SUPPLEMENT TO THE FIDELITY(registered trademark) AGGRESSIVE GROWTH
FUND (FORMERLY FIDELITY EMERGING GROWTH FUND) JANUARY 29, 1999
PROSPECTUS

The Board of Trustees of Fidelity Aggressive Growth Fund has
authorized an increase in the redemption fee (payable to the fund)
from 0.75% to 1.50% of the amount redeemed on shares held less than 90
days that are redeemed on or after March 20, 2000.

The following information replaces the "Shareholder Fees" section of
the "Fee Table" on page 4.

SHAREHOLDER FEES (PAID BY THE INVESTOR DIRECTLY)

Sales charge (load) on         None
purchases and reinvested
distributions

Deferred sales charge (load)   None
on redemptions

Redemption fee on shares held  0.75%
less than 90 days that are
redeemed before March 20,
2000 (as a % of amount
redeemed)

Redemption fee on shares held  1.50%
less than 90 days that are
redeemed on or after March
20, 2000 (as a % of amount
redeemed)

Annual account maintenance     $12.00
fee (for accounts under
$2,500)

The following information replaces the second paragraph found under
the heading "Selling Shares" in the "Buying and Selling Shares"
section on page 12.

The fund will deduct a short-term trading fee of 0.75% from the
redemption amount if you sell your shares before March 20, 2000 after
holding them less than 90 days, and will deduct a short-term trading
fee of 1.50% from the redemption amount if you sell your shares on or
after March 20, 2000 after holding them less than 90 days. This fee is
paid to the fund rather than Fidelity, and is designed to offset the
brokerage commissions, market impact, and other costs associated with
fluctuations in fund asset levels and cash flow caused by short-term
shareholder trading.

SUPPLEMENT TO THE
FIDELITY(registered trademark) AGGRESSIVE GROWTH FUND
(FORMERLY FIDELITY EMERGING GROWTH FUND)
A FUND OF FIDELITY MT. VERNON STREET TRUST
JANUARY 29, 1999
STATEMENT OF ADDITIONAL INFORMATION

THE FOLLOWING INFORMATION REPLACES PARAGRAPH (III) IN THE "INVESTMENT
POLICIES AND LIMITATIONS" SECTION BEGINNING ON PAGE 2.

(iii) The fund may borrow money only (a) from a bank or from a
registered investment company or portfolio for which FMR or an
affiliate serves as investment adviser or (b) by engaging in reverse
repurchase agreements with any party (reverse repurchase agreements
are treated as borrowings for purposes of fundamental investment
limitation (3)).

THE FOLLOWING INFORMATION REPLACES PARAGRAPH (V) FOUND IN THE
"INVESTMENT POLICIES AND LIMITATIONS" SECTION BEGINNING ON PAGE 2.

(v) The fund does not currently intend to lend assets other than
securities to other parties, except by (a) lending money (up to 15% of
the fund's net assets) to a registered investment company or portfolio
for which FMR or an affiliate serves as investment adviser or (b)
acquiring loans, loan participations, or other forms of direct debt
instruments and, in connection therewith, assuming any associated
unfunded commitments of the sellers. (This limitation does not apply
to purchases of debt securities or to repurchase agreements.)

THE FOLLOWING INFORMATION REPLACES SIMILAR INFORMATION FOUND IN THE
"INVESTMENT POLICIES AND LIMITATIONS" SECTION UNDER THE HEADING
"EXPOSURE TO FOREIGN MARKETS" BEGINNING ON PAGE 3.

It is anticipated that in most cases the best available market for
foreign securities will be on an exchange or in over-the-counter (OTC)
markets located outside of the United States. Foreign stock markets,
while growing in volume and sophistication, are generally not as
developed as those in the United States, and securities of some
foreign issuers may be less liquid and more volatile than securities
of comparable U.S. issuers. Foreign security trading, settlement and
custodial practices (including those involving securities settlement
where fund assets may be released prior to receipt of payment) are
often less developed than those in U.S. markets, and may result in
increased risk or substantial delays in the event of a failed trade or
the insolvency of, or breach of duty by, a foreign broker-dealer,
securities depository or foreign subcustodian. For example, many
foreign countries are less prepared than the United States to properly
process and calculate information related to dates from and after
January 1, 2000. As a result, some foreign markets, brokers, banks or
securities depositories could experience at least temporary
disruptions, which could result in difficulty buying and selling
securities in certain foreign markets and pricing foreign investments,
and foreign issuers could fail to pay timely dividends, interest or
principal. In addition, the costs associated with foreign investments,
including withholding taxes, brokerage commissions and custodial
costs, are generally higher than with U.S. investments.

