JANUS ASPEN SERIES, 485BPOS, 1998-04-28

JANUS ASPEN SERIES
485BPOS, 1998-04-28

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Registration No. 33-63212

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

Form N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 /__/

Pre-Effective Amendment No. __ /__/

Post-Effective Amendment No. 16 /X/
and/or

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT
OF 1940 /__/

Amendment No. 18 /X/

(Check appropriate box or boxes.)

JANUS ASPEN SERIES
(Exact Name of Registrant as Specified in Charter)

100 Fillmore Street, Denver, Colorado 80206-4928
Address of Principal Executive Offices (Zip Code)

Registrant's Telephone No., including Area Code: 303-333-3863

Thomas A. Early - 100 Fillmore Street, Denver, Colorado 80206-4928
(Name and Address of Agent for Service)

Approximate Date of Proposed Offering: May 1, 1998

It is proposed that this filing will become effective (check appropriate line):

___ immediately upon filing pursuant to paragraph (b) of Rule 485.
_X_ on May 1, 1998 pursuant to paragraph (b) of Rule 485.
___ 60 days after filing pursuant to paragraph (a)(1) of Rule 485.
___ on __(date)__ pursuant to paragraph (a)(1) of Rule 485.
___ 75 days after filing pursuant to paragraph (a)(2) of Rule 485.
___ on __(date)__ pursuant to paragraph (a)(2) of Rule 485.

If appropriate, check the following line:

this post-effective amendment designates a new effective
___ date for a previously filed post-effective amendment.

<PAGE>

JANUS ASPEN SERIES
Cross Reference Sheet
Between the Prospectuses and Statements of
Additional Information and Form N-1A Item

Form N-1A Item

Part A Caption in Prospectus

1. Cover Page Cover Page

2. Synopsis Cover Page

3. Condensed Financial Expense Information; Financial
Information Highlights (all prospectuses except
Growth and Income Portfolio -
Institutional Shares and Growth and
Income Portfolio - Retirement Shares);
Appendix B - Explanation of Rating
Categories; An Explanation of
Performance Terms

4. General Description of The Portfolio(s) Investment Objective
Registrant and Policies; General Portfolio
Policies; Additional Risk Factors; Other
Information; Appendix A - Glossary of
Investment Terms; Appendix B -
Explanation of Rating Categories

5. Management of the Fund Management of the Portfolio(s);
Portfolio Transactions; Management
Expenses and Expense Limits; Other
Service Providers; Other Information

5A. Management's Discussion Not Applicable
of Fund Performance

6. Capital Stock and Other Distributions and Taxes; Shareholder's
Securities Guide

7. Purchase of Securities Shareholder's Guide
Being Offered

8. Redemption or Repurchase Shareholder's Guide

9. Pending Legal Proceedings Not Applicable

<PAGE>

Part B Caption in Statement of Additional
Information

10. Cover Page Cover Page

11. Table of Contents Table of Contents

12. General Information and Miscellaneous Information
History

13. Investment Objectives and Investment Objectives; Portfolio
Policies Policies, Investment Restrictions; Types
of Securities and Investment Techniques

14. Management of the Fund Investment Adviser; Officers and
Trustees

15. Control Persons and Principal Shareholders
Principal Holders of
Securities

16. Investment Advisory and Investment Adviser; Custodian, Transfer
Other Services Agent and Certain Affiliations;
Portfolio Transactions and Brokerage;
Officers and Trustees; Miscellaneous
Information

17. Brokerage Allocation and Portfolio Transactions and Brokerage
Other Practices

18. Capital Stock and Other Shares of the Trust; Miscellaneous
Securities Information

19. Purchase, Redemption and Shares of the Trust
Pricing of Securities Being
Offered

20. Tax Status Income Dividends, Capital Gains
Distributions and Tax Status (all
Statements of Additional Information
except Money Market Portfolio -
Institutional Shares and Money Market
Portfolio - Retirement Shares);
Dividends and Tax Status (Money Market
Portfolio - Institutional Shares and
Money Market Portfolio - Retirement
Shares only)

21. Underwriters Not Applicable

22. Calculation of Performance Performance Information
Data

23. Financial Statements Financial Statements

<PAGE>

JANUS ASPEN SERIES

Prospectus

MAY 1, 1998

This prospectus describes ten mutual funds with a variety of investment
objectives, including growth of capital, current income and a combination of
growth and income (the "Portfolios"). Each Portfolio is a series of Janus Aspen
Series (the "Trust") and currently offers two classes of shares. The
Institutional Shares are sold under the name "Janus Aspen Series." The Trust is
registered with the Securities and Exchange Commission ("SEC") as an open-end
management investment company. The Institutional Shares of each Portfolio
(collectively, the "Shares") are offered by this prospectus in connection with
investment in and payments under variable annuity contracts and variable life
insurance contracts (collectively "variable insurance contracts"), as well as
certain qualified retirement plans. Janus Capital Corporation ("Janus Capital")
serves as investment adviser to each Portfolio. Janus Capital has been in the
investment advisory business for over 27 years and currently manages
approximately $80 billion in assets.

The Trust sells and redeems its Shares at net asset value without any sales
charges, commissions or redemption fees. Each variable insurance contract
involves fees and expenses not described in this Prospectus. Certain Portfolios
may not be available in connection with a particular contract and certain
contracts may limit allocations among the Portfolios. See the accompanying
contract prospectus for information regarding contract fees and expenses and any
restrictions on purchases or allocations.

This Prospectus contains information about the Shares that a prospective
purchaser of a variable insurance contract or plan participant should consider
before allocating purchase payments or premiums to the Portfolios. It should be
read carefully in conjunction with the separate account prospectus of the
specific insurance product that accompanies this Prospectus and retained for
future reference. Additional information about the Shares is contained in a
Statement of Additional Information ("SAI") filed with the SEC. The SAI dated
May 1, 1998 is incorporated by reference into this Prospectus. Copies of the SAI
are available upon request and without charge by writing or calling your
insurance company or plan sponsor.

FLEXIBLE INCOME PORTFOLIO AND HIGH-YIELD PORTFOLIO MAY INVEST ALL OF THEIR
ASSETS IN HIGH-YIELD CORPORATE DEBT SECURITIES, COMMONLY KNOWN AS "JUNK BONDS."
SEE "ADDITIONAL RISK FACTORS" ON PAGE 13 FOR THE RISKS ASSOCIATED WITH INVESTING
IN THESE SECURITIES.

AN INVESTMENT IN THE MONEY MARKET PORTFOLIO IS NEITHER INSURED NOR GUARANTEED BY
THE U.S. GOVERNMENT. THERE IS NO ASSURANCE THAT THE MONEY MARKET PORTFOLIO WILL
BE ABLE TO MAINTAIN A STABLE NET ASSET VALUE OF $1.00 PER SHARE.

THESE SECURITIES HAVE NOT BEEN APPROVED BY THE SEC NOR HAS THE SEC PASSED ON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

THIS PROSPECTUS DOES NOT CONSTITUTE AN OFFER TO SELL SECURITIES IN ANY STATE OR
OTHER JURISDICTION TO ANY PERSON TO WHOM IT IS UNLAWFUL TO MAKE SUCH AN OFFER IN
SUCH STATE OR OTHER JURISDICTION.

JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998
<PAGE>

CONTENTS

<TABLE>
<S> <C>
PORTFOLIOS AT A GLANCE
Brief description of the Portfolios......................... 2
EXPENSE INFORMATION
Each Portfolio's annual operating expenses.................. 3
Financial Highlights - a summary of financial data.......... 4
PERFORMANCE TERMS
An explanation of performance terms......................... 6
THE PORTFOLIOS IN DETAIL
Investment Objectives and Policies of the Growth,
Combination and Fixed-Income Portfolios.................. 7
General Portfolio Policies of the Portfolios other than
Money Market Portfolio.................................... 12
Additional Risk Factors of the Portfolios other than Money
Market Portfolio.......................................... 13
MONEY MARKET PORTFOLIO
Investment Objectives, Policies and Techniques.............. 15
MANAGEMENT OF THE PORTFOLIOS
Investment Adviser and Investment Personnel................. 19
Personal Investing.......................................... 20
Portfolio Transactions...................................... 20
Management Expenses and Expense Limits...................... 20
Other Service Providers..................................... 21
Other Information........................................... 21
DISTRIBUTIONS AND TAXES
Distributions............................................... 23
Taxes....................................................... 23
SHAREHOLDER'S GUIDE
Purchases................................................... 24
Redemptions................................................. 24
Shareholder Communications.................................. 24
APPENDIX A
Glossary of Investment Terms................................ 25
APPENDIX B
Explanation of Rating Categories............................ 28
</TABLE>

JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998 1
<PAGE>

PORTFOLIOS AT A GLANCE

This section is designed to provide you with a brief overview of the Portfolios
and their investment emphasis. A more detailed discussion of the Portfolios'
investment objectives and policies begins on page 7.

GROWTH PORTFOLIO
Focus: A diversified portfolio that seeks long-term growth of capital by
investing primarily in common stocks, with an emphasis on companies with larger
market capitalizations.
Inception: September 1993
Manager: James P. Craig, III
Assistant Managers: David C. Decker
Blaine P. Rollins

AGGRESSIVE GROWTH PORTFOLIO
Focus: A nondiversified portfolio that seeks long-term growth of capital by
investing primarily in common stocks, with an emphasis on securities issued by
medium-sized companies.
Inception: September 1993
Manager: James P. Goff

CAPITAL APPRECIATION PORTFOLIO
Focus: A nondiversified portfolio that seeks long-term growth of capital by
investing primarily in common stocks of issuers of any size.
Inception: May 1997
Manager: Scott W. Schoelzel

INTERNATIONAL GROWTH PORTFOLIO
Focus: A diversified portfolio that seeks long-term growth of capital by
investing primarily in common stocks of foreign issuers.
Inception: May 1994

Managers: Laurence J. Chang

Helen Young Hayes

WORLDWIDE GROWTH PORTFOLIO
Focus: A diversified portfolio that seeks long-term growth of capital by
investing primarily in common stocks of foreign and domestic issuers.
Inception: September 1993
Manager: Helen Young Hayes
Assistant Manager: Laurence J. Chang

BALANCED PORTFOLIO
Focus: A diversified portfolio that seeks long-term growth of capital, balanced
by current income. The Portfolio normally invests 40-60% of its assets in
securities selected primarily for their growth potential and 40-60% of its
assets in securities selected primarily for their income potential.
Inception: September 1993
Manager: Blaine P. Rollins

EQUITY INCOME PORTFOLIO
Focus: A diversified portfolio that seeks current income and long-term growth of
capital by investing primarily in income-producing equity securities.
Inception: May 1997
Manager: Blaine P. Rollins

FLEXIBLE INCOME PORTFOLIO
Focus: A diversified portfolio that seeks to maximize total return from a
combination of income and capital appreciation by investing primarily in
income-producing securities.
Inception: September 1993
Manager: Ronald V. Speaker

HIGH-YIELD PORTFOLIO
Focus: A diversified portfolio that seeks high current income as its primary
objective. Capital appreciation is a secondary objective when consistent with
the primary objective. The Portfolio seeks to achieve these objectives by
investing primarily in high-yield/high-risk fixed-income securities.
Inception: May 1996
Manager: Sandy R. Rufenacht

MONEY MARKET PORTFOLIO
Focus: A money market mutual fund that seeks maximum current income to the
extent consistent with stability of capital. The Portfolio seeks to achieve this
objective by investing primarily in high quality debt obligations and
obligations of financial institutions.
Inception: May 1995
Manager: Sharon S. Pichler

2 JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998
<PAGE>

EXPENSE INFORMATION

The following tables and example are designed to assist participants in
qualified plans that invest in the Shares of the Portfolios in understanding the
various costs and expenses that you will bear directly or indirectly as an
investor in the Shares. OWNERS OF VARIABLE INSURANCE CONTRACTS THAT INVEST IN
THE SHARES SHOULD REFER TO THE VARIABLE INSURANCE CONTRACT PROSPECTUS FOR A
DESCRIPTION OF COSTS AND EXPENSES, AS THE TABLES AND EXAMPLE DO NOT REFLECT
DEDUCTIONS AT THE SEPARATE ACCOUNT LEVEL OR CONTRACT LEVEL FOR ANY CHARGES THAT
MAY BE INCURRED UNDER A CONTRACT.

SHAREHOLDER TRANSACTION EXPENSES (applicable to each Portfolio)

<TABLE>
<S> <C>
Maximum sales load imposed on purchases None
Maximum sales load imposed on reinvested dividends None
Deferred sales charges on redemptions None
Redemption fee None
Exchange fee None
</TABLE>

ANNUAL OPERATING EXPENSES (after fee waivers and reductions)(1)
(expressed as a percentage of average net assets)

<TABLE>
<CAPTION>
- -------------------------------------------------------------------------------------------------------------------
MANAGEMENT OTHER TOTAL OPERATING
FEE EXPENSES EXPENSES
- -------------------------------------------------------------------------------------------------------------------
<S> <C> <C> <C> <C>

Growth Portfolio 0.65% 0.05% 0.70%
Aggressive Growth Portfolio 0.73% 0.03% 0.76%
Capital Appreciation Portfolio(2) 0.23% 1.03% 1.26%
International Growth Portfolio 0.67% 0.29% 0.96%
Worldwide Growth Portfolio 0.66% 0.08% 0.74%
Balanced Portfolio 0.76% 0.07% 0.83%
Equity Income Portfolio(2) 0.00% 1.25% 1.25%
Flexible Income Portfolio 0.65% 0.10% 0.75%
High-Yield Portfolio 0.00% 1.00% 1.00%
Money Market Portfolio 0.22% 0.28% 0.50%
------------------------------------------------------------------------------------------------------------------
</TABLE>

(1) Management fees for Growth, Aggressive Growth, Capital Appreciation,
International Growth, Worldwide Growth, Balanced and Equity Income
Portfolios reflect a reduced fee schedule effective July 1, 1997. The
management fee for each of these Portfolios reflects the new rate applied to
net assets as of December 31, 1997. Other expenses are based on gross
expenses of the Shares before expense offset arrangements for the fiscal
year ended December 31, 1997. The information for each Portfolio other than
the Flexible Income Portfolio is net of fee waivers or reductions from Janus
Capital. Fee reductions for the Growth, Aggressive Growth, Capital
Appreciation, International Growth, Worldwide Growth, Balanced and Equity
Income Portfolios reduce the management fee to the level of the
corresponding Janus retail fund. Other waivers, if applicable, are first
applied against the management fee and then against other expenses. Without
such waivers or reductions, the Management Fee, Other Expenses and Total
Operating Expenses for the Shares would have been 0.74%, 0.04%, and 0.78%
for Growth Portfolio; 0.74%, 0.04%, and 0.78% for Aggressive Growth
Portfolio; 1.14%, 1.05%, and 2.19% for Capital Appreciation Portfolio;
0.79%, 0.29% and 1.08% for International Growth Portfolio; 0.72%, 0.09% and
0.81% for Worldwide Growth Portfolio; 0.77%, 0.06% and 0.83% for Balanced
Portfolio; 0.76%, 4.99%, and 5.75% for Equity Income Portfolio; 0.75%, 2.52%
and 3.27% for High-Yield Portfolio; and 0.25%, 0.30% and 0.55% for Money
Market Portfolio, respectively. Janus Capital may modify or terminate the
waivers or reductions at any time upon at least 90 days' notice to the
Trustees.

(2) Based on annualized expenses incurred during the initial fiscal period.

EXAMPLE

Assume you invest $1,000, the Shares of the Portfolios return 5% annually and
each Portfolio's expense ratio remains as listed above. The example below shows
the operating expenses that you would indirectly bear as an investor in the
Shares of the Portfolios.

<TABLE>
<CAPTION>
- -------------------------------------------------------------------------------------------------------
1 YEAR 3 YEARS 5 YEARS 10 YEARS
- -------------------------------------------------------------------------------------------------------
<S> <C> <C> <C> <C> <C>

Growth Portfolio $ 7 $22 $39 $ 87
Aggressive Growth Portfolio $ 8 $24 $42 $ 94
Capital Appreciation Portfolio $13 $40 $69 $152
International Growth Portfolio $10 $31 $53 $118
Worldwide Growth Portfolio $ 8 $24 $41 $ 92
Balanced Portfolio $ 8 $26 $46 $103
Equity Income Portfolio $13 $40 $69 $151
Flexible Income Portfolio $ 8 $24 $42 $ 93
High-Yield Portfolio $10 $32 $55 $122
Money Market Portfolio $ 5 $16 $28 $ 63
------------------------------------------------------------------------------------------------------
</TABLE>

THE EXAMPLE SHOULD NOT BE CONSIDERED A REPRESENTATION OF PAST OR FUTURE RETURNS
OR EXPENSES WHICH MAY BE MORE OR LESS THAN THOSE SHOWN.

JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998 3
<PAGE>

FINANCIAL HIGHLIGHTS

Unless otherwise noted, the information below is for fiscal periods ending on
December 31st of each year. The accounting firm of Price Waterhouse LLP has
audited the Portfolios' financial statements since their inception. Their report
is included in the Portfolios' Annual Report, which is incorporated by reference
into the SAI. A detailed explanation of the Financial Highlights can be found on
page 6.

GROWTH PORTFOLIO
INSTITUTIONAL SHARES 1997 1996 1995 1994 1993(1)
<S> <C> <C> <C> <C> <C>
---------------------------------------------------------------------------------------------------
1. NET ASSET VALUE, BEGINNING OF
PERIOD $15.51 $13.45 $10.57 $10.32 $10.00
---------------------------------------------------------------------------------------------------
INCOME FROM INVESTMENT OPERATIONS:
2. Net investment income .15 .17 .28 .09 .03
3. Net gains or (losses) on securities
(both realized and unrealized) 3.34 2.29 2.90 .20 .32
---------------------------------------------------------------------------------------------------
4. Total from investment operations 3.49 2.46 3.18 .29 .35
---------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
5. Dividends (from net investment
income) (.15) (.17) (.30) (.04) (.03)
6. Tax return of capital distributions -- -- -- -- --
7. Distributions (from capital gains) (.37) (.23) -- -- --
---------------------------------------------------------------------------------------------------
8. Total distributions (.52) (.40) (.30) (.04) (.03)
---------------------------------------------------------------------------------------------------
9. NET ASSET VALUE, END OF PERIOD $18.48 $15.51 $13.45 $10.57 $10.32
---------------------------------------------------------------------------------------------------
10. Total return* 22.75% 18.45% 30.17% 2.76% 3.50%
---------------------------------------------------------------------------------------------------
11. Net assets, end of period (in
thousands) $608,281 $325,789 $126,911 $43,549 $7,482
12. Average net assets for the period
(in thousands) $477,914 $216,125 $77,344 $26,464 $3,191
13. Ratio of gross expenses to average
net assets** 0.70%(9) 0.69%(8) 0.78%(7) N/A N/A
14. Ratio of net expenses to average
net assets** 0.69% 0.69% 0.76% 0.88%(4)(6) 0.25%(5)
15. Ratio of net investment income to
average net assets** 0.91% 1.39% 1.24% 1.45% 2.54%
16. Portfolio turnover rate** 122% 87% 185% 169% 162%
17. Average commission rate $0.0500 $0.0466 N/A N/A N/A
---------------------------------------------------------------------------------------------------

<CAPTION>
CAPITAL
APPRECIATION
AGGRESSIVE GROWTH PORTFOLIO PORTFOLIO
INSTITUTIONAL SHARES 1997 1996 1995 1994 1993(1) 1997(3)
<S> <C> <C> <C> <C> <C> <C>
---------------------------------------------------------------------------------------------------
1. NET ASSET VALUE, BEGINNING OF
PERIOD $18.24 $17.08 $13.62 $11.80 $10.00 $10.00
---------------------------------------------------------------------------------------------------
INCOME FROM INVESTMENT OPERATIONS:
2. Net investment income -- -- .24 .11 .01 .05
3. Net gains or (losses) on securities
(both realized and unrealized) 2.31 1.36 3.47 1.82 1.80 2.61
---------------------------------------------------------------------------------------------------
4. Total from investment operations 2.31 1.36 3.71 1.93 1.81 2.66
---------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
5. Dividends (from net investment
income) -- -- (.25) (.11) (.01) (.04)
6. Tax return of capital distributions -- (.01) -- -- -- --
7. Distributions (from capital gains) -- (.19) -- -- -- --
---------------------------------------------------------------------------------------------------
8. Total distributions -- (.20) (.25) (.11) (.01) (.04)
---------------------------------------------------------------------------------------------------
9. NET ASSET VALUE, END OF PERIOD $20.55 $18.24 $17.08 $13.62 $11.80 $12.62
---------------------------------------------------------------------------------------------------
10. Total return* 12.66% 7.95% 27.48% 16.33% 18.05% 26.60%
---------------------------------------------------------------------------------------------------
11. Net assets, end of period (in
thousands) $508,198 $383,693 $185,911 $41,289 $1,985 $6,833
12. Average net assets for the period
(in thousands) $418,464 $290,629 $107,582 $14,152 $1,091 $2,632
13. Ratio of gross expenses to average
net assets** 0.76%(9) 0.76%(8) 0.86%(7) N/A N/A 1.26%(9)
14. Ratio of net expenses to average
net assets** 0.76% 0.76% 0.84% 1.05%(4)(6) 0.25%(5) 1.25%
15. Ratio of net investment income to
average net assets** (0.10%) (0.27%) 0.58% 2.18% 0.34% 1.43%
16. Portfolio turnover rate** 130% 88% 155% 259% 31% 101%
17. Average commission rate $0.0367 $0.0347 N/A N/A N/A $0.0375
---------------------------------------------------------------------------------------------------
</TABLE>

<TABLE>
<CAPTION>
INTERNATIONAL GROWTH PORTFOLIO
INSTITUTIONAL SHARES 1997 1996 1995 1994(2)
<S> <C> <C> <C> <C>
--------------------------------------------------------------------------------
1. NET ASSET VALUE, BEGINNING OF
PERIOD $15.72 $11.95 $9.72 $10.00
--------------------------------------------------------------------------------
INCOME FROM INVESTMENT
OPERATIONS:
2. Net investment income .11 .05 .09 (.09)
3. Net gains or (losses) on
securities (both realized and
unrealized) 2.80 4.06 2.16 (.19)
--------------------------------------------------------------------------------
4. Total from investment
operations 2.91 4.11 2.25 (.28)
--------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
5. Dividends (from net investment
income) (.11) (.11) (.02) --
6. Dividends (in excess of net
investment income) -- -- -- --
7. Tax return of capital
distributions -- -- -- --
8. Distributions (from capital
gains) (.01) (.23) -- --
9. Distributions (in excess of
realized gains) (.03) -- -- --
--------------------------------------------------------------------------------
10. Total distributions (0.15) (.34) (.02) --
--------------------------------------------------------------------------------
11. NET ASSET VALUE, END OF PERIOD $18.48 $15.72 $11.95 $9.72
--------------------------------------------------------------------------------
12. Total return* 18.51% 34.71% 23.15% (2.80%)
--------------------------------------------------------------------------------
13. Net assets, end of period (in
thousands) $161,091 $27,192 $1,608 $1,353
14. Average net assets for the
period (in thousands) $96,164 $7,437 $1,792 $1,421
15. Ratio of gross expenses to
average net assets** 0.96%(9) 1.26%(8) 2.69%(7) N/A
16. Ratio of net expenses to
average net assets** 0.96% 1.25% 2.50% 2.50%(6)
17. Ratio of net investment income
to average net assets** 0.70% 0.62% (0.80%) (1.30%)
18. Portfolio turnover rate** 86% 65% 211% 275%
19. Average commission rate $0.0241 $0.0305 N/A N/A
--------------------------------------------------------------------------------

<CAPTION>
WORLDWIDE GROWTH PORTFOLIO
INSTITUTIONAL SHARES 1997 1996 1995 1994 1993(1)
<S> <C> <C> <C> <C> <C>
--------------------------------------------------------------------------------
1. NET ASSET VALUE, BEGINNING OF
PERIOD $19.44 $15.31 $12.07 $11.89 $10.00
--------------------------------------------------------------------------------
INCOME FROM INVESTMENT
OPERATIONS:
2. Net investment income .16 .16 .11 .04 .02
3. Net gains or (losses) on
securities (both realized and
unrealized) 4.14 4.27 3.19 .14 1.89
--------------------------------------------------------------------------------
4. Total from investment
operations 4.30 4.43 3.30 .18 1.91
--------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
5. Dividends (from net investment
income) (.17) (.17) (.06) -- (.01)
6. Dividends (in excess of net
investment income) (.02) -- -- -- --
7. Tax return of capital
distributions -- -- -- -- --
8. Distributions (from capital
gains) (.16) (.13) -- -- (.01)
9. Distributions (in excess of
realized gains) -- -- -- -- --
--------------------------------------------------------------------------------
10. Total distributions (.35) (.30) (.06) -- (.02)
--------------------------------------------------------------------------------
11. NET ASSET VALUE, END OF PERIOD $23.39 $19.44 $15.31 $12.07 $11.89
--------------------------------------------------------------------------------
12. Total return* 22.15% 29.04% 27.37% 1.53% 19.10%
--------------------------------------------------------------------------------
13. Net assets, end of period (in
thousands) $1,576,548 $582,603 $108,563 $37,728 $4,856
14. Average net assets for the
period (in thousands) $1,148,951 $304,111 $59,440 $22,896 $2,200
15. Ratio of gross expenses to
average net assets** 0.74%(9) 0.80%(8) 0.90%(7) N/A N/A
16. Ratio of net expenses to
average net assets** 0.74% 0.80% 0.87% 1.18%(4)(6) 0.25%(5)
17. Ratio of net investment income
to average net assets** 0.67% 0.83% 0.95% 0.50% 0.84%
18. Portfolio turnover rate** 80% 62% 113% 217% 57%
19. Average commission rate $0.0337 $0.0345 N/A N/A N/A
--------------------------------------------------------------------------------
</TABLE>

* Total return not annualized for periods of less than one year.
** Annualized for periods of less than one full year.
(1) September 13, 1993 (inception) to December 31, 1993.
(2) May 2, 1994 (inception) to December 31, 1994.
(3) May 1, 1997 (inception) to December 31, 1997.
(4) Commissions payable by the Portfolio for transactions effected by a
broker-dealer affiliated with Janus Capital were credited against the
Portfolio's operating expenses. The effect of such directed brokerage
arrangement was de minimis.
(5) The ratio was 2.16%, 5.79% and 2.71%, respectively, for the Growth,
Aggressive Growth and Worldwide Growth Portfolios, before waiver of certain
fees and/or voluntary reduction of adviser's fees to the effective rate of
the corresponding Janus retail fund.

(6) The ratio was 1.23%, 1.14%, 4.67% and 1.49%, respectively, for the Growth,
Aggressive Growth, International Growth and Worldwide Growth Portfolios,
before waiver of certain fees and/or voluntary reduction of adviser's fees
to the effective rate of the corresponding Janus retail fund.

(7) The ratio was 0.98%, 0.93%, 3.57% and 1.09%, respectively, for the Growth,
Aggressive Growth, International Growth and Worldwide Growth Portfolios,
before waiver of certain fees and/or voluntary reduction of adviser's fees
to the effective rate of the corresponding Janus retail fund.

(8) The ratio was 0.83%, 0.83%, 2.21% and 0.91%, respectively, for the Growth,
Aggressive Growth, International Growth and Worldwide Growth Portfolios,
before waiver of certain fees and/or voluntary reduction of adviser's fees
to the effective rate of the corresponding Janus retail fund.

(9) The ratio was 0.78%, 0.78%, 2.19%, 1.08% and 0.81%, respectively for the
Growth, Aggressive Growth, Capital Appreciation, International Growth and
Worldwide Growth Portfolios, before voluntary reduction of adviser's fees to
the effective rate of the corresponding Janus retail fund.

4 JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998
<PAGE>

<TABLE>
<CAPTION>
EQUITY
INCOME
BALANCED PORTFOLIO PORTFOLIO
INSTITUTIONAL SHARES 1997 1996 1995 1994 1993(1) 1997(2)
<S> <C> <C> <C> <C> <C> <C>
- ---------------------------------------------------------------------------------------------------------
1. NET ASSET VALUE, BEGINNING OF PERIOD $14.77 $13.03 $10.63 $10.64 $10.00 $10.00
- ---------------------------------------------------------------------------------------------------------
INCOME FROM INVESTMENT OPERATIONS:
2. Net investment income .34 .32 .17 .15 .08 .01
3. Net gains or (losses) on securities
(both realized and unrealized) 2.89 1.81 2.45 (.06) .64 3.46
- ---------------------------------------------------------------------------------------------------------
4. Total from investment operations 3.23 2.13 2.62 .09 .72 3.47
- ---------------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
5. Dividends (from net investment income) (.35) (.30) (.22) (.10) (.08) (.01)
6. Tax return of capital distributions -- -- -- -- -- --
7. Distributions (from capital gains) (.18) (.09) -- -- -- --
- ---------------------------------------------------------------------------------------------------------
8. Total distributions (.53) (.39) (.22) (.10) (.08) (.01)
- ---------------------------------------------------------------------------------------------------------
9. NET ASSET VALUE, END OF PERIOD $17.47 $14.77 $13.03 $10.63 $10.64 $13.46
- ---------------------------------------------------------------------------------------------------------
10. Total return* 22.10% 16.18% 24.79% 0.84% 7.20% 34.70%
- ---------------------------------------------------------------------------------------------------------
11. Net assets, end of period (in thousands) $362,409 $85,480 $14,021 $3,153 $537 $3,047
12. Average net assets for the period (in
thousands) $176,432 $43,414 $5,739 $2,336 $521 $1,101
13. Ratio of gross expenses to average net
assets** 0.83%(8) 0.94%(7) 1.37%(6) N/A N/A 1.25%(8)
14. Ratio of net expenses to average net
assets** 0.82% 0.92% 1.30% 1.57%(3)(5) 0.25%(4) 1.25%
15. Ratio of net investment income to
average net assets** 2.87% 2.92% 2.41% 1.90% 2.69% 0.35%
16. Portfolio turnover rate** 139% 103% 149% 158% 126% 128%
17. Average commission rate $0.0456 $0.0426 N/A N/A N/A $0.0382
- ---------------------------------------------------------------------------------------------------------

FLEXIBLE INCOME PORTFOLIO
INSTITUTIONAL SHARES 1997 1996 1995 1994 1993(1)
<S> <C> <C> <C> <C> <C>
- ---------------------------------------------------------------------------------------------------------
1. NET ASSET VALUE, BEGINNING OF PERIOD $11.24 $11.11 $9.48 $9.97 $10.00
- ---------------------------------------------------------------------------------------------------------
INCOME FROM INVESTMENT OPERATIONS:
2. Net investment income .67 .74 .53 .47 .11
3. Net gains or (losses) on securities
(both realized and unrealized) .62 .24 1.70 (.56) (.04)
- ---------------------------------------------------------------------------------------------------------
4. Total from investment operations 1.29 .98 2.23 (.09) .07
- ---------------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
5. Dividends (from net investment income) (.64) (.72) (.60) (.40) (.10)
6. Tax return of capital distributions -- -- -- -- --
7. Distributions (from capital gains) (.11) (.13) -- -- --
- ---------------------------------------------------------------------------------------------------------
8. Total distributions (.75) (.85) (.60) (.40) (.10)
- ---------------------------------------------------------------------------------------------------------
9. NET ASSET VALUE, END OF PERIOD $11.78 $11.24 $11.11 $9.48 $9.97
- ---------------------------------------------------------------------------------------------------------
10. Total return* 11.76% 9.19% 23.86% (0.91%) 0.70%
- ---------------------------------------------------------------------------------------------------------
11. Net assets, end of period (in thousands) $54,098 $25,315 $10,831 $1,924 $538
12. Average net assets for the period (in
thousands) $36,547 $17,889 $5,556 $1,636 $497
13. Ratio of gross expenses to average net
assets** 0.75% 0.84% 1.07% N/A N/A
14. Ratio of net expenses to average net
assets** 0.75% 0.83% 1.00% 1.00%(5) 1.00%(4)
15. Ratio of net investment income to
average net assets** 6.90% 7.31% 7.46% 5.49% 3.77%
16. Portfolio turnover rate** 119% 250% 236% 234% 508%
17. Average commission rate N/A N/A N/A N/A N/A
- ---------------------------------------------------------------------------------------------------------
</TABLE>

* Total return not annualized for periods of less than one year.
** Annualized for periods of less than one full year.
(1) September 13, 1993 (inception) to December 31, 1993.
(2) May 1, 1997 (inception) to December 31, 1997.
(3) Commissions payable by the Portfolio for transactions effected by a
broker-dealer affiliated with Janus Capital were credited against the
Portfolio's operating expenses. The effect of such directed brokerage
arrangement was de minimis.
(4) The ratio was 7.92% and 5.27%, respectively, for the Balanced and Flexible
Income Portfolios, before waiver of certain fees and/or voluntary reduction
of adviser's fees to the effective rate of the corresponding Janus retail
fund.
(5) The ratio was 1.74% and 1.35%, respectively, for the Balanced and Flexible
Income Portfolios, before waiver of certain fees and/or voluntary reduction
of adviser's fees to the effective rate of the corresponding Janus retail
fund.

