<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM CEPHALON,
INC.'S FORM 10-Q FOR THE QUARTER ENDED SEPTEMBER 30, 1998 AND IS QUALIFIED IN
ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
       
                             
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-START>                             JAN-01-1998
<PERIOD-END>                               SEP-30-1998
<CASH>                                       3,717,000
<SECURITIES>                                77,665,000
<RECEIVABLES>                                        0
<ALLOWANCES>                                         0
<INVENTORY>                                          0
<CURRENT-ASSETS>                            86,210,000
<PP&E>                                      33,792,000
<DEPRECIATION>                              12,629,000
<TOTAL-ASSETS>                             108,900,000
<CURRENT-LIABILITIES>                       18,798,000
<BONDS>                                     15,408,000
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                       287,000
<OTHER-SE>                                  71,467,000
<TOTAL-LIABILITY-AND-EQUITY>               108,900,000
<SALES>                                              0
<TOTAL-REVENUES>                             9,753,000
<CGS>                                                0
<TOTAL-COSTS>                                        0
<OTHER-EXPENSES>                            32,783,000
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                           1,457,000
<INCOME-PRETAX>                           (41,143,000)
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                                  0
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                              (41,143,000)
<EPS-PRIMARY>                                   (1.45)
<EPS-DILUTED>                                   (1.45)