JANUS ASPEN SERIES
497, 1999-07-21
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<PAGE>

                                         [JANUS LOGO]
                                         [JANUS LOGO]

                   Janus Aspen Series

                              PROSPECTUS
                              MAY 1, 1999
                              High-Yield Portfolio

                   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>

    [JANUS LOGO]

                Janus Aspen Series consists of eleven mutual funds (the
                "Portfolios"), one of which is described in this prospectus.
                Each Portfolio currently offers two classes of shares. The
                Institutional Shares, (the "Shares"), are sold under the name of
                "Janus Aspen Series" and are offered by this prospectus in
                connection with investment in and payments under variable
                annuity contracts and variable life insurance contracts, as well
                as certain qualified retirement plans.

                Janus Aspen Series sells and redeems its Shares at net asset
                value without sales charges, commissions or redemption fees.
                Each variable insurance contract involves fees and expenses that
                are not described in this Prospectus. See the accompanying
                contract prospectus for information regarding contract fees and
                expenses and any restrictions on purchases or allocations.

                This prospectus contains information that a prospective
                purchaser of a variable insurance contract or plan participant
                should consider in conjunction with the accompanying separate
                account prospectus of the specific insurance company product
                before allocating purchase payments or premiums to the
                Portfolio.
<PAGE>
                                                              Table of contents

<TABLE>
                <S>                                                           <C>
                RISK/RETURN SUMMARY
                   High-Yield Portfolio.....................................    2
                   Fees and expenses........................................    4
                INVESTMENT OBJECTIVE, PRINCIPAL INVESTMENT STRATEGIES AND
                RISKS
                   High-Yield Portfolio.....................................    5
                   General portfolio policies...............................    6
                   Risks for High-Yield Portfolio...........................    8
                MANAGEMENT OF THE PORTFOLIOS
                   Investment adviser.......................................   11
                   Management expenses and expense limits...................   11
                   Investment personnel.....................................   12
                OTHER INFORMATION...........................................   13
                DISTRIBUTIONS AND TAXES
                   Distributions............................................   14
                   Taxes....................................................   14
                SHAREHOLDER'S GUIDE
                   Purchases................................................   15
                   Redemptions..............................................   15
                   Shareholder communications...............................   16
                FINANCIAL HIGHLIGHTS........................................   17
                GLOSSARY
                   Glossary of investment terms.............................   18
                RATING CATEGORIES
                   Explanation of rating categories.........................   22

</TABLE>

                                                            Table of contents  1
<PAGE>
Risk return summary

HIGH-YIELD PORTFOLIO

          High-Yield Portfolio is designed for long-term investors who primarily
          seek current income.

1. WHAT IS THE INVESTMENT OBJECTIVE OF HIGH-YIELD PORTFOLIO?

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

          - HIGH-YIELD PORTFOLIO seeks to obtain high current income. Capital
            appreciation is a secondary objective when consistent with its
            primary objective.

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

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

          In addition to considering economic factors such as the effect of
          interest rates on the Portfolio'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 Portfolio's assets may be in cash or
          similar investments.

          High-Yield Portfolio 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.

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

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

          The Portfolio invests in a variety of fixed-income 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 Portfolio's
          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.

          High-Yield Portfolio may invest an unlimited amount of its assets in
          high-yield/high-risk securities, also known as "junk" bonds which 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 High-Yield Portfolio may vary significantly, depending upon its
          holdings of junk bonds.

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

 2 Janus Aspen Series
<PAGE>

          The following information provides some indication of the risks of
          investing in High-Yield Portfolio by showing how High-Yield
          Portfolio's performance has varied over time. The bar chart depicts
          the change in performance from year-to-year during the period
          indicated, but does not include charges and expenses attributable to
          any insurance product which would lower the performance illustrated.
          The Portfolio does not impose any sales or other charges that would
          affect total return computations. Total return figures include the
          effect of the Portfolio's expenses. The table compares the average
          annual returns for the Shares of the Portfolio for the periods
          indicated to a broad-based securities market index.

