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                                                                     EXHIBIT 5.1

                                  April 23,1999


Integrated Silicon Solution, Inc.
2231 Lawson Lane
Santa Clara, CA 95054

        RE:  REGISTRATION STATEMENT ON FORM S-8

Ladies and Gentlemen:

        We have examined the Registration Statement on Form S-8 to be filed by
you with the Securities and Exchange Commission on or about April 26, 1999 (the
"Registration Statement") in connection with the registration under the
Securities Act of 1933, as amended (the "Act"), of 500,000 shares of your Common
Stock issuable under your 1998 Stock Plan and 75,000 shares of your Common Stock
issuable under your 1995 Director Stock Option Plan. Such shares of Common Stock
are referred to herein as the "Shares" and the 1998 Stock Plan and the 1995
Director Stock Option Plan are referred to herein as the "Plans". As your
counsel in connection with this transaction, we have examined the proceedings
taken and are familiar with the proceedings proposed to be taken by you in
connection with the issuance and sale of the Shares pursuant to the Plans.

        It is our opinion that, upon completion of the actions being taken, or
contemplated by us as your counsel to be taken by you prior to the issuance of
the Shares pursuant to the Registration Statement and the Plans and upon
completion of the actions being taken in order to permit such transactions to be
carried out in accordance with the securities laws of the various states where
required, the Shares will be legally and validly issued, fully-paid and
non-assessable.

        We consent to the use of this opinion as an exhibit to the Registration
Statement, and further consent to the use of our name wherever appearing in the
Registration Statement and any amendments thereto.

                                            Very truly yours,

                                            WILSON SONSINI GOODRICH & ROSATI
                                            Professional Corporation

                                            /s/ WILSON SONSINI GOODRICH & ROSATI