Exhibit 32

      CERTIFICATION PURSUANT TO 18 U.S.C. SEC. 1350, AS ADOPTED PURSUANT TO
                   SEC. 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the filing with the Securities and Exchange Commission of the
Quarterly Report on Form 10-Q of OM Group, Inc. (the "Company") for the quarter
ended March 31, 2005 (the "Report"), each of the undersigned officers of the
Company certifies, pursuant to 18 U.S.C. Sec. 1350, as adopted pursuant to Sec.
906 of the Sarbanes-Oxley Act of 2002, that:

      (1)   The Report fully complies with the requirements of Section 13(a) or
            15(d) of the Securities Exchange Act of 1934, as amended; and

      (2)   The information contained in the Report fairly presents, in all
            material respects, the financial condition and results of operations
            of the Company.

Dated: September 23, 2005

/s/ Joseph M. Scaminace
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Joseph M. Scaminace
Chairman of the Board and
Chief Executive Officer

/s/ R. Louis Schneeberger
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R. Louis Schneeberger
Chief Financial Officer