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                                                                      EXHIBIT 24

                                POWER OF ATTORNEY



         The undersigned director of OM Group, Inc. (the "Company"), a Delaware
corporation, which anticipates filing with the Securities and Exchange
Commission, Washington, D.C., under the provisions of the Securities Exchange
Act of 1934, as amended, an Annual Report on Form 10-K for the Company's fiscal
year ended December 31, 2003, hereby constitutes and appoints R. LOUIS
SCHNEEBERGER and CAROLYN J. BULLER, and each of them, with full power of
substitution and resubstitution, as attorneys or attorney to sign for the
undersigned and in his or her name, place and stead, as director of said
Company, said Annual Report and any and all amendments and exhibits thereto, and
any and all applications and documents to be filed with the Securities and
Exchange Commission pertaining to such Annual Report, with full power and
authority to do and perform any and all acts and things whatsoever requisite,
necessary or advisable to be done in the premises, as fully and for all intents
and purposes as the undersigned could do if personally present, hereby approving
the acts of said attorneys, and each of them and any such substitute.

         IN WITNESS WHEREOF, this Power of Attorney has been signed this 14th
day of January, 2005.



                                                /s/ Lee R. Brodeur
                                             ----------------------------------
                                             Lee R. Brodeur





<PAGE>


                                POWER OF ATTORNEY


         The undersigned director of OM Group, Inc. (the "Company"), a Delaware
corporation, which anticipates filing with the Securities and Exchange
Commission, Washington, D.C., under the provisions of the Securities Exchange
Act of 1934, as amended, an Annual Report on Form 10-K for the Company's fiscal
year ended December 31, 2003, hereby constitutes and appoints R. LOUIS
SCHNEEBERGER and CAROLYN J. BULLER, and each of them, with full power of
substitution and resubstitution, as attorneys or attorney to sign for the
undersigned and in his or her name, place and stead, as director of said
Company, said Annual Report and any and all amendments and exhibits thereto, and
any and all applications and documents to be filed with the Securities and
Exchange Commission pertaining to such Annual Report, with full power and
authority to do and perform any and all acts and things whatsoever requisite,
necessary or advisable to be done in the premises, as fully and for all intents
and purposes as the undersigned could do if personally present, hereby approving
the acts of said attorneys, and each of them and any such substitute.

         IN WITNESS WHEREOF, this Power of Attorney has been signed this 10th
day of January, 2005.



                                                /s/ Frank Butler
                                             ----------------------------------
                                             Frank Butler



<PAGE>


                                POWER OF ATTORNEY



         The undersigned director of OM Group, Inc. (the "Company"), a Delaware
corporation, which anticipates filing with the Securities and Exchange
Commission, Washington, D.C., under the provisions of the Securities Exchange
Act of 1934, as amended, an Annual Report on Form 10-K for the Company's fiscal
year ended December 31, 2003, hereby constitutes and appoints R. LOUIS
SCHNEEBERGER and CAROLYN J. BULLER, and each of them, with full power of
substitution and resubstitution, as attorneys or attorney to sign for the
undersigned and in his or her name, place and stead, as director of said
Company, said Annual Report and any and all amendments and exhibits thereto, and
any and all applications and documents to be filed with the Securities and
Exchange Commission pertaining to such Annual Report, with full power and
authority to do and perform any and all acts and things whatsoever requisite,
necessary or advisable to be done in the premises, as fully and for all intents
and purposes as the undersigned could do if personally present, hereby approving
the acts of said attorneys, and each of them and any such substitute.

         IN WITNESS WHEREOF, this Power of Attorney has been signed January 11,
2005.



                                                /s/ John E. Mooney
                                             ----------------------------------
                                             John E. Mooney




<PAGE>


                                POWER OF ATTORNEY


         The undersigned director of OM Group, Inc. (the "Company"), a Delaware
corporation, which anticipates filing with the Securities and Exchange
Commission, Washington, D.C., under the provisions of the Securities Exchange
Act of 1934, as amended, an Annual Report on Form 10-K for the Company's fiscal
year ended December 31, 2003, hereby constitutes and appoints R. LOUIS
SCHNEEBERGER and CAROLYN J. BULLER, and each of them, with full power of
substitution and resubstitution, as attorneys or attorney to sign for the
undersigned and in his or her name, place and stead, as director of said
Company, said Annual Report and any and all amendments and exhibits thereto, and
any and all applications and documents to be filed with the Securities and
Exchange Commission pertaining to such Annual Report, with full power and
authority to do and perform any and all acts and things whatsoever requisite,
necessary or advisable to be done in the premises, as fully and for all intents
and purposes as the undersigned could do if personally present, hereby approving
the acts of said attorneys, and each of them and any such substitute.

         IN WITNESS WHEREOF, this Power of Attorney has been signed January 10,
2005.



                                                /s/ Katharine L. Plourde
                                             ----------------------------------
                                             Katharine L. Plourde





<PAGE>


                                POWER OF ATTORNEY


         The undersigned director of OM Group, Inc. (the "Company"), a Delaware
corporation, which anticipates filing with the Securities and Exchange
Commission, Washington, D.C., under the provisions of the Securities Exchange
Act of 1934, as amended, an Annual Report on Form 10-K for the Company's fiscal
year ended December 31, 2003, hereby constitutes and appoints R. LOUIS
SCHNEEBERGER and CAROLYN J. BULLER, and each of them, with full power of
substitution and resubstitution, as attorneys or attorney to sign for the
undersigned and in his or her name, place and stead, as director of said
Company, said Annual Report and any and all amendments and exhibits thereto, and
any and all applications and documents to be filed with the Securities and
Exchange Commission pertaining to such Annual Report, with full power and
authority to do and perform any and all acts and things whatsoever requisite,
necessary or advisable to be done in the premises, as fully and for all intents
and purposes as the undersigned could do if personally present, hereby approving
the acts of said attorneys, and each of them and any such substitute.

         IN WITNESS WHEREOF, this Power of Attorney has been signed January 11,
2005.



                                                /s/ William J. Reidy
                                             ----------------------------------
                                             William Reidy



<PAGE>


                                POWER OF ATTORNEY



         The undersigned director of OM Group, Inc. (the "Company"), a Delaware
corporation, which anticipates filing with the Securities and Exchange
Commission, Washington, D.C., under the provisions of the Securities Exchange
Act of 1934, as amended, an Annual Report on Form 10-K for the Company's fiscal
year ended December 31, 2003, hereby constitutes and appoints R. LOUIS
SCHNEEBERGER and CAROLYN J. BULLER, and each of them, with full power of
substitution and resubstitution, as attorney or attorneys to sign for the
undersigned and in his or her name, place and stead, as director of said
Company, said Annual Report and any and all amendments and exhibits thereto, and
any and all applications and documents to be filed with the Securities and
Exchange Commission pertaining to such Annual Report, with full power and
authority to do and perform any and all acts and things whatsoever requisite,
necessary or advisable to be done in the premises, as fully and for all intents
and purposes as the undersigned could do if personally present, hereby approving
the acts of said attorneys, and each of them and any such substitute.

         IN WITNESS WHEREOF, this Power of Attorney has been signed January 10,
2005.



                                                /s/ Markku Toivanen
                                             ----------------------------------
                                             Markku Toivanen