<TABLE> <S> <C>

<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE OM
GROUP, INC. CONSOLIDATED BALANCE SHEETS AT DECEMBER 31, 1998 AND 1997 AND THE OM
GROUP, INC. STATEMENTS OF CONSOLIDATED INCOME FOR THE YEAR ENDED DECEMBER 31,
1998 AND 1997 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL
STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
       
<S>                             <C>                     <C>
<PERIOD-TYPE>                   12-MOS                   12-MOS
<FISCAL-YEAR-END>                          DEC-31-1998             DEC-31-1997
<PERIOD-END>                               DEC-31-1998             DEC-31-1997
<CASH>                                           7,750                  13,193
<SECURITIES>                                         0                       0
<RECEIVABLES>                                   82,296                  81,282
<ALLOWANCES>                                     1,390                     680
<INVENTORY>                                    283,264                 219,201
<CURRENT-ASSETS>                               420,241                 322,909
<PP&E>                                         338,768                 229,728
<DEPRECIATION>                                  93,423                  74,112
<TOTAL-ASSETS>                                 870,719                 601,063
<CURRENT-LIABILITIES>                          119,567                 100,682
<BONDS>                                              0                       0
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                          0                       0
<COMMON>                                           240                     222
<OTHER-SE>                                     403,903                 301,019
<TOTAL-LIABILITY-AND-EQUITY>                   870,719                 601,063
<SALES>                                        521,226                 487,296
<TOTAL-REVENUES>                               521,226                 487,296
<CGS>                                          376,274                 369,933
<TOTAL-COSTS>                                  434,302                 416,724
<OTHER-EXPENSES>                                    40                   (815)
<LOSS-PROVISION>                                     0                       0
<INTEREST-EXPENSE>                              15,560                  13,410
<INCOME-PRETAX>                                 71,324                  57,977
<INCOME-TAX>                                    22,966                  19,534
<INCOME-CONTINUING>                             48,358                  38,443
<DISCONTINUED>                                       0                       0
<EXTRAORDINARY>                                      0                       0
<CHANGES>                                            0                       0
<NET-INCOME>                                    48,358                  38,443
<EPS-PRIMARY>                                     2.11                    1.84
<EPS-DILUTED>                                     2.05                    1.78
        





</TABLE>