worldwide Fund prospectus  39
<PAGE>

               bonds may be issued with any maturity but generally have
               maturities of at least ten years. U.S. government securities also
               include indirect obligations of the U.S. government that are
               issued by federal agencies and government sponsored entities.
               Unlike Treasury securities, agency securities generally are not
               backed by the full faith and credit of the U.S. government. Some
               agency securities are supported by the right of the issuer to
               borrow from the Treasury, others are supported by the
               discretionary authority of the U.S. government to purchase the
               agency's obligations and others are supported only by the credit
               of the sponsoring agency.

               VARIABLE AND FLOATING RATE SECURITIES have variable or floating
               rates of interest and, under certain limited circumstances, may
               have varying principal amounts. These securities pay interest at
               rates that are adjusted periodically according to a specified
               formula, usually with reference to some interest rate index or
               market interest rate. The floating rate tends to decrease the
               security's price sensitivity to changes in interest rates.

               WARRANTS are securities, typically issued with preferred stocks
               or bonds, that give the holder the right to buy a proportionate
               amount of common stock at a specified price, usually at a price
               that is higher than the market price at the time of issuance of
               the warrant. The right may last for a period of years or
               indefinitely.

               WHEN-ISSUED, DELAYED DELIVERY AND FORWARD TRANSACTIONS generally
               involve the purchase of a security with payment and delivery at
               some time in the future - i.e., beyond normal settlement. The
               Fund does not earn interest on such securities until settlement
               and bears the risk of market value fluctuations in between the
               purchase and settlement dates. New issues of stocks and bonds,
               private placements and U.S. government securities may be sold in
               this manner.

 40 Janus Worldwide Fund prospectus
<PAGE>

II. FUTURES, OPTIONS AND OTHER DERIVATIVES

               FORWARD CONTRACTS are contracts to purchase or sell a specified
               amount of a financial instrument for an agreed upon price at a
               specified time. Forward contracts are not currently exchange
               traded and are typically negotiated on an individual basis. The
               Fund may enter into forward currency contracts to hedge against
               declines on the value of securities denominated in, or whose
               value is tied to, a currency other than the U.S. dollar or to
               reduce the impact of currency appreciation on purchases of such
               securities. It may also enter into forward contracts to purchase
               or sell securities or other financial indices.

               FUTURES CONTRACTS are contracts that obligate the buyer to
               receive and the seller to deliver an instrument or money at a
               specified price on a specified date. The Fund may buy and sell
               futures contracts on foreign currencies, securities and financial
               indices including interest rates or an index of U.S. government,
               foreign government, equity or fixed-income securities. The Fund
               may also buy options on futures contracts. An option on a futures
               contract gives the buyer the right, but not the obligation, to
               buy or sell a futures contract at a specified price on or before
               a specified date. Futures contracts and options on futures are
               standardized and traded on designated exchanges.

               INDEXED/STRUCTURED SECURITIES are typically short- to
               intermediate-term debt securities whose value at maturity or
               interest rate is linked to currencies, interest rates, equity
               securities, indices, commodity prices or other financial
               indicators. Such securities may be positively or negatively
               indexed (i.e., their value may increase or decrease if the
               reference index or instrument appreciates). Indexed/structured
               securities may have return characteristics similar to direct
               investments in the underlying instruments and may be more
               volatile than the underlying instruments. The Fund bears the
               market risk of an investment in the underlying instruments, as
               well as the credit risk of the issuer.

                                             Janus Worldwide Fund prospectus  41
<PAGE>

               OPTIONS are the right, but not the obligation, to buy or sell a
               specified amount of securities or other assets on or before a
               fixed date at a predetermined price. The Fund may purchase and
               write put and call options on securities, securities indices and
               foreign currencies.

 42 Janus Worldwide Fund prospectus
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 44
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                                  [JANUS LOGO]

        You can request other information, including a Statement of
        Additional Information, Annual Report or Semiannual Report, free
        of charge, by contacting Janus at 1-800-525-3713 or visiting our
        Web site at janus.com. In the Fund's Annual Report, you will
        find a discussion of the market conditions and investment
        strategies that significantly affected the Fund's performance
        during its last fiscal year. Other information is also available
        from financial intermediaries that sell shares of the Fund.

        The Statement of Additional Information provides detailed
        information about the Fund and is incorporated into this
        Prospectus by reference. You may review the Fund's Statement of
        Additional Information at the Public Reference Room of the SEC
        or get text only copies for a fee, by writing to or calling the
        Public Reference Room, Washington, D.C. 20549-6009
        (1-800-SEC-0330). You may obtain the Statement of Additional
        Information for free from the SEC's Web site at
        http://www.sec.gov.

                    Investment Company Act File No. 811-1879

                                 1-800-525-3713
                     PO Box 173375  Denver, CO  80217-3375
                                   janus.com
4241



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