           HIGH-YIELD PORTFOLIO - INSTITUTIONAL SHARES

                 ANNUAL RETURNS FOR PERIODS ENDED 12/31

                 A BAR CHART showing Total Annual Returns for High-Yield
                 Portfolio - Institutional Shares from 1997 through 1998:

                                                           1997       1998
                                                           ----       ----
                                                           15.98%    1.26%

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

                 Best Quarter  1st-1998 5.52%    Worst Quarter  3rd-1998 (6.07%)



                          Average annual total return for periods ended 12/31/98
                          ------------------------------------------------------

<TABLE>
<CAPTION>
                                                                                           Since Inception
                                                                                 1 year       (5/1/96)
                <S>                                                              <C>       <C>
                High-Yield Portfolio - Institutional Shares                      1.26%         10.97%
                Lehman Brothers High-Yield Bond Index*                           1.60%          7.15%
                                                                             ------------------------------
</TABLE>

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

          High-Yield Portfolio's past performance does not necessarily indicate
          how it will perform in the future.

                                                          Risk return summary  3
<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 Portfolio. However, each variable
          insurance contract involves fees and expenses not described in this
          prospectus. See the accompanying contract prospectus for information
          regarding contract fees and expenses and any restrictions on purchases
          or allocations.

          ANNUAL FUND OPERATING EXPENSES are paid out of the Portfolio'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 on the next page
          shows, these costs are borne indirectly by all shareholders.

          This table and example are designed to assist participants in
          qualified plans that invest in the Shares of the Portfolio in
          understanding the fees and expenses that you may pay as an investor in
          the Shares. The information shown is based upon gross expenses
          (without the effect of expense offset arrangements) for the fiscal
          year ended December 31, 1998. OWNERS OF VARIABLE INSURANCE CONTRACTS
          THAT INVEST IN THE SHARES SHOULD REFER TO THE VARIABLE INSURANCE
          CONTRACT PROSPECTUS FOR A DESCRIPTION OF FEES AND EXPENSES, AS THE
          TABLE AND EXAMPLE DO NOT REFLECT DEDUCTIONS AT THE SEPARATE ACCOUNT
          LEVEL OR CONTRACT LEVEL FOR ANY CHARGES THAT MAY BE INCURRED UNDER A
          CONTRACT.
<TABLE>
<CAPTION>

                                                         Total Annual Fund                              Total Annual Fund
                                                         Operating Expenses                             Operating Expenses
                               Management      Other       Without Waivers             Total                With Waivers
                                   Fee        Expenses     or Reductions*     Waivers and Reductions       or Reductions*
- --------------------------------------------------------------------------------------------------------------------------
 <S>                           <C>            <C>             <C>                   <C>                     <C>
 High-Yield Portfolio           0.75%          1.36%          2.11%                  1.11%                  1.00%
- --------------------------------------------------------------------------------------------------------------------------
</TABLE>

- --------------------------------------------------------------------------------
   * All expenses are stated both with and without contractual waivers and
     fee reductions by Janus Capital. Other waivers, if applicable, are first
     applied against the Management Fee and then against Other Expenses.
     Janus Capital has agreed to continue the waivers and fee reductions
     until at least the next annual renewal of the advisory agreement.
- --------------------------------------------------------------------------------

   EXAMPLE:
   THE FOLLOWING EXAMPLE IS BASED ON EXPENSES WITHOUT WAIVERS OR
   REDUCTIONS. This example is intended to help you compare the cost of
   investing in the Portfolio with the cost of investing in other mutual
   funds. The example assumes that you invest $10,000 in the Portfolio 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 Portfolio'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>
    High-Yield Portfolio                                           $214       $661      $1,134      $2,441
</TABLE>

 4 Janus Aspen Series
<PAGE>
                                     Investment objective, principal investment
                                                strategies and risks

          High-Yield Portfolio has a similar investment objective and similar
          principal investment strategies to Janus High-Yield Fund. Although it
          is anticipated that the Portfolio and Janus High-Yield Fund will hold
          similar securities, differences in asset size, cash flow needs and
          other factors may result in differences in investment performance. The
          expenses of the Portfolio and Janus High-Yield Fund are expected to
          differ. The variable contract owner will also bear various insurance
          related costs at the insurance company level. You should review the
          accompanying separate account prospectus for a summary of fees and
          expenses.

