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                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


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


                                   FORM 10-K/A
                               (AMENDMENT NO. 1)



(Mark One)

[X]     ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
        ACT OF 1934 FOR THE FISCAL YEAR ENDED DECEMBER 31, 1999

                                       OR

[ ]     TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
        EXCHANGE ACT OF 1934

                         COMMISSION FILE NUMBER: 0-16617

                               ALTERA CORPORATION
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

               DELAWARE                                  77-0016691
     (STATE OR OTHER JURISDICTION OF                  (I.R.S. EMPLOYER
     INCORPORATION OR ORGANIZATION)                IDENTIFICATION NUMBER)

                101 INNOVATION DRIVE, SAN JOSE, CALIFORNIA 95134
          (Address of Principal Executive Offices, including Zip Code)

                                 (408) 544-7000
              (Registrant's Telephone Number, Including Area Code)

        Securities Registered Pursuant to Section 12(b) of the Act: NONE

          Securities Registered Pursuant to Section 12(g) of the Act:
                         COMMON STOCK, $0.001 PAR VALUE

        Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports) and (2) has been subject to such
requirements for the past 90 days. YES [X] NO [ ]

        Indicate by check mark if disclosure of delinquent filers pursuant to
Item 405 of Regulation S-K is not contained herein, and will not be contained,
to the best of registrant's knowledge, in definitive proxy or information
statements incorporated by reference in Part III of the Form 10-K or any
amendment to this Form 10-K. ____

        The aggregate market value of the registrant's Common Stock held by
non-affiliates of the registrant was approximately $14,554,443,000 as of March
1, 2000, based upon the closing sale price on the Nasdaq National Market for
that date.

        There were 199,520,091 shares of the registrant's Common Stock issued
and outstanding as of March 1, 2000.

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        This Report on Form 10-K/A (Amendment No. 1) is being filed for the sole
purpose of adding an exhibit to the Report on Form 10-K filed by the registrant
on March 24, 2000.


Item 14. EXHIBITS, FINANCIAL STATEMENT SCHEDULE AND REPORTS ON FORM 10-K

        (a)     The following document is filed as part of this Amendment No. 1:





Exhibit No.       Description
- -----------       -----------
               
#13.1(a)          Annual Report to Stockholders for the fiscal year ended
                  December 31, 1999 (to be deemed filed only to the extent
                  required by the instructions to Exhibits for Reports on Form
                  10-K).



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(a)     Filed herewith.


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                                   SIGNATURES


        Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the registrant has duly caused this Report to be signed on
its behalf, by the undersigned thereto duly authorized.


                                        ALTERA CORPORATION


                                        By: /s/ Nathan Sarkisian
                                           ------------------------------------
                                           Nathan Sarkisian
                                           Senior Vice President and
                                           Chief Financial Officer

March 29, 2000





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                                 EXHIBIT INDEX





Exhibit No.       Description
- -----------       -----------
               
#13.1(a)          Annual Report to Stockholders for the fiscal year ended
                  December 31, 1999 (to be deemed filed only to the extent
                  required by the instructions to Exhibits for Reports on Form
                  10-K).





- -------------------
(a)     Filed herewith.