<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM "CEPHALON,
INC.'S FORM 10-Q FOR THE QUARTER ENDED MARCH 31, 2000* AND IS QUALIFIED IN ITS
ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<CIK> 0000873364
<NAME> CEPHALON, INC.

                             
<PERIOD-TYPE>                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-1999
<PERIOD-START>                             JAN-01-2000
<PERIOD-END>                               MAR-31-2000
<CASH>                                      14,281,000
<SECURITIES>                               140,821,000
<RECEIVABLES>                                5,908,000
<ALLOWANCES>                                         0
<INVENTORY>                                 11,747,000
<CURRENT-ASSETS>                           174,237,000
<PP&E>                                      36,087,000
<DEPRECIATION>                              15,609,000
<TOTAL-ASSETS>                             196,399,000
<CURRENT-LIABILITIES>                       20,220,000
<BONDS>                                     13,519,000
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                     25,000
<COMMON>                                       339,000
<OTHER-SE>                                 158,089,000
<TOTAL-LIABILITY-AND-EQUITY>               196,399,000
<SALES>                                     13,463,000
<TOTAL-REVENUES>                            18,296,000
<CGS>                                        1,792,000
<TOTAL-COSTS>                                1,792,000
<OTHER-EXPENSES>                            12,902,000
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                           1,212,000
<INCOME-PRETAX>                            (9,571,000)
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                        (9,571,000)
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                              (11,837,000)
<EPS-BASIC>                                     (0.36)
<EPS-DILUTED>                                   (0.36)