INVESTMENT OBJECTIVES AND PRINCIPAL INVESTMENT STRATEGIES

          This section takes a closer look at the investment objective of
          High-Yield Portfolio, its principal investment strategies and certain
          risks of investing in High-Yield Portfolio. 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 8-10 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.

          In addition to considering economic factors such as the effect of
          interest rates on the Portfolio'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 Portfolio's assets may be in
          cash or similar investments.

          High-Yield Portfolio 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.

The following questions and answers are designed to help you better understand
High-Yield Portfolio'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
          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 HIGH-YIELD PORTFOLIO MANAGE INTEREST RATE RISK?

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

3. WHAT IS MEANT BY THE PORTFOLIO'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

              Investment objective, principal investment strategies and risks  5
<PAGE>

          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 Portfolio with
          each effective maturity "weighted" according to the percentage of net
          assets that it represents.

4. WHAT IS MEANT BY THE PORTFOLIO'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
          portfolio 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 Portfolio's duration is usually shorter than its average
          maturity.

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

          A high-yield/high-risk security (also called a "junk" bond) is a debt
          security 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

          Unless otherwise stated, 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 Portfolio exceeds a
          limit as a result of market fluctuations or the sale of other
          securities, it will not be required to dispose of any securities.

          CASH POSITION
          When the portfolio manager believes that market conditions are
          unfavorable for profitable investing, or when he is otherwise unable
          to locate attractive investment opportunities, the Portfolio's cash or
          similar investments may increase. In other words, the Portfolio does
          not always stay fully invested in stocks and 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 Portfolio's cash position to protect its
          assets or maintain liquidity.

          When the Portfolio'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 Portfolio remained more fully
          invested in stocks or bonds.

OTHER TYPES OF INVESTMENTS

          High-Yield Portfolio invests primarily in fixed-income securities
          which may include corporate bonds and notes, government securities,
          preferred stock, high-yield/high-risk fixed-income securities and
          municipal obligations. The Portfolio 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

 6 Janus Aspen Series
<PAGE>

          - options, futures, forwards 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 Portfolio 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 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 Portfolio's Trustees, certain restricted securities may be
          deemed liquid, and will not be counted toward this 15% limit.

          FOREIGN SECURITIES
          The Portfolio may invest without limit in foreign equity and debt
          securities. The Portfolio 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 Portfolio may invest in special situations. A special situation
          arises when, in the opinion of the Portfolio's 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 Portfolio'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 Portfolio generally intends to purchase securities for long-term
          investment although, to a limited extent, the Portfolio 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 Portfolio 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 Portfolio's holdings whenever the
          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 Portfolio's
          performance.

              Investment objective, principal investment strategies and risks  7
<PAGE>

RISKS FOR HIGH-YIELD PORTFOLIO

          Because the Portfolio 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
          Portfolio'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 High-Yield Portfolio.

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 Ratings Service and Moody's Investors
          Service, Inc. 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 22 for a description of
          rating categories.

 8 Janus Aspen Series
<PAGE>

3. HOW COULD THE PORTFOLIO'S INVESTMENTS IN FOREIGN SECURITIES AFFECT ITS
   PERFORMANCE?

          The Portfolio 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 Portfolio's performance may depend on issues
          other than the performance of a particular company. These issues
          include:

          - CURRENCY RISK. As long as the Portfolio holds a foreign security,
            its value will be affected by the value of the local currency
            relative to the U.S. dollar. When the Portfolio 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
            Portfolio'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.