   THE FOLLOWING INFORMATION SUPPLEMENTS INFORMATION FOUND IN THE
"PERFORMANCE" SECTION BEGINNING ON PAGE 12.

   The Board of Trustees of Fidelity Aggressive Growth Fund has
authorized an increase in the redemption fee (payable to the fund)
from 0.75% to 1.50% of the amount redeemed on shares held less than 90
days that are redeemed on or after March 20, 2000.

   THE FOLLOWING INFORMATION REPLACES SIMILAR INFORMATION FOUND IN THE
"PERFORMANCE" SECTION BEGINNING ON PAGE 12.

   CALCULATING HISTORICAL FUND RESULTS. The following table shows
performance for the fund. Returns do not include the effect of the
fund's 0.75% short-term trading fee, applicable to shares held less
than 90 days that are redeemed before March 20, 2000.

   THE FOLLOWING INFORMATION REPLACES SIMILAR INFORMATION FOUND IN THE
"PERFORMANCE" SECTION BEGINNING ON PAGE 12.

   Explanatory Notes: With an initial investment of $10,000 in the
fund on December 28, 1990, the net amount invested in fund shares was
$10,000. The cost of the initial investment ($10,000) together with
the aggregate cost of reinvested dividends and capital gain
distributions for the period covered (their cash value at the time
they were reinvested) amounted to $24,879. If distributions had not
been reinvested, the amount of distributions earned from the fund over
time would have been smaller, and cash payments for the period would
have amounted to $20 for dividends and $11,890 for capital gain
distributions. The figures in the table do not include the effect of
the fund's 3.00% sales charge (which was in effect during the period
January 1, 1992 through September 30, 1998) or its 0.75% short-term
trading fee applicable to shares held less than 90 days that are
redeemed before March 20, 2000.

THE FOLLOWING INFORMATION FOUND IN THE "TRUSTEES AND OFFICERS" SECTION
BEGINNING ON PAGE 16 HAS BEEN REMOVED.

LEONARD M. RUSH (52), Assistant Treasurer (1994), is an employee of
FMR (1994). Prior to becoming Assistant Treasurer of the Fidelity
funds, Mr. Rush was Chief Compliance Officer of FMR Corp. (1993-1994)
and Chief Financial Officer of Fidelity Brokerage Services, Inc.
(1990-1993).

THE FOLLOWING INFORMATION SUPPLEMENTS THE INFORMATION FOUND IN THE
"TRUSTEES AND OFFICERS" SECTION BEGINNING ON PAGE 16.

NED C. LAUTENBACH (55), Member of the Advisory Board (1999), has been
a partner of Clayton, Dubilier & Rice, Inc. (private equity investment
firm) since September 1998. Mr. Lautenbach was Senior Vice President
of IBM Corporation from 1992 until his retirement in July 1998. From
1993 to 1995 he was Chairman of IBM World Trade Corporation. He also
was a member of IBM's Corporate Executive Committee from 1994 to July
1998. He is a Director of PPG Industries Inc. (glass, coating and
chemical manufacturer), Dynatech Corporation (global communications
equipment), Eaton Corporation (global manufacturer of highly
engineered products) and ChoicePoint Inc. (data identification,
retrieval, storage, and analysis).

THE FOLLOWING INFORMATION REPLACES THE COMPENSATION TABLE FOUND IN THE
"TRUSTEES AND OFFICERS" SECTION BEGINNING ON PAGE 16.

The following table sets forth information describing the compensation
of each Trustee and Member of the Advisory Board of the fund for his
or her services for the fiscal year ended November 30, 1998, or
calendar year ended December 31, 1998, as applicable.