(6) The ratio was 1.55% for the Balanced Portfolio, before voluntary reduction
of adviser's fees to the effective rate of the Janus Balanced Fund.

(7) The ratio was 1.07% for the Balanced Portfolio, before voluntary reduction
of adviser's fees to the effective rate of the Janus Balanced Fund.

(8) The ratio was 0.83% and 5.75%, respectively, for the Balanced and Equity
Income Portfolios, before waiver of certain fees and/or voluntary reduction
of adviser's fees to the effective rate of the Corresponding Janus retail
fund.

<TABLE>
<CAPTION>
HIGH-YIELD
PORTFOLIO MONEY MARKET PORTFOLIO
INSTITUTIONAL SHARES 1997 1996(1) 1997 1996 1995(4)
<S> <C> <C> <C> <C> <C>
- -------------------------------------------------------------------------------------------------------------
1. NET ASSET VALUE, BEGINNING OF PERIOD $10.83 $10.00 $1.00 $1.00 $1.00
- -------------------------------------------------------------------------------------------------------------
INCOME FROM INVESTMENT OPERATIONS:
2. Net investment income .70 .43 .05 .05 .04
3. Net gains or (losses) on securities (both realized and
unrealized) .99 .80 -- -- --
- -------------------------------------------------------------------------------------------------------------
4. Total from investment operations 1.69 1.23 .05 .05 .04
- -------------------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
5. Dividends (from net investment income) (.68) (.40) (.05) (.05) (.04)
6. Tax return of capital distributions -- -- -- -- --
7. Distributions (from capital gains) (.06) -- --
- -------------------------------------------------------------------------------------------------------------
8. Total distributions (.74) (.40) (.05) (.05) (.04)
- -------------------------------------------------------------------------------------------------------------
9. NET ASSET VALUE, END OF PERIOD $11.78 $10.83 $1.00 $1.00 $1.00
- -------------------------------------------------------------------------------------------------------------
10. Total return* 15.98% 12.40% 5.17% 5.05% 3.63%
- -------------------------------------------------------------------------------------------------------------
11. Net assets, end of period (in thousands) $2,914 $783 $15,374 $6,016 $1,735
12. Average net assets for the period (in thousands) $1,565 $459 $8,926 $3,715 $1,543
13. Ratio of gross expenses to average net assets** 1.00%(3) 1.01%(2) 0.50% 0.50% 0.50%
14. Ratio of net expenses to average net assets** 1.00% 1.00% 0.50%(7) 0.50%(6) 0.50%(5)
15. Ratio of net investment income to average net assets** 7.98% 5.74% 5.17% 4.93% 5.30%
16. Portfolio turnover rate** 299% 301% N/A N/A N/A
17. Average commission rate N/A N/A N/A N/A N/A
- -------------------------------------------------------------------------------------------------------------
</TABLE>

* Total return not annualized for periods of less than one year.
** Annualized for periods of less than one full year.
(1) May 1, 1996 (inception) to 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) May 1, 1995 (inception) to December 31, 1995.
(5) The ratio was 1.07% before waiver of certain fees incurred by the Portfolio.
(6) The ratio was 0.78% before waiver of certain fees incurred by the Portfolio.

(7) The ratio was 0.55% before waiver of certain fees incurred by the Portfolio.

JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998 5
<PAGE>

UNDERSTANDING THE
FINANCIAL HIGHLIGHTS

This section is designed to help you better understand the information
summarized in the Financial Highlights tables. The tables contain important
historical operating information that may be useful in making your investment
decision or understanding how your investment has performed. The Portfolios'
Annual Report contains additional information about each Portfolio's
performance, including a comparison to an appropriate securities index. To
request a copy of the Annual Report, please call or write your insurance
company.

NET ASSET VALUE ("NAV") is the value of a single Share of a Portfolio. It is
computed by adding the value of all of a Portfolio's investments and other
assets, subtracting any liabilities and dividing the result by the number of
shares outstanding. The difference between NET ASSET VALUE, BEGINNING OF PERIOD
AND NET ASSET VALUE, END OF PERIOD in the Financial Highlights tables represents
the change in value of a Share of a Portfolio over the fiscal period, but not
its total return. The NAV of the Money Market Portfolio's Shares is expected to
be $1.00.

NET INVESTMENT INCOME is the per share amount of dividends and interest income
earned on securities held by a Portfolio, less Portfolio expenses. DIVIDENDS
(FROM NET INVESTMENT INCOME) are the per share amount that a Portfolio paid from
net investment income.

NET GAINS OR (LOSSES) ON SECURITIES is the per share increase or decrease in
value of the securities a Portfolio holds. A gain (or loss) is realized when
securities are sold. A gain (or loss) is unrealized when securities increase or
decrease in value but are
not sold. DISTRIBUTIONS (FROM CAPITAL GAINS) are the per share amount that a
Portfolio paid from net realized gains.

TOTAL RETURN is the percentage increase or decrease in the value of an
investment over a stated period of time. Total return includes both changes in
NAV and income. For the purposes of calculating total return, it is assumed that
dividends and distributions are reinvested at the NAV on the day of the
distribution.

RATIO OF GROSS EXPENSES TO AVERAGE NET ASSETS is the total of a Portfolio's
operating expenses before expense offset arrangements divided by its average net
assets for the stated period. The Portfolios were not required to disclose the
ratio of gross expenses to average net assets prior to 1995. RATIO OF NET
EXPENSES TO AVERAGE NET ASSETS reflects reductions in a Portfolio's expenses
through the use of brokerage commissions and uninvested cash balances earning
interest or balance credits.

RATIO OF NET INVESTMENT INCOME TO AVERAGE NET ASSETS is a Portfolio's net
investment income divided by its average net assets for the stated period.

PORTFOLIO TURNOVER RATE is a measure of the amount of a Portfolio's buying and
selling activity. It is computed by dividing total purchases or sales, whichever
is less, by the average monthly market value of a Portfolio's securities. The
Money Market Portfolio does not calculate portfolio turnover.

AVERAGE COMMISSION RATE is the total of a Portfolio's agency commission paid on
equity securities trades divided by the number of shares purchased and sold.

PERFORMANCE TERMS

This section will help you understand various terms that are commonly used to
describe a Portfolio's performance. You may see references to these terms in our
newsletters or advertisements (or those published by participating insurance
companies) and in media articles. Newsletters and advertisements may include
comparisons of a Portfolio's performance to the performance of other mutual
funds, mutual fund averages or recognized stock market indices. Growth
Portfolio, Aggressive Growth Portfolio, International Growth Portfolio,
Worldwide Growth Portfolio, Capital Appreciation Portfolio, Balanced Portfolio
and Equity Income Portfolio generally measure performance in terms of total
return, while Flexible Income Portfolio, High-Yield Portfolio and Money Market
Portfolio generally use yield.

CUMULATIVE TOTAL RETURN represents the actual rate of return on an investment
for a specified period. The Financial Highlights tables show total return for a
single fiscal period. Cumulative total return is generally quoted for more than
one year (e.g., the life of a Portfolio). A cumulative total return does not
show interim fluctuations in the value of an investment.

AVERAGE ANNUAL TOTAL RETURN represents the average annual percentage change of
an investment over a specified period. It is calculated by taking the cumulative
total return for the stated period and determining what constant annual return
would have produced the same cumulative return. Average annual returns for more
than one year tend to smooth out variations in a Portfolio's return and are not
the same as actual annual results.

YIELD shows the rate of income the Shares earn on investments as a percentage of
the Share price. It is calculated by dividing net investment income for a 30-day
period (7-day period for the Money Market Portfolio) by the average number of
Shares entitled to receive dividends and dividing the result by the Share's NAV
per share at the end of the 30-day period. Yield does not include changes in
NAV.

6 JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998
<PAGE>

Yields are calculated according to standardized SEC formulas and may not equal
the income on an investor's account. Yield is usually quoted on an annualized
basis. An annualized yield represents the amount you would earn if you remained
in a Portfolio for a year and the Shares of that Portfolio continued to have the
same yield for the entire year.

EFFECTIVE YIELD is similar to yield in that it is calculated over the same time
frame, but instead the net investment income is compounded and then annualized.
Due to the compounding effect, the effective yield will normally be higher than
the yield.

THE PORTFOLIOS IMPOSE NO SALES OR OTHER CHARGES THAT WOULD AFFECT TOTAL RETURN
OR YIELD COMPUTATIONS. YIELD AND TOTAL RETURN FIGURES OF THE PORTFOLIOS INCLUDE
THE EFFECT OF DEDUCTING EACH PORTFOLIO'S EXPENSES, BUT MAY NOT INCLUDE CHARGES
AND EXPENSES ATTRIBUTABLE TO ANY PARTICULAR INSURANCE PRODUCT. PORTFOLIO
PERFORMANCE FIGURES ARE BASED UPON HISTORICAL RESULTS AND ARE NOT INTENDED TO
INDICATE FUTURE PERFORMANCE. INVESTMENT RETURNS AND NET ASSET VALUE WILL
FLUCTUATE SO THAT SHARES, WHEN REDEEMED, MAY BE WORTH MORE OR LESS THAN THEIR
ORIGINAL COST.

THE PORTFOLIOS IN DETAIL

This section takes a closer look at the Portfolios' investment objectives,
policies and the securities in which they invest. Please carefully review the
"Additional Risk Factors" section of this Prospectus for a more detailed
discussion of the risks associated with certain investment techniques. Appendix
A contains a more detailed description of investment terms used throughout this
Prospectus. You should carefully consider your investment goals, time horizon
and risk tolerance before choosing a Portfolio.

Each Portfolio has an investment objective and policies that are similar to
those of a Janus retail fund, as illustrated in the chart on this page. Although
it is anticipated that each Portfolio and its corresponding retail fund will
hold similar securities, differences in asset size and cash flow needs as well
as the relative weightings of securities selections may result in differences in
investment performance. Expenses of each Portfolio and its corresponding retail
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 contract fees and
expenses.

Policies that are noted as "fundamental" cannot be changed without a shareholder
vote. All other policies, including each Portfolio's investment objective, are
not fundamental and may be changed by the Portfolios' Trustees without a
shareholder vote. You will be notified of any such changes that are material. If
there is a material change in a Portfolio's objective or policies, you should
consider whether that Portfolio remains an appropriate investment for your
variable insurance contract or qualified retirement plan.

EACH OF THE PORTFOLIOS HAS A SIMILAR INVESTMENT
OBJECTIVE AND SIMILAR INVESTMENT POLICIES TO AN EXISTING JANUS RETAIL FUND.

Growth Portfolio....................................................Janus Fund
Aggressive Growth Portfolio..............................Janus Enterprise Fund
Capital Appreciation Portfolio..............................Janus Olympus Fund
International Growth Portfolio.............................Janus Overseas Fund
Worldwide Growth Portfolio................................Janus Worldwide Fund
Balanced Portfolio.........................................Janus Balanced Fund
Equity Income Portfolio...............................Janus Equity Income Fund
Flexible Income Portfolio...........................Janus Flexible Income Fund
High-Yield Portfolio.....................................Janus High-Yield Fund
Money Market Portfolio.................................Janus Money Market Fund

GROWTH PORTFOLIO, AGGRESSIVE GROWTH PORTFOLIO, CAPITAL APPRECIATION PORTFOLIO,
INTERNATIONAL GROWTH PORTFOLIO AND WORLDWIDE GROWTH PORTFOLIO ARE DESIGNED FOR
LONG-TERM INVESTORS WHO SEEK GROWTH OF CAPITAL ONLY AND WHO CAN TOLERATE THE
GREATER RISKS ASSOCIATED WITH COMMON STOCK INVESTMENTS.

GROWTH PORTFOLIOS
Investment Objective:..........................................Growth of Capital
Primary Holdings:..................................................Common Stocks
Shareholder's Investment Horizon:......................................Long-Term

GROWTH PORTFOLIO
The investment objective of this Portfolio is long-term growth of capital in a
manner consistent with the preservation of capital. It is a diversified
portfolio that pursues its objective by investing primarily in common stocks of
issuers of any size. This Portfolio generally invests in larger, more
established issuers.

JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998 7
<PAGE>

continue to be considered medium-sized companies for the purpose of this policy.
As of December 31, 1997, the MidCap Index included companies with
capitalizations between approximately $213 million and $13.7 billion. The range
of the MidCap Index is expected to change on a regular basis. Subject to the
above policy, the Portfolio may also invest in smaller or larger issuers.

CAPITAL APPRECIATION PORTFOLIO
The investment objective of this Portfolio is long-term growth of capital. It is
a nondiversified portfolio that pursues its objective by investing primarily in
common stocks of issuers of any size, which may include larger well-established
issuers and/or smaller emerging growth companies.

INTERNATIONAL GROWTH PORTFOLIO
The investment objective of this Portfolio is long-term growth of capital. It is
a diversified portfolio that pursues its objective primarily through investments
in common stocks of issuers located outside the United States. The Portfolio has
the flexibility to invest on a worldwide basis in companies and other
organizations of any size, regardless of country of organization or place of
principal business activity. The Portfolio normally invests at least 65% of its
total assets in securities of issuers from at least five different countries,
excluding the United States. Although the Portfolio intends to invest
substantially all of its assets in issuers located outside the United States, it
may at times invest in U.S. issuers, and it may at times invest all of its
assets in fewer than five countries or even a single country.

WORLDWIDE GROWTH PORTFOLIO
The investment objective of this Portfolio is long-term growth of capital in a
manner consistent with the preservation of capital. It is a diversified
portfolio that pursues its objective primarily through investments in common
stocks of foreign and domestic issuers. The Portfolio has the flexibility to
invest on a worldwide basis in companies and other organizations of any size,
regardless of country of organization or place of principal business activity.
Worldwide Growth Portfolio normally invests in issuers from at least five
different countries, including the United States. The Portfolio may at times
invest in fewer than five countries or even a single country.

TYPES OF INVESTMENTS
Each of these Portfolios invests primarily in common stocks of foreign and
domestic companies. However, the percentage of each Portfolio's assets invested
in common stocks will vary and each Portfolio may at times hold substantial
positions in cash equivalents or interest bearing securities. See "General
Portfolio Policies" on page 12. Each Portfolio may invest to a lesser degree in
other types of securities including preferred stocks, warrants, convertible
securities and debt securities when its portfolio manager perceives an
opportunity for capital growth from such securities or to receive a return on
idle cash. Some securities that the Portfolios purchase may be on a when-issued,
delayed delivery or forward commitment basis. The Portfolios may invest up to
25% of their assets in mortgage- and asset-backed securities, up to 10% of their
assets in zero coupon, pay-in-kind and step coupon securities, and without limit
in indexed/structured securities. No Growth Portfolio will invest 35% or more of
its assets in high-yield/high-risk securities.

Although Worldwide Growth Portfolio and International Growth Portfolio are
committed to foreign investing, Growth Portfolio, Aggressive Growth Portfolio
and Capital Appreciation Portfolio may also invest without limit in foreign
equity and debt securities. The Portfolios 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 ("PFICs"). These
Portfolios may use futures, options and other derivatives for hedging purposes
or for non-hedging purposes such as seeking to enhance return. See "Additional
Risk Factors" on page 13 for a discussion of the risks associated with foreign
investing and derivatives.

THE FOLLOWING QUESTIONS ARE DESIGNED TO HELP YOU BETTER UNDERSTAND AN INVESTMENT
IN THE GROWTH PORTFOLIOS.

Q:
A: HOW ARE COMMON STOCKS SELECTED?

Each of these Portfolios invests substantially all of its assets in common
stocks to the extent its portfolio manager believes that the relevant
market environment favors profitable investing in those securities. Portfolio
managers generally take a "bottom up" approach to building their portfolios. In
other words, they seek to identify individual companies with earnings growth
potential that may not be recognized by the market at large. Although themes may
emerge in any Portfolio, securities are generally selected without regard to any
defined industry sector or other similarly defined selection procedure.
Realization of income is not a significant investment consideration. Any income
realized on these Portfolios' investments will be incidental to their
objectives.

Q:
A: ARE THE SAME CRITERIA USED TO SELECT FOREIGN SECURITIES?

Generally, yes. Portfolio managers seek companies that meet their
selection criteria, regardless of country of organization or place of
principal business activity. 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. See "Additional Risk Factors" on page 13.

8 JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998
<PAGE>

Q:
A: WHAT IS THE MAIN RISK OF INVESTING IN A GROWTH PORTFOLIO?

Since the Growth Portfolios usually invest heavily in common stocks, the
fundamental risk is that the value of the stocks a Portfolio holds might
decrease. Stock values may fluctuate in response to the activities of an
individual company or in response to general market and economic conditions.
Historically, common stocks have provided greater long-term returns and have
entailed greater short-term risks than other investment choices. Smaller or
newer issuers are more likely to realize more substantial growth as well as
suffer more significant losses than larger or more established issuers.
Investments in such companies can be both more volatile and more speculative.
See "Additional Risk Factors" on page 13.

Q:
A: WHAT IS MEANT BY "MARKET CAPITALIZATION"?

Market capitalization is the most commonly used measure of the size and
value of a company. It is computed by multiplying the current market price
of a share of the company's stock by the total number of its shares outstanding.
As noted previously, market capitalization is an important investment criteria
for Aggressive Growth Portfolio which may invest in small- to medium-sized
companies to a greater degree. Although Growth Portfolio, Capital Appreciation
Portfolio, International Growth Portfolio and Worldwide Growth Portfolio do not
emphasize companies of any particular size, Portfolios with a larger asset base
are more likely to invest in larger, more-established issuers.

Q:
A: HOW DOES A DIVERSIFIED PORTFOLIO DIFFER FROM A NONDIVERSIFIED PORTFOLIO?

Diversification is a means of reducing risk by investing a Portfolio's
assets in a broad range of stocks or other securities. A "nondiversified"
portfolio 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 share price of a nondiversified portfolio, its share price
can be expected to fluctuate more than a comparable diversified portfolio.
Aggressive Growth Portfolio and Capital Appreciation Portfolio are
nondiversified portfolios.

Q:
A: HOW DO THESE PORTFOLIOS TRY TO REDUCE RISK?

Diversification of a Portfolio's assets reduces the effect of any single
holding on its overall portfolio value. A Portfolio may also use futures,
options and other derivative instruments to protect its portfolio from movements
in securities' prices and interest rates. The Portfolios may use a variety of
currency hedging techniques, including forward currency contracts, to manage
exchange rate risk when investing directly in foreign markets. See "Additional
Risk Factors" on page 13. In addition, to the extent that a Portfolio holds a
larger cash position, it may not participate in market declines to the same
extent as if the Portfolio remained more fully invested in common stocks.

BALANCED PORTFOLIO AND EQUITY INCOME PORTFOLIO ARE DESIGNED FOR INVESTORS WHO
PRIMARILY SEEK GROWTH OF CAPITAL INCLUDING AN EMPHASIS ON INCOME. THEY ARE NOT
DESIGNED FOR INVESTORS WHO DESIRE A CONSISTENT LEVEL OF INCOME.

COMBINATION PORTFOLIOS
Investment Objective:..........................................Growth of Capital
Including an Emphasis on Income
Primary Holdings:..............................................Common Stocks and
Income-Producing Securities
Shareholder's Investment Horizon:......................................Long-Term

BALANCED PORTFOLIO
The investment objective of this Portfolio is long-term capital growth,
consistent with preservation of capital and balanced by current income. It is a
diversified portfolio that, under normal circumstances, pursues its objective by
investing 40-60% of its assets in securities selected primarily for their growth
potential and 40-60% of its assets in securities selected primarily for their
income potential. This Portfolio normally invests at least 25% of its assets in
fixed-income senior securities, which include debt securities and preferred
stocks.

EQUITY INCOME PORTFOLIO
The investment objective of this Portfolio is current income and long-term
growth of capital. It is a diversified portfolio that pursues its objective by
normally investing at least 65% of its invested assets in income-producing
equity securities. Equity securities include common stocks, preferred stocks,
warrants and securities convertible into common or preferred stocks. Growth
potential is a significant investment consideration and the Portfolio may hold
securities selected solely for their growth potential.

TYPES OF INVESTMENTS
Both of the Combination Portfolios may invest in a combination of common stocks,
preferred stocks, convertible securities, debt securities and other fixed-income
securities. The Combination Portfolios may invest in the types of investments
previously described under "Growth Portfolios" on page 7. Although each of the
Combination Portfolios places some emphasis on the income objective, investors
should keep in mind that the Combination Portfolios are not designed to produce
a consistent level of income.

THE FOLLOWING QUESTIONS ARE DESIGNED TO HELP YOU BETTER UNDERSTAND AN INVESTMENT
IN THE COMBINATION PORTFOLIOS.

Q:
A: HOW DO THE COMBINATION PORTFOLIOS DIFFER FROM EACH OTHER?

Equity Income Portfolio emphasizes investments in dividend-paying common
stocks and other equity securities characterized by relatively greater
price stability. Balanced Portfolio places a greater emphasis on the income
component of its portfolio and invests to a greater degree in debt securities

JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998 9
<PAGE>

and preferred stock. As a result, it is expected to be the less volatile of the
Combination Portfolios.

Q:
A: HOW DOES EQUITY INCOME PORTFOLIO TRY TO LIMIT PORTFOLIO VOLATILITY?

Equity Income Portfolio seeks to provide a lower level of volatility than
the stock market at large, as measured by the S&P 500. The lower
volatility by this Portfolio is expected to result primarily from investments in
dividend-paying common stocks and other equity securities characterized by
relatively greater price stability. The greater price stability sought by Equity
Income Portfolio may be characteristic of companies that generate above average
free cash flows. A company may use free cash flows for a number of purposes
including commencing or increasing dividend payments, repurchasing its own stock
or retiring outstanding debt. The portfolio manager also considers growth
potential in selecting this Portfolio's securities and may hold securities
selected solely for their growth potential.

Q:
A: HOW ARE EQUITY SECURITIES SELECTED?

The growth component of Balanced Portfolio is expected to consist
primarily of common stocks and Equity Income Portfolio invests
substantially all of its assets in common stocks. The selection criteria for
common stocks are described on page 8. Because income is a part of the
investment objective of the Combination Portfolios, a portfolio manager may
consider dividend-paying characteristics to a greater degree in selecting equity
securities for these Portfolios. The Combination Portfolios may also find
opportunities for capital growth from debt securities because of the anticipated
changes in interest rates, credit standing, currency relationships or other
factors.

Q:
HOW ARE ASSETS ALLOCATED BETWEEN THE GROWTH AND INCOME COMPONENTS OF
A: BALANCED PORTFOLIO?

Balanced Portfolio may shift assets between the growth and income
components of its portfolio based on its portfolio manager's analysis of
relevant market, financial and economic conditions. If the portfolio manager
believes that growth securities will provide better returns than the yields then
available or expected on income-producing securities, the Portfolio will place a
greater emphasis on the growth component.
Q:
WHAT TYPES OF SECURITIES MAKE UP THE INCOME COMPONENT OF BALANCED
A: PORTFOLIO?

The income component of the Balanced Portfolio will consist of securities
that the portfolio manager believes have income potential. Such securities
may include equity securities, convertible securities and all types of debt
securities. Equity securities may be included in the income component of the
Balanced Portfolio if they currently pay dividends or a portfolio manager
believes they have the potential for either increasing their dividends or
commencing dividends, if none are currently paid.

FLEXIBLE INCOME PORTFOLIO AND HIGH-YIELD PORTFOLIO AND ARE DESIGNED FOR THOSE
INVESTORS WHO PRIMARILY SEEK CURRENT INCOME.

FIXED-INCOME PORTFOLIOS
Investment Objective:
Flexible Income Portfolio.........................................Total Return
High-Yield Portfolio....................................................Income
Primary Holdings:....................................Income-Producing Securities
Shareholder's Investment Horizon:
Flexible Income Portfolio and
High-Yield Portfolio.............................Intermediate- to Long-Term

FLEXIBLE INCOME PORTFOLIO
The investment objective of this Portfolio is to obtain maximum total return,
consistent with preservation of capital. The Portfolio pursues its objective
primarily through investments in income-producing securities. Total return is
expected to result from a combination of current income and capital
appreciation, although income will normally be the dominant component of total
return. As a fundamental policy, this Portfolio will invest at least 80% of its
assets in income-producing securities.

Flexible Income Portfolio may invest in a wide variety of income-producing
securities including corporate bonds and notes, government securities,
index/structured securities, preferred stock, income-producing common stocks,
debt securities that are convertible or exchangeable into equity securities, and
debt securities that carry with them the right to acquire equity securities as
evidenced by warrants attached to or acquired with the securities. The Portfolio
may invest to a lesser degree in common stocks, other equity securities or debt
securities that are not currently paying dividends or interest. The Portfolio
may purchase securities of any maturity and quality and the average maturity and
quality of its portfolio may vary substantially.

Flexible Income Portfolio may invest without limit in foreign securities,
including those of corporate and government issuers. The Portfolio may invest
without limit in high-yield/high-risk securities and may have substantial
holdings of such securities. The Portfolio may invest without limit in mortgage-
and asset-backed securities and in zero coupon, pay-in-kind and step coupon
securities. The risks of foreign securities and high-yield securities are
described under "Additional Risk Factors" on page 13.

The Portfolio may purchase defaulted debt securities if, in the opinion of Janus
Capital it appears likely that the issuer may resume interest payments or other
advantageous developments appear likely in the near term. Defaulted debt
securities may be illiquid and subject to the Portfolio's limit on illiquid
investments.

10 JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998
<PAGE>

the credit standing of an issuer whose securities are held by this Portfolio or
from a general lowering of interest rates, or both. This Portfolio pursues its
objectives by investing primarily in high-yield/high-risk fixed-income
securities. This Portfolio will normally invest at least 65% of its total assets
in those securities. In addition, the Portfolio may invest in all of the types
of securities previously described under Flexible Income Portfolio.

The high yields sought by this Portfolio are expected to result primarily from
investments in longer-term, lower quality corporate bonds, commonly referred to
as "junk" bonds. This Portfolio considers lower quality securities to be
securities rated below investment grade by established rating agencies or
unrated securities of comparable quality. Securities rated BB or lower by
Standard & Poor's Ratings Services ("Standard & Poor's") or Ba or lower by
Moody's Investors Service, Inc. ("Moody's") are below investment grade. Lower
quality securities are often considered to be more speculative and involve
greater risk of default or price changes due to changes in interest rates,
economic conditions and the issuer's credit-worthiness. As a result, their
market prices tend to fluctuate more than higher quality securities of
comparable maturity. Additional risks of lower quality securities are described
under "Additional Risk Factors" on page 13.

TYPES OF INVESTMENTS
In addition to the investment policies described above, each Fixed-Income
Portfolio may purchase securities on a when-issued, delayed delivery or forward
commitment basis. In addition, each Portfolio may use futures, options and other
derivatives for hedging purposes or for non-hedging purposes such as seeking to
enhance return. See "Additional Risk Factors" on page 13. When its portfolio
manager is unable to locate investment opportunities with favorable risk/reward
characteristics, the cash position of any Portfolio may increase and the
Portfolio may have substantial holdings of cash or cash equivalent short-term
obligations. See "General Portfolio Policies" on page 12.

THE FOLLOWING QUESTIONS ARE DESIGNED TO HELP YOU BETTER UNDERSTAND AN INVESTMENT
IN THE FIXED-INCOME PORTFOLIOS.

Q:
A: HOW DO INTEREST RATES AFFECT THE VALUE OF MY INVESTMENT?

A fundamental risk associated with any fund that invests in fixed-income
securities (e.g., a bond fund) is the risk that the value of the
securities it holds will rise or fall as interest rates change. 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 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 portfolio may react to interest rate changes.

Q:
A: WHAT IS MEANT BY A 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, such as a Portfolio. Some
types of bonds, such as mortgage-backed securities, which are subject to
prepayment risk, and securities with call provisions, may also have an
"effective maturity" that is shorter than the stated date. With respect to GNMA
securities and other mortgage-backed securities, effective maturity is likely to
be substantially less than the stated maturities of the mortgages in the
underlying pools. With respect to obligations with call provisions, effective
maturity is typically the next call date on which the obligation reasonably may
be expected to be called. 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 a Portfolio with each effective maturity "weighted"
according to the percentage of net assets that it represents.

Q:
A: WHAT IS MEANT BY A PORTFOLIO'S "DURATION"?

A bond's duration indicates the time it will take an investor to recoup
his or her 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 Portfolio with each duration
"weighted" according to the percentage of net assets that it represents. Because
duration accounts for interest payments, a Portfolio's duration is usually
shorter than its average maturity.

Q:
HOW DO FLEXIBLE INCOME PORTFOLIO AND HIGH-YIELD PORTFOLIO MANAGE INTEREST
A: RATE RISK?

Each of these Portfolios may vary the average-weighted effective maturity
of its portfolio to reflect its portfolio manager's analysis of interest
rate trends and other factors. A Portfolio's average-weighted effective maturity
will tend to be shorter when its portfolio manager expects interest rates to
rise and longer when its portfolio manager expects interest rates to fall. The
Portfolios may also use futures, options and other derivatives to manage
interest rate risk. See "Additional Risk Factors" on page 13.

Q:
A: WHAT IS MEANT BY "CREDIT QUALITY"?

JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998 11
<PAGE>

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.

Q:
A: HOW IS CREDIT QUALITY MEASURED?

Ratings published by nationally recognized 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 Appendix B for a
description of rating categories.

Q:
A: WHAT IS A HIGH-YIELD/HIGH-RISK SECURITY?

A high-yield 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.

Q:
A: WHAT RISKS DO HIGH-YIELD/HIGH-RISK SECURITIES PRESENT?