4. ARE THERE SPECIAL RISKS ASSOCIATED WITH INVESTMENTS IN HIGH-YIELD/HIGH-RISK
   SECURITIES?

          High-yield/high-risk securities (or "junk" bonds) are securities rated
          below investment grade by the primary rating agencies such as Standard
          & Poor's and Moody's. The value of lower quality securities generally
          is more dependent on credit risk, or the ability of the issuer to meet
          interest and principal payments, than investment grade debt
          securities. Issuers of high-yield securities 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 High-Yield Portfolio may invest a significant portion of its
          assets in high-yield/high-risk securities, 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 22 for a
          description of bond rating categories.

              Investment objective, principal investment strategies and risks  9
<PAGE>

5. HOW DOES THE PORTFOLIO TRY TO REDUCE RISK?

          The Portfolio may use futures, options and other derivative
          instruments to "hedge" or protect its portfolio from adverse movements
          in securities prices and interest rates. The Portfolio 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 Portfolio.
          However, the Portfolio's performance could be worse than if the
          Portfolio 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.

6. 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 Year 2000 readiness when selecting portfolio holdings.
          However, there is no guarantee that the information the portfolio
          manager receives regarding a company's Year 2000 readiness is
          completely accurate. If a company has not satisfactorily addressed
          Year 2000 issues, the Portfolio's performance could suffer.

 10 Janus Aspen Series
<PAGE>
                                                     Management of the portfolio

INVESTMENT ADVISER

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

          Janus Capital began serving as investment adviser to Janus Fund in
          1970 and currently serves as investment adviser to all of the Janus
          retail 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 Portfolio's investments. Janus Capital also furnishes
          certain administrative, compliance and accounting services for the
          Portfolio, and may be reimbursed by the Portfolio 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 Portfolio and pays the salaries, fees and expenses of all
          Portfolio officers and those Trustees who are affiliated with Janus
          Capital.

          Participating insurance companies that purchase the Portfolio's shares
          may perform certain administrative services relating to the Portfolio
          and Janus Capital or the Portfolio may pay those companies for such
          services.

MANAGEMENT EXPENSES AND EXPENSE LIMITS

          The Portfolio pays Janus Capital a management fee which is calculated
          daily. The advisory agreement with the Portfolio spells out the
          management fee and other expenses that the Portfolio must pay. The
          Portfolio is subject to the following management fee schedule
          (expressed as an annual rate). In addition, the Shares of the
          Portfolio incur 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.

<TABLE>
<CAPTION>
                                                          Average Daily
                                                           Net Assets         Annual Rate      Expense Limit
Fee Schedule                                               of Portfolio       Percentage (%)    Percentage (%)
- --------------------------------------------------------------------------------------------------------------
<S>                                                     <C>                  <C>               <C>
     High-Yield Portfolio                               First $300 Million        0.75           1.00(1)
                                                        Over $300 Million         0.65
- --------------------------------------------------------------------------------------------------------------
</TABLE>

(1) Janus Capital has agreed to limit the Portfolio's expenses as indicated
    until at least the next annual renewal of the advisory contracts.

                                                 Management of the portfolio  11
<PAGE>

INVESTMENT PERSONNEL

PORTFOLIO MANAGER

SANDY R. RUFENACHT
- --------------------------------------------------------------------------------
            is Executive Vice President and portfolio manager of High-Yield
            Portfolio, which he has managed or co-managed since October 1996.
            He previously co-managed Flexible Income Portfolio from January
            1997 to May 1998. Mr. Rufenacht joined Janus Capital in 1990 and
            has managed Janus Short-Term Bond Fund since January 1996. He is
            also the portfolio manager of Janus High-Yield Fund. He
            previously co-managed Janus Flexible Income Fund from June 1996
            to February 1998. He holds a Bachelor of Arts in Business from
            the University of Northern Colorado.

