1
                                                            As Filed Pursuant to
                                                        Rule 424(b)(3) under the
                                                          Securities Act of 1933
                                                      Registration No. 333-95649

PROSPECTUS SUPPLEMENT NO. 3 DATED JULY 10, 2000

TEKELEC
- --------------------------------------------------------------------------------
$135,000,000
3.25% CONVERTIBLE SUBORDINATED DISCOUNT NOTES DUE 2004 AND
SHARES OF COMMON STOCK ISSUABLE UPON CONVERSION THEREOF
- --------------------------------------------------------------------------------

        The purpose of this supplement is to amend and supplement the prospectus
dated February 16, 2000, as amended and supplemented by supplement no. 1 thereto
dated March 15, 2000 and supplement no. 2 thereto dated May 16, 2000, relating
to the offer for resale of up to $135,000,000 aggregate principal amount at
maturity of Tekelec's 3.25% Convertible Subordinated Discount Notes due 2004,
and such shares of common stock as may be issued upon conversion of the notes.

        The prospectus is hereby further amended and supplemented to include in
the "Selling Securityholders" table the information in the table set forth below
regarding an additional selling securityholder and a selling securityholder
whose beneficial ownership of notes has increased from the information set forth
in the prospectus, as amended and supplemented by supplement nos. 1 and 2
thereto. The following table is based upon information provided to us by or on
behalf of the selling securityholders named below and indicates with respect to
each such selling securityholder:

        -   the aggregate principal amount of the notes beneficially owned by
            such selling securityholder as of July 10, 2000;

        -   the maximum amount of notes that such selling securityholder may
            offer under the prospectus;

        -   the number of shares of Tekelec common stock beneficially owned by
            such selling securityholder as of July 10, 2000; and

        -   the maximum number of shares of common stock that may be offered for
            the account of such selling securityholder (including its
            transferees, pledgees, donees or their successors) under the
            prospectus.



                                                                                                  NO. OF
                                                                AGGREGATE        PRINCIPAL        SHARES OF          NO. OF
                                                                PRINCIPAL          AMOUNT       COMMON STOCK        SHARES OF
                                                                 AMOUNT           OF NOTES       OWNED PRIOR       COMMON STOCK
       NAME OF SELLING SECURITYHOLDER                           OF NOTES          OFFERED        TO OFFERING*        OFFERED*
       ----------------------------------------------         ----------       ----------       -------------     --------------
                                                                                                      
       Forrestal Funding Master Trust.......................   5,000,000        5,000,000           281,696          281,696
       Kentfield Trading, Ltd...............................  19,685,000       19,685,000         1,109,039        1,109,039



 ..........................

*       Reflects the shares of common stock into which the notes held by such
        securityholder are convertible at the initial conversion rate. The
        conversion rate and the number of shares of common stock issuable upon
        conversion of the notes are subject to adjustment under certain
        circumstances. See "Description of the Notes -- Conversion" in the
        prospectus.

        The selling securityholders named above may, in transactions exempt from
the registration requirements of the Securities Act of 1933, as amended, have
sold, transferred or otherwise disposed of all or a portion of their notes and
common stock since the date on which they provided the information in the table
regarding their notes and common stock. Any such sales would affect the data in
the above table.


THE DATE OF THIS PROSPECTUS SUPPLEMENT IS JULY 10, 2000.