Exhibit 23

Consent of Independent Registered Public Accounting Firm

We consent to the incorporation by reference in the following Registration Statements of our reports dated February 26, 2008, with respect to the consolidated financial statements and schedule of OM Group, Inc. and subsidiaries, and the effectiveness of internal control over financial reporting of OM Group, Inc. and subsidiaries included in the Annual Report (Form 10-K) for the year ended December 31, 2007:

Registration
Statement	Description	Filing Date
333-07531	OM Group, Inc. Non-Employee Directors’	July 3, 1996
	Equity Compensation Plan—Form S-8
	Registration Statement—250,000 Shares
333-47230	OM Group, Inc. 1998 Long-Term Incentive	October 3, 2000
	Compensation Plan—Form S-8 Registration
	Statement—2,000,000 Shares
333-65852	OM Group, Inc. 1998 Long-Term Incentive	July 25, 2001
	Compensation Plan—Form S-8 Registration
	Statement—2,000,000 Shares
333-141033	OM Group, Inc. 2002 Stock Incentive Plan	March 2, 2007
	and Inducement Stock Option Grant to
	Joseph M. Scaminace—Form S-8
	Registration Statement—1,488,934 Shares
333-145238	OM Group, Inc. 2007 Incentive Compensation	August 8, 2007
	Plan—Form S-8 Registration Statement —3,000,000 Shares

 
Cleveland, Ohio
February 26, 2008