 12 Janus Aspen Series
<PAGE>
                                                               Other information

          CLASSES OF SHARES

          The Portfolio currently offers two classes of Shares, one of which,
          the Institutional Shares, are offered pursuant to this prospectus and
          are sold under the name Janus Aspen Series. The Shares offered by this
          Prospectus are available only in connection with investment in and
          payments under variable insurance contracts as well as certain
          qualified retirement plans. Retirement Shares of the Portfolio are
          offered by separate prospectus and are available only to qualified
          plans using plan service providers that are compensated for providing
          distribution and/or recordkeeping and other administrative services.
          Because the expenses of each class may differ, the performance of each
          class is expected to differ. If you would like additional information
          about the Retirement Shares, please call 1-800-525-0020.

          CONFLICTS OF INTEREST

          The Shares offered by this prospectus are available only to variable
          annuity and variable life separate accounts of insurance companies
          that are unaffiliated with Janus Capital and to certain qualified
          retirement plans. Retirement Shares of the Portfolio (offered through
          a separate prospectus) are available to certain qualified plans.
          Although the Portfolio does not currently anticipate any disadvantages
          to policy owners because the Portfolio offers its shares to such
          entities, there is a possibility that a material conflict may arise.
          The Trustees monitor events in order to identify any disadvantages or
          material irreconcilable conflicts and to determine what action, if
          any, should be taken in response. If a material disadvantage or
          conflict occurs, the Trustees may require one or more insurance
          company separate accounts or qualified plans to withdraw its
          investments in the Portfolio or substitute Shares of another
          Portfolio. If this occurs, the Portfolio may be forced to sell its
          securities at disadvantageous prices. In addition, the Trustees may
          refuse to sell Shares of the Portfolio to any separate account or
          qualified plan or may suspend or terminate the offering of the
          Portfolio's Shares if such action is required by law or regulatory
          authority or is in the best interests of the Portfolio's shareholders.
          It is possible that a qualified plan investing in the Retirement
          Shares of the Portfolio could lose its qualified plan status under the
          Internal Revenue Code, which could have adverse tax consequences on
          insurance company separate accounts investing in the Shares. Janus
          Capital intends to monitor such qualified plans and the Portfolio may
          discontinue sales to a qualified plan and require plan participants
          with existing investments in the Retirement Shares to redeem those
          investments if a plan loses (or in the opinion of Janus Capital is at
          risk of losing) its qualified plan status.

          YEAR 2000

          Preparing for Year 2000 is a high priority for Janus Capital, which
          has established a dedicated group to address this issue. Janus Capital
          has devoted considerable internal resources and has engaged one of the
          foremost experts in the field to help achieve Year 2000 readiness.
          Janus Capital does not anticipate that Year 2000-related issues will
          have a material impact on its ability to continue to provide the
          Portfolio with service at current levels; however, Janus Capital
          cannot make any assurances that the steps it has taken to ensure Year
          2000 readiness will be successful. In addition, there can be no
          assurance that Year 2000 issues will not affect the companies in which
          the Portfolio invests or worldwide markets and economies.

                                                           Other information  13
<PAGE>
Distributions and taxes

DISTRIBUTIONS

          To avoid taxation of the Portfolio, the Internal Revenue Code requires
          the Portfolio to distribute net income and any net gains realized on
          its investments annually. The Portfolio'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.

          Each class of the Portfolio makes semi-annual distributions in June
          and December of substantially all of its investment income and an
          annual distribution in June of its net realized gains, if any. All
          dividends and capital gains distributions from Shares of the Portfolio
          will automatically be reinvested into additional Shares of the
          Portfolio.