High-yield securities are often considered to be more speculative and
involve greater risk of default or price changes due to changes in
economic and industry conditions and the issuer's creditworthiness. Their market
prices tend to fluctuate more than higher quality securities as a result of
changes in these factors.

The default rate of lower quality debt securities is likely to be higher when
issuers have difficulty meeting projected goals or obtaining additional
financing. This could occur during economic recessions or periods of high
interest rates. In addition, there may be a smaller market for lower quality
securities than for higher quality securities, making lower quality securities
more difficult to sell promptly at an acceptable price.

The junk bond market can experience sudden and sharp price swings. Because
Flexible Income Portfolio and High-Yield Portfolio may invest a significant
portion of their portfolios in high-yield/high-risk securities, investors in
such Portfolios should be willing to tolerate a corresponding increase in the
risk of significant and sudden changes in NAV.

GENERAL PORTFOLIO POLICIES OF THE
PORTFOLIOS OTHER THAN MONEY
MARKET PORTFOLIO
Unless otherwise stated, each of the following policies applies to all of the
Portfolios other than the Money Market Portfolio. The percentage limitations
included in these policies and elsewhere in this Prospectus apply only at the
time of purchase of the security. For example, if a 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 a Portfolio's manager believes that market conditions are not favorable for
profitable investing or when the portfolio manager is otherwise unable to locate
favorable investment opportunities, a Portfolio's investments may be hedged to a
greater degree and/or its cash or similar investments may increase. In other
words, the Portfolios do not always stay fully invested in stocks and bonds.
Cash or similar investments are a residual - they represent the assets that
remain after a portfolio manager has committed available assets to desirable
investment opportunities. Partly because the portfolio managers act
independently of each other, the cash positions of the Portfolios may vary
significantly. Larger hedged positions and/or larger cash positions may serve as
a means of preserving capital in unfavorable market conditions.

Securities that the Portfolios may invest in as means of receiving a return on
idle cash include high-grade commercial paper, certificates of deposit,
repurchase agreements or other short-term debt obligations. The Portfolios may
also invest in money market funds (including funds managed by Janus Capital).
When a Portfolio is hedged or its investments in cash or similar investments
increase, it may not participate in stock or bond market advances or declines to
the same extent that it would if the Portfolio was not hedged or remained more
fully invested in stocks or bonds.

DIVERSIFICATION
The Investment Company Act of 1940 (the "1940 Act") classifies investment
companies as either diversified or nondiversified. All of the Portfolios (except
Aggressive Growth and Capital Appreciation Portfolio) qualify as diversified
funds under

12 JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998
<PAGE>

the 1940 Act and are subject to the following diversification requirements:

- - As a fundamental policy, no Portfolio may own more than 10% of the outstanding
voting shares of any issuer.

- - As a fundamental policy, with respect to 50% of the total assets of Aggressive
Growth Portfolio and Capital Appreciation Portfolio and 75% of the total
assets of the other Portfolios, no Portfolio will purchase a security of any
issuer (other than cash items and U.S. government securities, as defined in
the 1940 Act) if such purchase would cause a Portfolio's holdings of that
issuer to amount to more than 5% of that Portfolio's total assets.

- - No Portfolio will invest more than 25% of its total assets in a single issuer
(other than U.S. government securities).

- - Aggressive Growth Portfolio and Capital Appreciation Portfolio reserve the
right to become diversified portfolios by limiting the investments in which
more than 5% of their total net assets are invested.

INTERNAL REVENUE SERVICE (IRS) LIMITATIONS
In addition to the diversification requirements stated above, each Portfolio
intends to comply with the diversification requirements currently imposed by the
IRS on separate accounts of insurance companies as a condition of maintaining
the tax-deferred status of variable contracts. More specific information may be
contained in the participating insurance company's separate account prospectus.

INDUSTRY CONCENTRATION
As a fundamental policy, no Portfolio will invest 25% or more of its total
assets in any particular industry (excluding U.S. government securities).

PORTFOLIO TURNOVER
Each Portfolio generally intends to purchase securities for long-term investment
rather than short-term gains. However, short-term transactions may 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 initial investment
decision. Changes are made in a Portfolio whenever its portfolio manager
believes such changes are desirable. Portfolio turnover rates are generally not
a factor in making buy and sell decisions.

To a limited extent, a Portfolio may purchase securities in anticipation of
relatively short-term price gains. A Portfolio may also sell one security and
simultaneously purchase the same or comparable security to take advantage of
short-term differentials in bond yields or securities prices. 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.

ILLIQUID INVESTMENTS
Each Portfolio may invest up to 15% of its net assets in illiquid investments,
including restricted securities or private placements that are not deemed to be
liquid by Janus Capital. If illiquid securities exceed 15% of a Portfolio's net
assets after the time of purchase, the Portfolio will take steps to reduce in an
orderly fashion its holdings of illiquid securities. An illiquid investment is a
security or other position that cannot be disposed of quickly in the normal
course of business. Some securities cannot be sold to the U.S. public because of
their terms or because of SEC regulations. Janus Capital will follow guidelines
established by the Trustees of the Trust ("Trustees") in making liquidity
determinations for Rule 144A securities and other securities, including
privately placed commercial paper and municipal lease obligations.

BORROWING AND LENDING
Each Portfolio may borrow money and lend securities or other assets, as follows:

- - Each Portfolio may borrow money for temporary or emergency purposes in amounts
up to 25% of its total assets.

- - Each Portfolio may mortgage or pledge securities as collateral for borrowings
in amounts up to 15% of its net assets.

- - As a fundamental policy, each Portfolio may lend securities or other assets
if, as a result, no more than 25% of its total assets would be lent to other
parties.

Under the terms of an exemptive order received from the SEC, each Portfolio may
borrow money from or lend money to each other and other funds that permit such
transactions and for which Janus Capital serves as investment adviser. All such
borrowing and lending will be subject to the above percentage limits.

ADDITIONAL RISK FACTORS OF THE PORTFOLIOS OTHER THAN MONEY MARKET PORTFOLIO

FOREIGN SECURITIES
INVESTMENTS IN FOREIGN SECURITIES, INCLUDING THOSE OF FOREIGN GOVERNMENTS, MAY
INVOLVE GREATER RISKS THAN INVESTING IN COMPARABLE DOMESTIC SECURITIES.

Securities of some foreign companies and governments may be traded in the United
States, but many foreign securities are traded primarily in foreign markets. The
risks of foreign investing include:

- - CURRENCY RISK. A Portfolio may buy the local currency when it buys a foreign
currency denominated security and sell the local currency when it sells the
security. As long as a Portfolio holds a foreign security, its value will be
affected by the value of the local currency relative to the U.S. dollar. When
a Portfolio sells a foreign denominated security, its value may be worth less
in U.S. dollars even though the security increases in value in its home
country. U.S. dollar denominated securities of foreign issuers may also be
affected by currency risk.

relatively unstable governments 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 a Portfolio's assets from that country. The Portfolios may
invest in emerging market countries. Emerging market countries involve greater
risks such as immature economic structures, national policies restricting
investments by foreigners, and different legal systems.

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

- - MARKET RISK. Foreign securities markets, particularly those of underdeveloped
or developing 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. There may be limited legal recourse against an
issuer in the event of a default on a debt instrument.

- - TRANSACTION COSTS. Transaction costs of buying and selling foreign securities,
including brokerage, tax and custody costs, are generally higher than those
involved in domestic transactions.

Foreign securities purchased indirectly (e.g., depositary receipts) are subject
to many of the above risks, including currency risk, because their values depend
on the performance of a foreign security denominated in its home currency.

INVESTMENTS IN SMALLER COMPANIES
SMALLER OR NEWER COMPANIES MAY SUFFER MORE SIGNIFICANT LOSSES AS WELL AS REALIZE
MORE SUBSTANTIAL GROWTH THAN LARGER OR MORE ESTABLISHED ISSUERS.

Smaller or newer companies may lack depth of management, they may be unable to
generate funds necessary for growth or potential development, or they may 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 be 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 wider
price fluctuations. Investments in such companies tend to be more volatile and
somewhat more speculative.

FUTURES, OPTIONS AND OTHER DERIVATIVE INSTRUMENTS
Each Portfolio may enter into futures contracts on securities, financial indices
and foreign currencies and options on such contracts ("futures contracts") and
may invest in options on securities, financial indices and foreign currencies
("options"), forward contracts and interest rate swaps and swap-related products
(collectively "derivative instruments"). The Portfolios intend to use most
derivative instruments primarily to hedge against potential adverse movements in
securities prices, foreign currency markets or interest rates. To a limited
extent, the Portfolios may also use derivative instruments for non-hedging
purposes such as seeking to increase a Portfolio's income or otherwise seeking
to enhance return. Please refer to Appendix A to this Prospectus and the SAI for
a more detailed discussion of these instruments.

The use of derivative instruments exposes the Portfolios to additional
investment risks and transaction costs. Risks inherent in the use of derivative
instruments include:

- - the risk that interest rates, securities prices and currency markets will not
move in the direction that a portfolio manager anticipates;

- - imperfect correlation between the price of derivative instruments and
movements in the prices of the securities, interest rates or currencies being
hedged;

- - the fact that skills needed to use these strategies are different from those
needed to select portfolio securities;

- - inability to close out certain hedged positions to avoid adverse tax
consequences;

- - the possible absence of a liquid secondary market for any particular
instrument and possible exchange-imposed price fluctuation limits, either of
which may make it difficult or impossible to close out a position when
desired;

- - leverage risk, that is, the risk that adverse price movements in an instrument
can result in a loss substantially greater than a Portfolio's initial
investment in that instrument (in some cases, the potential loss is
unlimited); and

- - particularly in the case of privately-negotiated instruments, the risk that
the counterparty will fail to perform its obligations, which could leave a
Portfolio worse off than if it had not entered into the position.

Although the Portfolios' Managers believe the use of derivative instruments will
benefit the Portfolios, a Portfolio's performance could be worse than if the
Portfolio had not used such instruments if the portfolio manager's judgement
proves incorrect.

When a Portfolio invests in a derivative instrument, it may be required to
segregate cash and other liquid assets or certain portfolio securities with its
custodian to "cover" the Portfolio's position. Assets segregated or set aside
generally may not be disposed of so long as the Portfolio maintains the
positions requiring segregation or cover. Segregating assets could diminish the
Portfolio's return due to the opportunity losses of foregoing other potential
investments with the segregated assets.

14 JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998
<PAGE>

HIGH-YIELD/HIGH-RISK SECURITIES
HIGH-YIELD/HIGH-RISK SECURITIES (OR "JUNK" BONDS) ARE DEBT 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 the ability
of the issuer to meet interest and principal payments (i.e., credit risk) than
is the case for higher quality securities. Conversely, the value of higher
quality securities may be more sensitive to interest rate movements than lower
rated securities. Issuers of high-yield/high-risk securities may not be as
strong financially as those issuing bonds with higher credit ratings.
Investments in such companies are considered to be more speculative than higher
quality investments.

Issuers of high-yield/high-risk securities are more vulnerable to real or
perceived economic changes (for instance, an economic downturn or prolonged
period of rising interest rates), political changes or adverse developments
specific to the issuer. Adverse economic, political or other developments may
impair the issuer's ability to service principal and interest obligations, to
meet projected business goals and to obtain additional financing, particularly
if the issuer is highly leveraged. In the event of a default, a Portfolio would
experience a reduction of its income and could expect a decline in the market
value of the defaulted securities.

The market for lower quality securities is generally less liquid than the market
for higher quality securities. Adverse publicity and investor perceptions as
well as new or proposed laws may also have a greater negative impact on the
market for lower quality securities. Unrated debt, while not necessarily of
lower quality than rated securities, may not have as broad a market as higher
quality securities. Sovereign debt of foreign governments is generally rated by
country. Because these ratings do not take into account individual factors
relevant to each issue and may not be updated regularly, Janus Capital may treat
such securities as unrated debt.

The market prices of high-yield/high-risk securities structured as zero coupon
or pay-in-kind securities are generally affected to a greater extent by interest
rate changes and tend to be more volatile than securities which pay interest
periodically. In addition, zero coupon, pay-in-kind and delayed interest bonds
often do not pay interest until maturity. However, the Portfolios must recognize
imputed interest income and pay dividends to shareholders even though it has
received no cash. In some instances, the Portfolios may have to sell securities
to have sufficient cash to pay the dividends.

Please refer to Appendix B for a description of bond rating categories.

SHORT SALES
Each Portfolio may engage in "short sales against the box." This technique
involves selling either a security that a Portfolio owns, or a security
equivalent in kind and amount that a Portfolio has the right to obtain, for
delivery at a specified date in the future. A Portfolio may enter into a short
sale against the box to hedge against anticipated declines in the market price
of portfolio securities. If the value of the securities sold short increases
prior to the scheduled delivery date, the Portfolio loses the opportunity to
participate in the gain.

SPECIAL SITUATIONS
Each Portfolio may invest in "special situations" from time to time. A special
situation arises when, in the opinion of a 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.
Investment in special situations may carry an additional risk of loss in the
event that the anticipated development does not occur or does not attract the
expected attention.

See Appendix A for risks associated with certain other investments.

MONEY MARKET PORTFOLIO IS DESIGNED FOR INVESTORS WHO PRIMARILY SEEK MAXIMUM
CURRENT INCOME TO THE EXTENT CONSISTENT WITH STABILITY OF CAPITAL.

MONEY MARKET PORTFOLIO

INVESTMENT OBJECTIVE
The Portfolio's investment objective is to seek maximum current income to the
extent consistent with stability of capital. There can be no assurance that the
Portfolio will achieve its investment objective or be able to maintain a stable
net asset value of $1.00 per share.

INVESTMENT POLICIES
The Portfolio will invest only in eligible high quality, short-term money market
instruments that present minimal credit risks, as determined by Janus Capital,
the Portfolio's investment adviser, pursuant to procedures adopted by the
Trustees. The Portfolio may invest only in U.S. dollar-denominated instruments
that have a remaining maturity of 397 days or less (as calculated pursuant to
Rule 2a-7 under the Investment Company Act of 1940) and will maintain a
dollar-weighted average portfolio maturity of 90 days or less.

Except to the limited extent permitted by Rule 2a-7 and except for U.S.
Government Securities (as defined below), the Portfolio will not invest more
than 5% of its total assets in the securities of any one issuer. Investment in
demand features, guarantees and other types of instruments are subject to the
diversification limits under Rule 2a-7. The Portfolio may not invest more than
25% of its total assets in any one industry, except that this limit does not
apply to U.S. Government Securities, bank obligations or municipal securities.
To ensure adequate liquidity, the Portfolio may not invest more than 10% of its
net assets in illiquid securities, including repurchase agreements maturing in
more than seven days (unless subject to

JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998 15
<PAGE>

a demand feature) and certain time deposits that are subject to early withdrawal
penalties and mature in more than seven days. Janus Capital determines and
monitors the liquidity of portfolio securities under the supervision of the
Trustees.

RATINGS
High quality money market instruments include those that (i) are rated (or, if
unrated, are issued by an issuer with comparable outstanding short-term debt
that is rated) in one of the two highest rating categories for short-term debt
by any two nationally recognized statistical rating organizations ("NRSROs") or,
if only one NRSRO has issued a rating, by that NRSRO or (ii) are otherwise
unrated and determined by Janus Capital to be of comparable quality. The
Portfolio will invest at least 95% of its total assets in securities in the
highest rating category (as determined pursuant to Rule 2a-7). Descriptions of
the rating categories of Standard & Poor's, Moody's, and certain other NRSROs
are contained in Appendix B. A further description of the Money Market
Portfolio's investment policies is included in the Money Market Portfolio's SAI.

Although the Portfolio only invests in high quality money market instruments, an
investment in the Portfolio is subject to risk even if all securities in its
portfolio are paid in full at maturity. All money market instruments, including
U.S. Government Securities, can change in value as a result of changes in
interest rates, the issuer's actual or perceived creditworthiness or the
issuer's ability to meet its obligations.

TYPES OF INVESTMENTS
The Portfolio pursues its objective by investing primarily in high quality debt
obligations and obligations of financial institutions. It may invest in U.S.
Government Securities (as defined below) and municipal securities, although the
Portfolio expects to invest in such securities to a lesser degree.

DEBT OBLIGATIONS
The Portfolio may invest in debt obligations of domestic issuers, including
commercial paper (short-term promissory notes issued by companies to finance
their, or their affiliates', current obligations), notes and bonds, and variable
amount master demand notes. The payment obligations on these instruments may be
backed by securities, swap agreements or other assets, by a guarantee of a third
party or solely by the unsecured promise of the issuer to make payments when
due. The Portfolio may invest in privately issued commercial paper or other
securities that are restricted as to disposition under the federal securities
laws. In general, sales of these securities may not be made absent registration
under the Securities Act of 1933 (the "1933 Act") or the availability of an
appropriate exemption therefrom. Pursuant to Section 4(2) of the 1933 Act or
Rule 144A adopted under the 1933 Act, however, some of these securities are
eligible for resale to institutional investors, and accordingly, Janus Capital
may determine that a liquid market exists for such a security pursuant to
guidelines adopted by the Trustees.

OBLIGATIONS OF FINANCIAL INSTITUTIONS
The Portfolio may invest in obligations of financial institutions. Examples of
obligations in which it may invest include negotiable certificates of deposit,
bankers' acceptances, time deposits and other obligations of U.S. banks
(including savings and loan associations) having total assets in excess of one
billion dollars and U.S. branches of foreign banks having total assets in excess
of ten billion dollars. The Portfolio may also invest in Eurodollar and Yankee
bank obligations as discussed below and other U.S. dollar-denominated
obligations of foreign banks having total assets in excess of ten billion
dollars that Janus Capital believes are of an investment quality comparable to
obligations of U.S. banks in which the Portfolio may invest.

Certificates of deposit represent an institution's obligation to repay funds
deposited with it that earn a specified interest rate over a given period.
Bankers' acceptances are negotiable obligations of a bank to pay a draft which
has been drawn by a customer and are usually backed by goods in international
trade. Time deposits are non-negotiable deposits with a banking institution that
earn a specified interest rate over a given period. Fixed time deposits, which
are payable at the stated maturity date and bear a fixed rate of interest,
generally may be withdrawn on demand by the Portfolio but may be subject to
early withdrawal penalties that could reduce the Portfolio's yield. Unless there
is a readily available market for them, time deposits that are subject to early
withdrawal penalties and that mature in more than seven days will be treated as
illiquid securities.

Eurodollar bank obligations are dollar-denominated certificates of deposit or
time deposits issued outside the U.S. capital markets by foreign branches of
U.S. banks and by foreign banks. Yankee bank obligations are dollar-denominated
obligations issued in the U.S. capital markets by foreign banks.

Foreign, Eurodollar (and to a limited extent, Yankee) bank obligations are
subject to certain sovereign risks. One such risk is the possibility that a
foreign government might prevent dollar-denominated funds from flowing across
its borders. Other risks include: adverse political and economic developments in
a foreign country; the extent and quality of government regulation of financial
markets and institutions; the imposition of foreign withholding taxes; and
expropriation or nationalization of foreign issuers.

16 JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998
<PAGE>

guaranteed by the Small Business Administration or issued by the Government
National Mortgage Association. In addition, U.S. Government Securities in which
the Portfolio may invest include securities supported primarily or solely by the
creditworthiness of the issuer, such as securities of the Federal National
Mortgage Association, the Federal Home Loan Mortgage Corporation and the
Tennessee Valley Authority. There is no guarantee that the U.S. government will
support securities not backed by its full faith and credit. Accordingly,
although these securities have historically involved little risk of loss of
principal if held to maturity, they may involve more risk than securities backed
by the full faith and credit of the U.S. government.

MUNICIPAL SECURITIES
The municipal securities in which the Portfolio may invest include municipal
notes and short-term municipal bonds. Municipal notes are generally used to
provide for the issuer's short-term capital needs and generally have maturities
of 397 days or less. The Portfolio may also invest in high quality participation
interests in municipal securities. A more detailed description of various types
of municipal securities is contained in Appendix B in the SAI.

Yields on municipal securities are dependent on a variety of factors, including
the general conditions of the money market and of the municipal bond and
municipal note markets, the size of a particular offering, the maturity of the
obligation and the rating of the issue. Obligations of issuers of municipal
securities are subject to the provisions of bankruptcy, insolvency and other
laws affecting the rights and remedies of creditors, such as the Bankruptcy
Reform Act of 1978, as amended. Therefore, the possibility exists that, as a
result of litigation or other conditions, the ability of any issuer to pay, when
due, the principal of and interest on its municipal securities may be materially
affected.

PARTICIPATION INTERESTS
The Portfolio may invest in participation interests in any type of security in
which the Portfolio may invest. A participation interest gives a Portfolio an
undivided interest in the underlying securities in the proportion that the
Portfolio's participation interest bears to the total principal amount of the
underlying securities. Participation interests usually carry a demand feature,
as described below, backed by a letter of credit or guarantee of the institution
that issued the interests permitting the holder to tender them back to the
institution.

DEMAND FEATURES
The Portfolio may invest in securities that are subject to puts and stand-by
commitments ("demand features"). Demand features give the Portfolio the right to
resell securities at specified periods prior to their maturity dates to the
seller or to some third party at an agreed-upon price or yield. Securities with
demand features may involve certain expenses and risks, including the inability
of the issuer of the instrument to pay for the securities at the time the
instrument is exercised, non-marketability of the instrument and differences
between the maturity of the underlying security and the maturity of the
instrument. Securities may cost more with demand features than without them.
Demand features can serve three purposes: to shorten the maturity of a variable
or floating rate security, to enhance the instrument's credit quality and to
provide a source of liquidity. Demand features are often issued by third party
financial institutions, generally domestic and foreign banks. Accordingly, the
credit quality and liquidity of the Portfolio's investments may be dependent in
part on the credit quality of the banks supporting its investments. This will
result in exposure to risks pertaining to the banking industry, including the
foreign banking industry. Brokerage firms and insurance companies also provide
certain liquidity and credit support.

VARIABLE AND FLOATING RATE SECURITIES
The securities in which the Portfolio invests may have variable or floating
rates of interest. 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. Securities with ultimate maturities
of greater than 397 days may be purchased only pursuant to Rule 2a-7. Under that
Rule, only those long-term instruments that have demand features which comply
with certain requirements and certain variable rate U.S. Government Securities
may be purchased. Similar to fixed rate debt instruments, variable and floating
rate instruments are subject to changes in value based on changes in market
interest rates or changes in the issuer's or guarantor's creditworthiness. The
rate of interest on securities purchased by the Portfolio may be tied to
short-term Treasury or other government securities or indices on securities that
are permissible investments of the Portfolio, as well as other money market
rates of interest. The Portfolio will not purchase securities whose values are
tied to interest rates or indices that are not appropriate for the duration and
volatility standards of a money market fund.

MORTGAGE- AND ASSET-BACKED SECURITIES
The Portfolio may purchase fixed or adjustable rate mortgage-backed securities
issued by the Government National Mortgage Association, Federal National
Mortgage Association or the Federal Home Loan Mortgage Corporation, or other
governmental or government-related entities. In addition, the Portfolio may
purchase other asset-backed securities, including securities backed by
automobile loans, equipment leases or credit card receivables. These securities
directly or indirectly represent a participation in, or are secured by and
payable from, fixed or adjustable rate mortgage or other loans which may be
secured by real estate or other assets. Unlike traditional debt instruments,
payments on these securities include both interest and a partial payment of
principal. Prepayments of the principal of underlying loans may shorten the
effective maturities of these securities and may result in the Portfolio having
to reinvest proceeds at a lower interest rate.

JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998 17
<PAGE>

an agreed-upon price on an agreed-upon future date. The resale price reflects a
market rate of interest that is not related to the coupon rate or maturity of
the purchased securities.

REVERSE REPURCHASE AGREEMENTS
The Portfolio may enter into reverse repurchase agreements. Reverse repurchase
agreements are transactions in which the Portfolio sells a security and
simultaneously commits to repurchase that security from the buyer at an agreed
upon price on an agreed upon future date. This technique will be used primarily
for temporary or emergency purposes, such as meeting redemption requests.

DELAYED DELIVERY SECURITIES
The Portfolio may purchase securities on a when-issued or delayed delivery
basis. Securities so purchased are subject to market price fluctuation from the
time of purchase but no interest on the securities accrues to the Portfolio
until delivery and payment for the securities take place. Accordingly, the value
of the securities on the delivery date may be more or less than the purchase
price. Forward commitments will be entered into only when the Portfolio has the
intention of taking possession of the securities, but it may sell the securities
before the settlement date if deemed advisable.

BORROWING AND LENDING
The Portfolio may borrow money for temporary or emergency purposes in amounts up
to 25% of its total assets. It may not mortgage or pledge securities except to
secure permitted borrowings. As a fundamental policy, the Portfolio will not
lend securities or other assets if, as a result, more than 25% of its total
assets would be lent to other parties. The Portfolio does not currently intend
to engage in securities lending; however, under the terms of an exemptive order
received from the SEC, the Portfolio may borrow money from or lend money to
other funds that permit such transactions and are advised by Janus Capital.

18 JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998
<PAGE>

MANAGEMENT OF
THE PORTFOLIOS

TRUSTEES

The Trustees oversee the business affairs of the Trust and are responsible for
major decisions relating to each Portfolio's investment objective and policies.
The Trustees delegate the day-to-day management of the Portfolios to the
officers of the Trust and meet at least quarterly to review the Portfolios'
investment policies, performance, expenses and other business affairs.

INVESTMENT ADVISER
Janus Capital, 100 Fillmore Street, Denver, Colorado 80206-4928, is the
investment adviser to each of the Portfolios and is responsible for the
day-to-day management of the investment portfolios and other business affairs of
the Portfolios.

Janus Capital has served as investment adviser to Janus Fund since its inception
in 1970 and currently serves as investment adviser to all of the Janus retail
funds, as well as adviser or subadviser to other mutual funds and individual,
corporate, charitable and retirement accounts.

Kansas City Southern Industries, Inc. ("KCSI") owns approximately 83% of the
outstanding voting stock of Janus Capital, most of which it acquired in 1984.
KCSI is a publicly traded holding company whose primary subsidiaries are engaged
in transportation, information processing and financial services. Thomas H.
Bailey, President and Chairman of the Board of Janus Capital, owns approximately
12% of its voting stock and, by agreement with KCSI, selects a majority of Janus
Capital's Board.

Janus Capital furnishes continuous advice and recommendations concerning each
Portfolio's investments. Janus Capital also furnishes certain administrative,
compliance and accounting services for the Portfolios, and may be reimbursed by
the Portfolios 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 Portfolios 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 Portfolios' Shares may
perform certain administrative services relating to the Portfolios and Janus
Capital or the Portfolios may pay those companies for such services.

INVESTMENT PERSONNEL

PORTFOLIO MANAGERS

LAURENCE J. CHANG is Executive Vice President and co-manager of International
Growth Portfolio and Janus Overseas Fund which he has co-managed since May 1998
and April 1998, respectively. He served as assistant portfolio manager for these
funds since 1996. He is also assistant portfolio manager for Worldwide Growth
Portfolio and Janus Worldwide Fund. Mr. Chang joined Janus Capital in 1993 after
receiving a Masters Degree in Political Science from Stanford University. From
1989 to 1993, he was a Project Director for the National Security Archives, a
nonprofit research organization. He is a Chartered Financial Analyst.

JAMES P. CRAIG, III is Chief Investment Officer of Janus Capital. He is
Executive Vice President and portfolio manager of Growth Portfolio, which he has
managed since inception. Mr. Craig previously managed Balanced Portfolio from
September 1993 through April 1996. He has managed Janus Fund since 1986 and has
co-managed Janus Venture Fund since February 1, 1997. Mr. Craig previously
managed Janus Venture Fund from its inception to December 1993 and Janus
Balanced Fund from December 1993 to December 1995. He holds a Bachelor of Arts
in Business from the University of Alabama and a Master of Arts in Finance from
the Wharton School of the University of Pennsylvania.

JAMES P. GOFF is Executive Vice President and portfolio manager of Aggressive
Growth Portfolio, which he has managed since inception. Mr. Goff joined Janus
Capital in 1988 and has managed Janus Enterprise Fund since its inception. Mr.
Goff co-managed or managed Janus Venture Fund from December 1993 to February 1,
1997. He holds a Bachelor of Arts in Economics from Yale University and is a
Chartered Financial Analyst.

HELEN YOUNG HAYES is Executive Vice President and portfolio manager of Worldwide
Growth Portfolio and co-manager of International Growth Portfolio, which she has
managed or co-managed since inception. Ms. Hayes joined Janus Capital in 1987
and has managed or co-managed Janus Worldwide Fund and Janus Overseas Fund since
their inceptions. She holds a Bachelor of Arts in Economics from Yale University
and is a Chartered Financial Analyst.

SHARON S. PICHLER is Executive Vice President and portfolio manager of Money
Market Portfolio, which she has managed since inception. She also has managed
Janus Money Market Fund, Janus Government Money Market Fund and Janus Tax-
Exempt Money Market Fund since inception. She holds a Bachelor of Arts in
Economics from Michigan State University and a Master of Business Administration
from the University of Texas at San Antonio. Ms. Pichler is a Chartered
Financial Analyst.

BLAINE P. ROLLINS is Executive Vice President and portfolio manager of Balanced
Portfolio, which he has managed since May 1996 and Equity Income Portfolio,
which he has managed since inception. He is an assistant portfolio manager of
Growth Portfolio. Mr. Rollins joined Janus Capital in 1990 and has managed Janus
Balanced Fund since January 1996 and Janus Equity Income Fund since June 1996.
He has been an assistant portfolio manager of Janus Fund since January 1995. He
gained
JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998 19
<PAGE>

experience as a fixed-income trader and equity research analyst prior to
managing Balanced Portfolio. He holds a Bachelor of Science in Finance from the
University of Colorado and is a Chartered Financial Analyst.

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
is also the Executive Vice President and portfolio manager of Short-Term Bond
Portfolio which he has managed since May 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.

SCOTT W. SCHOELZEL is Executive Vice President and portfolio manager of Capital
Appreciation Portfolio, which he has managed since its inception. He is
portfolio manager of Janus Twenty Fund, which he has managed since August 1997.
He previously managed Janus Olympus Fund from its inception to August 1997. Mr.
Schoelzel joined Janus Capital in January 1994. From 1991 to 1993, Mr. Schoelzel
was a portfolio manager at Founders Asset Management, Denver, Colorado. He holds
a Bachelor of Arts in Business from Colorado College.

RONALD V. SPEAKER is Executive Vice President and portfolio manager of Flexible
Income Portfolio which he has managed or co-managed since its inception. He
previously served as co-manager of High-Yield Portfolio, from its inception to
May 1998. He managed Short-Term Bond Portfolio from its inception through April
1996. Mr. Speaker joined Janus Capital in 1986. He has managed or co-managed
Janus Flexible Income Fund since December 1991 and previously managed both Janus
Short-Term Bond Fund and Janus Federal Tax-Exempt Fund from inception through
December 1995. He previously managed or co-managed Janus High-Yield Fund from
its inception to February 1998. 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 SEC 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.

ASSISTANT PORTFOLIO MANAGER

DAVID C. DECKER is an assistant portfolio manager of the Growth Portfolio. He is
also an assistant portfolio manager of Janus Fund. He is Executive Vice
President and portfolio manager of Janus Special Situations Fund. Mr. Decker
received a Masters of Business Administration in Finance from the Fuqua School
of Business at Duke University and a Bachelor's Degree in Economics and
Political Science from Tufts University. He is a Chartered Financial Analyst.

