<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM CEPHALON,
INC'S FORM 10-Q FOR THE QUARTER ENDED MARCH 31, 1999 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-01-1999
<PERIOD-END>                               MAR-31-1999
<CASH>                                       5,118,000
<SECURITIES>                                73,389,000
<RECEIVABLES>                                        0
<ALLOWANCES>                                         0
<INVENTORY>                                          0
<CURRENT-ASSETS>                            84,833,000
<PP&E>                                      34,075,000
<DEPRECIATION>                              13,906,000
<TOTAL-ASSETS>                             108,407,000
<CURRENT-LIABILITIES>                       21,441,000
<BONDS>                                     38,503,000
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                       288,000
<OTHER-SE>                                  44,504,000
<TOTAL-LIABILITY-AND-EQUITY>               108,407,000
<SALES>                                      1,730,000
<TOTAL-REVENUES>                             4,230,000
<CGS>                                          188,000
<TOTAL-COSTS>                                  188,000
<OTHER-EXPENSES>                             9,972,000
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                           1,275,000
<INCOME-PRETAX>                           (19,941,000)
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                                  0
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                              (19,941,000)
<EPS-PRIMARY>                                   (0.69)
<EPS-DILUTED>                                   (0.69)