EXHIBIT 23

Consent of Independent Registered Public Accounting Firm

We hereby consent to the incorporation by reference in the Registration Statement on Form S-8 (Nos. 333-02667, 333-77845, 333-95949, 333-36874 and 333-120450) of Omnicare, Inc. of our report dated February 26, 2009 relating to the consolidated financial statements, financial statement schedule, and the effectiveness of internal control over financial reporting, which appears in this Form 10-K.

/s/ PricewaterhouseCoopers LLP

PricewaterhouseCoopers LLP

Cincinnati, Ohio

February 26, 2009