<ARTICLE> 5 <CIK> 0001022079 <NAME> QUEST DIAGNOSTICS INCORPORATED <MULTIPLIER> 1000 <CURRENCY> US <PERIOD-TYPE> 12-MOS <FISCAL-YEAR-END> DEC-31-1998 <PERIOD-START> JAN-01-1998 <PERIOD-END> DEC-31-1998 <EXCHANGE-RATE> 1 <CASH> 202,908 <SECURITIES> 0 <RECEIVABLES> 220,861 <ALLOWANCES> 70,701 <INVENTORY> 31,164 <CURRENT-ASSETS> 578,187 <PP&E> 240,389 <DEPRECIATION> 349,141 <TOTAL-ASSETS> 1,360,240 <CURRENT-LIABILITIES> 309,465 <BONDS> 0 <PREFERRED-MANDATORY> 0 <PREFERRED> 1,000 <COMMON> 1,197,377 <OTHER-SE> (630,447) <TOTAL-LIABILITY-AND-EQUITY> 1,360,240 <SALES> 1,458,607 <TOTAL-REVENUES> 1,458,607 <CGS> 861,044 <TOTAL-COSTS> 1,342,678 <OTHER-EXPENSES> 6,968 <LOSS-PROVISION> 89,428 <INTEREST-EXPENSE> 33,403 <INCOME-PRETAX> 53,861 <INCOME-TAX> 26,976 <INCOME-CONTINUING> 26,885 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 26,885 <EPS-PRIMARY> 0.90 <EPS-DILUTED> 0.89