PERSONAL INVESTING
Janus Capital does not permit portfolio managers to purchase and sell securities
for their own accounts, except under the limited exceptions contained in Janus
Capital's policy governing personal investing. Janus Capital's policy requires
investment and other personnel to conduct their personal investment activities
in a manner that Janus Capital believes is not detrimental to the Portfolios or
Janus Capital's other advisory clients. See the SAI for more detailed
information.

PORTFOLIO TRANSACTIONS
Purchases and sales of securities on behalf of each Portfolio are executed by
broker-dealers selected by Janus Capital. Broker-dealers are selected on the
basis of their ability to obtain best price and execution for a Portfolio's
transactions and recognizing brokerage, research and other services provided to
the Portfolio and to Janus Capital. Janus Capital may consider sales of shares
of the Portfolios or other Janus funds by a broker-dealer or the recommendation
of a broker-dealer to its customers that they purchase a Portfolio's shares as a
factor in the selection of broker-dealers to execute portfolio transactions.
Janus Capital may also consider payments made by brokers effecting transactions
for a Portfolio i) to the Portfolio or ii) to other persons on behalf of the
Portfolio for services provided to the Portfolio for which it would be obligated
to pay. The Portfolios' Trustees have authorized Janus Capital to place
portfolio transactions on an agency basis with a broker-dealer affiliated with
Janus Capital. When transactions for a Portfolio are effected with that
broker-dealer, the commissions payable by the Portfolio are credited against
certain Portfolio operating expenses serving to reduce those expenses. The SAI
further explains the selection of broker-dealers.

MANAGEMENT EXPENSES AND EXPENSE LIMITS
Each Portfolio pays Janus Capital a management fee which is calculated daily.
The advisory agreement with each Portfolio spells out the management fee and
other expenses that the Portfolios must pay. Each of the Portfolios is subject
to the

20 JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998
<PAGE>

following management fee schedule (expressed as an annual rate):

<TABLE>
<CAPTION>
AVERAGE DAILY
NET ASSETS ANNUAL RATE EXPENSE LIMIT
FEE SCHEDULE OF PORTFOLIO PERCENTAGE(%) PERCENTAGE(%)
- --------------------------------------------------------------------------
<S> <C> <C> <C>
Growth Portfolio First $300 Million 0.75 N/A(1)
Next $200 Million 0.70
Over $500 Million 0.65
- --------------------------------------------------------------------------
Aggressive First $300 Million 0.75 N/A(1)
Growth Next $200 Million 0.70
Portfolio Over $500 Million 0.65
- --------------------------------------------------------------------------
Capital First $300 Million 0.75 1.25(1)(3)
Appreciation Next $200 Million 0.70
Portfolio Over $500 Million 0.65
- --------------------------------------------------------------------------
International First $300 Million 0.75 N/A(1)
Growth Next $200 Million 0.70
Portfolio Over $500 Million 0.65
- --------------------------------------------------------------------------
Worldwide First $300 Million 0.75 N/A(1)
Growth Next $200 Million 0.70
Portfolio Over $500 Million 0.65
- --------------------------------------------------------------------------
Balanced First $300 Million 0.75 N/A(1)
Portfolio Next $200 Million 0.70
Over $500 Million 0.65
- --------------------------------------------------------------------------
Equity Income First $300 Million 0.75 1.25(1)(3)
Portfolio Next $200 Million 0.70
Over $500 Million 0.65
- --------------------------------------------------------------------------
Flexible Income First $300 Million 0.65 1.00(2)
Portfolio Over $300 Million 0.55
- --------------------------------------------------------------------------
High-Yield First $300 Million 0.75 1.00(2)
Portfolio Over $300 Million 0.65
- --------------------------------------------------------------------------
Money Market All Asset Levels 0.25 0.50(2)
Portfolio
- --------------------------------------------------------------------------
</TABLE>

(1) Janus Capital has agreed to reduce Growth, Aggressive Growth, Capital
Appreciation, International Growth, Worldwide Growth, Balanced and Equity
Income Portfolio's advisory fee to the extent that such fee exceeds the
effective rate of the Janus retail fund corresponding to such Portfolio.
Janus Capital may terminate this fee reduction at any time upon at least
90 days' notice to the Trustees. The effective rate is the advisory fee
calculated by the corresponding retail fund as of the last day of each
calendar quarter (expressed as an annual rate). The effective rates of
Janus Fund, Janus Enterprise Fund, Janus Olympus Fund, Janus Overseas
Fund, Janus Worldwide Fund, Janus Balanced Fund and Janus Equity Income
Fund were 0.65%, 0.72%, 0.70%, 0.66%, 0.65%, 0.73% and 0.75%,
respectively, for the quarter ended March 31, 1998.

(2) Janus Capital may terminate or modify the expense limitation at any time
upon at least 90 days' notice to the Trustees.

(3) Janus Capital has agreed to limit the expenses of Capital Appreciation
Portfolio and Equity Income Portfolio to 1.25% of average net assets
through at least May 1, 1999.

Differences in the actual management fees incurred by the Portfolios are due
primarily to variances in the asset sizes of the corresponding retail funds. As
asset size increases, the annual rate of the management fee rate declines in
accordance with the above schedule (except for the Money Market Portfolio). In
addition, the Shares of each 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. The fee schedule for the Growth and Combination Portfolios was
effective July 1, 1997.

During the most recent fiscal year (or period) the Portfolios paid the following
management fees expressed as a percentage of average net assets: Growth
Portfolio 0.65%; Aggressive Growth Portfolio 0.73%; Capital Appreciation
Portfolio 0.74%; International Growth Portfolio 0.67%; Worldwide Growth
Portfolio 0.66%; Balanced Portfolio 0.76%; and Equity Income Portfolio 0.81%.

OTHER SERVICE PROVIDERS
The following parties provide the Portfolios with administrative and other
services.

CUSTODIAN FOR PORTFOLIOS OTHER THAN
MONEY MARKET PORTFOLIO
State Street Bank and Trust Company
P.O. Box 0351
Boston, Massachusetts 02117-0351

CUSTODIAN FOR MONEY MARKET PORTFOLIO
UMB Bank, N.A.
P.O. Box 419226
Kansas City, Missouri 64141-6226

TRANSFER AGENT
Janus Service Corporation
P.O. Box 173375
Denver, Colorado 80217-3375

Janus Service Corporation is a wholly-owned subsidiary of Janus Capital.

OTHER INFORMATION
ORGANIZATION
The Trust is a "mutual fund" that was organized as a Delaware business trust on
May 20, 1993. A mutual fund is an investment vehicle that pools money from
numerous investors and invests the money to achieve a specified objective. The
Trust offers Shares in twelve separate series, ten of which are offered by this
Prospectus.

Each 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
each Portfolio are offered by separate prospectus and are available only to
participant directed qualified plans using plan service providers that are
compensated for providing distribution and/or recordkeeping and other
administrative services provided to plan participants. 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.

JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998 21
<PAGE>

requiring a shareholder vote under the 1940 Act. Separate votes are taken by
each class or Portfolio only if a matter affects or requires the vote of only
that class or Portfolio or the interest of a class or Portfolio in the matter
differs from the interest of the other class or Portfolios of the Trust. As a
shareholder, you are entitled to one vote for each share that you own.

An insurance company issuing a variable contract invested in Shares of a
Portfolio will request voting instructions from variable contract holders. Under
current law, the insurance company must vote all Shares held by the separate
account in proportion to the voting instructions received.

CONFLICTS OF INTEREST
Each Portfolio's Shares 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
Portfolios (offered through a separate prospectus) are available to certain
participant directed qualified plans. Although the Portfolios do not currently
anticipate any disadvantages to policy owners arising out of the fact that each
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 anticipated disadvantages or material irreconcilable conflicts 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 plans to withdraw its investments in one or more Portfolios or
substitute shares of another Portfolio. If this occurs, a Portfolio may be
forced to sell securities at disadvantageous prices. In addition, the Trustees
may refuse to sell shares of any Portfolio to any separate account or may
suspend or terminate the offering of a Portfolio's shares if such action is
required by law or regulatory authority or is in the best interests of that
Portfolio's shareholders. It is possible that a qualified plan investing in the
Retirement Shares of the Portfolios 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 Portfolios 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.

MASTER/FEEDER OPTION
The Trust may in the future seek to achieve any Portfolio's investment objective
by investing all of that Portfolio's assets in another investment company having
the same investment objective and substantially the same investment policies and
restrictions as those applicable to that Portfolio. Unless otherwise required by
law, this policy may be implemented by the Trustees without shareholder
approval.

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 entered
into a consulting arrangement with one of the foremost experts in Year 2000
compliance to help Janus Capital successfully achieve Year 2000 compliance.
Janus Capital does not anticipate that the move to Year 2000 will have a
material impact on its ability to continue to provide the Portfolios with
service at current levels.

THE VALUATION OF SHARES
The NAV of the Shares of a Portfolio is determined at the close of the regular
trading session of the New York Stock Exchange (the "NYSE") (normally 4:00 p.m.,
New York time) each day that the NYSE is open. NAV per Share is determined by
dividing the total value of the securities and other assets, less liabilities,
by the total number of Shares outstanding.

For the Portfolios other than the Money Market Portfolio, 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.

For the Money Market Portfolio, portfolio securities are valued at their
amortized cost. Amortized cost valuation involves valuing an instrument at its
cost and thereafter assuming a constant amortization to maturity (or such other
date as permitted by Rule 2a-7) of any discount or premium. If fluctuating
interest rates cause the market value of a portfolio to deviate more than 1/2 of
1% from the value determined on the basis of amortized cost, the Trustees will
consider whether any action, such as adjusting the Share's NAV to reflect
current market conditions, should be initiated to prevent any material dilutive
effect on shareholders.

22 JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998
<PAGE>

DISTRIBUTIONS AND TAXES

DISTRIBUTIONS
TO AVOID TAXATION OF THE PORTFOLIOS, THE INTERNAL REVENUE CODE REQUIRES EACH
PORTFOLIO TO DISTRIBUTE NET INCOME AND ANY NET GAINS REALIZED ON ITS INVESTMENTS
ANNUALLY. ORDINARY 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, IF ANY, ARE PAID TO SHAREHOLDERS AS CAPITAL GAINS
DISTRIBUTIONS.

PORTFOLIOS OTHER THAN MONEY
MARKET PORTFOLIO

Each class of each Portfolio, other than Money Market 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 a Portfolio
will automatically be reinvested into additional Shares of that Portfolio.

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

MONEY MARKET PORTFOLIO
For the Shares of Money Market Portfolio, dividends representing substantially
all of the net investment income and any net realized gains on sales of
securities are declared daily, Saturdays, Sundays and holidays included, and
distributed on the last business day of each month. If a month begins on a
Saturday, Sunday or holiday, dividends for those days are declared at the end of
the preceding month and distributed on the first business day of the month. All
distributions will be automatically reinvested in Shares of the Portfolio.

TAXES
TAXES ON DISTRIBUTIONS
Because Shares of the Portfolios 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 a 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 in the Shares depends on the
features of the variable insurance contracts purchased from a participating
insurance company. Further information may be found in the prospectus of the
separate account offering such contract.

TAXATION OF THE PORTFOLIOS
Dividends, interest and some gains received by the Portfolios on foreign
securities may be subject to withholding of foreign taxes. The Portfolios 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 election is not made, any foreign taxes paid or accrued will represent
an expense to the Portfolios which will reduce their investment income.

The Portfolios do not expect to pay any federal income or excise taxes because
they intend to meet certain requirements of the Internal Revenue Code. In
addition, each 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.

JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998 23
<PAGE>

SHAREHOLDER'S GUIDE

INVESTORS MAY NOT PURCHASE OR REDEEM SHARES OF THE PORTFOLIOS 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
SPECIFIC PORTFOLIOS AS INVESTMENT OPTIONS FOR A CONTRACT OR A QUALIFIED PLAN.

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 each Portfolio.

All investments in the Portfolios are credited to a participating insurance
company's separate account or a qualified plan immediately upon acceptance of
the investment by a Portfolio. Investments will be processed at the NAV next
determined after an order is received and accepted by a Portfolio.

Each 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 a Portfolio. Any Portfolio may
discontinue sales of its shares if management believes that a substantial
further increase may adversely affect that Portfolio's ability to achieve its
investment objective. In such event, however, it is anticipated that existing
policy owners and plan participants invested in that Portfolio would be
permitted to continue to authorize investment in such Portfolio and to reinvest
any dividends or capital gains distributions.

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 any 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. 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 COMMUNICATIONS
Shareholders will receive annual and semiannual reports including the financial
statements of the Shares of the Portfolios that they have authorized for
investment. Each report will show the investments owned by each Portfolio and
the market values thereof, as well as other information about the Portfolios and
their operations. The Trust's fiscal year ends December 31.

24 JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998
<PAGE>

APPENDIX A

GLOSSARY OF INVESTMENT TERMS
This glossary provides a more detailed description of some of the types of
securities and other instruments in which the non-Money Market Portfolios may
invest. These Portfolios may invest in these instruments to the extent permitted
by their investment objective and policies. The Portfolios are 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 Portfolios may purchase commercial paper issued
under Section 4(2) of the Securities Act of 1933.

COMMON STOCK represents a share of ownership in a company and usually carries
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.

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, a 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 income includes dividends, interest,
royalties, rents and annuities. To avoid taxes and interest that the Portfolios
must pay if these investments are profitable, the Portfolios may make various
elections permitted by the tax laws. These elections could require that the
Portfolios 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 STOCK is a class of stock that generally pays dividends at a specified
rate and has 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 a 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, a 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 a 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.

JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998 25
<PAGE>

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 a 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.

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 Portfolios do not earn interest on
such securities until settlement and bear the risk of market value fluctuations
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 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 of comparable 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 Portfolios may enter into forward currency contracts to
hedge against declines in the value of non-dollar denominated securities or to
reduce the impact of currency appreciation on purchases of non-dollar
denominated securities. They 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 Portfolios 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
Portfolios 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. A 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

26 JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998
<PAGE>

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

JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998 27
<PAGE>

APPENDIX B

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 the adviser 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>
<CAPTION>
BOND RATING EXPLANATION
- --------------------------------------------------------------
<S> <C>
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>

MOODY'S INVESTORS SERVICE, INC.

<TABLE>
<S> <C>
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 different 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 year ended December 31, 1997, the percentage of securities
holdings for the Flexible Income Portfolio and High-Yield Portfolio by rating
category based upon a weighted monthly average was:

<TABLE>
<CAPTION>
FLEXIBLE INCOME HIGH-YIELD
BONDS - S&P RATING PORTFOLIO PORTFOLIO
<S> <C> <C>
AAA 21% 0%
AA 0% 0%
A 15% 0%
BBB 12% 0%
BB 11% 2%
B 27% 74%
CCC 1% 6%
CC 0% 0%
C 0% 0%
Preferred Stock 2% 1%
Cash and Options 11% 17%
- -------------------------------------------------
TOTAL 100% 100%
- -------------------------------------------------
</TABLE>

No other Portfolio held 5% or more of its assets in bonds rated below investment
grade for the fiscal year ended December 31, 1997.

28 JANUS ASPEN SERIES PROSPECTUS MAY 1, 1998
<PAGE>

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<PAGE>

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<PAGE>
JANUS ASPEN SERIES
PROSPECTUS

Growth Portfolio
Aggressive Growth Portfolio
Capital Appreciation Portfolio
International Growth Portfolio
Worldwide GrowthPortfolio
Balanced Portfolio
Equity Income Portfolio
Flexible Income Portfolio
High-Yield Portfolio
Money Market Portfolio

[LOGO] P.O. Box 173375 o Denver, CO 80217-3375 o 1-800-525-1068

<PAGE>

JANUS ASPEN SERIES
RETIREMENT SHARES

Prospectus

MAY 1, 1998

This prospectus describes ten mutual funds with a variety of investment
objectives, including growth of capital, current income and a combination of
growth and income (the "Portfolios"). This prospectus offers a separate class of
shares of each Portfolio (collectively, the "Shares") to certain participant
directed qualified retirement plans. Janus Capital Corporation ("Janus Capital")
serves as investment adviser to each Portfolio. Janus Capital has been in the
investment advisory business for over 27 years and currently manages
approximately $80 billion in assets.

Each Portfolio is a series of Janus Aspen Series (the "Trust"). The Trust is
registered with the Securities and Exchange Commission ("SEC") as an open-end
management investment company. The Trust sells and redeems its Shares at net
asset value without any sales charges, commissions or redemption fees. Certain
Portfolios may not be available in connection with a particular qualified plan.
Contact your plan sponsor for further information.

This Prospectus contains information about the Shares that a plan participant
should consider before investing and should be read carefully and retained for
future reference. Additional information about the Shares is contained in a
Statement of Additional Information ("SAI") filed with the SEC. The SAI dated
May 1, 1998 is incorporated by reference into this Prospectus. Copies of the SAI
are available upon request and without charge by writing or calling your plan
sponsor.

FLEXIBLE INCOME PORTFOLIO AND HIGH-YIELD PORTFOLIO MAY INVEST ALL OF THEIR
ASSETS IN HIGH-YIELD CORPORATE DEBT SECURITIES, COMMONLY KNOWN AS "JUNK BONDS."
SEE "ADDITIONAL RISK FACTORS" ON PAGE 14 FOR THE RISKS ASSOCIATED WITH INVESTING
IN THESE SECURITIES.

THE PORTFOLIOS' SHARES ARE NOT BANK DEPOSITS, ARE NOT ENDORSED OR GUARANTEED BY
ANY BANK, AND ARE NOT INSURED BY THE FEDERAL DEPOSIT INSURANCE CORPORATION, THE
FEDERAL RESERVE BOARD, OR ANY OTHER GOVERNMENT AGENCY.

THESE SECURITIES HAVE NOT BEEN APPROVED BY THE SEC NOR HAS THE SEC PASSED ON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

THIS PROSPECTUS DOES NOT CONSTITUTE AN OFFER TO SELL SECURITIES IN ANY STATE OR
OTHER JURISDICTION TO ANY PERSON TO WHOM IT IS UNLAWFUL TO MAKE SUCH AN OFFER IN
SUCH STATE OR OTHER JURISDICTION.

JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998
<PAGE>

CONTENTS

<TABLE>
<S> <C>
PORTFOLIOS AT A GLANCE
Brief description of the Portfolios......................... 2
EXPENSE INFORMATION
Each Portfolio's annual operating expenses.................. 3
Financial Highlights - a summary of financial data.......... 4
PERFORMANCE TERMS
An Explanation of Performance Terms......................... 7
THE PORTFOLIOS IN DETAIL
Investment Objectives and Policies of the Growth,
Combination and Fixed-Income Portfolios.................. 8
General Portfolio Policies of the Portfolios other than
Money Market Portfolio.................................... 13
Additional Risk Factors Policies of the Portfolios other
than Money Market Portfolio............................... 14
MONEY MARKET PORTFOLIO
Investment Objectives, Policies and Techniques.............. 16
MANAGEMENT OF THE PORTFOLIOS
Investment Adviser and Investment Personnel................. 19
Personal Investing.......................................... 20
Portfolio Transactions...................................... 20
Management Expenses and Expense Limits...................... 21
Other Service Providers..................................... 21
Participant Administration Fee and Distribution Fee......... 21
Other Information........................................... 22
DISTRIBUTIONS AND TAXES
Distributions............................................... 23
Taxes....................................................... 23
SHAREHOLDER'S GUIDE
Purchases................................................... 24
Redemptions................................................. 24
Shareholder Communications.................................. 24
APPENDIX A
Glossary of Investment Terms................................ 25
APPENDIX B
Explanation of Rating Categories............................ 28
</TABLE>

JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998 1
<PAGE>

PORTFOLIOS AT A GLANCE

INTERNATIONAL GROWTH PORTFOLIO
Focus: A diversified portfolio that seeks long-term growth of capital by
investing primarily in common stocks of foreign issuers.
Inception: May 1994

Managers:Laurence J. Chang

Helen Young Hayes

HIGH-YIELD PORTFOLIO
Focus: A diversified portfolio that seeks high current income as its primary
objective. Capital appreciation is a secondary objective when consistent with
the primary objective. The Portfolio seeks to achieve these objectives by
investing primarily in high-yield/high risk fixed-income securities.
Fund Inception: May 1996
Fund Manager: Sandy R. Rufenacht

2 JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998
<PAGE>

EXPENSE INFORMATION

SHAREHOLDER TRANSACTION EXPENSES (applicable to each Portfolio)

ANNUAL OPERATING EXPENSES (after fee waivers and reductions)(1)
(expressed as a percentage of average net assets)

<TABLE>
<CAPTION>
- -------------------------------------------------------------------------------------------------------------------------
MANAGEMENT 12B-1 OTHER TOTAL OPERATING
FEE(1) FEE(2) EXPENSES(1,3) EXPENSES(1)
- -------------------------------------------------------------------------------------------------------------------------
<S> <C> <C> <C> <C> <C>

Growth Portfolio -- Retirement Shares 0.65% 0.25% 0.30% 1.20%
Aggressive Growth Portfolio -- Retirement Shares 0.73% 0.25% 0.34% 1.32%
Capital Appreciation Portfolio -- Retirement Shares(4) 0.23% 0.25% 1.25% 1.73%
International Growth Portfolio -- Retirement Shares 0.67% 0.25% 0.53% 1.45%
Worldwide Growth Portfolio -- Retirement Shares 0.66% 0.25% 0.35% 1.26%
Balanced Portfolio -- Retirement Shares 0.76% 0.25% 0.31% 1.32%
Equity Income Portfolio -- Retirement Shares(4) 0.00% 0.25% 1.49% 1.74%
Flexible Income Portfolio -- Retirement Shares 0.65% 0.25% 0.33% 1.23%
High-Yield Portfolio -- Retirement Shares 0.00% 0.25% 1.25% 1.50%
Money Market Portfolio -- Retirement Shares 0.22% 0.25% 0.53% 1.00%
------------------------------------------------------------------------------------------------------------------------
</TABLE>

(1) Management fees for Growth Portfolio, Aggressive Growth Portfolio, Capital
Appreciation Portfolio, International Growth Portfolio, Worldwide Growth
Portfolio, Balanced Portfolio and Equity Income Portfolio reflect a reduced
fee schedule effective July 1, 1997. The management fee for each Portfolio
reflects the new rate applied to net assets as of December 31, 1997. Other
expenses are based on the estimated gross expenses before expense offset
arrangements, net of fee reductions and waivers from Janus Capital for the
fiscal year ended December 31, 1997. Fee reductions for the Growth,
Aggressive Growth, Capital Appreciation, International Growth, Worldwide
Growth, Balanced and Equity Income Portfolios reduce the management fee to
the level of the corresponding Janus retail fund. Other waivers, if
applicable, are first applied against the management fee and then against
other expenses. Without such waivers or reductions, the Management Fee,
Other Expenses and Total Operating Expenses for the Shares are estimated to
be 0.74%, 0.54% and 1.28% for Growth Portfolio; 0.74%, 0.60% and 1.34% for
Aggressive Growth Portfolio; 1.14%, 1.52% and 2.66% for Capital Appreciation
Portfolio; 0.79%, 0.78% and 1.57% for International Growth Portfolio; 0.72%,
0.60% and 1.32% for Worldwide Growth Portfolio; 0.77%, 0.56% and 1.33% for
Balanced Portfolio; 0.76%, 5.43% and 6.19% for Equity Income Portfolio;
0.65%, 0.58% and 1.23% for Flexible Income Portfolio; 0.75%, 2.67% and 3.42%
for High-Yield Portfolio; and 0.25%, 0.85% and 1.10% for Money Market
Portfolio, respectively. Janus Capital may modify or terminate the waivers
or reductions at any time upon at least 90 days' notice to the Trustees.
(2) Long-term shareholders may pay more than the economic equivalent of the
maximum front-end sales charges permitted by the National Association of
Securities Dealers, Inc.
(3) Includes compensation to service providers who provide recordkeeping,
subaccounting, and other administrative services to plan participants who
invest in the Shares. See "Participant Administration Fee" for more details.

(4) Based on annualized expenses incurred during the initial fiscal period.

EXAMPLE

<TABLE>
<CAPTION>
- ----------------------------------------------------------------------------------------------------------------
1 YEAR 3 YEARS 5 YEARS 10 YEARS
- ----------------------------------------------------------------------------------------------------------------
<S> <C> <C> <C> <C> <C>

Growth Portfolio -- Retirement Shares $12 $38 $66 $145
Aggressive Growth Portfolio -- Retirement Shares $13 $42 $72 $159
Capital Appreciation Portfolio -- Retirement Shares $18 $54 $94 $204
International Growth Portfolio -- Retirement Shares $15 $46 $79 $174
Worldwide Growth Portfolio -- Retirement Shares $13 $40 $69 $152
Balanced Portfolio -- Retirement Shares $13 $42 $72 $159
Equity Income Portfolio -- Retirement Shares $18 $55 $94 $205
Flexible Income Portfolio -- Retirement Shares $13 $39 $68 $149
High-Yield Portfolio -- Retirement Shares $15 $47 $82 $179
Money Market Portfolio -- Retirement Shares $12 $38 $66 $145
---------------------------------------------------------------------------------------------------------------
</TABLE>

THE EXAMPLE SHOULD NOT BE CONSIDERED A REPRESENTATION OF PAST OR FUTURE RETURNS
OR EXPENSES WHICH MAY BE MORE OR LESS THAN THOSE SHOWN.

JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998 3
<PAGE>

FINANCIAL HIGHLIGHTS

Unless otherwise noted, the information below is for fiscal periods ending on
December 31st. The accounting firm of Price Waterhouse LLP has audited the
Portfolios' financial statements since their inception. Their report is included
in the Portfolios' Annual Report, which is incorporated by reference into the
SAI. A detailed explanation of the Financial Highlights can be found on page 6.

<TABLE>
<CAPTION>
AGGRESSIVE CAPITAL INTERNATIONAL WORLDWIDE
GROWTH GROWTH APPRECIATION GROWTH GROWTH
PORTFOLIO PORTFOLIO PORTFOLIO PORTFOLIO PORTFOLIO
RETIREMENT SHARES 1997(1) 1997(1) 1997(1) 1997(1) 1997(1)
<S> <C> <C> <C> <C> <C>
------------------------------------------------------------------------------------------------------------------------------
1. NET ASSET VALUE, BEGINNING OF PERIOD $16.18 $16.12 $10.00 $16.80 $20.72
------------------------------------------------------------------------------------------------------------------------------
INCOME FROM INVESTMENT OPERATIONS:
2. Net investment income .04 (.06) .12 .04 .14
3. Net gains or (losses) on securities (both realized and
unrealized) 2.71 4.43 2.50 1.73 2.80
------------------------------------------------------------------------------------------------------------------------------
4. Total from investment operations 2.75 4.37 2.62 1.77 2.94
------------------------------------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
5. Dividends (from net investment income) (.10) -- -- (.09) (.14)
6. Tax return of capital distributions -- -- -- -- --
7. Distributions (from capital gains) (.37) -- -- (.04) (.16)
------------------------------------------------------------------------------------------------------------------------------
8. Total distributions (.47) -- -- (.13) (.30)
------------------------------------------------------------------------------------------------------------------------------
9. NET ASSET VALUE, END OF PERIOD $18.46 $20.49 $12.62 $18.44 $23.36
------------------------------------------------------------------------------------------------------------------------------
10. Total return* 17.22% 27.11% 26.20% 10.53% 14.22%
------------------------------------------------------------------------------------------------------------------------------
11. Net assets, end of period (in thousands) $12 $13 $13 $11 $403
12. Average net assets for the period (in thousands) $11 $11 $12 $11 $11
13. Ratio of gross expenses to average net assets** 1.20%(2) 1.32%(2) 1.73%(2) 1.45%(2) 1.26%(2)
14. Ratio of net expenses to average net assets** 1.20% 1.32% 1.73% 1.45% 1.26%
15. Ratio of net investment income to average net assets** 0.29% (0.62%) 1.55% 0.26% 0.16%
16. Portfolio turnover rate** 122% 130% 101% 86% 80%
17. Average commission rate $0.0500 $0.0367 $0.0375 $0.0241 $0.0337
------------------------------------------------------------------------------------------------------------------------------
</TABLE>

* Total return not annualized for periods of less than one year.
** Annualized for periods of less than one full year.
(1) May 1, 1997 (inception) to December 31, 1997.

(2) The ratio was 1.28%, 1.34%, 2.66%, 1.57%, and 1.32%, respectively for the
Growth, Aggressive Growth, Capital Appreciation, International Growth and
Worldwide Growth Portfolios, before waiver of certain fees and/or voluntary
reduction of adviser's fees to the corresponding Janus retail fund.

<TABLE>
<CAPTION>
EQUITY INCOME FLEXIBLE INCOME
BALANCED PORTFOLIO PORTFOLIO PORTFOLIO
RETIREMENT SHARES 1997(1) 1997(1) 1997(1)
<S> <C> <C> <C>
- ----------------------------------------------------------------------------------------------------------------------
1. NET ASSET VALUE, BEGINNING OF PERIOD $15.38 $10.00 $11.41
- ----------------------------------------------------------------------------------------------------------------------
INCOME FROM INVESTMENT OPERATIONS:
2. Net investment income .27 .01 .50
3. Net gains or (losses) on securities (both realized and
unrealized) 2.30 3.41 .58
- ----------------------------------------------------------------------------------------------------------------------
4. Total from investment operations 2.57 3.42 1.08
- ----------------------------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
5. Dividends (from net investment income) (.30) -- (.61)
6. Tax return of capital distributions -- -- --
7. Distributions (from capital gains) (.18) -- (.11)
- ----------------------------------------------------------------------------------------------------------------------
8. Total distributions (.48) -- (.72)
- ----------------------------------------------------------------------------------------------------------------------
9. NET ASSET VALUE, END OF PERIOD $17.47 $13.42 $11.77
- ----------------------------------------------------------------------------------------------------------------------
10. Total return* 16.92% 34.20% 9.73%
- ----------------------------------------------------------------------------------------------------------------------
11. Net assets, end of period (in thousands) $12 $13 $11
12. Average net assets for the period (in thousands) $11 $12 $10
13. Ratio of gross expenses to average net assets** 1.32%(2) 1.74%(2) 1.23%(2)
14. Ratio of net expenses to average net assets** 1.32% 1.74% 1.23%
15. Ratio of net investment income to average net assets** 2.38% 0.07% 6.39%
16. Portfolio turnover rate** 139% 128% 119%
17. Average commission rate $0.0456 $0.0382 N/A
- ----------------------------------------------------------------------------------------------------------------------
</TABLE>

* Total return not annualized for periods of less than one year.
** Annualized for periods of less than one full year.
(1) May 1, 1997 (inception) to December 31, 1997.

(2) The ratio was 1.33%, 6.19% and 1.23%, respectively for the Balanced, Equity
Income and Flexible Income Portfolios, before waiver of certain fees and/or
voluntary reduction of adviser's fees to the effective rate of the
corresponding Janus retail fund.

