EXHIBIT 5.1

                                 April 19, 2002

LSI Logic Corporation
1551 McCarthy Boulevard
Milpitas, California 95035

        RE:    REGISTRATION STATEMENT OF FORM S-3

        Ladies and Gentlemen:

        We are acting as counsel for LSI Logic Corporation., a Delaware
corporation (the "Company") in connection with the registration under the
Securities Act of 1933, as amended, of $490,000,000 aggregate principal amount
of 4.00% Convertible Subordinated Notes due 2006 (the "Notes"), and such
indeterminate number of shares of Common Stock, $0.01 par value (the "Common
Stock"), of the Company, as may be required for issuance upon conversion of the
Notes (the "Conversion Shares"). The Notes and the Conversion Shares are to be
offered and sold by certain securityholders of the Company (the "Selling
Securityholders"). In this regard we have participated in the preparation of a
Registration Statement on Form S-3 relating to the Notes and the Conversion
Shares (such Registration Statement, as it may be amended from time to time, is
herein referred to as the "Registration Statement").

        We are of the opinion that the Notes have been duly authorized and are
binding obligations of the Company entitled to the benefits of the Indenture,
dated as of October 30, 2001, between the Company and State Street Bank and
Trust Company of California, N.A., as Trustee.

        We are of the further opinion that the Conversion Shares have been duly
authorized and, when issued by the Company upon conversion of the Notes in
accordance with the Indenture, will be legally issued, fully paid and
nonassessable.

        Our opinions set forth herein are qualified as to:

        (i)        limitations imposed by bankruptcy, insolvency,
                   reorganization, arrangement, fraudulent conveyance,
                   moratorium or other similar laws relating to or affecting the
                   rights of creditors generally, including, without limitation,
                   laws relating to fraudulent transfers or conveyances and
                   preferences:

        (ii)       rights to indemnification and contribution which may be
                   limited by applicable law or equitable principles, and

        (iii)      the effect of general principles of equity, including without
                   limitation, concepts of materiality, reasonableness, good
                   faith and fair dealing, and the possible unavailability of
                   specific performance, injunctive relief or other equitable
                   relief, and limitations on rights of acceleration regardless
                   of whether considered in a proceeding in equity or at law.

        To the extent that the obligations of the Company under the Indenture
may be dependent upon such matters, we assume for purposes of this opinion that
the Trustee under the Indenture has been duly organized, is validly existing and
is in good standing under the laws of its jurisdiction of organization; that the
Trustee is duly qualified to engage in the activities contemplated by the
Indenture; that the Indenture has been duly authorized, executed and delivered
by the Trustee and constitutes a legally valid, binding and enforceable





obligation of the Trustee enforceable against the Trustee in accordance with its
terms; that the Trustee is in compliance, generally and with respect to acting
as trustee under the Indenture, with all applicable laws and regulations; and
that the Trustee has the requisite organizational and legal power and authority
to perform its obligations under the Indenture.

        We hereby consent to the filing of this opinion as Exhibit 5.1 to the
Registration Statement and to the use of our name under the caption "Legal
Matters" in the Registration Statement and the Prospectus included therein.

                                      Sincerely,

                                      WILSON SONSINI GOODRICH & ROSATI
                                      Professional Corporation

                                      /s/ Wilson Sonsini Goodrich & Rosati, P.C.