<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                        ---------------------------------
                                  FORM 10-K/A

(Mark One)
[X] ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
    EXCHANGE ACT OF 1934

For the fiscal year ended     September 30, 1999
                          ---------------------------

                                       OR

TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT
OF 1934

For the transition period from                        to
                               ----------------------    -----------------------
Commission file number       0-23084
                       -----------------

                        INTEGRATED SILICON SOLUTION, INC.
                        ---------------------------------
             (Exact name of Registrant as specified in its charter)


           DELAWARE                                      77-0199971
-------------------------------             ------------------------------------
(State or other jurisdiction of             (I.R.S. Employer Identification No.)
incorporation or organization)

2231 Lawson Lane, Santa Clara, California                     95054
---------------------------------------------               ----------
 (Address of principal executive offices)                    zip code

Registrant's telephone number, including area code (408) 588-0800
                                                   ---------------

Securities registered pursuant to Section 12(b) of the Act:

                                                      Name of each exchange
          Title of each class                          on which registered
COMMON STOCK, PAR VALUE $0.0001 PER SHARE            NASDAQ NATIONAL MARKET
-----------------------------------------            ----------------------

           Securities registered pursuant to Section 12(g) of the Act:

                                      NONE
                       -----------------------------------
                                (Title of Class)

      Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days. Yes [ X ] No [ ]

      Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K. [ X ]

      The aggregate market value of the voting stock held by non-affiliates of
the registrant, based upon the closing price of such stock on December 10, 1999,
as reported by the Nasdaq National Market, was approximately $192.0 million.
Shares of Common Stock held by each officer and director and by each person who
owns 5% or more of the outstanding Common Stock have been excluded in that such
persons may be deemed to be affiliates. This determination of affiliate status
is not necessarily a conclusive determination for other purposes.

      The number of outstanding shares of the registrant's Common Stock on
December 10, 1999 was 20,407,713.

                       DOCUMENTS INCORPORATED BY REFERENCE

      Portions of the Proxy Statement for the Registrant's 1999 Annual Meeting
of Stockholders to be held on February 7, 2000 are incorporated by reference in
Part III of this Form 10-K.


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                      AMENDED FILING OF FORM 10-K FOR 1999

This amendment is being filed for the sole purpose of filing as an Exhibit the
Audited Financial Statements of Integrated Circuit Solution Incorporation
(formerly known as Integrated Silicon Solution Taiwan Inc.).

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<TABLE>
<CAPTION>
     Exhibit
     Number       Description of Document
     --------     -----------------------
<S>               <C>
     2.1(6)       Agreement and Plan of Reorganization dated November 5,
                  1997 by and among the Company, Nexcom Technology, Inc. and
                  certain shareholders of Nexcom Technology, Inc.

     3.1(2)       Restated Certificate of Incorporation of Registrant.

     3.3(1)       Bylaws of Registrant.

     4.2(1)       Form of Common Stock Certificate.

     10.1(1)      Form of Indemnification Agreement.

     10.2(1)***   Form of 1993 Employee Stock Purchase Plan, as amended,
                  and form of Subscription Agreement.

     10.3(1)***   Form of 1989 Stock Plan, as amended, and form of Stock Option
                  Agreements.

     10.4 (1)     Information and Registration Rights Agreement dated as of
                  March 17, 1993 among the Registrant and certain holders of the
                  Registrant's Common Stock, as amended.

     10.5(1)*     Letter Agreement dated September 14, 1994 between Taiwan
                  Semiconductor Manufacturing Company, Ltd. ("TSMC") and the
                  Registrant.

     10.6(1)*     Joint Development Contract between Chartered Semiconductor
                  Manufacturing Pte. Ltd. and the Registrant dated July 21, 1994.

     10.7(1)      Subscription and Shareholders Agreement Relating to Valery
                  Limited dated March 30, 1994.

     10.8(1)      Long term line of credit between Bank of Communication and
                  Registrant.

     10.9(1)      Short term line of credit between International Commercial
                  Bank of China and Registrant.

     10.10(1)***  1995 Director Stock Option Plan.

     10.11(2)*    Option I Agreement between the Registrant and TSMC dated April
                  21, 1995.

     10.12(2)*    Option II Agreement between the Registrant and TSMC dated
                  April 21, 1995.

     10.13(3)*    UMC/ISSI-Taiwan Foundry Venture Agreement dated August 31,
                  1995.

     10.14(3)*    UMC/ISSI-Taiwan Fabven Foundry Capacity Agreement dated August
                  31, 1995.

     10.15(8)     Second Amended and Restated Limited Liability Company
                  Agreement of WaferTech, LLC, a Delaware limited liability
                  company, dated as of October 28, 1997.

     10.16(4)**   Purchase Agreement by and between Taiwan Semiconductor
                  Manufacturing Corporation, as Seller, and Analog Devices,
                  Inc., Altera Corporation and Integrated Silicon Solution,
                  Inc., as Buyers.

     10.17(5)*    Amendment to Option I and Option II Agreement between the
                  Company and TSMC dated September 23, 1996.

     10.18(5)     Sublease Agreement for facility located at 2231 Lawson Lane,
                  Santa Clara, California.

     10.19(7)***  Nonstatutory Stock Plan

     10.20(8)***  1998 ISSI-Taiwan Stock Plan

     10.21(9)***  1998 Stock Plan

     10.22        Financial Statements with Independent Auditors' Report for
                  Integrated Circuit Solution Incorporation

     21.1(1)      Subsidiaries of the Registrant

   + 23.1         Consent of Ernst & Young LLP, Independent Auditors

     24.1         Power of Attorney (see page 46).

   + 27.1         Financial Data Schedule

     +            Previously filed.

     *            Confidential treatment granted for certain portions of this
                  exhibit.

     **           Confidential treatment requested for certain portions of this
                  exhibit. The portions of this exhibit for which confidential
                  treatment is being requested have been blacked out in the
                  copies filed with the related report and the confidential
                  portions so omitted have been filed separately with the
                  Securities and Exchange Commission.

     ***          Management contract or compensatory plan or arrangement
                  required to be filed as an exhibit to this Report on Form 10-K
                  pursuant to form 14(c) of this report.

</TABLE>

(1)      Incorporated by reference to the Company's Registration Statement on
         Form S-1, as amended (file no. 33-72960).

(2)      Incorporated by reference to the Company's Registration Statement on
         Form S-1, as amended (file no. 33-91520)

(3)      Incorporated by reference to the Company's Annual Report on Form 10-K
         for the period ended September 30, 1995.

(4)      Incorporated by reference to the Company's Quarterly Report on Form
         10-Q for the period ended
         June 30, 1996.

(5)      Incorporated by reference to the Company's Annual Report on Form 10-K
         for the period ended
         September 30, 1996.

(6)      Incorporated by reference to the Company's Annual Report on Form 10-K
         for the period ended
         September 30, 1997.

(7)      Incorporated by reference to the Company's Registration Statement on
         Form S-8 filed April 30, 1997.

(8)      Incorporated by reference to the Company's Annual Report on Form 10-K
         for the period ended
         September 30, 1998

(9)      Incorporated by reference to the Company's Registration Statement on
         Form S-8 filed April 26, 1999.

       (b)Reports on Form 8-K

       (c)Exhibits
          See (a) above

       (d)Financial statement schedules
          See (a) above