4 JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998
<PAGE>

<TABLE>
<CAPTION>
MONEY MARKET
HIGH-YIELD PORTFOLIO PORTFOLIO
RETIREMENT SHARES 1997(1) 1997(1)
<S> <C> <C>
- -------------------------------------------------------------------------------------------------
1. NET ASSET VALUE, BEGINNING OF PERIOD $11.19 $1.00
- -------------------------------------------------------------------------------------------------
INCOME FROM INVESTMENT OPERATIONS:
2. Net investment income .59 .03
3. Net gains or (losses) on securities (both realized and
unrealized) .71 --
- -------------------------------------------------------------------------------------------------
4. Total from investment operations 1.30 .03
- -------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
5. Dividends (from net investment income) (.65) (.03)
6. Tax return of capital distributions -- --
7. Distributions (from capital gains) (.06) --
- -------------------------------------------------------------------------------------------------
8. Total distributions (.71) (.03)
- -------------------------------------------------------------------------------------------------
9. NET ASSET VALUE, END OF PERIOD $11.78 $1.00
- -------------------------------------------------------------------------------------------------
10. Total return* 11.96% 3.13%
- -------------------------------------------------------------------------------------------------
11. Net assets, end of period (in thousands) $11 $10
12. Average net assets for the period (in thousands) $11 $10
13. Ratio of gross expenses to average net assets** 1.50%(2) 1.00%(2)
14. Ratio of net expenses to average net assets** 1.50% 1.00%
15. Ratio of net investment income to average net assets** 7.42% 4.66%
16. Portfolio turnover rate** 299% N/A
17. Average commission rate N/A N/A
- -------------------------------------------------------------------------------------------------
</TABLE>

* Total return not annualized for periods of less than one year.
** Annualized for periods of less than one full year.
(1) May 1, 1997 (inception) to December 31, 1997.

(2) The ratio was 3.42% and 1.10% for the High-Yield and Money Market
Portfolios, before waiver of certain fees incurred by the Portfolios.

JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998 5
<PAGE>

UNDERSTANDING THE
FINANCIAL HIGHLIGHTS

NET ASSET VALUE ("NAV") is the value of a single Share of a Portfolio. It is
computed by adding the value of all of a Portfolio's investments and other
assets, subtracting any liabilities and dividing the result by the number of
shares outstanding. The difference between line 1 and line 9 in the Financial
Highlights tables represents the change in value of a Share of a Portfolio over
the fiscal period, but not its total return. The NAV of the Money Market
Portfolio's Shares is expected to be $1.00.

NET GAINS OR (LOSSES) ON SECURITIES is the per share increase or decrease in
value of the securities a Portfolio holds. A gain (or loss) is realized when
securities are sold. A gain (or loss) is unrealized when securities increase or
decrease in value but are not sold. DISTRIBUTIONS (FROM CAPITAL GAINS) are the
per share amount that a Portfolio paid from net realized gains.

RATIO OF GROSS EXPENSES TO AVERAGE NET ASSETS is the total of a Portfolio's
operating expenses before expense offset arrangements divided by its average net
assets for the stated period. RATIO OF NET EXPENSES TO AVERAGE NET ASSETS
reflects reductions in a Portfolio's expenses through the use of brokerage
commissions and uninvested cash balances earning interest or balance credits.

RATIO OF NET INVESTMENT INCOME TO AVERAGE NET ASSETS is a Portfolio's net
investment income divided by its average net assets for the stated period.

AVERAGE COMMISSION RATE is the total of a Portfolio's agency commission paid on
equity securities trades divided by the number of shares purchased and sold.

6 JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998
<PAGE>

PERFORMANCE TERMS

This section will help you understand various terms that are commonly used to
describe a Portfolio's performance. You may see references to these terms in our
newsletters or advertisements and in media articles. Newsletters and
advertisements may include comparisons of a Portfolio's performance to the
performance of other mutual funds, mutual fund averages or recognized stock
market indices. Growth Portfolio, Aggressive Growth Portfolio, Capital
Appreciation Portfolio, International Growth Portfolio, Worldwide Growth
Portfolio, Balanced Portfolio and Equity Income Portfolio generally measure
performance in terms of total return, while Flexible Income Portfolio,
High-Yield Portfolio, and Money Market Portfolio generally use yield.

CUMULATIVE TOTAL RETURN represents the actual rate of return on an investment
for a specified period. Cumulative total return is generally quoted for more
than one year (e.g., the life of a Portfolio). A cumulative total return does
not show interim fluctuations in the value of an investment.

YIELD shows the rate of income the Shares earn on investments as a percentage of
the Share price. It is calculated by dividing net investment income for a 30-day
period (7-day period for Money Market Portfolio) by the average number of Shares
entitled to receive dividends and dividing the result by the Share's NAV at the
end of such period. Yield does not include changes in NAV.

PORTFOLIO PERFORMANCE FIGURES ARE BASED UPON HISTORICAL RESULTS AND ARE NOT
INTENDED TO INDICATE FUTURE PERFORMANCE. INVESTMENT RETURNS AND NET ASSET VALUE
WILL FLUCTUATE SO THAT SHARES, WHEN REDEEMED, MAY BE WORTH MORE OR LESS THAN
THEIR ORIGINAL COST.

JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998 7
<PAGE>

THE PORTFOLIOS IN DETAIL

Each Portfolio has an investment objective and policies that are similar to
those of a Janus retail fund, as illustrated in the chart below. Although it is
anticipated that each Portfolio and its corresponding retail fund will hold
similar securities, differences in asset size and cash flow needs as well as the
relative weightings of securities selections may result in differences in
investment performance. Expenses of each Portfolio and its corresponding retail
fund are expected to differ.

Policies that are noted as "fundamental" cannot be changed without a shareholder
vote. All other policies, including each Portfolio's investment objective, are
not fundamental and may be changed by the Portfolios' Trustees without a
shareholder vote. You will be notified of any such changes that are material. If
there is a material change in a Portfolio's objective or policies, you should
consider whether that Portfolio remains an appropriate investment for your
qualified retirement plan.
EACH OF THE PORTFOLIOS HAS A SIMILAR INVESTMENT
OBJECTIVE AND SIMILAR INVESTMENT POLICIES TO AN EXISTING JANUS RETAIL FUND.

AGGRESSIVE GROWTH PORTFOLIO
The investment objective of this Portfolio is long-term growth of capital. It is
a nondiversified portfolio that pursues its investment objective by normally
investing at least 50% of its equity assets in securities issued by medium-sized
companies. Medium-sized companies are those whose market capitalizations fall
within the range of companies in the S&P MidCap 400 Index (the "MidCap Index").
Companies whose capitalization falls outside this range after the Portfolio's
initial purchase continue to be considered medium-sized companies for the
purpose of this policy. As of December 31, 1997, the MidCap Index included
companies with capitalizations between approximately $213 million and $13.7
billion. The range of the MidCap Index is expected to change on a regular basis.
Subject to the above policy, the Portfolio may also invest in smaller or larger
issuers.

8 JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998
<PAGE>

in issuers from at least five different countries, including the United States.
The Portfolio may at times invest in fewer than five countries or even a single
country.

TYPES OF INVESTMENTS
Each of these Portfolios invests primarily in common stocks of foreign and
domestic companies. However, the percentage of each Portfolio's assets invested
in common stocks will vary and each Portfolio may at times hold substantial
positions in cash equivalents or interest bearing securities. See "General
Portfolio Policies" on page 13. Each Portfolio may invest to a lesser degree in
other types of securities including preferred stocks, warrants, convertible
securities and debt securities when its portfolio manager perceives an
opportunity for capital growth from such securities or to receive a return on
idle cash. Some securities that the Portfolios purchase may be on a when-issued,
delayed delivery or forward commitment basis. The Portfolios may invest up to
25% of their assets in mortgage- and asset-backed securities, up to 10% of their
assets in zero coupon, pay-in-kind and step coupon securities, and without limit
in indexed/structured securities. No Growth Portfolio will invest 35% or more of
its assets in high-yield/high-risk securities.

Although Worldwide Growth Portfolio and International Growth Portfolio are
committed to foreign investing, Growth Portfolio, Aggressive Growth Portfolio
and Capital Appreciation Portfolio may also invest without limit in foreign
equity and debt securities. The Portfolios 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 ("PFICs"). These
Portfolios may use futures, options and other derivatives for hedging purposes
or for non-hedging purposes such as seeking to enhance return. See "Additional
Risk Factors" on page 14 for a discussion of the risks associated with foreign
investing and derivatives.

THE FOLLOWING QUESTIONS ARE DESIGNED TO HELP YOU BETTER UNDERSTAND AN INVESTMENT
IN THE GROWTH PORTFOLIOS.

Q:
A: HOW ARE COMMON STOCKS SELECTED?

Q:
A: ARE THE SAME CRITERIA USED TO SELECT FOREIGN SECURITIES?

Q:
A: WHAT IS THE MAIN RISK OF INVESTING IN A GROWTH PORTFOLIO?

Since the Growth Portfolios usually invest heavily in common stocks, the
fundamental risk is that the value of the stocks a Portfolio holds might
decrease. Stock values may fluctuate in response to the activities of an
individual company or in response to general market and/or economic conditions.
Historically, common stocks have provided greater long-term returns and have
entailed greater short-term risks than other investment choices. Smaller or
newer issuers are more likely to realize more substantial growth as well as
suffer more significant losses than larger or more established issuers.
Investments in such companies can be both more volatile and more speculative.
See "Additional Risk Factors" on page 14.

Q:
A: WHAT IS MEANT BY "MARKET CAPITALIZATION"?

Q:
A: HOW DOES A DIVERSIFIED PORTFOLIO DIFFER FROM A NONDIVERSIFIED PORTFOLIO?

JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998 9
<PAGE>

Q:
A: HOW DO THESE PORTFOLIOS TRY TO REDUCE RISK?

Diversification of a Portfolio's assets reduces the effect of any single
holding on its overall portfolio value. A Portfolio may also use futures,
options and other derivative instruments to protect its portfolio from movements
in securities' prices and interest rates. The Portfolios may use a variety of
currency hedging techniques, including forward currency contracts, to manage
exchange rate risk. See "Additional Risk Factors" on page 14. In addition, to
the extent that a Portfolio holds a larger cash position, it might not
participate in market declines to the same extent as if the Portfolio remained
more fully invested in common stocks.

COMBINATION PORTFOLIOS
Investment Objective:.............................Growth of Capital Including an
Emphasis on Income
Primary Holdings:..............................................Common Stocks and
Income-Producing Securities
Shareholder's Investment Horizon:......................................Long-Term

TYPES OF INVESTMENTS
Both of the Combination Portfolios may invest in a combination of common stocks,
preferred stocks, convertible securities, debt securities and other fixed-income
securities. The Combination Portfolios may invest in the types of investments
previously described under "Growth Portfolios" on page 8. Although each of the
Combination Portfolios places some emphasis on the income objective, investors
should keep in mind that the Combination Portfolios are not designed to produce
a consistent level of income.

THE FOLLOWING QUESTIONS ARE DESIGNED TO HELP YOU BETTER UNDERSTAND AN INVESTMENT
IN THE COMBINATION PORTFOLIOS.

Q:
A: HOW DO THE COMBINATION PORTFOLIOS DIFFER FROM EACH OTHER?

Q:
A: HOW DOES EQUITY INCOME PORTFOLIO TRY TO LIMIT PORTFOLIO VOLATILITY?

Equity Income Portfolio seeks to provide a lower level of volatility than
the stock market at large, as measured by the S&P 500. The lower
volatility sought by this Portfolio is expected to result primarily from
investments in dividend-paying common stocks and other equity securities
characterized by relatively greater price stability. The greater price stability
sought by Equity Income Portfolio may be characteristic of companies that
generate above average free cash flows. A company may use free cash flows for a
number of purposes including commencing or increasing dividend payments,
repurchasing its own stock or retiring outstanding debt. The portfolio manager
also considers growth potential in selecting this Portfolio's securities and may
hold securities selected solely for their growth potential.

Q:
A: HOW ARE EQUITY SECURITIES SELECTED?

The growth component of Balanced Portfolio is expected to consist
primarily of common stocks and Equity Income Portfolio invests
substantially all of its assets in common stocks. The selection criteria for
common stocks are described on page 9. Because income is a part of the
investment objective of the Combination Portfolios, a portfolio manager may
consider dividend-paying characteristics to a greater degree in selecting equity
securities for these Portfolios. The Combination Portfolios may also find
opportunities for capital growth from debt securities because of the anticipated
changes in interest rates, credit standing, currency relationships or other
factors.

Q:
HOW ARE ASSETS ALLOCATED BETWEEN THE GROWTH AND INCOME COMPONENTS OF
A: BALANCED PORTFOLIO?

10 JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998
<PAGE>

then available or expected on income-producing securities, the Portfolio will
place a greater emphasis on the growth component.
Q:
WHAT TYPES OF SECURITIES MAKE UP THE INCOME COMPONENT OF BALANCED
A: PORTFOLIO?

The income component of the Balanced Portfolio will consist of securities
that the portfolio manager believes have income potential. Such securities
may include equity securities, convertible securities and all types of debt
securities. Equity securities may be included in the income component of the
Balanced Portfolio if they currently pay dividends or a portfolio manager
believes they have potential for either increasing their dividends or commencing
dividends, if none are currently paid.

FLEXIBLE INCOME PORTFOLIO AND HIGH-YIELD PORTFOLIO ARE DESIGNED FOR THOSE
INVESTORS WHO PRIMARILY SEEK CURRENT INCOME.

HIGH-YIELD PORTFOLIO
The primary investment objective of this Portfolio is to obtain high current
income. Capital appreciation is a secondary objective when consistent with its
primary objective. Capital appreciation may result, for example, from an
improvement in the credit standing of an issuer whose securities are held by
this Portfolio or from a general lowering of interest rates, or both. This
Portfolio pursues its objectives by investing primarily in high-yield/high-risk
fixed-income securities. This Portfolio will normally invest at least 65% of its
total assets in those securities. In addition, the Portfolio may invest in all
of the types of securities previously described under Flexible Income Portfolio.

TYPES OF INVESTMENTS
In addition to the investment policies described above, each Fixed-Income
Portfolio may purchase securities on a when-issued, delayed delivery or forward
commitment basis. In addition, each Portfolio may use futures, options and other
derivatives for hedging purposes or for non-hedging purposes, such as seeking to
enhance return. See "Additional Risk Factors" on page 14. When its portfolio
manager is unable to locate investment opportunities with favorable risk/reward
characteristics, the cash position of any Portfolio may increase and the
Portfolio may have substantial holdings of cash or cash equivalent short-term
obligations. See "General Portfolio Policies" on page 13.

JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998 11
<PAGE>

THE FOLLOWING QUESTIONS ARE DESIGNED TO HELP YOU BETTER UNDERSTAND AN INVESTMENT
IN THE FIXED-INCOME PORTFOLIOS.

Q:
A: HOW DO INTEREST RATES AFFECT THE VALUE OF MY INVESTMENT?

A fundamental risk associated with any fund that invests in fixed-income
securities (e.g., a bond fund) is the risk that the value of the
securities it holds will rise or fall as interest rates change. 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 portfolio may react to interest rate changes.

Q:
A: WHAT IS MEANT BY A PORTFOLIO'S "AVERAGE-WEIGHTED EFFECTIVE MATURITY"?

Q:
A: WHAT IS MEANT BY A 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 fund is calculated by
averaging the duration of bonds held by a Portfolio with each duration
"weighted" according to the percentage of net assets that it represents. Because
duration accounts for interest payments, a Portfolio's duration is usually
shorter than its average maturity.

Q:
HOW DO FLEXIBLE INCOME PORTFOLIO AND HIGH-YIELD PORTFOLIO MANAGE INTEREST
A: RATE RISK?

Q:
A: WHAT IS MEANT BY "CREDIT QUALITY"?

Credit quality measures the likelihood that the issuer will meet its
obligations on a bond. One of the fundamental risks associated with all
bond 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.

Q:
A: HOW IS CREDIT QUALITY MEASURED?

Q:
A: WHAT IS A HIGH-YIELD/HIGH-RISK SECURITY?

Q:
A: WHAT RISKS DO HIGH-YIELD/HIGH-RISK SECURITIES PRESENT?

The default rate of lower quality debt securities is likely to be higher when
issuers have difficulty meeting projected goals or obtaining additional
financing.

12 JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998
<PAGE>

This could occur during economic recessions or periods of high interest rates.
In addition, there may be a smaller market for lower quality securities than for
higher quality securities, making lower quality securities more difficult to
sell promptly at an acceptable price.

The junk bond market can experience sudden and sharp price swings. Because
Flexible Income portfolio and High-Yield Portfolio may invest a significant
portion of their portfolios in high-yield/high-risk securities, investors in
such Portfolios should be willing to tolerate a corresponding increase in the
risk of significant and sudden changes in NAV.

GENERAL PORTFOLIO POLICIES OF PORTFOLIOS OTHER THAN MONEY MARKET PORTFOLIO
Unless otherwise stated, each of the following policies applies to all of the
Portfolios other than the Money Market Portfolio. The percentage limitations
included in these policies and elsewhere in this Prospectus apply only at the
time of purchase of the security. For example, if a 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 a Portfolio's manager believes that market conditions are not favorable for
profitable investing or when the portfolio manager is otherwise unable to locate
favorable investment opportunities, a Portfolio's investments may be hedged to a
greater degree and/or its cash or similar investments may increase. In other
words, the Portfolios do not always stay fully invested in stocks and bonds.
Cash or similar investments are a residual -- they represent the assets that
remain after a portfolio manager has committed available assets to desirable
investment opportunities. Partly because the portfolio managers act
independently of each other, the cash positions of the Portfolios may vary
significantly. Larger hedged positions and/or larger cash positions may serve as
a means of preserving capital in unfavorable market conditions.

DIVERSIFICATION
The Investment Company Act of 1940 (the "1940 Act") classifies investment
companies as either diversified or nondiversified. All of the Portfolios (except
Aggressive Growth Portfolio and Capital Appreciation Portfolio) qualify as
diversified funds under the 1940 Act and are subject to the following
diversification requirements:

- - As a fundamental policy, no Portfolio may own more than 10% of the outstanding
voting shares of any issuer.

- - No Portfolio will invest more than 25% of its total assets in a single issuer
(other than U.S. government securities).

INTERNAL REVENUE SERVICE (IRS) LIMITATIONS
In addition to the diversification requirements stated above, because a class of
shares of the Portfolios are sold in connection with variable insurance
contracts, each Portfolio intends to comply with the diversification
requirements currently imposed by the IRS on separate accounts of insurance
companies as a condition of maintaining the tax-deferred status of variable
contracts.

INDUSTRY CONCENTRATION
As a fundamental policy, no Portfolio will invest 25% or more of its total
assets in any particular industry (excluding U.S. government securities).

To a limited extent, a Portfolio may purchase securities in anticipation of
relatively short-term price gains. A Portfolio may also sell one security and
simultaneously purchase the same or a

JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998 13
<PAGE>

comparable security to take advantage of short-term differentials in bond yields
or securities prices. 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.

BORROWING AND LENDING
Each Portfolio may borrow money and lend securities or other assets, as follows:

- - Each Portfolio may borrow money for temporary or emergency purposes in amounts
up to 25% of its total assets.

- - Each Portfolio may mortgage or pledge securities as collateral for borrowings
in amounts up to 15% of its net assets.

- - As a fundamental policy, each Portfolio may lend securities or other assets
if, as a result, no more than 25% of its total assets would be lent to other
parties.

ADDITIONAL RISK FACTORS OF PORTFOLIOS OTHER THAN MONEY MARKET PORTFOLIO

FOREIGN SECURITIES
INVESTMENTS IN FOREIGN SECURITIES, INCLUDING THOSE OF FOREIGN GOVERNMENTS, MAY
INVOLVE GREATER RISKS THAN INVESTING IN COMPARABLE DOMESTIC SECURITIES.

Securities of some foreign companies and governments may be traded in the United
States, but many foreign securities are traded primarily in foreign markets. The
risks of foreign investing include:

- - POLITICAL AND ECONOMIC RISK. Foreign investments may be subject to heightened
political and economic risks, particularly in underdeveloped or developing
countries which may have relatively unstable governments 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 a Portfolio's assets
from that country. The Portfolios may invest in emerging market countries.
Emerging market countries involve greater risks such as immature economic
structures, national policies restricting investments by foreigners, and
different legal systems.

- - TRANSACTION COSTS. Transaction costs of buying and selling foreign securities,
including brokerage, tax and custody costs, are generally higher than those
involved in domestic transactions.

INVESTMENTS IN SMALLER COMPANIES
SMALLER OR NEWER COMPANIES MAY SUFFER MORE SIGNIFICANT LOSSES AS WELL AS REALIZE
MORE SUBSTANTIAL GROWTH THAN LARGER OR MORE ESTABLISHED ISSUERS.

14 JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998
<PAGE>

securities of larger or more established issuers, and may be subject to wider
price fluctuations. Investments in such companies tend to be more volatile and
somewhat more speculative.

The use of derivative instruments exposes the Portfolios to additional
investment risks and transaction costs. Risks inherent in the use of derivative
instruments include:

- - the risk that interest rates, securities prices and currency markets will not
move in the direction that a portfolio manager anticipates;

- - imperfect correlation between the price of derivative instruments and
movements in the prices of the securities, interest rates or currencies being
hedged;

- - the fact that skills needed to use these strategies are different from those
needed to select portfolio securities;

- - inability to close out certain hedged positions to avoid adverse tax
consequences;

Although the Portfolios' managers believe the use of derivative instruments will
benefit the Portfolios, a Portfolio's performance could be worse than if the
Portfolio had not used such instruments if the portfolio manager's judgement
proves incorrect.

The market for lower quality securities is generally less liquid than the market
for higher quality securities. Adverse publicity and investor perceptions as
well as new or proposed laws may also have a greater negative impact on the
market for lower quality securities. Unrated debt, while not necessarily of
lower quality than rated securities, may not have as broad a market as rated
securities. Sovereign debt of foreign governments is generally rated by country.
Because these ratings do not take into account individual factors relevant to
each issue and may not be updated regularly, Janus Capital may treat such
securities as unrated debt.

JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998 15
<PAGE>

Please refer to Appendix B for a description of bond rating categories.

SPECIAL SITUATIONS
Each Portfolio may invest in "special situation" from time to time. A special
situation arises when, in the opinion of a 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.
Investment in special situations may carry an additional risk of loss in the
event that the anticipated development does not occur or does not attract the
expected attention.

See Appendix A for risks associated with certain other investments.

MONEY MARKET PORTFOLIO IS DESIGNED FOR INVESTORS WHO PRIMARILY SEEK MAXIMUM
CURRENT INCOME TO THE EXTENT CONSISTENT WITH STABILITY OF CAPITAL.

MONEY MARKET PORTFOLIO
INVESTMENT OBJECTIVE
The Portfolio's investment objective is to seek maximum current income to the
extent consistent with stability of capital. There can be no assurance that the
Portfolio will achieve its investment objective or be able to maintain a stable
net asset value of $1.00 per share.

INVESTMENT POLICIES
The Portfolio will invest only in eligible high quality, short-term money market
instruments that present minimal credit risks, as determined by Janus Capital,
the Portfolio's investment adviser, pursuant to procedures adopted by the
Trustees. The Portfolio may invest only in U.S. dollar-denominated instruments
that have a remaining maturity of 397 days or less (as calculated pursuant to
Rule 2a-7 under the 1940 Act) and will maintain a dollar-weighted average
portfolio maturity of 90 days or less.

Except to the limited extent permitted by Rule 2a-7 and except for U.S.
Government Securities (as defined below), the Portfolio will not invest more
than 5% of its total assets in the securities of any one issuer. Investment in
demand features, guarantees and other types of instruments or features are
subject to the diversification limits under Rule 2a-7. The Portfolio may not
invest more than 25% of its total assets in any one industry, except that this
limit does not apply to U.S. Government Securities, bank obligations or
municipal securities. To ensure adequate liquidity, the Portfolio may not invest
more than 10% of its net assets in illiquid securities, including repurchase
agreements maturing in more than seven days (unless subject to a demand feature)
and certain time deposits that are subject to early withdrawal penalties and
mature in more than seven days. Janus Capital determines and monitors the
liquidity of portfolio securities under the supervision of the Trustees.

RATINGS
High quality money market instruments include those that (i) are rated (or, if
unrated, are issued by an issuer with comparable outstanding short-term debt
that is rated) in one of the two highest rating categories for short-term debt
by any two nationally recognized statistical rating organizations ("NRSROs") or,
if only one NRSRO has issued a rating, by that NRSRO or (ii) are otherwise
unrated and determined by Janus Capital to be of comparable quality. The
Portfolio will invest at least 95% of its total assets in securities in the
highest rating category (as determined pursuant to Rule 2a-7). Descriptions of
the rating categories of Standard & Poor's, Moody's and certain other NRSROs are
contained in Appendix B. A further description of the Money Market Portfolio's
investment policies is included in the Money Market Portfolio's SAI.

16 JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998
<PAGE>

exemption therefrom. Pursuant to Section 4(2) of the 1933 Act or Rule 144A
adopted under the 1933 Act, however, some of these securities are eligible for
resale to institutional investors, and accordingly, Janus Capital may determine
that a liquid market exists for such a security pursuant to guidelines adopted
by the Trustees.

U.S. GOVERNMENT SECURITIES
The Portfolio may invest without limit in U.S. Government Securities. U.S.
Government Securities shall have the meaning set forth in the 1940 Act. The 1940
Act defines U.S. Government Securities to include securities issued or
guaranteed by the U.S. government, its agencies and instrumentalities. U.S.
Government Securities may also include repurchase agreements collateralized by
and municipal securities escrowed with or refunded with U.S. Government
Securities. U.S. Government Securities in which the Portfolio may invest include
U.S. Treasury securities and obligations issued or guaranteed by U.S. government
agencies and instrumentalities that are backed by the full faith and credit of
the U.S. government, such as those guaranteed by the Small Business
Administration or issued by the Government National Mortgage Association. In
addition, U.S. Government Securities in which the Portfolio may invest include
securities supported primarily or solely by the creditworthiness of the issuer,
such as securities of the Federal National Mortgage Association, the Federal
Home Loan Mortgage Corporation and the Tennessee Valley Authority. There is no
guarantee that the U.S. government will support securities not backed by its
full faith and credit. Accordingly, although these securities have historically
involved little risk of loss of principal if held to maturity, they may involve
more risk than securities backed by the full faith and credit of the U.S.
government.

DEMAND FEATURES
The Portfolio may invest in securities that are subject to puts and stand-by
commitments ("demand features"). Demand features give the Portfolio the right to
resell securities at

JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998 17
<PAGE>

specified periods prior to their maturity dates to the seller or to some third
party at an agreed-upon price or yield. Securities with demand features may
involve certain expenses and risks, including the inability of the issuer of the
instrument to pay for the securities at the time the instrument is exercised,
non-marketability of the instrument and differences between the maturity of the
underlying security and the maturity of the instrument. Securities may cost more
with demand features than without them. Demand features can serve three
purposes: to shorten the maturity of a variable or floating rate security, to
enhance the instrument's credit quality and to provide a source of liquidity.
Demand features are often issued by third party financial institutions,
generally domestic and foreign banks. Accordingly, the credit quality and
liquidity of the Portfolio's investments may be dependent in part on the credit
quality of the banks supporting its investments. This will result in exposure to
risks pertaining to the banking industry, including the foreign banking
industry. Brokerage firms and insurance companies also provide certain liquidity
and credit support.

REPURCHASE AGREEMENTS
The Portfolio may seek additional income by entering into collateralized
repurchase agreements. Repurchase agreements are transactions in which the
Portfolio purchases securities and simultaneously commits to resell those
securities to the seller at an agreed-upon price on an agreed-upon future date.
The resale price reflects a market rate of interest that is not related to the
coupon rate or maturity of the purchased securities.

18 JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998
<PAGE>

MANAGEMENT OF
THE PORTFOLIOS

TRUSTEES

The Trustees oversee the business affairs of the Trust and are responsible for
major decisions relating to each Portfolio's investment objectives and policies.
The Trustees delegate the day-to-day management of the Portfolios to the
officers of the Trust and meet at least quarterly to review the Portfolios'
investment policies, performance, expenses and other business affairs.

The Portfolios pay all of their expenses not assumed by Janus Capital, including
transfer agent and custodian fees and expenses, legal and auditing fees,
registration fees and expenses, and independent Trustees' fees and expenses and
certain other expenses. Service providers to qualified plans that purchase the
Shares receive fees for providing recordkeeping, subaccounting and other
administrative services, as described under "Participant Administration Fee and
Distribution Fee" on page 21.

INVESTMENT PERSONNEL
PORTFOLIO MANAGERS

SHARON S. PICHLER is Executive Vice President and portfolio manager of Money
Market Portfolio, which she has managed since inception. She has also managed
Janus Money Market Fund, Janus Government Money Market Fund and Janus Tax-
Exempt Money Market Fund since inception. She holds a Bachelor of Arts in
Economics from Michigan State University and a Master of Business Administration
from the University of Texas at San Antonio. Ms. Pichler is a Chartered
Financial Analyst.

BLAINE P. ROLLINS is Executive Vice President and portfolio manager of Balanced
Portfolio, which he has managed since May

JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998 19
<PAGE>

1996 and Equity Income Portfolio, which he has managed since inception. He is an
assistant portfolio manager of Growth Portfolio. Mr. Rollins joined Janus
Capital in 1990 and has managed Janus Balanced Fund since June 1996 and Janus
Equity Income Fund since May 1996. He has been an assistant portfolio manager of
Janus Fund since January 1995. He gained experience as a fixed-income trader and
equity research analyst prior to managing Balanced Portfolio. He holds a
Bachelor of Science in Finance from the University of Colorado and is a
Chartered Financial Analyst.

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
is also the Executive Vice President and portfolio manager of Short-Term Bond
Portfolio, which he has managed since May 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.

ASSISTANT PORTFOLIO MANAGER

20 JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998
<PAGE>

<TABLE>
<CAPTION>
AVERAGE DAILY
NET ASSETS ANNUAL RATE EXPENSE LIMIT
FEE SCHEDULE OF PORTFOLIO PERCENTAGE(%) PERCENTAGE(%)
- ------------------------------------------------------------------------
<S> <C> <C> <C>
Growth Portfolio First $300 Million 0.75 N/A(1)
Next $200 Million 0.70
Over $500 Million 0.65
- ------------------------------------------------------------------------
Aggressive First $300 Million 0.75 N/A(1)
Growth Next $200 Million 0.70
Portfolio Over $500 Million 0.65
- ------------------------------------------------------------------------
Capital First $300 Million 0.75 1.25(1)(3)
Appreciation Next $200 Million 0.70
Portfolio Over $500 Million 0.65
- ------------------------------------------------------------------------
International First $300 Million 0.75 N/A(1)
Growth Next $200 Million 0.70
Portfolio Over $500 Million 0.65
- ------------------------------------------------------------------------
Worldwide First $300 Million 0.75 N/A(1)
Growth Next $200 Million 0.70
Portfolio Over $500 Million 0.65
- ------------------------------------------------------------------------
Balanced First $300 Million 0.75 N/A(1)
Portfolio Next $200 Million 0.70
Over $500 Million 0.65
- ------------------------------------------------------------------------
Equity Income First $300 Million 0.75 1.25(1)(3)
Portfolio Next $200 Million 0.70
Over $500 Million 0.65
- ------------------------------------------------------------------------
Flexible Income First $300 Million 0.65 1.00(2)
Portfolio Over $300 Million 0.55
- ------------------------------------------------------------------------
High-Yield First $300 Million 0.75 1.00(2)
Portfolio Over $300 Million 0.65
- ------------------------------------------------------------------------
Money Market All asset levels 0.25 0.50(2)
Portfolio
- ------------------------------------------------------------------------
</TABLE>

(1) Janus Capital has agreed to reduce Growth, Aggressive Growth, Capital
Appreciation, International Growth, Worldwide Growth, Balanced and Equity
Income Portfolio's advisory fee to the extent that such fee exceeds the
effective rate of the Janus retail fund corresponding to such Portfolio.
Janus Capital may terminate this fee reduction at any time upon at least
90 days' notice to the Trustees. The effective rate is the advisory fee
calculated by the corresponding retail fund as of the last day of each
calendar quarter (expressed as an annual rate). The effective rate of
Janus Fund, Janus Enterprise Fund, Janus Olympus Fund, Janus Overseas
Fund, Janus Worldwide Fund, Janus Balanced Fund and Janus Equity Income
Fund were 0.65%, 0.72%, 0.70%, 0.66%, 0.65%, 0.73% and 0.75%,
respectively, for the quarter ended March 31, 1998.

