<ARTICLE> 5 <CIK> 0001022079 <NAME> QUEST DIAGNOSTICS <MULTIPLIER> 1000 <CURRENCY> US <PERIOD-TYPE> 9-MOS <FISCAL-YEAR-END> DEC-31-1998 <PERIOD-START> JAN-01-1998 <PERIOD-END> SEP-30-1998 <EXCHANGE-RATE> 1 <CASH> 180,996 <SECURITIES> 0 <RECEIVABLES> 236,393 <ALLOWANCES> 72,646 <INVENTORY> 29,799 <CURRENT-ASSETS> 561,685 <PP&E> 241,418 <DEPRECIATION> 352,166 <TOTAL-ASSETS> 1,366,165 <CURRENT-LIABILITIES> 303,363 <BONDS> 0 <PREFERRED-MANDATORY> 0 <PREFERRED> 1,000 <COMMON> 299 <OTHER-SE> 560,093 <TOTAL-LIABILITY-AND-EQUITY> 1,366,165 <SALES> 1,095,327 <TOTAL-REVENUES> 1,095,327 <CGS> 646,710 <TOTAL-COSTS> 1,006,072 <OTHER-EXPENSES> 2,459 <LOSS-PROVISION> 67,292 <INTEREST-EXPENSE> 26,548 <INCOME-PRETAX> 43,972 <INCOME-TAX> 22,426 <INCOME-CONTINUING> 21,546 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 21,546 <EPS-PRIMARY> 0.72 <EPS-DILUTED> 0.71