<TABLE> <S> <C>
<PAGE>
<ARTICLE> 5
<LEGEND>
This schedule contains summary financial information extracted from Cephalon,
Inc.'s Form 10-Q for the quarter ended June 30, 2000 and is qualified in its
entirety by reference to such financial statements.
</LEGEND>
<CIK> 0000873364
<NAME> CEPHALON, INC.
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-1999
<PERIOD-START> JAN-01-2000
<PERIOD-END> JUN-30-2000
<CASH> 29,010,000
<SECURITIES> 121,377,000
<RECEIVABLES> 11,017,000
<ALLOWANCES> 0
<INVENTORY> 14,465,000
<CURRENT-ASSETS> 176,895,000
<PP&E> 40,369,000
<DEPRECIATION> 16,030,000
<TOTAL-ASSETS> 203,687,000
<CURRENT-LIABILITIES> 29,330,000
<BONDS> 13,486,000
0
25,000
<COMMON> 348,000
<OTHER-SE> 160,300,000
<TOTAL-LIABILITY-AND-EQUITY> 203,687,000
<SALES> 28,750,000
<TOTAL-REVENUES> 38,006,000
<CGS> 5,074,000
<TOTAL-COSTS> 5,074,000
<OTHER-EXPENSES> 27,377,000
<LOSS-PROVISION> 0
<INTEREST-EXPENSE> 2,949,000
<INCOME-PRETAX> (16,400,000)
<INCOME-TAX> 0
<INCOME-CONTINUING> (16,400,000)
<DISCONTINUED> 0
<EXTRAORDINARY> 0
<CHANGES> 0
<NET-INCOME> (20,931,000)
<EPS-BASIC> (0.63)
<EPS-DILUTED> (0.63)
</TABLE>