                                                    
COMPENSATION TABLE

Trustees and Members of the  Aggregate Compensation from  Total Compensation from the
Advisory Board               Aggressive Growth FundB,C,D  Fund Complex*,A

Edward C. Johnson 3d**       $ 0                          $ 0

J. Gary Burkhead**           $ 0                          $ 0

Ralph F. Cox                 $ 768                        $ 223,500

Phyllis Burke Davis          $ 763                        $ 220,500

Robert M. Gates              $ 774                        $ 223,500

E. Bradley Jones             $ 768                        $ 222,000

Donald J. Kirk               $ 784                        $ 226,500

Ned C. Lautenbach***         $ 0                          $ 0

Peter S. Lynch**             $ 0                          $ 0

William O. McCoy             $ 774                        $ 223,500

Gerald C. McDonough          $ 952                        $ 273,500

Marvin L. Mann               $ 763                        $ 220,500

Robert C. Pozen**            $ 0                          $ 0

Thomas R. Williams           $ 774                        $ 223,500



* Information is for the calendar year ended December 31, 1998 for 237
funds in the complex.

** Interested Trustees of the fund and Mr. Burkhead are compensated by
FMR.

*** Effective October 14, 1999, Mr. Lautenbach serves as a Member of
the Advisory Board.

A Compensation figures include cash, amounts required to be deferred,
and may include amounts deferred at the election of Trustees. For the
calendar year ended December 31, 1998, the Trustees accrued required
deferred compensation from the funds as follows: Ralph F. Cox,
$75,000; Phyllis Burke Davis, $75,000; Robert M. Gates, $75,000; E.
Bradley Jones, $75,000; Donald J. Kirk, $75,000; William O. McCoy,
$75,000; Gerald C. McDonough, $87,500; Marvin L. Mann, $75,000; and
Thomas R. Williams, $75,000. Certain of the non-interested Trustees
elected voluntarily to defer a portion of their compensation as
follows: Ralph F. Cox, $55,039; Marvin L. Mann, $55,039; Thomas R.
Williams, $63,433; and William O. McCoy, $55,039.

B Compensation figures include cash, and may include amounts required
to be deferred and amounts deferred at the election of Trustees.

C The following amounts are required to be deferred by each
non-interested Trustee: Ralph F. Cox, $348; Phyllis Burke Davis, $348;
Robert M. Gates, $348; E. Bradley Jones, $348; Donald J. Kirk, $348;
William O. McCoy, $348; Gerald C. McDonough, $407; Marvin L. Mann,
$348; and Thomas R. Williams, $348.

D Certain of the non-interested Trustees' aggregate compensation from
the fund includes accrued voluntary deferred compensation as follows:
Ralph F. Cox, $295; Marvin L. Mann, $295; William O. McCoy, $270; and
Thomas R. Williams, $295.

THE FOLLOWING INFORMATION REPLACES THE "GROUP FEE RATE" AND "EFFECTIVE
ANNUAL FEE RATE" SCHEDULES FOUND ON PAGE 20.



                                                 
GROUP FEE RATE SCHEDULE                 EFFECTIVE ANNUAL FEE RATES

Average Group Assets  Annualized  Rate  Group Net Assets  Effective Annual Fee Rate

 0 - $3 billion       .5200%            $ 1 billion       .5200%

 3 - 6                .4900              50               .3823

 6 - 9                .4600              100              .3512

 9 - 12               .4300              150              .3371

 12 - 15              .4000              200              .3284

 15 - 18              .3850              250              .3219

 18 - 21              .3700              300              .3163

 21 - 24              .3600              350              .3113

 24 - 30              .3500              400              .3067

 30 - 36              .3450              450              .3024

 36 - 42              .3400              500              .2982

 42 - 48              .3350              550              .2942

 48 - 66              .3250              600              .2904

 66 - 84              .3200              650              .2870

 84 - 102             .3150              700              .2838

 102 - 138            .3100              750              .2809

 138 - 174            .3050              800              .2782

 174 - 210            .3000              850              .2756

 210 - 246            .2950              900              .2732

 246 - 282            .2900              950              .2710

 282 - 318            .2850              1,000            .2689

 318 - 354            .2800              1,050            .2669

 354 - 390            .2750              1,100            .2649

 390 - 426            .2700              1,150            .2631

 426 - 462            .2650              1,200            .2614

 462 - 498            .2600              1,250            .2597

 498 - 534            .2550              1,300            .2581

 534 - 587            .2500              1,350            .2566

 587 - 646            .2463              1,400            .2551

 646 - 711            .2426

 711 - 782            .2389

 782 - 860            .2352

 860 - 946            .2315

 946 - 1,041          .2278

 1,041 - 1,145        .2241

 1,145 - 1,260        .2204

 over - 1,260         .2167