<TABLE> <S> <C>

<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE OM
GROUP, INC. CONSOLIDATED BALANCE SHEETS AT DECEMBER 31, 1997 AND 1996 AND THE OM
GROUP INC. STATEMENTS OF CONSOLIDATED INCOME FOR THE TWELVE MONTHS ENDED
DECEMBER 31, 1997 AND 1996 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH
FINANCIAL STATEMENTS.
</LEGEND>
<RESTATED> 
<MULTIPLIER> 1,000
                                                                     
<S>                             <C>                     <C>
<PERIOD-TYPE>                   12-MOS                   12-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1996
<PERIOD-END>                               DEC-31-1997             DEC-31-1996
<CASH>                                          13,193                   7,818
<SECURITIES>                                         0                       0
<RECEIVABLES>                                   81,282                  60,264
<ALLOWANCES>                                       680                     210
<INVENTORY>                                    219,201                 195,050
<CURRENT-ASSETS>                               324,749                 275,370
<PP&E>                                         224,359                 167,805
<DEPRECIATION>                                  74,112                  57,184
<TOTAL-ASSETS>                                 601,063                 443,456
<CURRENT-LIABILITIES>                          100,682                 101,509
<BONDS>                                              0                       0
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                          0                       0
<COMMON>                                           222                     188
<OTHER-SE>                                     301,019                 185,134
<TOTAL-LIABILITY-AND-EQUITY>                   601,063                 443,456
<SALES>                                        487,296                 387,999
<TOTAL-REVENUES>                               487,296                 387,999
<CGS>                                          369,933                 304,025
<TOTAL-COSTS>                                  416,724                 336,578
<OTHER-EXPENSES>                                 (815)                   (467)
<LOSS-PROVISION>                                     0                       0
<INTEREST-EXPENSE>                              13,410                   7,485
<INCOME-PRETAX>                                 57,977                  44,403
<INCOME-TAX>                                    19,534                  14,356
<INCOME-CONTINUING>                             38,443                  30,047
<DISCONTINUED>                                       0                       0
<EXTRAORDINARY>                                      0                       0
<CHANGES>                                            0                       0
<NET-INCOME>                                    38,443                  30,047
<EPS-PRIMARY>                                     1.84                    1.61
<EPS-DILUTED>                                     1.78                    1.56
        

</TABLE>