          HOW DISTRIBUTIONS AFFECT NAV

          Distributions are paid to shareholders as of the record date of the
          distribution of the Portfolio, regardless of how long the shares have
          been held. Undistributed income and realized gains are included in the
          daily NAV of the Portfolio's Shares. The Share price of the Portfolio
          drops by the amount of the distribution, net of any subsequent market
          fluctuations. For example, assume that on December 31, the Shares of
          High-Yield Portfolio declared a dividend in the amount of $0.25 per
          share. If the price of High-Yield Portfolio's Shares was $10.00 on
          December 30, the share price on December 31 would be $9.75, barring
          market fluctuations.

TAXES

          TAXES ON DISTRIBUTIONS

          Because Shares of the Portfolio may be purchased only through variable
          insurance contracts and qualified plans, it is anticipated that any
          income dividends or capital gains distributions made by the Shares of
          the Portfolio will be exempt from current taxation if left to
          accumulate within the variable insurance contract or qualified plan.
          Generally, withdrawals from such contracts may be subject to ordinary
          income tax and, if made before age 59 1/2, a 10% penalty tax. The tax
          status of your investment depends on the features of your qualified
          plan or variable insurance contract. Further information may be found
          in your plan documents or in the prospectus of the separate account
          offering such contract.

          TAXATION OF THE PORTFOLIO

          Dividends, interest and some gains received by the Portfolio on
          foreign securities may be subject to withholding of foreign taxes. The
          Portfolio may from year to year make the election permitted under
          Section 853 of the Internal Revenue Code to pass through such taxes to
          shareholders. If such election is not made, any foreign taxes paid or
          accrued will represent an expense to the Portfolio which will reduce
          its investment income.

          The Portfolio does not expect to pay any federal income or excise
          taxes because it intends to meet certain requirements of the Internal
          Revenue Code. In addition, the Portfolio intends to qualify under the
          Internal Revenue Code with respect to the diversification requirements
          related to the tax-deferred status of insurance company separate
          accounts.

 14 Janus Aspen Series
<PAGE>
                                                             Shareholder's guide

          INVESTORS MAY NOT PURCHASE OR REDEEM SHARES OF THE PORTFOLIO DIRECTLY.
          SHARES MAY BE PURCHASED OR REDEEMED ONLY THROUGH VARIABLE INSURANCE
          CONTRACTS OFFERED BY THE SEPARATE ACCOUNTS OF PARTICIPATING INSURANCE
          COMPANIES OR THROUGH QUALIFIED RETIREMENT PLANS. REFER TO THE
          PROSPECTUS FOR THE PARTICIPATING INSURANCE COMPANY'S SEPARATE ACCOUNT
          OR YOUR PLAN DOCUMENTS FOR INSTRUCTIONS ON PURCHASING OR SELLING OF
          VARIABLE INSURANCE CONTRACTS AND ON HOW TO SELECT THE PORTFOLIO AS AN
          INVESTMENT OPTION FOR A CONTRACT OR A QUALIFIED PLAN.

PRICING OF PORTFOLIO SHARES

          Investments will be processed at the NAV next determined after an
          order is received and accepted by the Portfolio or its agent. In order
          to receive a day's price, your order must be received by the close of
          the regular trading session of the New York Stock Exchange any day
          that the NYSE is open. 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.

          To the extent the Portfolio holds securities that are primarily listed
          on foreign exchanges that trade on weekends or other days when the
          Portfolio does not price its shares, the NAV of the Portfolio's shares
          may change on days when shareholders will not be able to purchase or
          redeem the Portfolio's shares.

PURCHASES

          Purchases of Shares may be made only by the separate accounts of
          insurance companies for the purpose of funding variable insurance
          contracts or by qualified plans. Refer to the prospectus of the
          appropriate insurance company separate account or your plan documents
          for information on how to invest in the Shares of the Portfolio.
          Participating insurance companies and certain other designated
          organizations are authorized to receive purchase orders on the
          Portfolio's behalf.

