1
PROSPECTUS SUPPLEMENT                           FILED PURSUANT TO RULE 424(b)(4)
TO PROSPECTUS DATED JULY 1, 1999                      REGISTRATION NO. 333-80611



                                  $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, and the prospectus supplements dated July 22,
1999, August 23, 1999, October 4, 1999, November 9, 1999, December 10, 1999, and
March 23, 2000, 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
                                                     OF NOTES         PERCENTAGE OF       NUMBER OF SHARES       PERCENTAGE OF
                                                BENEFICIALLY OWNED        NOTES           OF COMMON STOCK         COMMON STOCK
NAME                                             THAT MAY BE SOLD      OUTSTANDING      THAT MAY BE SOLD(1)     OUTSTANDING (2)
- ----                                            ------------------    -------------     -------------------     ---------------
                                                                                                         

Colgate-Palmolive Company Retirement Trust          $1,250,000             *                   79,737                *

Julius Baer Securities                                 500,000             *                   31,895                *

Pell Rudman Trust Company                            1,395,000             *                   88,987                *


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

*    Less than 1%

(1)  Assumes conversion of the full amount of notes held by such holder at the
     conversion price of $15.6765 per share (adjusted from the initial
     conversion price of $31.353, pursuant to a two-for-one stock split
     effective February 4, 2000 and distributed on February 16, 2000); 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 306,632,229 shares of common stock outstanding as of
     April 27, 2000, 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 April 28, 2000.