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                                                                     EXHIBIT 5.1

                                December 14, 2000




LSI Logic Corporation
1551 McCarthy Boulevard
Milpitas, California 95035

        RE:  REGISTRATION STATEMENT ON FORM S-3

Ladies and Gentlemen:

        We have examined the Registration Statement on Form S-3 to be filed by
you with the Securities and Exchange Commission on or about December 14, 2000
(the "Registration Statement") in connection with the registration under the
Securities Act of 1933, as amended, of a total of 1,389,431 shares of your
Common Stock (the "Shares"), to be offered for sale by the Selling Stockholders
named therein. As legal counsel for LSI Logic Corporation, we have examined the
proceedings taken in connection with the sale of the Shares by the Selling
Stockholders in the manner set forth in the Registration Statement in the
Section entitled "Plan of Distribution." It is our opinion that the Shares are
legally and validly issued, fully paid and nonassessable.

        We consent to the use of this opinion as an exhibit to the Registration
Statement, including the prospectus constituting a part thereof, and further
consent to the use of our name wherever it appears in the Registration Statement
and any amendments thereto.

                                   Very truly yours,

                                   WILSON SONSINI GOODRICH & ROSATI
                                   Professional Corporation



                                   /s/ WILSON SONSINI GOODRICH & ROSATI