1
PROSPECTUS SUPPLEMENT                           Filed Pursuant to Rule 424(b)(4)
To Prospectus Dated July 1, 1999                      Registration No. 333-80611

                                [LSI LOGIC LOGO]

                                  $345,000,000

                              LSI Logic Corporation
                 4 1/4% Convertible Subordinated Notes due 2004
                           and Shares of Common Stock

     This prospectus supplement relates to the resale by the selling
securityholders of 4 1/4% convertible subordinated notes due 2004 of LSI Logic
Corporation and the shares of common stock, par value of $0.01 per share, of LSI
Logic Corporation issuable upon the conversion of the notes.

     This prospectus supplement should be read in conjunction with the
prospectus dated July 1, 1999, the prospectus supplements dated July 22, 1999
and August 23, 1999, which are to be delivered with this prospectus supplement.
All capitalized terms used but not defined in the prospectus supplement shall
have the meanings given them in the prospectus.

     The table below sets forth information as of the date hereof concerning
beneficial ownership of the notes of the selling securityholders as listed
below. All information concerning beneficial ownership has been furnished by the
selling securityholders.




                                                 Principal Amount                       Number of Shares
                                                     of Notes         Percentage of     of Common Stock      Percentage of
                                                Beneficially Owned        Notes         That May Be Sold      Common Stock
Name                                             That May Be Sold      Outstanding            (1)           Outstanding (2)
- ----                                            ------------------    -------------     ----------------    ---------------
                                                                                                     
Aristeia International Ltd.                         $  299,000              *                       9,537          *

Aristeia Trading, L.L.C.                               201,000              *                       6,411          *

CIBC World Markets International Arbitage            3,000,000              *                      95,685          *
Corp.

CPR USA, Inc.                                          775,000              *                      24,719          *

Gryphon Domestic III, L.L.C.                           170,000              *                       5,422          *

Investcorp SAM Fund Limited                            200,000              *                       6,379          *

Knoxville Utilities Board Retirement System            112,000              *                       3,572          *

Lehman Brothers, Inc.                                1,000,000              *                      31,895          *

Liberty View Funds L.P.                              1,000,000              *                      31,895          *

The Northwestern Mutual Life Insurance               7,250,000             2.1%                   231,238          *
Company-General Account

The Northwestern Mutual Life Insurance                 750,000              *                      23,921          *
Company-Group Annuity Separate Account

State Street Bank Custodian for 6E Pension           1,765,000              *                      56,294          *
Trust

The TCW Group, Inc.                                  1,360,000              *                      43,377          *

Toronto Dominion (New York), Inc.                   10,000,000             2.9%                   318,949          *

   2
- ---------------
*Less than 1%

(1)  Assumes conversion of the full amount of notes held by such holder at the
     initial conversion price of $31.353 per share; such conversion price is
     subject to adjustment as described under "Description of Notes --
     Conversion of Notes." Accordingly, the number of shares of common stock
     issuable upon conversion of the Notes may increase or decrease from time to
     time. Under the terms of the Indenture, fractional shares will not be
     issued upon conversion of the notes; cash will be paid in lieu of
     fractional shares, if any.

(2)  Computed in accordance with Rule 13d-3(d)(i) promulgated under the Exchange
     Act and based upon 147,188,962 shares of common stock outstanding as of
     October 1, 1999, treating as outstanding the number of shares of common
     stock shown as being issuable upon the assumed conversion by the named
     holder of the full amount of such holder's notes but not assuming the
     conversion of the notes of any other holder.

                                ---------------

The securities offered hereby involve a high degree of risk. See "Risk Factors"
beginning on page 7 of the prospectus.

          THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE
            SECURITIES AND EXCHANGE COMMISSION NOR HAS THE SECURITIES
              AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COM-
                 MISSION PASSED UPON THE ACCURACY OR ADEQUACY OF
                   THIS PROSPECTUS. ANY REPRESENTATION TO THE
                         CONTRARY IS A CRIMINAL OFFENSE.

                                ---------------

            The date of this Prospectus Supplement is October 4 1999.