          The Portfolio reserves the right to reject any specific purchase
          order. Purchase orders may be refused if, in Janus Capital's opinion,
          they are of a size that would disrupt the management of the Portfolio.
          Although there is no present intention to do so, the Portfolio may
          discontinue sales of its shares if management and the Trustees believe
          that continued sales may adversely affect the Portfolio's ability to
          achieve its investment objective. If sales of the Portfolio's Shares
          are discontinued, it is expected that existing policy owners and plan
          participants invested in the Portfolio would be permitted to continue
          to authorize investment in the Portfolio and to reinvest any dividends
          or capital gains distributions, absent highly unusual circumstances.

REDEMPTIONS

          Redemptions, like purchases, may be effected only through the separate
          accounts of participating insurance companies or through qualified
          plans. Please refer to the appropriate separate account prospectus or
          plan documents for details.

          Shares of the Portfolio may be redeemed on any business day.
          Redemptions are processed at the NAV next calculated after receipt and
          acceptance of the redemption order by the Portfolio or its agent.
          Redemption proceeds will normally be wired to the participating
          insurance company the business day following receipt of the redemption
          order, but in no event later than seven days after receipt of such
          order.

                                                         Shareholder's guide  15
<PAGE>

SHAREHOLDER COMMUNICATIONS

          Shareholders will receive annual and semiannual reports including the
          financial statements of the Shares of the Portfolio. Each report will
          show the investments owned by the Portfolio and the market values
          thereof, as well as other information about the Portfolio and its
          operations. The Trust's fiscal year ends December 31.

 16 Janus Aspen Series
<PAGE>
                                                            Financial highlights

          The financial highlights table is intended to help you understand the
          Institutional Shares' financial performance for the life of the
          Portfolio. Items 1 through 9 reflect financial results for a single
          Share. Total return in the table represents the rate that an investor
          would have earned (or lost) on an investment in the Institutional
          Shares of the Portfolio (assuming reinvestment of all dividends and
          distributions) but does not include charges and expenses attributable
          to any insurance product. This information has been audited by
          PricewaterhouseCoopers LLP, whose report, along with the Portfolio's
          financial statements, is included in the Annual Report, which is
          available upon request and incorporated by reference into the SAI.

<TABLE>
<CAPTION>
HIGH-YIELD PORTFOLIO - INSTITUTIONAL SHARES
- -----------------------------------------------------------------------------------------------
                                                                   Periods ending December 31
                                                                  1998        1997      1996(1)
<S>                                                             <C>         <C>         <C>
  1. NET ASSET VALUE, BEGINNING OF PERIOD                        $11.78      $10.83      $10.00
     INCOME FROM INVESTMENT OPERATIONS:
  2. Net investment income                                         0.87        0.70        0.43
  3. Net gains or losses on securities (both realized and
     unrealized)                                                 (0.70)        0.99        0.80
  4. Total from investment operations                              0.17        1.69        1.23
     LESS DISTRIBUTIONS:
  5. Dividends (from net investment income)                      (0.89)      (0.68)      (0.40)
  6. Tax return of capital distributions                             --          --          --
  7. Distributions (from capital gains)                          (0.05)      (0.06)          --
  8. Distributions (in excess of realized gains)                 (0.16)          --          --
  9. Total distributions                                         (1.10)      (0.74)      (0.40)
 10. NET ASSET VALUE, END OF PERIOD                              $10.85      $11.78      $10.83
 11. Total return*                                                1.26%      15.98%      12.40%
 12. Net assets, end of period (in thousands)                    $2,977      $2,914        $783
 13. Average net assets for the period (in thousands)            $3,281      $1,565        $459
 14. Ratio of gross expenses to average net assets**              1.00%(4)    1.00%(3)     1.01(2)
 15. Ratio of net expenses to average net assets**                1.00%       1.00%       1.00%
 16. Ratio of net investment income to average net assets**       7.76%       7.98%       5.74%
 17. Portfolio turnover rate**                                     301%        299%        301%
- ------------------------------------------------------------------------------------------------
</TABLE>

 *  Total return not annualized for periods of less than one full year.
**  Annualized for periods of less than one full year.
(1) May 1, 1996 (inception) through December 31, 1996.
(2) The ratio was 6.29% before waiver of certain fees incurred by the Portfolio.
(3) The ratio was 3.27% before waiver of certain fees incurred by the Portfolio.
(4) The ratio was 2.11% before waiver of certain fees incurred by the Portfolio.