(2) Janus Capital may terminate or modify the expense limitation at any time
upon at least 90 days' notice to the Trustees. The Distribution Fee and
Participant Administration Fee described on this page are not included in
the expense limit.

(3) Janus Capital has agreed to limit the expenses of Capital Appreciation
Portfolio and Equity Income Portfolio to 1.25% of average net assets
through at least May 1, 1999. The Distribution Fee and Participant
Administration Fee described on this page are not included in the expense
limit.

Differences in the actual management fees incurred by the Portfolios are due
primarily to variances in the asset sizes of the corresponding retail funds. As
asset size increases, the annual rate of the management fee declines in
accordance with the above schedule (except for the Money Market Portfolio). In
addition, the Shares of each Portfolio incur expenses not assumed by Janus
Capital, including the participant administration fee and distribution fee
described below, 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. The fee schedule for the Growth and Combination Portfolios was
effective July 1, 1997.

OTHER SERVICE PROVIDERS
The following parties provide the Portfolios with administrative and other
services.

CUSTODIAN FOR PORTFOLIOS OTHER THAN
MONEY MARKET PORTFOLIO
State Street Bank and Trust Company
P.O. Box 0351
Boston, Massachusetts 02117-0351

CUSTODIAN FOR MONEY MARKET PORTFOLIO
UMB Bank, N.A.
P.O. Box 419226
Kansas City, Missouri 64141-6226

TRANSFER AGENT
Janus Service Corporation
P.O. Box 173375
Denver, Colorado 80217-3375

DISTRIBUTOR
Janus Distributors, Inc.
100 Fillmore Street
Denver, Colorado 80206-4928

Janus Service Corporation and Janus Distributors, Inc. are wholly-owned
subsidiaries of Janus Capital.

PARTICIPANT ADMINISTRATION FEE AND
DISTRIBUTION FEE
PARTICIPANT ADMINISTRATION FEE
Janus Service Corporation ("Janus Service"), the Trust's transfer agent,
receives a participant administration fee at an annual rate of up to .25% of the
average daily net assets of the Shares of each Portfolio for providing or
procuring recordkeeping, subaccounting and other administrative services to plan
participants who invest in the Shares. Janus Service expects to use this fee to
compensate qualified plan service providers for providing these services.

DISTRIBUTION FEE
Under a distribution and service plan ("Plan") adopted in accordance with Rule
12b-1 under the 1940 Act, the Shares may pay Janus Distributors, Inc. ("JDI"),
the distributor of the

JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998 21
<PAGE>

Shares, a fee at an annual rate of up to 0.25% of the average daily net assets
of the Shares of a Portfolio. Under the terms of the Plan, the Trust is
authorized to make payments to JDI for remittance to qualified plan service
providers as compensation for distribution and shareholder servicing performed
by such service providers. The Plan permits the compensation of such service
providers at an annual rate of up to .25% of the average daily net assets of the
Shares of a Portfolio for activities which are primarily intended to result in
sales of the Shares, including but not limited to preparing, printing and
distributing prospectuses, SAIs, shareholder reports, and educational materials
to prospective and existing plan participants; responding to inquiries by
qualified plan participants; receiving and answering correspondence; and similar
activities.

Each Portfolio currently offers two classes of shares, one of which, the
Retirement Shares are offered pursuant to this Prospectus. The Shares offered by
this prospectus are available only to participant directed qualified plans using
plan service providers that are compensated for providing distribution and/or
recordkeeping and other administrative services provided to plan participants.
Institutional Shares of each Portfolio are available only in connection with
investment in and payments under variable insurance contracts as well as certain
qualified retirement plans. 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 Institutional Shares, please call 1-800-525-0020.

SHAREHOLDER MEETINGS AND VOTING RIGHTS
The Trust does not intend to hold annual shareholder meetings. However, special
meetings may be called for a specific class or Portfolio or for the Trust as a
whole for purposes such as electing or removing Trustees, terminating or
reorganizing the Trust, changing fundamental policies, or for any other purpose
requiring a shareholder vote under the 1940 Act. Separate votes are taken by
each class or Portfolio, only if a matter affects or requires the vote of only
that class or Portfolio or the interest of a class or Portfolio in the matter
differs from the interest of the other class or Portfolios of the Trust. As a
shareholder, you are entitled to one vote for each share that you own.

CONFLICTS OF INTEREST
The Shares offered by this prospectus are available only to certain qualified
plans. Institutional Shares of the Portfolios (offered through a separate
prospectus) are available to variable annuity and variable life separate
accounts of insurance companies that are unaffiliated with Janus Capital, as
well as certain qualified retirement plans. Although the Portfolios do not
currently anticipate any disadvantages to policy owners or plan participants
will develop arising out of the fact that each 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 anticipated disadvantages or
material irreconcilable conflicts 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 plans to withdraw
its investments in one or more Portfolios or substitute Shares of another
Portfolio. If this occurs, a Portfolio may be forced to sell securities at
disadvantageous prices. In addition, the Trustees may refuse to sell shares of
any Portfolio to any separate account or qualified plan or may suspend or
terminate the offering of a Portfolio's shares if such action is required by law
or regulatory authority or is in the best interests of that Portfolio's
shareholders.

THE VALUATION OF SHARES
The net asset value ("NAV") of the Shares of a Portfolio is determined at the
close of the regular trading session of the New York Stock Exchange (the "NYSE")
(normally 4:00 p.m., New York time) each day that the NYSE is open. NAV per
Share is determined by dividing the total value of the securities and other
assets, less liabilities, by the total number of Shares outstanding.

For the Money Market Portfolio, portfolio securities are valued at their
amortized cost. Amortized cost valuation involves valuing an instrument at its
cost and thereafter assuming a constant amortization to maturity (or such other
date as permitted by Rule 2a-7) of any discount or premium. If fluctuating
interest rates cause the market value of the portfolio to deviate more than 1/2
of 1% from the value determined on the basis of amortized cost, the Trustees
will consider whether any action, such as adjusting the Share's NAV to reflect
current market conditions, should be initiated to prevent any material dilutive
effect on shareholders.

22 JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998
<PAGE>

DISTRIBUTIONS AND TAXES

PORTFOLIOS OTHER THAN MONEY
MARKET PORTFOLIO
Each class of each Portfolio, other than Money Market Portfolio, makes
semiannual 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 a Portfolio
will automatically be reinvested into additional Shares of that Portfolio.

HOW DISTRIBUTIONS AFFECT NAV
Distributions other than daily income dividends, are paid to shareholders as of
the record date of the distribution of a Portfolio, regardless of how long the
shares have been held. Undistributed income and realized gains are included in
the daily NAV of a Portfolio's Shares. The Share price drops by the amount of
the distribution, net of any subsequent market fluctuations. For example, assume
that on December 31, the Shares of Growth Portfolio declared a dividend in the
amount of $0.25 per share. If the price of Growth 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 the Shares may be purchased only through qualified plans, it is
anticipated that any income dividends or capital gains distributions made by the
Shares of a Portfolio will be exempt from current taxation if left to accumulate
within the qualified plan. Generally, withdrawals from qualified plans 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 in the Shares depends on the features of
your qualified plan. For further information, contact your plan sponsor.

TAXATION OF THE PORTFOLIOS
Dividends, interest and some gains received by the Portfolios on foreign
securities may be subject to withholding of foreign taxes. The Portfolios 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 election is not made, any foreign taxes paid or accrued will represent
an expense to the Portfolios which will reduce their investment income.

The Portfolios do not expect to pay any federal income or excise taxes because
they intend to meet certain requirements of the Internal Revenue Code. In
addition, because a class of shares of each Portfolio are sold in connection
with variable annuity contracts and variable life insurance contracts, each
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.

JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998 23
<PAGE>

SHAREHOLDER'S GUIDE

INVESTORS MAY NOT PURCHASE OR REDEEM SHARES OF THE PORTFOLIOS DIRECTLY. SHARES
MAY BE PURCHASED OR REDEEMED ONLY THROUGH QUALIFIED RETIREMENT PLANS. REFER TO
YOUR PLAN DOCUMENTS FOR INSTRUCTIONS ON HOW TO SELECT SPECIFIC PORTFOLIOS AS
INVESTMENT OPTIONS FOR A QUALIFIED PLAN.

PURCHASES
Purchases of Shares may be made only by qualified plans. Refer to your plan
documents for information on how to invest in the Shares each Portfolio.

All investments in the Portfolios are credited to a qualified plan immediately
upon acceptance of the investment by a Portfolio. Investments will be processed
at the NAV next determined after an order is received and accepted by a
Portfolio.

Each 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 a Portfolio. Any Portfolio may
discontinue sales of its shares if management believes that a substantial
further increase may adversely affect that Portfolio's ability to achieve its
investment objective. In such event, however, it is anticipated that existing
plan participants invested in that Portfolio would be permitted to continue to
authorize investment in such Portfolio and to reinvest any dividends or capital
gains distributions. The Portfolios may discontinue sales to a qualified plan
and require plan participants with existing investments in the Shares to redeem
those investments if the plan loses (or in the opinion of Janus Capital, is at
risk of losing) its qualified plan status under the Internal Revenue Code.

REDEMPTIONS
Redemptions, like purchases, may be effected only through qualified plans.
Please refer to the appropriate plan documents for details.

Shares of any 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. Redemption proceeds will normally be wired to
the qualified plan the business day following receipt of the redemption order,
but in no event later than seven days after receipt of such order.

24 JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998
<PAGE>

APPENDIX A

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.

JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998 25
<PAGE>

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

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

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 Portfolios do not earn interest on
such securities until settlement and bear the risk of market value fluctuations
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 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 securities generally fluctuates
more in response to changes in interest rates than interest-paying securities of
comparable 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 Portfolios 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. They may also enter into
forward contracts to purchase or sell securities or other financial indices.

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

26 JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998
<PAGE>

JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998 27
<PAGE>

APPENDIX B

EXPLANATION OF RATING CATEGORIES

STANDARD & POOR'S RATINGS SERVICES

<TABLE>
<CAPTION>
BOND RATING EXPLANATION
- --------------------------------------------------------------
<S> <C>
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>

MOODY'S INVESTORS SERVICE, INC.

SECURITIES HOLDINGS BY RATING CATEGORY

No other Portfolio held 5% or more of its assets in bonds rated below investment
grade for the fiscal year ended December 31, 1997.

28 JANUS ASPEN SERIES PROSPECTUS -- RETIREMENT SHARES MAY 1, 1998
<PAGE>

This page intentionally left blank.
<PAGE>
JANUS ASPEN SERIES
RETIREMENT SHARES
PROSPECTUS

[LOGO] P.O. Box 173375 o Denver, CO 80217-3375 o 1-800-525-0020

Janus Distributors, Inc. Member NASD (5/98)

<PAGE>

JANUS ASPEN SERIES
SHORT-TERM BOND PORTFOLIO

Prospectus

MAY 1, 1998

Short-Term Bond Portfolio (the "Portfolio") is a diversified mutual fund that
seeks a high level of current income while minimizing interest rate risk by
investing in shorter term fixed-income securities. Its average weighted maturity
is normally less than three years. The Portfolio pursues its objective by
investing primarily in short- and intermediate-term fixed-income securities.

THE PORTFOLIO IS CLOSED TO NEW INVESTORS EFFECTIVE MAY 1, 1998. JANUS CAPITAL
CORPORATION ("JANUS CAPITAL") ANTICIPATES LIQUIDATION OF THE PORTFOLIO SOON
AFTER REQUIRED REGULATORY APPROVALS ARE OBTAINED. IN ANTICIPATION OF THE
PROPOSED LIQUIDATION OF THE PORTFOLIO, THE PORTFOLIO MAY BEGIN TO SHORTEN ITS
DOLLAR-WEIGHTED AVERAGE PORTFOLIO EFFECTIVE MATURITY AND TO INVEST IN
LOWER-YIELDING MORE LIQUID SECURITIES AND CASH TO FACILITATE AN ORDERLY
LIQUIDATION OF THE PORTFOLIO'S ASSETS.

The Portfolio is a series of Janus Aspen Series (the "Trust"). The Institutional
Shares are sold under the name "Janus Aspen Series." The Trust is registered
with the Securities and Exchange Commission ("SEC") as an open-end management
investment company. The Institutional Shares of the Portfolio (the "Shares") are
offered by this prospectus in connection with investment in and payments under
variable annuity contracts and variable life insurance contracts (collectively
"variable insurance contracts"), as well as certain qualified retirement plans.
The Trust sells and redeems its Shares at net asset value without any sales
charges, commissions or redemption fees. 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.

This Prospectus contains information about the Shares that a prospective
purchaser of a variable insurance contract or plan participant should consider
before allocating purchase payments or premiums to the Portfolio. It should be
read carefully in conjunction with the separate account prospectus of the
specific insurance product that accompanies this Prospectus and retained for
future reference. Additional information about the Shares is contained in a
Statement of Additional Information ("SAI") filed with the SEC. The SAI dated
May 1, 1998 is incorporated by reference into this Prospectus. Copies of the SAI
are available upon request and without charge by writing or calling your
insurance company or plan sponsor.

THESE SECURITIES HAVE NOT BEEN APPROVED BY THE SEC NOR HAS THE SEC PASSED ON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

THIS PROSPECTUS DOES NOT CONSTITUTE AN OFFER TO SELL SECURITIES IN ANY STATE OR
OTHER JURISDICTION TO ANY PERSON TO WHOM IT IS UNLAWFUL TO MAKE SUCH AN OFFER IN
SUCH STATE OR OTHER JURISDICTION.

JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998
<PAGE>

CONTENTS

<TABLE>
<S> <C>
THE PORTFOLIO AT A GLANCE
Brief description of the Portfolio.......................... 2
EXPENSE INFORMATION
The Portfolio's annual operating expenses................... 3
Financial Highlights - a summary of financial data.......... 4
PERFORMANCE TERMS
An explanation of performance terms......................... 6
THE PORTFOLIO IN DETAIL
Investment Objective and Policies........................... 7
General Portfolio Policies.................................. 8
Additional Risk Factors..................................... 9
MANAGEMENT OF THE PORTFOLIO
Investment Adviser and Investment Personnel................. 12
Personal Investing.......................................... 12
Management Expenses and Expense Limits...................... 12
Portfolio Transactions...................................... 12
Other Service Providers..................................... 13
Other Information........................................... 13
DISTRIBUTIONS AND TAXES
Distributions............................................... 15
Taxes....................................................... 15
SHAREHOLDER'S GUIDE
Purchases................................................... 16
Redemptions................................................. 16
Shareholder Communications.................................. 16
APPENDIX A
Glossary of Investment Terms................................ 17
APPENDIX B
Explanation of Ratings Categories........................... 20
</TABLE>

JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998 1
<PAGE>

PORTFOLIO AT A GLANCE

This section is designed to provide you with a brief overview of the Portfolio
and its investment emphasis. A more detailed discussion of the Portfolio's
investment objective and policies begins on page 7.

INVESTMENT OBJECTIVE:
The investment objective of the Portfolio is to seek a high a level of current
income as is consistent with the preservation of capital.

PRIMARY HOLDINGS:
A diversified portfolio that pursues its investment objective by investing
primarily in short- and intermediate-term fixed income securities. Under normal
circumstances, it is expected that the Portfolio's dollar-weighted average
portfolio effective maturity will not exceed three years.

SHAREHOLDER INVESTMENT HORIZON:
The Portfolio is designed for those investors who primarily seek current income.

FUND ADVISER:

Janus Capital serves as the Portfolio's investment adviser. Janus Capital has
been in the investment advisory business for over 27 years and currently manages
approximately $80 billion in assets.

PORTFOLIO MANAGER:
Sandy R. Rufenacht

PORTFOLIO INCEPTION:
September 1993

2 JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998
<PAGE>

EXPENSE INFORMATION

The following tables and example are designed to assist participants in
qualified plans that invest in the Shares of the Portfolio in understanding the
various costs and expenses that you will bear directly or indirectly as an
investor in the Shares. OWNERS OF VARIABLE INSURANCE CONTRACTS THAT INVEST IN
THE SHARES SHOULD REFER TO THE VARIABLE INSURANCE CONTRACT PROSPECTUS FOR A
DESCRIPTION OF COSTS AND EXPENSES, AS THE TABLES AND EXAMPLE DO NOT REFLECT
DEDUCTIONS AT THE SEPARATE ACCOUNT LEVEL OR CONTRACT LEVEL FOR ANY CHARGES THAT
MAY BE INCURRED UNDER A CONTRACT.

SHAREHOLDER TRANSACTION EXPENSES

ANNUAL OPERATING EXPENSES (AFTER FEE WAIVERS)(1)
(expressed as a percentage of average net assets)

<TABLE>
<S> <C> <C>
- -----------------------------------------------------------------------
MANAGEMENT FEE 0.39%
OTHER EXPENSES 0.26%
- -----------------------------------------------------------------------
TOTAL OPERATING EXPENSES 0.65%
- -----------------------------------------------------------------------
</TABLE>

(1) The fees and expenses in the table above are based on gross expenses of the
Shares before expense offset arrangements for the fiscal year ended December
31, 1997. The information is net of fee waivers from Janus Capital. Without
such waivers, the Management Fee, Other Expenses and Total Operating
Expenses for the Shares would have been 0.65%, 0.26%, and 0.91%,
respectively. Janus Capital may modify or terminate the waivers at any time
upon at least 90 days' notice to the Trustees.

EXAMPLE

Assume you invest $1,000, the Shares of the Portfolio return
5% annually and the expense ratio remains as listed above.
The example shows the operating expenses that you would
indirectly bear as an investor in the Shares of the
Portfolio. $7 $21 $36 $81
- ----------------------------------------------------------------------------------------------------------------
</TABLE>

THE EXAMPLE SHOULD NOT BE CONSIDERED A REPRESENTATION OF PAST OR FUTURE RETURNS
OR EXPENSES WHICH MAY BE MORE OR LESS THAN THOSE SHOWN.

JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998 3
<PAGE>

FINANCIAL HIGHLIGHTS

Unless otherwise noted, the information below is for fiscal periods ending on
December 31 of each year. The accounting firm of Price Waterhouse LLP has
audited the Portfolio's financial statements since its inception. Their report
is included in the Portfolio's Annual Report, which is incorporated by reference
into the SAI. A DETAILED EXPLANATION OF THE FINANCIAL HIGHLIGHTS CAN BE FOUND ON
PAGE 5.

<TABLE>
<CAPTION>
SHORT-TERM BOND PORTFOLIO
INSTITUTIONAL SHARES 1997 1996 1995 1994 1993(1)
- ---------------------------------------------------------------------------------------------------------------------------
<C> <S> <C> <C> <C> <C> <C> <C>
1. Net asset value, beginning of period $ 9.97 $10.03 $9.72 $9.93 $10.00
- ---------------------------------------------------------------------------------------------------------------------------
INCOME FROM INVESTMENT OPERATIONS:
2. Net investment income 1.85 .42 .60 .35 .11
Net gains or (losses) on securities (both realized and
3. unrealized) (1.19) (.03) .31 (.26) (.08)
- ---------------------------------------------------------------------------------------------------------------------------
4. Total from investment operations .66 .39 .91 .09 .03
- ---------------------------------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
5. Dividends (from net investment income) (1.75) (.44) (.60) (.30) (.10)
6. Tax return of capital distributions -- -- -- -- --
7. Distributions (from capital gains) -- (.01) -- -- --
- ---------------------------------------------------------------------------------------------------------------------------
8. Total distributions (1.75) (.45) (.60) (.30) (.10)
- ---------------------------------------------------------------------------------------------------------------------------
9. Net asset value, end of period $ 8.88 $9.97 $10.03 $9.72 $9.93
- ---------------------------------------------------------------------------------------------------------------------------
10. Total return* 6.72% 3.98% 9.54% 0.92% 0.30%
- ---------------------------------------------------------------------------------------------------------------------------
11. Net assets, end of period (in thousands) $ 2,735 $11,901 $3,187 $2,902 $502
12. Average net assets for the period (in thousands) $12,407 $7,168 $2,727 $1,774 $492
13. Ratio of gross expenses to average net assets** 0.65%(6) 0.66%(5) 0.70%(4) N/A N/A
14. Ratio of net expenses to average net assets** 0.65% 0.65% 0.65% 0.65%(3) 0.65%(2)
15. Ratio of net investment income to average net assets** 5.83% 5.44% 6.02% 5.00% 3.57%
16. Portfolio turnover rate** 204% 416% 417% 256% 91%
17. Average commission rate N/A N/A N/A N/A N/A
- ---------------------------------------------------------------------------------------------------------------------------
</TABLE>

* Total return not annualized for periods of less than one year.
**( )Annualized for periods of less than one full year.
(1) September 13, 1993 (inception) to December 31, 1993.

(2) The ratio was 5.33% before waiver of certain fees incurred by the Portfolio.

(3) The ratio was 1.40% before waiver of certain fees incurred by the Portfolio.

(4) The ratio was 1.37% before waiver of certain fees incurred by the Portfolio.

(5) The ratio was 0.84% before waiver of certain fees incurred by the Portfolio.

(6) The ratio was 0.91% before waiver of certain fees incurred by the Portfolio.

4 JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998
<PAGE>

UNDERSTANDING THE
FINANCIAL HIGHLIGHTS

This section is designed to help you better understand the information
summarized in the Financial Highlights table. The table contains important
historical operating information that may be useful in making your investment
decision or understanding how your investment has performed. The Portfolio's
Annual Report contains additional information about the Portfolio's performance,
including a comparison to an appropriate securities index. To request a copy of
the Annual Report, please call or write your insurance company.

NET ASSET VALUE ("NAV") is the value of a single Share of the Portfolio. It is
computed by adding the value of all of the Portfolio's investments and other
assets, subtracting any liabilities and dividing the result by the number of
shares outstanding. The difference between line 1 and line 9 in the Financial
Highlights table represents the change in value of a Share of the Portfolio over
the fiscal period, but not its total return.

NET INVESTMENT INCOME is the per share amount of dividends and interest income
earned on securities held by the Portfolio, less Portfolio expenses. DIVIDENDS
(FROM NET INVESTMENT INCOME) are the per share amount that the Portfolio paid
from net investment income.

NET GAINS OR (LOSSES) ON SECURITIES is the per share increase or decrease in
value of the securities the Portfolio holds. A gain (or loss) is realized when
securities are sold. A gain (or loss) is unrealized when securities increase or
decrease in value but are not sold. DISTRIBUTIONS (FROM CAPITAL GAINS) are the
per share amount that the Portfolio paid from net realized gains.

RATIO OF GROSS EXPENSES TO AVERAGE NET ASSETS is the total of the Portfolio's
operating expenses before expense offset arrangements divided by its average net
assets for the stated period. The Portfolio was not required to disclose the
ratio of gross expenses to average net assets prior to 1995. RATIO OF NET
EXPENSES TO AVERAGE NET ASSETS reflects reductions in the Portfolio's expenses
through the use of brokerage commissions and uninvested cash balances earning
interest or balance credits.

RATIO OF NET INVESTMENT INCOME TO AVERAGE NET ASSETS is the Portfolio's net
investment income divided by its average net assets for the stated period.

PORTFOLIO TURNOVER RATE is a measure of the amount of the Portfolio's buying and
selling activity. It is computed by dividing total purchases or sales, whichever
is less, by the average monthly market value of the Portfolio's securities.

AVERAGE COMMISSION RATE is the total of the Portfolio's agency commission paid
on equity securities trades divided by the number of shares purchased and sold.

JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998 5
<PAGE>

PERFORMANCE TERMS

This section will help you understand various terms that are commonly used to
describe the Portfolio's performance. You may see references to these terms in
our newsletters or advertisements (or those published by participating insurance
companies) and in media articles. Newsletters and advertisements may include
comparisons of the Portfolio's performance to the performance of other mutual
funds, mutual fund averages or recognized stock market indices. The Portfolio
generally measures performance in terms of yield.

CUMULATIVE TOTAL RETURN represents the actual rate of return on an investment
for a specified period. The Financial Highlights table shows total return for a
single fiscal period. Cumulative total return is generally quoted for more than
one year (e.g., the life of the Portfolio). A cumulative total return does not
show interim fluctuations in the value of an investment.

AVERAGE ANNUAL TOTAL RETURN represents the average annual percentage change of
an investment over a specified period. It is calculated by taking the cumulative
total return for the stated period and determining what constant annual return
would have produced the same cumulative return. Average annual returns for more
than one year tend to smooth out variations in the Portfolio's return and are
not the same as actual annual results.

YIELD shows the rate of income the Shares earn on investments as a percentage of
the Share price. It is calculated by dividing the Portfolio's net investment
income for a 30-day period by the average number of shares entitled to receive
dividends and dividing the result by the Share's NAV per share at the end of the
30-day period. Yield does not include changes in NAV.

Yields are calculated according to standardized SEC formulas and may not equal
the income on an investor's account. Yield is usually quoted on an annualized
basis. An annualized yield represents the amount you would earn if you remained
in the Portfolio for a year and the Shares of the Portfolio continued to have
the same yield for the entire year.

THE PORTFOLIO IMPOSES NO SALES OR OTHER CHARGES THAT WOULD AFFECT TOTAL RETURN
COMPUTATIONS. YIELD AND TOTAL RETURN FIGURES OF THE PORTFOLIO INCLUDE THE EFFECT
OF DEDUCTING THE PORTFOLIO'S EXPENSES, BUT MAY NOT INCLUDE CHARGES AND EXPENSES
ATTRIBUTABLE TO ANY PARTICULAR INSURANCE PRODUCT. PORTFOLIO PERFORMANCE FIGURES
ARE BASED UPON HISTORICAL RESULTS AND ARE NOT INTENDED TO INDICATE FUTURE
PERFORMANCE. INVESTMENT RETURNS AND NET ASSET VALUE WILL FLUCTUATE SO THAT
SHARES, WHEN REDEEMED, MAY BE WORTH MORE OR LESS THAN THEIR ORIGINAL COST.

6 JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998
<PAGE>

THE PORTFOLIO IN DETAIL

This section takes a closer look at the Portfolio's investment objective,
policies and the securities in which it invests. Please carefully review the
"Additional Risk Factors" section of this Prospectus for a more detailed
discussion of the risks associated with certain investment techniques. Appendix
A contains a more detailed description of investment terms used throughout this
Prospectus. You should carefully consider your investment goals, time horizon
and risk tolerance before investing in the Portfolio.

The Portfolio's investment objective and policies are similar to those of Janus
Short-Term Bond Fund, a retail fund managed by Janus Capital. Although it is
anticipated that the Portfolio and Janus Short-Term Bond Fund will hold similar
securities, differences in asset size and cash flow needs as well as the
relative weightings of securities selections may result in differences in
investment performance. Expenses of the Portfolio and Janus Short-Term Bond 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 contract fees and
expenses.

Policies that are noted as "fundamental" cannot be changed without a shareholder
vote. All other policies, including the Portfolio's investment objective, are
not fundamental and may be changed by the Portfolio's Trustees without a
shareholder vote. You will be notified of any such changes that are material. If
there is a material change in the Portfolio's objective or policies, you should
consider whether the Portfolio remains an appropriate investment for your
variable insurance contract or qualified retirement plan.

THE PORTFOLIO IS DESIGNED FOR THOSE INVESTORS WHO PRIMARILY SEEK CURRENT INCOME.

SHORT-TERM BOND PORTFOLIO
Investment Objective:.....................................................Income
Primary Holdings:....................................Income-Producing Securities
Shareholder's Investment Horizon:......................................Short- to
Intermediate-Term

INVESTMENT OBJECTIVE
The investment objective of the Portfolio is to seek as high a level of current
income as is consistent with preservation of capital. The Portfolio pursues its
objective by investing primarily in short- and intermediate-term fixed-income
securities. Under normal circumstances, it is expected that the Portfolio's
dollar-weighted average portfolio effective maturity will not exceed three
years.

Effective maturity is the weighted average period over which a security's
principal is expected to be paid, and differs from stated maturity in that it
estimates the effect of expected principal prepayments and call provisions.
Targeting effective maturity provides additional flexibility in portfolio
management but, all else being equal, could result in higher volatility than a
fund targeting a stated maturity or maturity range. See the question and answer
section below for a more detailed discussion of the Portfolio's maturity policy.

Short-Term Bond Portfolio will normally invest at least 65% of its assets in
debt securities. Subject to this policy and subject to its maturity limits, the
Portfolio may invest in a wide variety of income-producing securities including
corporate bonds and notes, government securities, indexed/structured securities,
preferred stock, income-producing common stocks, debt securities that are
convertible or exchangeable into equity securities, and debt securities that
carry with them the right to acquire equity securities as evidenced by warrants
attached to or acquired with the securities. The Portfolio may invest to a
lesser degree in common stocks, other equity securities or debt securities that
are not currently paying dividends or interest.

TYPES OF INVESTMENTS
Short-Term Bond Portfolio may purchase securities on a when-issued, delayed
delivery or forward commitment basis. The Portfolio's investments in mortgage-
and asset-backed securities will not exceed 25% of assets and its investments in
zero coupon, pay-in-kind and step coupon securities will not exceed 10% of
assets. The Portfolio may invest without limit in indexed/structured securities.
The Portfolio will invest less than 35% of its net assets in
high-yield/high-risk securities. The Portfolio may invest without limit in
foreign securities, including those of corporate and government issuers. In
addition, the Portfolio may use futures, options and other derivatives for
hedging purposes or for non-hedging purposes such as seeking to enhance return.
See "Additional Risk Factors" on page 9.

THE FOLLOWING QUESTIONS ARE DESIGNED TO HELP YOU BETTER UNDERSTAND AN INVESTMENT
IN SHORT-TERM BOND PORTFOLIO.

Q: HOW DO INTEREST RATES AFFECT THE VALUE OF MY INVESTMENT?

A: A fundamental risk associated with any fund that invests in fixed-income
securities (e.g., a bond fund) is the risk that the value of the
securities it holds will rise or fall as interest rates change. 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.
A bond fund's average-weighted effective maturity and its duration are measures
of how the portfolio may react to interest rate changes.

JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998 7
<PAGE>

Q: WHAT IS MEANT BY THE PORTFOLIO'S "AVERAGE-WEIGHTED EFFECTIVE MATURITY"?

