Prospectus Supplement No. 1                     Filed pursuant to Rule 424(b)(3)
to Prospectus dated June 5, 2002                File No. 333-82788

                                 CEPHALON, INC.

           $600,000,000 2-1/2% CONVERTIBLE SUBORDINATED NOTES DUE 2006

         This document supplements information contained in that certain
prospectus of Cephalon, Inc. dated June 5, 2002, as amended and supplemented
from time to time, relating to the potential resale from time to time of
$600,000,000 2-1/2% Convertible Subordinated Notes due 2006 and 7,407,480 shares
of common stock by the selling securityholders identified in the prospectus and
any prospectus supplements. This prospectus supplement is not complete without,
and may not be delivered or utilized except in connection with the prospectus,
including any amendments or supplements thereto.

         The following table supplements, or amends, as noted, the information
contained in the table set forth in the prospectus under the caption "Selling
Securityholders." This table sets forth information regarding (1) the beneficial
ownership of the notes, and the maximum principal amount of notes that each may
offer and (2) the number of shares of common stock that each selling
securityholder may sell under this prospectus. Because the selling
securityholders may offer all or a portion of the notes and the common stock, if
converted, under the prospectus, we cannot estimate with certainty the principal
amount of the notes or the common stock that the selling securityholders will
hold upon termination of any sale. For this reason, we have assumed that either
all of the principal amount of notes offered by a selling securityholder or all
of the shares of common stock offered will be sold. The following table is based
upon information furnished to us by the selling securityholders as of the date
such information was provided to us.



                                                                                       BENEFICIAL OWNERSHIP AFTER
                                                                 NUMBER OF           RESALE OF NOTES OR COMMON STOCK
                              NUMBER OF                          SHARES OF      -----------------------------------------
                              SHARES OF    PRINCIPAL AMOUNT     COMMON STOCK                          NUMBER OF
                            COMMON STOCK       OF NOTES        ISSUABLE UPON    PRINCIPAL             SHARES OF
NAME OF SELLING             BENEFICIALLY     BENEFICIALLY      CONVERSION OF    AMOUNT OF              COMMON
SECURITYHOLDER (1)            OWNED (2)        OWNED (2)           NOTES          NOTES     PERCENT     STOCK     PERCENT
------------------            ---------        ---------           -----          -----     -------     -----     -------
                                                                                             
The following information
amends the information
set forth in the
prospectus originally
filed or as previously
amended or supplemented:

RAM Trading Ltd.                  -          $ 16,000,000         197,532           -          -          -          -


                                                                                             
The following information
supplements the
information set forth in
the prospectus originally
filed or as previously
amended or supplemented:

Nations Convertible               -           $ 2,000,000          24,691           -          -          -          -
Securities Fund



(1) The information set forth herein is as of June 7, 2002 and will be updated
as required.


(2) Beneficial ownership is determined in accordance with the rules of the SEC
and generally includes voting or investment power with respect to securities.

         Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or passed upon the
adequacy or accuracy of this prospectus supplement. Any representation to the
contrary is a criminal offense.


            The date of this prospectus supplement is June 11, 2002.