                                                        Financial highlights  17
<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 Portfolio may
          invest. The Portfolio may invest in these instruments to the extent
          permitted by its investment objectives and policies. The Portfolio 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 Portfolio 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 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 SECURITIES are securities 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 securities 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 certain amounts of passive income or hold
          certain amounts of assets for the production of passive income.
          Passive

 18 Janus Aspen Series
<PAGE>

          income includes dividends, interest, royalties, rents and annuities.
          To avoid taxes and interest that the Portfolio must pay if these
          investments are profitable, the Portfolio may make various elections
          permitted by the tax laws. These elections could require that the
          Portfolio 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.

          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
          Portfolio and a simultaneous agreement by the seller (generally a bank
          or dealer) to repurchase the security from the Portfolio 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 Portfolio 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
          Portfolio to another party (generally a bank or dealer) in return for
          cash and an agreement by the Portfolio to buy the security back at a
          specified price and time. This technique will be used primarily to
          provide cash to satisfy unusually high 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 Portfolio from a
          dealer that give the Portfolio 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.

          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.

                                                Glossary of investment terms  19
<PAGE>

          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 stock 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 Portfolio
          does not earn interest on such securities until settlement and bear
          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 Portfolio 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 Portfolio 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 Portfolio 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 Portfolio bears the market risk of an investment in the underlying
          instruments, 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

 20 Janus Aspen Series
<PAGE>

          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 Portfolio may purchase and write
          put and call options on securities, securities indices and foreign
          currencies.

                                                Glossary of investment terms  21
<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.

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>

 22 Janus Aspen Series
<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>

          Unrated securities will be treated as noninvestment grade securities
          unless the 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.

                                            Explanation of rating categories  23
<PAGE>

SECURITIES HOLDINGS BY RATING CATEGORY

          During the fiscal period ended December 31, 1998, the percentage of
          securities holdings for High-Yield Portfolio by rating category based
          upon a weighted monthly average was:

<TABLE>
<CAPTION>
                HIGH-YIELD PORTFOLIO
                ----------------------------------------------------------------------------------------
                <S>                                                           <C>
                    BONDS-S&P RATING:
                 AAA                                                                        3%
                 AA                                                                         0%
                 A                                                                          0%
                 BBB                                                                        1%
                 BB                                                                         2%
                 B                                                                         60%
                 CCC                                                                        2%
                 CC                                                                         0%
                 C                                                                          0%
                 Preferred Stock                                                            3%
                 Cash and Options                                                          29%
                 TOTAL                                                                    100%
                ----------------------------------------------------------------------------------------
</TABLE>

 24 Janus Aspen Series
<PAGE>

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                                            Explanation of rating categories  25
<PAGE>

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 26 Janus Aspen Series
<PAGE>

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<PAGE>

[JANUS LOGO]
        1-800-29JANUS
        100 Fillmore Street
        Denver, Colorado 80206-4928
        janus.com

You can request other information, including a Statement of
Additional Information, Annual Report or Semiannual Report, free of
charge, by contacting your insurance company or plan sponsor or
visiting our Web site at janus.com. In the Portfolio's Annual
Report, you will find a discussion of the market conditions and
investment strategies that significantly affected the Portfolio's
performance during its last fiscal year. Other information is also
available from financial intermediaries that sell Shares of the
Portfolio.

The Statement of Additional Information provides detailed
information about the Portfolio and is incorporated into this
Prospectus by reference. You may review the Portfolio'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. 811-7736



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