A: The stated maturity of a bond is the date when the issuer must repay the
bond's entire principal value to an investor, such as the Portfolio. Some
types of bonds, such as mortgage-backed securities, which are subject to
prepayment risk, and securities with call provisions, may also have an
"effective maturity" that is shorter than the stated date. With respect to GNMA
securities and other mortgage-backed securities, effective maturity is likely to
be substantially less than the stated maturities of the mortgages in the
underlying pools. With respect to obligations with call provisions, effective
maturity is typically the next call date on which the obligation reasonably may
be expected to be called. 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 a Portfolio with each effective maturity "weighted"
according to the percentage of net assets that it represents.

Q: WHAT IS MEANT BY THE PORTFOLIO'S "DURATION"?

A: A bond's duration indicates the time it will take an investor to recoup
his or her 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 the Portfolio 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.

Q: HOW DOES THE PORTFOLIO MANAGE INTEREST RATE RISK?

A: The Portfolio may vary its average-weighted effective maturity to reflect
its portfolio manager's analysis of interest rate trends and other
factors. The Portfolio's average-weighted effective maturity will tend to be
shorter when its portfolio manager expects interest rates to rise and longer
when its portfolio manager expects interest rates to fall. The Portfolio may
also use futures, options and other derivatives to manage interest rate risk.
See "Additional Risk Factors" on page 9.

Q: WHAT IS MEANT BY "CREDIT QUALITY"?

A: Credit quality measures the likelihood that the issuer will meet its
obligations on a bond. One of the fundamental risks associated with all
bond 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.

Q: HOW IS CREDIT QUALITY MEASURED?

A: Ratings published by nationally recognized rating agencies such as
Standard & Poor's Rating Services ("Standard & Poor's") and Moody's
Investors Service, Inc. ("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 Appendix B for a
description of rating categories.

GENERAL PORTFOLIO POLICIES
In investing its assets, the Portfolio 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. 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's manager believes that market conditions are not favorable
for profitable investing or when the portfolio manager is otherwise unable to
locate favorable investment opportunities, the Portfolio's investments may be
hedged to a greater degree and/or its 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 are a residual - they represent the assets
that remain after the portfolio manager has committed available assets to
desirable investment opportunities. A larger hedged position and/or larger cash
position may serve as a means of preserving capital in unfavorable market
conditions.

Securities that the Portfolio may invest in as means of receiving a return on
idle cash include high-grade commercial paper, certificates of deposit,
repurchase agreements or other short-term debt obligations. The Portfolio may
also invest in money market funds (including funds managed by Janus Capital).
When the Portfolio is hedged or its cash or similar investments increase, it may
not participate in stock or bond market advances or declines to the same extent
that it would if the Portfolio was hedged or remained more fully invested in
stocks or bonds.

DIVERSIFICATION
The Investment Company Act of 1940 (the "1940 Act") classifies investment
companies as either diversified or nondiversified. The Portfolio qualifies as a
diversified fund under the 1940 Act and is subject to the following
diversification requirements:

- - As a fundamental policy, the Portfolio may not own more than 10% of the
outstanding voting shares of any issuer.

- - As a fundamental policy, with respect to 75% of its total assets, the
Portfolio will not purchase a security of any issuer (other than cash items
and U.S. government securities, as defined in the 1940 Act) if such purchase
would cause the

8 JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998
<PAGE>

Portfolio's holdings of that issuer to amount to more than 5% of the
Portfolio's total assets.

- - The Portfolio will not invest more than 25% of its total assets in a single
issuer (other than U.S. government securities).

INTERNAL REVENUE SERVICE (IRS) LIMITATIONS
In addition to the diversification requirements stated above, the Portfolio
intends to comply with the diversification requirements currently imposed by the
IRS on separate accounts of insurance companies as a condition of maintaining
the tax-deferred status of variable contracts. More specific information may be
contained in the participating insurance company's separate account prospectus.

INDUSTRY CONCENTRATION
As a fundamental policy, the Portfolio will not invest 25% or more of its total
assets in any particular industry (excluding U.S. government securities).

PORTFOLIO TURNOVER
The Portfolio generally intends to purchase securities for long-term investment
rather than short-term gains. However, short-term transactions may 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 initial investment
decision. Changes are made in the Portfolio whenever its portfolio manager
believes such changes are desirable. The portfolio turnover rate is generally
not a factor in making buy and sell decisions.

To a limited extent, the Portfolio may purchase securities in anticipation of
relatively short-term price gains. The Portfolio may also sell one security and
simultaneously purchase the same or comparable security to take advantage of
short-term differentials in bond yields or securities prices. 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.

ILLIQUID INVESTMENTS
The Portfolio may invest up to 15% of its net assets in illiquid investments,
including restricted securities or private placements that are not deemed to be
liquid by Janus Capital. If illiquid securities exceed 15% of the Portfolio's
net assets after the time of purchase, the Portfolio will take steps to reduce
in an orderly fashion its holdings of illiquid securities. An illiquid
investment is a security or other position that cannot be disposed of quickly in
the normal course of business. Some securities cannot be sold to the U.S. public
because of their terms or because of SEC regulations. Janus Capital will follow
guidelines established by the Trustees of the Trust ("Trustees") in making
liquidity determinations for Rule 144A securities and other securities,
including privately placed commercial paper and municipal lease obligations.

BORROWING AND LENDING
The Portfolio may borrow money and lend securities or other assets, as follows:

- - The Portfolio may borrow money for temporary or emergency purposes in amounts
up to 25% of its total assets.

- - The Portfolio may mortgage or pledge securities as collateral for borrowings
in amounts up to 15% of its net assets.

- - As a fundamental policy, the Portfolio may lend securities or other assets if,
as a result, no more than 25% of its total assets would be lent to other
parties.

Under the terms of an exemptive order received from the SEC, the Portfolio may
borrow money from or lend money to other funds that permit such transactions and
for which Janus Capital serves as investment adviser. All such borrowing and
lending will be subject to the above percentage limits.

ADDITIONAL RISK FACTORS

FOREIGN SECURITIES
INVESTMENTS IN FOREIGN SECURITIES, INCLUDING THOSE OF FOREIGN GOVERNMENTS, MAY
INVOLVE GREATER RISKS THAN INVESTING IN COMPARABLE DOMESTIC SECURITIES.

Securities of some foreign companies and governments may be traded in the United
States, but many foreign securities are traded primarily in foreign markets. The
risks of foreign investing include:

- - CURRENCY RISK. The Portfolio may buy the local currency when it buys a foreign
currency denominated security and sell the local currency when it sells the
security. 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 though 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 underdeveloped or developing
countries which may have relatively unstable governments 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. The Portfolio may invest in emerging market countries.
Emerging market countries involve greater risks such as immature economic
structures, national policies restricting investments by foreigners, and
different legal systems.

- - MARKET RISK. Foreign securities markets, particularly those of underdeveloped
or developing countries, may be less liquid

JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998 9
<PAGE>

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. There may be limited legal
recourse against an issuer in the event of a default on a debt instrument.

- - TRANSACTION COSTS. Transaction costs of buying and selling foreign securities,
including brokerage, tax and custody costs, are generally higher than those
involved in domestic transactions.

INVESTMENTS IN SMALLER COMPANIES
SMALLER OR NEWER COMPANIES MAY SUFFER MORE SIGNIFICANT LOSSES AS WELL AS REALIZE
MORE SUBSTANTIAL GROWTH THAN LARGER OR MORE ESTABLISHED ISSUERS.

FUTURES, OPTIONS AND OTHER DERIVATIVE INSTRUMENTS
The Portfolio may enter into futures contracts on securities, financial indices
and foreign currencies and options on such contracts ("futures contracts") and
may invest in options on securities, financial indices and foreign currencies
("options"), forward contracts and interest rate swaps and swap-related products
(collectively "derivative instruments"). The Portfolio intends to use most
derivative instruments primarily to hedge against potential adverse movements in
securities prices, foreign currency markets or interest rates. To a limited
extent, the Portfolio may also use derivative instruments for non-hedging
purposes such as seeking to increase its income or otherwise seeking to enhance
return. Please refer to Appendix A to this Prospectus and the SAI for a more
detailed discussion of these instruments.

The use of derivative instruments exposes the Portfolio to additional investment
risks and transaction costs. Risks inherent in the use of derivative instruments
include:

- - the risk that interest rates, securities prices and currency markets will not
move in the direction that the portfolio manager anticipates;

- - imperfect correlation between the price of derivative instruments and
movements in the prices of the securities, interest rates or currencies being
hedged;

- - the fact that skills needed to use these strategies are different from those
needed to select portfolio securities;

- - inability to close out certain hedged positions to avoid adverse tax
consequences;

- - leverage risk, that is, the risk that adverse price movements in an instrument
can result in a loss substantially greater than the Portfolio's initial
investment in that instrument (in some cases, the potential loss is
unlimited); and

- - particularly in the case of privately-negotiated instruments, the risk that
the counterparty will fail to perform its obligations, which could leave the
Portfolio worse off than if it had not entered into the position.

Although the portfolio manager believes the use of derivative instruments will
benefit the Portfolio, the Portfolio's performance could be worse than if the
Portfolio had not used such instruments if the portfolio manager's judgement
proves incorrect.

When the Portfolio invests in a derivative instrument, it may be required to
segregate cash and other liquid assets or certain portfolio securities with its
custodian to "cover" the Portfolio's position. Assets segregated or set aside
generally may not be disposed of so long as the Portfolio maintains the
positions requiring segregation or cover. Segregating assets could diminish the
Portfolio's return due to the opportunity losses of foregoing other potential
investments with the segregated assets.

10 JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998
<PAGE>

meet projected business goals and to obtain additional financing, particularly
if the issuer is highly leveraged. In the event of a default, the Portfolio
would experience a reduction of its income and could expect a decline in the
market value of the defaulted securities.

The market prices of high-yield/high-risk securities structured as zero coupon
or pay-in-kind securities are generally affected to a greater extent by interest
rate changes and tend to be more volatile than securities which pay interest
periodically. In addition, zero coupon, pay-in-kind and delayed interest bonds
often do not pay interest until maturity. However, the Portfolio must recognize
imputed interest income and pay dividends to shareholders even though it has
received no cash. In some instances, the Portfolio may have to sell securities
to have sufficient cash to pay the dividends.

SHORT SALES
The Portfolio may engage in "short sales against the box." This technique
involves selling either a security that the Portfolio owns, or a security
equivalent in kind and amount that the Portfolio has the right to obtain, for
delivery at a specified date in the future. The Portfolio may enter into a short
sale against the box to hedge against anticipated declines in the market price
of portfolio securities. If the value of the securities sold short increases
prior to the scheduled delivery date, the Portfolio loses the opportunity to
participate in the gain.

SPECIAL SITUATIONS
The Portfolio may invest in "special situations" from time to time. 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.
Investment in special situations may carry an additional risk of loss in the
event that the anticipated development does not occur or does not attract the
expected attention.

See Appendix A for risks associated with certain other investments.

JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998 11
<PAGE>

MANAGEMENT OF THE PORTFOLIO

TRUSTEES

The Trustees oversee the business affairs of the Trust and are responsible for
major decisions relating to the Portfolio's investment objective and policies.
The Trustees delegate the day-to-day management of the Portfolio to the officers
of the Trust and meet at least quarterly to review the Portfolio's investment
policies, performance, expenses and other business affairs.

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 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.

INVESTMENT PERSONNEL
PORTFOLIO MANAGER

SANDY R. RUFENACHT is Executive Vice President and portfolio manager of the
Portfolio, which he has managed since May 1996. He is also the 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.

PERSONAL INVESTING
Janus Capital does not permit portfolio managers to purchase and sell securities
for their own accounts, except under the limited exceptions contained in Janus
Capital's policy governing personal investing. Janus Capital's policy requires
investment and other personnel to conduct their personal investment activities
in a manner that Janus Capital believes is not detrimental to the Portfolio or
Janus Capital's other advisory clients. See the SAI for more detailed
information.

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):

<TABLE>
<CAPTION>
AVERAGE DAILY NET ANNUAL RATE EXPENSE LIMIT
ASSETS OF PORTFOLIO PERCENTAGE (%) PERCENTAGE (%)
-----------------------------------------------------
<S> <C> <C>
First $300 Million .65 .65
Over $300 Million .55
-----------------------------------------------------
</TABLE>

Janus Capital may terminate or modify the expense limitation at any time upon
at least 90 days' notice to the Trustees.

As asset size increases, the annual rate of the management fee declines in
accordance with the above schedule. 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.

12 JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998
<PAGE>

provided to the Portfolio for which it would be obligated to pay. The
Portfolio's Trustees have authorized Janus Capital to place portfolio
transactions on an agency basis with a broker-dealer affiliated with Janus
Capital. When transactions for the Portfolio are effected with that
broker-dealer, the commissions payable by the Portfolio are credited against
certain Portfolio operating expenses serving to reduce those expenses. The SAI
further explains the selection of broker-dealers.

OTHER SERVICE PROVIDERS
The following parties provide the Portfolio with administrative and other
services.

CUSTODIAN
State Street Bank and Trust Company
P.O. Box 0351
Boston, Massachusetts 02117-0351

TRANSFER AGENT
Janus Service Corporation
P.O. Box 173375
Denver, Colorado 80217-3375

Janus Service Corporation is a wholly-owned subsidiary of Janus Capital.

OTHER INFORMATION
ORGANIZATION
The Trust is a "mutual fund" that was organized as a Delaware business trust on
May 20, 1993. A mutual fund is an investment vehicle that pools money from
numerous investors and invests the money to achieve a specified objective. The
Trust consists of twelve separate series, one of which is offered by this
Prospectus.

SHAREHOLDER MEETINGS AND VOTING RIGHTS
The Trust does not intend to hold annual shareholder meetings. However, special
meetings may be called for the class or Portfolio or for the Trust as a whole
for purposes such as electing or removing Trustees, terminating or reorganizing
the Trust, changing fundamental policies, or for any other purpose requiring a
shareholder vote under the 1940 Act. Separate votes are taken by the class or
Portfolio only if a matter affects or requires the vote of only the class or
Portfolio or the interest of a class or Portfolio in the matter differs from the
interest of the other class or Portfolios of the Trust. As a shareholder, you
are entitled to one vote for each share that you own.

An insurance company issuing a variable contract invested in Shares of the
Portfolio will request voting instructions from variable contract holders. Under
current law, the insurance company must vote all Shares held by the separate
account in proportion to the voting instructions received.

CONFLICTS OF INTEREST
The Portfolio's Shares 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
participant directed qualified plans. Although the Portfolio does not currently
anticipate any disadvantages to policy owners arising out of the fact that it
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
anticipated disadvantages or material irreconcilable conflicts that may arise
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 plans to withdraw its investment in the Portfolio
or substitute shares of another portfolio of the Trust. If this occurs, the
Portfolio may be forced to sell securities at disadvantageous prices. In
addition, the Trustees may refuse to sell shares of the Portfolio to any
separate account 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.

MASTER/FEEDER OPTION
The Trust may in the future seek to achieve the Portfolio's investment objective
by investing all of the Portfolio's assets in another investment company having
the same investment objective and substantially the same investment policies and
restrictions as those applicable to the Portfolio. Unless otherwise required by
law, this policy may be implemented by the Trustees without shareholder
approval.

JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998 13
<PAGE>

THE VALUATION OF SHARES
The NAV of the Shares of the Portfolio is determined at the close of the regular
trading session of the New York Stock Exchange (the "NYSE") (normally 4:00 p.m.,
New York time) each day that the NYSE is open. NAV per share is determined by
dividing the total value of the securities and other assets, less liabilities,
by the total number of shares outstanding.

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.

14 JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998
<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. ORDINARY 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, IF ANY, ARE PAID TO SHAREHOLDERS AS CAPITAL GAINS
DISTRIBUTIONS. THE SHARES OF THE PORTFOLIO MAKES SEMIANNUAL 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 THE SHARES OF THE PORTFOLIO WILL BE
AUTOMATICALLY REINVESTED INTO ADDITIONAL SHARES OF THE PORTFOLIO.

HOW DISTRIBUTIONS AFFECT NAV
Distributions other than daily income dividends, 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 the Portfolio declared a
dividend in the amount of $0.25 per share. If the price of the Portfolio's Share
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 in the Shares depends on the features of
the variable insurance contracts purchased from a participating insurance
company. Further information may be found 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 as a foreign tax credit.
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.

JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998 15
<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.

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's
separate account or your plan documents for information on how to invest in the
Shares of the Portfolio.

All investments in the Portfolio are credited to a participating insurance
company's separate account or a qualified plan immediately upon acceptance of
the investment by the Portfolio. Investments will be processed at the NAV next
determined after an order is received and accepted by the Portfolio.

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. The Portfolio may discontinue
sales of its shares if management believes that a substantial further increase
may adversely affect the Portfolio's ability to achieve its investment
objective. In such event, however, it is anticipated 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.

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. 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 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 SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998
<PAGE>

APPENDIX A

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 objective 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.

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
under Section 4(2) of the Securities Act of 1933.

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.

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 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.

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 to provide cash to satisfy unusually high redemption
requests or for other temporary or emergency purposes.

JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998 17
<PAGE>

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.

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 bears the risk of market value
fluctuations 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 Portfolio may enter into forward currency contracts to
hedge against declines in the value of non-dollar denominated securities or to
reduce the impact of currency appreciation on purchases of non-dollar
denominated securities. The Portfolio 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

18 JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998
<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 Portfolio may purchase and write put and call options on securities,
securities indices and foreign currencies.

JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998 19
<PAGE>

APPENDIX B

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>
<CAPTION>
BOND RATING EXPLANATION
- --------------------------------------------------------------
<S> <C>
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>

MOODY'S INVESTORS SERVICE, INC.

20 JANUS ASPEN SERIES SHORT-TERM BOND PORTFOLIO PROSPECTUS MAY 1, 1998
<PAGE>

This page intentionally left blank.
<PAGE>

JANUS ASPEN SERIES
PROSPECTUS

Short-Term Bond Portfolio

[LOGO] P.O. Box 173375 o Denver, CO 80217-3375 o 1-800-525-1068

<PAGE>

JANUS ASPEN SERIES
GROWTH AND INCOME PORTFOLIO

Prospectus

MAY 1, 1998

Growth and Income Portfolio (the "Portfolio") is a no-load, diversified mutual
fund that seeks long-term growth of capital with a limited emphasis on income.
Although the Portfolio normally invests at least 25% of its assets in securities
that have income potential, it emphasizes equity securities selected for their
growth potential. The Portfolio is a series of Janus Aspen Series (the "Trust")
and currently offers two classes of Shares. The Institutional Shares are sold
under the name "Janus Aspen Series." The Trust is registered with the Securities
and Exchange Commission as an open-end management investment company. The
Portfolio is recently organized and has a limited operating history.

The Institutional Shares (the "Shares") of the Portfolio offered by this
Prospectus are issued and redeemed only in connection with investment in and
payments under variable annuity contracts and variable life insurance contracts
(collectively, "variable insurance contracts"), as well as certain qualified
retirement plans.

The Trust sells and redeems its Shares at net asset value without any sales
charges, commissions or redemption fees. Each variable insurance contract
involves fees and expenses not described in this Prospectus. The Portfolio may
not be available in connection with a particular contract. See the accompanying
contract prospectus for information regarding contract fees and expenses and any
restrictions on purchases or allocations.

This Prospectus contains information about the Portfolio that a prospective
purchaser of a variable insurance contract or plan participant should consider
before allocating purchase payments or premiums to the Portfolio. It should be
read carefully in conjunction with the separate account prospectus of the
specific insurance product that accompanies this Prospectus and retained for
future reference. Additional information about the Portfolio is contained in the
Statement of Additional Information ("SAI") dated May 1, 1998, which is filed
with the Securities and Exchange Commission ("SEC") and is incorporated by
reference into this Prospectus. The SAI is available upon request and without
charge by writing or calling your insurance company or plan sponsor.

THESE SECURITIES HAVE NOT BEEN APPROVED BY THE SEC NOR HAS THE SEC PASSED ON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

THIS PROSPECTUS DOES NOT CONSTITUTE AN OFFER TO SELL SECURITIES IN ANY STATE OR
OTHER JURISDICTION TO ANY PERSON TO WHOM IT IS UNLAWFUL TO MAKE SUCH AN OFFER IN
SUCH STATE OR OTHER JURISDICTION.

JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998

<PAGE>

CONTENTS

<TABLE>
<S> <C>
THE PORTFOLIO AT A GLANCE
Brief description of the Portfolio.......................... 2

EXPENSE INFORMATION......................................... 3
THE PORTFOLIO IN DETAIL
The Portfolio's Investment Objective and Policies........... 4
General Portfolio Policies.................................. 5
Additional Risk Factors..................................... 6
MANAGEMENT OF THE PORTFOLIO
Investment Adviser and Portfolio Manager.................... 9
Personal Investing.......................................... 9
Portfolio Transactions...................................... 9
Management Expenses and Expense Limits...................... 10
Other Service Providers..................................... 10
Other Information........................................... 10
DISTRIBUTIONS AND TAXES
Distributions............................................... 12
Taxes....................................................... 12
PERFORMANCE TERMS
An Explanation of Performance Terms......................... 13
SHAREHOLDER'S GUIDE
Purchases................................................... 14
Redemptions................................................. 14
Shareholder Communications.................................. 14
APPENDIX A
Glossary of Investment Terms................................ 15
</TABLE>

JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998 1

<PAGE>

PORTFOLIO AT A GLANCE

INVESTMENT OBJECTIVE
The investment objective of the Portfolio is long-term capital growth and
current income.

PRIMARY HOLDINGS

A diversified portfolio that emphasizes equity securities selected for their
growth potential, although the Portfolio will normally invest at least 25% of
its assets in securities that the portfolio manager believes have income
potential.

SHAREHOLDER'S INVESTMENT HORIZON
The Portfolio is designed for long-term investors who seek growth of capital
with a limited emphasis on income. The Portfolio is not designed for investors
who desire a consistent level of income nor is it a short-term trading vehicle
and should not be relied upon for short-term financial needs.

PORTFOLIO ADVISER

Janus Capital Corporation ("Janus Capital") serves as the Portfolio's investment
adviser. Janus Capital has been in the investment advisory business for over 27
years and currently manages approximately $80 billion in assets.

PORTFOLIO MANAGER

David J. Corkins

PORTFOLIO INCEPTION

May 1998

2 JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998

<PAGE>

EXPENSE INFORMATION

The following tables and example are designed to assist participants in
qualified plans that invest in the Portfolio in understanding the various costs
and expenses that you will bear directly or indirectly as an investor in the
Portfolio. OWNERS OF VARIABLE INSURANCE CONTRACTS THAT INVEST IN THE PORTFOLIO
SHOULD REFER TO THE VARIABLE INSURANCE CONTRACT PROSPECTUS FOR A DESCRIPTION OF
COSTS AND EXPENSES, AS THE TABLES AND EXAMPLE DO NOT REFLECT DEDUCTIONS AT THE
SEPARATE ACCOUNT LEVEL OR CONTRACT LEVEL FOR ANY CHARGES THAT MAY BE INCURRED
UNDER A CONTRACT.

SHAREHOLDER TRANSACTION EXPENSES

<TABLE>
<S> <C>
Maximum sales load imposed on purchases None
Maximum sales load imposed on reinvested dividends None
Deferred sales charges on redemptions None
Redemption fees None
Exchange fee None
</TABLE>

ANNUAL PORTFOLIO OPERATING EXPENSES (after fee waivers and reductions)(1)
(expressed as a percentage of average net assets)

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

Management Fee(1) 0.67%
Other Expenses(1) 0.30%
----------------------------------------------------------------------
Total Portfolio Operating Expenses(1) 0.97%
----------------------------------------------------------------------
</TABLE>

(1) The fees and expenses in the table above are based on the estimated gross
expenses before estimated expense offset arrangements that the Shares of the
Portfolio expect to incur in their initial fiscal year, net of fee
reductions or waivers from Janus Capital. Fee reductions reduce the
management fee to the level of the corresponding Janus retail fund. Other
waivers, if applicable, are first applied against the management fee and
then against other expenses. Without such waivers or reductions, the
Management Fee, Other Expenses and Total Portfolio Operating Expenses are
estimated to be 0.75%, 0.30% and 1.05%, respectively. Janus Capital may
modify or terminate the waivers or reductions at any time upon at least 90
days' notice to the Trustees.

EXAMPLE

<TABLE>
<CAPTION>
- -------------------------------------------------------------------------------------
1 YEAR 3 YEARS
- -------------------------------------------------------------------------------------
<S> <C> <C> <C>

Assume you invest $1,000, the Shares of the Portfolio
returns 5% annually and its expense ratio remains as listed
above. The example shows the operating expenses that you
would indirectly bear as an investor in the Shares of the
Portfolio. $10 $31
------------------------------------------------------------------------------------
</TABLE>

THE EXAMPLE SHOULD NOT BE CONSIDERED A REPRESENTATION OF PAST OR FUTURE RETURNS
OR EXPENSES WHICH MAY BE MORE OR LESS THAN THOSE SHOWN.

FINANCIAL HIGHLIGHTS

No Financial Highlights are presented for the Shares because the Shares did not
commence operations before May 1, 1998.

JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998 3

<PAGE>

THE PORTFOLIO IN DETAIL

This section takes a closer look at the Portfolio's investment objectives,
policies and the securities in which it invests. Please carefully review the
"Additional Risk Factors" section of this Prospectus for a more detailed
discussion of the risks associated with certain investment techniques and refer
to Appendix A for a more detailed description of the Portfolio's investments
(and certain of the risks associated with those investments). You should
carefully consider your own investment goals, time horizon and risk tolerance
before investing in the Portfolio.

The Portfolio's investment objectives and policies are similar to those of Janus
Growth and Income Fund, a Janus retail fund. Although it is anticipated that the
Portfolio and its corresponding retail fund will hold similar securities,
differences in asset size and cash flow needs as well as the relative weightings
of securities selections may result in differences in investment performance.
Expenses of the Portfolio and its corresponding retail fund are expected to
differ.

Policies that are noted as "fundamental" cannot be changed without a shareholder
vote. All other policies, including the Portfolio's investment objectives, are
not fundamental and may be changed by the Portfolio's Trustees without a
shareholder vote. You will be notified of any such changes that are material. If
there is a material change in the Portfolio's objectives or policies, you should
consider whether the Portfolio remains an appropriate investment for your
variable insurance contract or qualified retirement plan.

INVESTMENT OBJECTIVE

The investment objective of the Portfolio is long-term capital growth and
current income. It is a diversified portfolio that, under normal circumstances,
pursues its objective by investing up to 75% of its assets in equity securities
selected primarily for their growth potential and at least 25% of its assets in
securities that the portfolio manager believes have income potential. The
Portfolio normally emphasizes the growth component. However, in unusual
circumstances (such as those described under "Cash Position" on page 5), the
Portfolio may reduce the growth component of its portfolio to 25% of its assets.

TYPES OF INVESTMENTS
The Portfolio invests primarily in common stocks of domestic and foreign
companies. The Portfolio may invest to a lesser degree in other types of
securities including preferred stock, warrants, convertible securities and debt
securities when its portfolio manager perceives an opportunity for capital
growth from such securities or to receive a return on idle cash. The Portfolio
may purchase securities on a when-issued, delayed delivery or forward commitment
basis. The Portfolio may invest up to 25% of its assets in mortgage- and
asset-backed securities, up to 10% of its assets in zero coupon, pay-in-kind and
step coupon securities, and without limit in indexed/ structured securities. The
Portfolio will invest less than 35% of its assets in high-yield/high-risk
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. The Portfolio may use futures, options and other
derivatives for hedging purposes or for non-hedging purposes such as seeking to
enhance return. See "Additional Risk Factors" on page 6 for a discussion of the
risks associated with foreign investing and derivatives.

See Appendix A for a further description of the Portfolio's investments.

THE FOLLOWING QUESTIONS ARE DESIGNED TO HELP YOU BETTER UNDERSTAND AN INVESTMENT
IN THE PORTFOLIO.

A: HOW ARE EQUITY SECURITIES SELECTED?

The growth component of the Portfolio is expected to consist primarily of
common stocks. The selection criteria for common stocks are described
below. Because income is a part of the investment objective of the Portfolio,
the portfolio manager may consider dividend-paying characteristics in selecting
equity securities for this Portfolio. The Portfolio may also find opportunities
for capital growth from debt securities because of anticipated changes in
interest rates, credit standing, currency relationships or other factors.

The portfolio manager will invest in common stocks to the extent he believes
that the relevant market environment favors profitable investing in those
securities. The portfolio manager generally takes a "bottom up" approach to
building the portfolio. In other words, he seeks to identify individual
companies with earnings growth potential that may not be recognized by the
market at large. Although themes may emerge in the Portfolio, securities are
generally selected without regard to any defined industry sector or other
similarly defined selection procedure.

Q:
HOW ARE ASSETS ALLOCATED BETWEEN THE GROWTH AND INCOME COMPONENT OF THE
A: PORTFOLIO?

4 JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998

<PAGE>

manager believes that growth securities will provide better returns than the
yields then available or expected on income-producing securities, the Portfolio
will place a greater emphasis on the growth component.

Q:
A: WHAT TYPES OF SECURITIES MAKE UP THE INCOME COMPONENT OF THE PORTFOLIO?

The income component of the Portfolio will consist of securities that the
portfolio manager believes have income potential. Such securities may
include equity securities, convertible securities and all types of debt
securities. Equity securities may be included in the income component of the
Portfolio if they currently pay dividends or the portfolio manager believes they
have the potential for either increasing their dividends or commencing
dividends, if none are currently paid. Investors in the Portfolio should keep in
mind that the Portfolio is not designed to produce a consistent level of income.

Q:
A: ARE THE SAME CRITERIA USED TO SELECT FOREIGN SECURITIES?

Generally, yes. The portfolio manager seeks companies that meet his
selection criteria, regardless of country of organization or place of
principal business activity. 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. See "Additional Risk Factors" on page 6.

Q:
A: HOW DOES THE PORTFOLIO TRY TO REDUCE RISK?

Diversification of the Portfolio's assets reduces the effect of any single
holding on its overall portfolio value. The Portfolio may use futures,
options and other derivative instruments to protect the portfolio from 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. See "Additional Risk Factors" on page 6. In addition, to the
extent that the Portfolio holds a larger cash position, it might not participate
in market declines to the same extent as if it had remained more fully invested
in common stocks.

GENERAL PORTFOLIO POLICIES
The Portfolio will follow the general policies listed below in investing its
portfolio assets. The percentage limitations included in these policies and
elsewhere in this Prospectus apply at the time of purchase of the security. 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's manager believes that market conditions are not favorable
for profitable investing or when the portfolio manager is otherwise unable to
locate favorable investment opportunities, the Portfolio's investments may be
hedged to a greater degree and/or its 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 are a residual -- they represent the assets
that remain after a portfolio manager has committed available assets to
desirable investment opportunities. Larger hedged positions and/or larger cash
positions may serve as a means of preserving capital in unfavorable market
conditions.

Securities that the Portfolio may invest in as means of receiving a return on
idle cash include high-grade commercial paper, certificates of deposit,
repurchase agreements or other short-term debt obligations. The Portfolio may
also invest in money market funds (including funds managed by Janus Capital).
When a Portfolio is hedged or its investments in cash or similar investments
increase, it may not participate in stock or bond market advances or declines to
the same extent that it would if the Portfolio was not hedged or remained more
fully invested in stocks or bonds.

- - As a fundamental policy, the Portfolio may not own more than 10% of the
outstanding voting shares of any issuer.

- - The Portfolio will invest no more than 25% of its total assets in a single
issuer (other than U.S. government securities).

INDUSTRY CONCENTRATION
As a fundamental policy, the Portfolio will not invest 25% or more of its total
assets in any particular industry (excluding U.S. government securities).

JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998 5

<PAGE>

PORTFOLIO TURNOVER
The Portfolio generally intends to purchase securities for long-term investment
rather than short-term gains. However, short-term transactions may result from
liquidity needs, securities having reached a price or yield objective,
anticipated 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. Changes are made in the Portfolio whenever its portfolio
manager believes such changes are desirable. The portfolio turnover rate is
generally not a factor in making buy and sell decisions. The Portfolio's
turnover rate is not expected to exceed 200%.

To a limited extent, the Portfolio may purchase securities in anticipation of
relatively short-term price gains. 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. 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.

ILLIQUID INVESTMENTS
The Portfolio may invest up to 15% of its net assets in illiquid investments,
including restricted securities or private placements that are not deemed to be
liquid by Janus Capital. If illiquid securities exceed 15% of net assets after
the time of purchase, the Portfolio will take steps to reduce in an orderly
fashion its holdings of illiquid securities. An illiquid investment is a
security or other position that cannot be disposed of quickly in the normal
course of business. Some securities cannot be sold to the U.S. public because of
their terms or because of SEC regulations. Janus Capital will follow guidelines
established by the Trustees of the Trust ("Trustees") in making liquidity
determinations for Rule 144A securities and certain other securities, including
privately placed commercial paper.

BORROWING AND LENDING
The Portfolio may borrow money and lend securities or other assets, as follows:

- - The Portfolio may borrow money for temporary or emergency purposes in amounts
up to 25% of its total assets.

- - The Portfolio may mortgage or pledge securities as collateral for borrowings
in amounts up to 15% of its net assets.

- - As a fundamental policy, the Portfolio may lend securities or other assets if,
as a result, no more than 25% of its total assets would be lent to other
parties.

ADDITIONAL RISK FACTORS

SPECIAL SITUATIONS
The Portfolio may invest in "special situations" from time to time. A special
situation arises when, in the opinion of the Portfolio'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.
Investment in special situations may carry an additional risk of loss in the
event that the anticipated development does not occur or does not attract the
expected attention.

FOREIGN SECURITIES
INVESTMENTS IN FOREIGN SECURITIES, INCLUDING THOSE OF FOREIGN GOVERNMENTS, MAY
INVOLVE GREATER RISKS THAN INVESTING IN COMPARABLE DOMESTIC SECURITIES.

Securities of some foreign companies and governments may be traded in the United
States, but most foreign securities are traded primarily in foreign markets. The
risks of foreign investing include:

- - POLITICAL AND ECONOMIC RISK. Foreign investments may be subject to heightened
political and economic risks, particularly in underdeveloped or developing
countries which may have relatively unstable governments 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. The Portfolio may invest in emerging market countries.
Emerging market countries involve greater risks such as immature economic
structures, national policies restricting investments by foreigners, and
different legal systems.

- - MARKET RISK. Foreign securities markets, particularly those of underdeveloped
or developing countries, may be less liquid and more volatile than domestic
markets. Certain markets

6 JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998

<PAGE>

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. There may be limited legal recourse against an issuer in the
event of a default on a debt instrument.

- - TRANSACTION COSTS. Transaction costs of buying and selling foreign securities,
including brokerage, tax and custody costs, are generally higher than those
involved in domestic transactions.

FUTURES, OPTIONS AND OTHER DERIVATIVE INSTRUMENTS
The Portfolio may enter into futures contracts on securities, financial indices
and foreign currencies and options on such contracts ("futures contracts") and
may invest in options on securities, financial indices and foreign currencies
("options"), forward contracts and interest rate swaps and swap-related products
(collectively, "derivative instruments"). The Portfolio intends to use most
derivative instruments primarily to hedge the value of its portfolio holdings
against potential adverse movements in securities prices, foreign currency
markets or interest rates. To a limited extent, the Portfolio may also use
derivative instruments for non-hedging purposes such as seeking to increase the
Portfolio's income or otherwise seeking to enhance return. Please refer to
Appendix A to this Prospectus and the SAI for a more detailed discussion of
these instruments.

The use of derivative instruments exposes the Portfolio to additional investment
risks and transaction costs. Risks inherent in the use of derivative instruments
include:

- - the risk that interest rates, securities prices and currency markets will not
move in the directions that the portfolio manager anticipates;

- - imperfect correlation between the price of derivative instruments and
movements in the prices of the securities, interest rates or currencies being
hedged;

- - the fact that skills needed to use these strategies are different from those
needed to select portfolio securities;

- - inability to close out certain hedged positions to avoid adverse tax
consequences;

- - particularly in the case of privately negotiated instruments, the risk that
the counterparty will fail to perform its obligations, which could leave the
Portfolio worse off than if it had not entered into the position.

Although the portfolio manager believes the use of derivative instruments will
benefit the Portfolio, the Portfolio's performance could be worse than if it had
not used such instruments if the portfolio manager's judgment proves incorrect.

When the Portfolio invests in a derivative instrument, it may be required to
segregate cash and other liquid assets or portfolio securities with its
custodian to "cover" the Portfolio's position. Assets segregated or set aside
generally may not be disposed of so long as the Portfolio maintains the
positions requiring segregation or cover. Segregating assets could diminish the
Portfolio's return due to the opportunity losses of foregoing other potential
investments with the segregated assets.

The value of lower quality securities generally is more dependent on the ability
of the issuer to meet interest and principal payments (i.e., credit risk) than
is the case for higher quality securities. Conversely, the value of higher
quality securities may be more sensitive to interest rate movements than lower
quality securities. Issuers of high-yield securities may not be as strong
financially as those issuing bonds with higher credit ratings. Investments in
such companies are considered to be more speculative than higher quality
investments.

Issuers of high-yield securities may be more vulnerable to real or perceived
economic changes (for instance, an economic downturn or prolonged period of
rising interest rates), political changes or adverse developments specific to
the issuer. Adverse economic, political or other developments may impair the
issuer's ability to service principal and interest obligations, to meet
projected business goals and to obtain additional financing, particularly if the
issuer is highly leveraged. In the event of a default, the Portfolio would
experience a reduction of its income and could expect a decline in the market
value of the defaulted securities.

The market for lower quality securities is generally less liquid than the market
for higher quality securities. Adverse publicity and investor perceptions as
well as new or proposed laws may also have a greater negative impact on the
market for lower quality securities. Unrated debt, while not necessarily of
lower quality than rated securities, may not have as broad a market as rated
securities. Sovereign debt of foreign governments is generally rated by country.
Because these ratings do not take into account individual factors relevant to
each issue and may not be updated regularly, Janus Capital may treat such
securities as unrated debt.

JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998 7

<PAGE>

The market prices of high-yield/high-risk securities structured as zero coupon
or pay-in-kind securities are generally affected to a greater extent by interest
rate changes and tend to be more volatile than securities which pay interest
periodically. In addition, zero coupon, pay-in-kind and delayed interest bonds
often do not pay interest until maturity. However, the Portfolio must recognize
imputed interest income and pay dividends to shareholders even though it has
received no cash. In some instances, the Portfolio may have to sell securities
to have sufficient cash to pay the dividends.

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

SHORT SALES

The Portfolio may engage in "short sales against the box." This technique
involves selling either a security that the Portfolio owns, or a security
equivalent in kind and amount to the security sold short that the Portfolio has
the right to obtain, for delivery at a specified date in the future. The
Portfolio may enter into a short sale against the box to hedge against
anticipated declines in the market price of portfolio securities. If the value
of the securities sold short increases prior to the scheduled delivery date, the
Portfolio loses the opportunity to participate in the gain.

See Appendix A for risks associated with certain other investments.

8 JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998

<PAGE>

MANAGEMENT OF THE PORTFOLIO

TRUSTEES

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 its investment portfolio and other business affairs.

The Portfolio pays all of its expenses not assumed by Janus Capital, including
transfer agent and custodian fees and expenses, legal and auditing fees,
registration fees and expenses, and independent Trustees' fees and expenses and
certain other expenses. 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.

PORTFOLIO MANAGER

DAVID J. CORKINS is Executive Vice President and portfolio manager of the
Portfolio which he has managed since its inception. He is Executive Vice
President and portfolio manager of Janus Growth and Income Fund which he has
managed since August 1997. He previously served as an assistant portfolio
manager of Janus Mercury Fund. He joined Janus in 1995 as a research analyst
specializing in domestic financial services companies and a variety of foreign
industries. Prior to joining Janus, he was the Chief Financial Officer of Chase
U.S. Consumer Services, Inc., a Chase Manhattan mortgage business. He holds a
Bachelor of Arts in English and Russian from Dartmouth and received his Master
of Business Administration from Columbia University in 1993.

PERSONAL INVESTING
Janus Capital does not permit portfolio managers to purchase and sell securities
for their own accounts, except under the limited exceptions contained in Janus
Capital's policy governing personal investing. Janus Capital's policy requires
investment and other personnel to conduct their personal investment activities
in a manner that Janus Capital believes is not detrimental to the Portfolio or
Janus Capital's other advisory clients. See the SAI for more detailed
information.

PORTFOLIO TRANSACTIONS
Purchases and sales of securities on behalf of the Portfolio are executed by
broker-dealers selected by Janus Capital. Broker-dealers are selected on the
basis of their ability to obtain best price and execution for the Portfolio's
transactions and recognizing brokerage, research and other services provided to
the Portfolio and to Janus Capital. Janus Capital may consider sales of shares
of the Portfolio or other Janus funds by a broker-dealer or the recommendation
of a broker-dealer to its customers that they purchase a Portfolio's shares as a
factor in the selection of broker-dealers to execute portfolio transactions.
Janus Capital may also consider payments made by brokers effecting transactions
for the Portfolio i) to the Portfolio or ii) to other persons on behalf of the
Portfolio for services provided to the Portfolio for which it would be obligated
to pay. The Portfolio's Trustees have authorized Janus Capital to place
portfolio transactions on an agency basis with a broker-dealer affiliated with
Janus Capital. When transactions for the Portfolio are effected with that
broker-dealer, the commissions payable by the Portfolio are credited against
certain Portfolio operating expenses. The SAI further explains the selection of
broker-dealers.

JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998 9

<PAGE>

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):

<TABLE>
<CAPTION>
AVERAGE DAILY
NET ASSETS ANNUAL RATE
FEE SCHEDULE OF PORTFOLIO PERCENTAGE(%)
- -----------------------------------------------------------------
<S> <C> <C>
First $300 Million 0.75*
Next $200 Million 0.70
Next $200 Million 0.65
- -----------------------------------------------------------------
</TABLE>

* Janus Capital has agreed to reduce the Portfolio's advisory fee to the
extent that such fee exceeds the effective rate of Janus Growth and Income
Fund, the Janus retail fund corresponding to the Portfolio. Janus Capital
may terminate this fee reduction at any time upon at least 90 days' notice
to the Trustees. The effective rate is the advisory fee calculated by the
corresponding retail fund as of the last day of each calendar quarter
(expressed as an annual rate). The effective rate of Janus Growth and Income
Fund was .67% for the quarter ended March 31, 1998. In addition, Janus
Capital has agreed to limit the expenses of the Portfolio's Shares to an
annual rate of 1.25% of average net assets through at least May 1, 1999.

OTHER SERVICE PROVIDERS
The following parties provide the Portfolio with administrative and other
services.

CUSTODIAN
State Street Bank and Trust Company
P.O. Box 0351
Boston, Massachusetts 02117-0351

TRANSFER AGENT
Janus Service Corporation
P.O. Box 173375
Denver, Colorado 80217-3375

Janus Service Corporation is a wholly-owned subsidiary of Janus Capital.

OTHER INFORMATION
ORGANIZATION
The Trust is an open-end management investment company organized as a Delaware
business trust on May 20, 1993. The Portfolio has been established as a separate
series of the Trust.

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

SHAREHOLDER MEETINGS
The Trust does not intend to hold annual shareholder meetings. However, special
meetings may be called for a specific Portfolio or for the Trust as a whole for
purposes such as electing or removing Trustees, terminating or reorganizing the
Trust, changing fundamental policies, or for any other purpose requiring a
shareholder vote under the 1940 Act. Separate votes are taken by each class or
Portfolio only if a matter affects or requires the vote of only that class or
Portfolio or the interest of the class or Portfolio in the matter differs from
the interest of the other class or Portfolios of the Trust. As a shareholder,
you are entitled to one vote for each share that you own.

An insurance company issuing a variable contract invested in shares of the
Portfolio will request voting instructions from variable contract holders. Under
current law, the insurance company must vote all shares held by the separate
account in proportion to the voting instructions received.

CONFLICTS OF INTEREST

Portfolio shares 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. Although the Portfolio does
not currently anticipate any disadvantages to policy owners arising out of the
fact that the Portfolio offers its shares to such entities, there is a
possibility that disadvantages could occur or that a material conflict may
arise. The Trustees monitor events in order to identify any anticipated
disadvantages or material irreconcilable conflicts that may arise 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 plans to withdraw its investments in the Portfolio
or substitute shares of another Portfolio. As a result, the Portfolio may be
forced to sell securities at disadvantageous prices. In addition, the Trustees
may refuse to sell shares of the Portfolio to any separate account or may
suspend or terminate the offering of shares of the Portfolio 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

10 JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998

<PAGE>

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.

MASTER/FEEDER OPTION

The Trust may in the future seek to achieve the Portfolio's investment objective
by investing all of the Portfolio's assets in another investment company having
the same investment objective and substantially the same investment policies and
restrictions as those applicable to the Portfolio. Unless otherwise required by
law, this policy may be implemented by the Trustees without shareholder
approval.

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 entered
into a consulting arrangement with one of the foremost experts in Year 2000
compliance to help Janus Capital successfully achieve Year 2000 compliance.
Janus Capital does not anticipate that the move to Year 2000 will have a
material impact on its ability to continue to provide the Portfolio with service
at current levels.

THE VALUATION OF SHARES
The net asset value ("NAV") of the Shares of the Portfolio is determined at the
close of the regular trading session of the New York Stock Exchange (the "NYSE")
(normally 4:00 p.m., New York time) each day that the NYSE is open. NAV per
Share is determined by dividing the total value of the securities and other
assets, less liabilities, by the total number of Shares outstanding.

Securities are valued at market value or, if market information 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.

JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998 11

<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. ORDINARY 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, IF ANY, ARE PAID TO SHAREHOLDERS AS CAPITAL GAINS
DISTRIBUTIONS. EACH CLASS OF THE PORTFOLIO MAKES SEMIANNUAL 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 THE SHARES OF THE PORTFOLIO WILL BE
AUTOMATICALLY REINVESTED INTO ADDITIONAL SHARES OF THE PORTFOLIO.

HOW DISTRIBUTIONS AFFECT THE PORTFOLIO'S NAV

Distributions other than daily income dividends 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 drops by the amount of
the distribution, net of any subsequent market fluctuations. For example, assume
that on December 31, the Shares of the Portfolio declared a dividend in the
amount of $0.25 per share. If the price of the Portfolio's Shares was $10.00 on
December 30, the Share price on December 31 would be $9.75, barring market
fluctuations.

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 as a foreign tax credit.
If such an election is not made, any foreign taxes paid or accrued will
represent an expense to the Portfolio which will reduce its investment income.

12 JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998

<PAGE>

PERFORMANCE TERMS

This section will help you understand various terms that are commonly used to
describe the Portfolio's performance. You may see references to these terms in
our newsletters, advertisements (or those published by participating insurance
companies) and in media articles. Newsletters and advertisements may include
comparisons of the Portfolio's performance to the performance of other mutual
funds, mutual fund averages or recognized stock market indices. The Portfolio
generally measures performance in terms of total return.

CUMULATIVE TOTAL RETURN represents the actual rate of return on an investment
for a specified period. Cumulative total return is generally quoted for more
than one year (e.g., the life of the Portfolio). A cumulative total return does
not show interim fluctuations in the value of an investment.

AVERAGE ANNUAL TOTAL RETURN represents the average annual percentage change of
an investment over a specified period. It is calculated by taking the cumulative
total return for the stated period and determining what constant annual return
would have produced the same cumulative return. Average annual returns for more
than one year tend to smooth out variations in the Portfolio's return and are
not the same as actual annual results.

THE PORTFOLIO IMPOSES NO SALES OR OTHER CHARGES THAT WOULD AFFECT TOTAL RETURN
COMPUTATIONS. TOTAL RETURN FIGURES OF THE PORTFOLIO INCLUDE THE EFFECT OF
DEDUCTING THE PORTFOLIO'S EXPENSES, BUT MAY NOT INCLUDE CHARGES AND EXPENSES
ATTRIBUTABLE TO ANY PARTICULAR INSURANCE PRODUCT. PORTFOLIO PERFORMANCE FIGURES
ARE BASED UPON HISTORICAL RESULTS AND ARE NOT INTENDED TO INDICATE FUTURE
PERFORMANCE. INVESTMENT RETURNS AND NET ASSET VALUE WILL FLUCTUATE SO THAT
SHARES, WHEN REDEEMED, MAY BE WORTH MORE OR LESS THAN THEIR ORIGINAL COST.

JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998 13

<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 A VARIABLE INSURANCE CONTRACT AND ON HOW TO SELECT THE
PORTFOLIO AS AN INVESTMENT OPTION FOR A CONTRACT OR A QUALIFIED PLAN.

PURCHASES
Purchases of Portfolio 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's separate account or to your plan documents for information on how to
invest in the Shares of the Portfolio.

All investments in the Portfolio are credited to a participating insurance
company's separate account or a qualified plan immediately upon acceptance of
the investment by the Portfolio. Investments will be processed at the NAV next
calculated after an order is received and accepted by the Portfolio.

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 the size that
would disrupt the management of the Portfolio. The Portfolio may discontinue
sales of its shares if management believes that a substantial further increase
may adversely affect the Portfolio's ability to achieve its investment
objective. In such event, however, it is anticipated 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 distribution.

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 market values thereof, as well as other information
about the Portfolio and its operations. The Trust's fiscal year ends December
31.

14 JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998

<PAGE>

APPENDIX A

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
under Section 4(2) of the Securities Act of 1933.

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.

HIGH-YIELD/HIGH-RISK SECURITIES are securities that are rated below investment
grade by the primary rating agencies (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 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.

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.

JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998 15

<PAGE>

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.

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 bears the risk of market value
fluctuations 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 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. The Portfolio may also
enter into forward contracts to purchase or sell securities or other financial
indices.

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).

16 JANUS ASPEN SERIES PROSPECTUS -- GROWTH AND INCOME PORTFOLIO MAY 1, 1998

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<PAGE>
JANUS ASPEN SERIES
PROSPECTUS

Growth and Income Portfolio

[LOGO] P.O. Box 173375 o Denver, CO 80217-3375 o 1-800-525-1068

<PAGE>

JANUS ASPEN SERIES
GROWTH AND INCOME PORTFOLIO
RETIREMENT SHARES

Prospectus

MAY 1, 1998

Growth and Income Portfolio (the "Portfolio") is a no-load, diversified mutual
fund that seeks long-term growth of capital with a limited emphasis on income.
Although the Portfolio normally invests at least 25% of its assets in securities
that have income potential, it emphasizes equity securities selected for their
growth potential. The Portfolio is a series of Janus Aspen Series (the "Trust"),
an open-end management investment company. The Portfolio is recently organized
and has a limited operating history.

The Retirement Shares of the Portfolio (the "Shares") offered by this Prospectus
are issued in connection with certain participant directed qualified retirement
plans. The Trust sells and redeems its Shares at net asset value without any
sales charges, commissions or redemption fees.

This Prospectus contains information about the Shares that a prospective plan
participant should consider before investing and should be read carefully and
retained for future reference. Additional information about the Portfolio is
contained in the Statement of Additional Information ("SAI") dated May 1, 1998,
which is filed with the Securities and Exchange Commission ("SEC") and is
incorporated by reference into this Prospectus. The SAI is available upon
request and without charge by writing or calling your plan sponsor.

THESE SECURITIES HAVE NOT BEEN APPROVED BY THE SEC NOR HAS THE SEC PASSED ON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

THIS PROSPECTUS DOES NOT CONSTITUTE AN OFFER TO SELL SECURITIES IN ANY STATE OR
OTHER JURISDICTION TO ANY PERSON TO WHOM IT IS UNLAWFUL TO MAKE SUCH AN OFFER IN
SUCH STATE OR OTHER JURISDICTION.

JANUS ASPEN SERIES GROWTH AND INCOME PORTFOLIO PROSPECTUS -- RETIREMENT
SHARES MAY 1, 1998

<PAGE>

CONTENTS

<TABLE>
<S> <C>
PORTFOLIO AT A GLANCE
Brief description of the Portfolio.......................... 2
EXPENSE INFORMATION......................................... 3
THE PORTFOLIO IN DETAIL
The Portfolio's Investment Objective and Policies........... 4
General Portfolio Policies.................................. 5
Additional Risk Factors..................................... 6
MANAGEMENT OF THE PORTFOLIO
Investment Adviser and Portfolio Manager.................... 8
Personal Investing.......................................... 8
Portfolio Transactions...................................... 8
Management Expenses and Expense Limits...................... 9
Other Service Providers..................................... 9
Participant Administration Fee and Distribution Fee......... 9
Other Information........................................... 9
DISTRIBUTIONS AND TAXES
Distributions............................................... 11
Taxes....................................................... 11
PERFORMANCE TERMS
An Explanation of Performance Terms......................... 11
SHAREHOLDER'S GUIDE
Purchases................................................... 12
Redemptions................................................. 12
Shareholder Communications.................................. 12
APPENDIX A
Glossary of Investment Terms................................ 13
</TABLE>

JANUS ASPEN SERIES GROWTH AND INCOME PORTFOLIO PROSPECTUS -- RETIREMENT
SHARES MAY 1, 1998 1

<PAGE>

PORTFOLIO AT A GLANCE

INVESTMENT OBJECTIVE:
The investment objective of the Portfolio is long-term capital growth and
current income.

PRIMARY HOLDINGS:

SHAREHOLDER'S INVESTMENT HORIZON:
The Portfolio is designed for long-term investors who seek growth of capital
with a limited emphasis on income. The Portfolio is not designed for investors
who desire a consistent level of income nor is it a short-term trading vehicle
and should not be relied upon for short-term financial needs.

PORTFOLIO ADVISER:

PORTFOLIO MANAGER:

David J. Corkins

PORTFOLIO INCEPTION:

May 1998

2 JANUS ASPEN SERIES GROWTH AND INCOME PORTFOLIO PROSPECTUS -- RETIREMENT
SHARES MAY 1, 1998

<PAGE>

EXPENSE INFORMATION

SHAREHOLDER TRANSACTION EXPENSES

ANNUAL OPERATING EXPENSES (after fee waivers and reductions)(1)
(expressed as a percentage of average net assets)

<TABLE>
<S> <C>
- -------------------------------------------------------------------

Management Fee(1) 0.67%
12b-1 Fee(2) 0.25%
Other Expenses(1,3) 0.55%
- -------------------------------------------------------------------
Total Operating Expenses(1) 1.47%
- -------------------------------------------------------------------
</TABLE>

(1) The fees and expenses in the table above are based on the estimated gross
expenses before estimated expense offset arrangements that the Shares of the
Portfolio expect to incur their initial fiscal year, net of fee reductions
or waivers from Janus Capital. Fee reductions reduce the management fee to
the level of the corresponding Janus retail fund. Other waivers, if
applicable, are first applied against the management fee and then against
other expenses. Without such waivers or reductions, the Management Fee,
Other Expenses and Total Operating Expenses are estimated to be 0.75%, 0.55%
and 1.55%, respectively. Janus Capital may modify or terminate the waivers
or reductions at any time upon at least 90 days' notice to the Trustees.
Janus Capital has agreed to limit the expenses of the Portfolio's Shares to
an annual rate of 1.25% of average net assets through at least May 1, 1999.
The participant administration fee and distribution fee are not included in
the expense limit.

(2) Long-term shareholders may pay more than the economic equivalent of the
maximum front-end sales charges permitted by the National Association of
Securities Dealers, Inc.
(3) Includes compensation to service providers who provide recordkeeping,
subaccounting and other administrative services to plan participants who
invest in the Shares. See "Participant Administration Fee" for more details.

EXAMPLE

Assume you invest $1,000, the Shares of the Portfolio
returns 5% annually and its expense ratio remains as listed
above. The example shows the operating expenses that you
would indirectly bear as an investor in the Shares of the
Portfolio. $15 $46
------------------------------------------------------------------------------------
</TABLE>

THE EXAMPLE SHOULD NOT BE CONSIDERED A REPRESENTATION OF PAST OR FUTURE RETURNS
OR EXPENSES WHICH MAY BE MORE OR LESS THAN THOSE SHOWN.

FINANCIAL HIGHLIGHTS

No Financial Highlights are presented for the Shares because the Shares did not
commence operations before May 1, 1998.

JANUS ASPEN SERIES GROWTH AND INCOME PORTFOLIO PROSPECTUS -- RETIREMENT
SHARES MAY 1, 1998 3

<PAGE>

THE PORTFOLIO IN DETAIL

INVESTMENT OBJECTIVE

TYPES OF INVESTMENTS
The Portfolio invests primarily in common stocks of domestic and foreign
companies. The Portfolio may invest to a lesser degree in other types of
securities including preferred stock, warrants, convertible securities and debt
securities when its portfolio manager perceives an opportunity for capital
growth from such securities or to receive a return on idle cash. The Portfolio
may purchase securities on a when-issued, delayed delivery or forward commitment
basis. The Portfolio may invest up to 25% of its assets in mortgage- and
asset-backed securities, up to 10% of its assets in zero coupon, pay-in-kind and
step coupon securities, and without limit in indexed/structured securities. The
Portfolio will invest less than 35% of its assets in high-yield/high-risk
securities.

See Appendix A for a further description of the Portfolio's investments.

THE FOLLOWING QUESTIONS ARE DESIGNED TO HELP YOU BETTER UNDERSTAND AN INVESTMENT
IN THE PORTFOLIO.

A: HOW ARE EQUITY SECURITIES SELECTED?

Q:
HOW ARE ASSETS ALLOCATED BETWEEN THE GROWTH AND INCOME COMPONENT OF THE
A: PORTFOLIO?

The Portfolio may invest in a combination of common stocks, preferred
stocks, convertible securities, debt securities and other fixed-income
securities. The Portfolio may shift assets between the growth and income
components of its portfolio based on the portfolio manager's analysis of
relevant market, financial and economic conditions. If the portfolio manager
believes that growth securities will provide better returns than the yields then
available or expected on income-producing securities, the Portfolio will place a
greater emphasis on the growth component.

4 JANUS ASPEN SERIES GROWTH AND INCOME PORTFOLIO PROSPECTUS -- RETIREMENT
SHARES MAY 1, 1998

<PAGE>

Q:
A: WHAT TYPES OF SECURITIES MAKE UP THE INCOME COMPONENT OF THE PORTFOLIO?

Q:
A: ARE THE SAME CRITERIA USED TO SELECT FOREIGN SECURITIES?

Q:
A: HOW DOES THE PORTFOLIO TRY TO REDUCE RISK?

CASH POSITION
When the Portfolio's manager believes that market conditions are not favorable
for profitable investing or when the portfolio manager is otherwise unable to
locate favorable investment opportunities, the Portfolio's investments may be
hedged to a greater degree and/or its 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 are a residual -- they represent the assets
that remain after a portfolio manager has committed available assets to
desirable investment opportunities. Larger hedged positions and/or larger cash
positions may serve as a means of preserving capital in unfavorable market
conditions.

Securities that the Portfolio may invest in as means of receiving a return on
idle cash include high-grade commercial paper, certificates of deposit,
repurchase agreements or other short-term debt obligations. The Portfolio may
also invest in money market funds (including funds managed by Janus Capital).
When a Portfolio is hedged or its investments in cash or similar investments
increase, it may not participate in stock or bond market advances or declines to
the same extent that it would if the Portfolio was not hedged or remained more
fully invested in stocks or bonds.

- - As a fundamental policy, the Portfolio may not own more than 10% of the
outstanding voting shares of any issuer.

- - The Portfolio will invest no more than 25% of its total assets in a single
issuer (other than U.S. government securities).

INTERNAL REVENUE SERVICE (IRS) LIMITATIONS
In addition to the diversification requirements stated above, because a class of
shares of the Portfolio is sold in connection with variable annuity contracts
and variable life insurance contracts, the Portfolio intends to comply with the
diversification requirements currently imposed by the IRS on separate accounts
of insurance companies as a condition of maintaining the tax-deferred status of
variable contracts.

INDUSTRY CONCENTRATION
As a fundamental policy, the Portfolio will not invest 25% or more of its total
assets in any particular industry (excluding U.S. government securities).

JANUS ASPEN SERIES GROWTH AND INCOME PORTFOLIO PROSPECTUS -- RETIREMENT
SHARES MAY 1, 1998 5

<PAGE>

whenever its portfolio manager believes such changes are desirable. The
portfolio turnover rate is generally not a factor in making buy and sell
decisions. The Portfolio's turnover rate is not expected to exceed 200%.

To a limited extent, the Portfolio may purchase securities in anticipation of
relatively short-term price gains. 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. 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.

ILLIQUID INVESTMENTS
The Portfolio may invest up to 15% of its net assets in illiquid investments,
including restricted securities or private placements that are not deemed to be
liquid by Janus Capital. If illiquid securities exceed 15% of net assets after
the time of purchase, the Portfolio will take steps to reduce in an orderly
fashion its holdings of illiquid securities. An illiquid investment is a
security or other position that cannot be disposed of quickly in the normal
course of business. Some securities cannot be sold to the U.S. public because of
their terms or because of SEC regulations. Janus Capital will follow guidelines
established by the Trustees of the Trust ("Trustees") in making liquidity
determinations for Rule 144A securities and certain other securities, including
privately placed commercial paper.

BORROWING AND LENDING
The Portfolio may borrow money and lend securities or other assets, as follows:

- - The Portfolio may borrow money for temporary or emergency purposes in amounts
up to 25% of its total assets.

- - The Portfolio may mortgage or pledge securities as collateral for borrowings
in amounts up to 15% of its net assets.

- - As a fundamental policy, the Portfolio may lend securities or other assets if,
as a result, no more than 25% of its total assets would be lent to other
parties.

ADDITIONAL RISK FACTORS

FOREIGN SECURITIES
INVESTMENTS IN FOREIGN SECURITIES, INCLUDING THOSE OF FOREIGN GOVERNMENTS, MAY
INVOLVE GREATER RISKS THAN INVESTING IN COMPARABLE DOMESTIC SECURITIES.

Securities of some foreign companies and governments may be traded in the United
States, but most foreign securities are traded primarily in foreign markets. The
risks of foreign investing include:

- - POLITICAL AND ECONOMIC RISK. Foreign investments may be subject to heightened
political and economic risks, particularly in underdeveloped or developing
countries which may have relatively unstable governments 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. The Portfolio may invest in emerging market countries.
Emerging market countries involve greater risks such as immature economic
structures, national policies restricting investments by foreigners, and
different legal systems.

- - TRANSACTION COSTS. Transaction costs of buying and selling foreign securities,
including brokerage, tax and custody costs, are generally higher than those
involved in domestic transactions.

6 JANUS ASPEN SERIES GROWTH AND INCOME PORTFOLIO PROSPECTUS -- RETIREMENT
SHARES MAY 1, 1998