Exhibit 31.1


       RULE 13a-14(a) CERTIFICATION IN ACCORDANCE WITH SECTION 302 OF THE
                           SARBANES-OXLEY ACT OF 2002

I, Joel F. Gemunder, President and Chief Executive Officer of Omnicare, Inc.
(the "Company"), certify that:

1.    I have reviewed this report on Form 10-Q of the Company;

2.    Based on my knowledge, this report does not contain any untrue statement
      of a material fact or omit to state a material fact necessary to make the
      statements made, in light of the circumstances under which such statements
      were made, not misleading with respect to the period covered by this
      report;

3.    Based on my knowledge, the financial statements, and other financial
      information included in this report, fairly present in all material
      respects the financial condition, results of operations and cash flows of
      the Company as of, and for, the periods presented in this report;

4.    The Company's other certifying officer and I are responsible for
      establishing and maintaining disclosure controls and procedures (as
      defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the Company and
      have:

      a)   designed such disclosure controls and procedures, or caused such
           disclosure controls and procedures to be designed under our
           supervision, to ensure that material information relating to the
           Company, including its consolidated subsidiaries, is made known to us
           by others within those entities, particularly during the period in
           which this report is being prepared;
      b)   evaluated the effectiveness of the Company's disclosure controls and
           procedures and presented in this report our conclusions about the
           effectiveness of the disclosure controls and procedures, as of the
           end of the period covered by this report based on such evaluation;
           and
      c)   disclosed in this report any change in the Company's internal control
           over financial reporting that occurred during the Company's most
           recent fiscal quarter that has materially affected, or is reasonably
           likely to materially affect, the Company's internal control over
           financial reporting; and

5.    The Company's other certifying officer and I have disclosed, based on our
      most recent evaluation of internal control over financial reporting, to
      the Company's auditors and the audit committee of the Company's board of
      directors:

      a)   all significant deficiencies and material weaknesses in the design or
           operation of internal control over financial reporting which are
           reasonably likely to adversely affect the Company's ability to
           record, process, summarize and report financial information; and
      b)   any fraud, whether or not material, that involves management or other
           employees who have a significant role in the Company's internal
           control over financial reporting.

     Date:  November 14, 2003

           /s/ Joel F. Gemunder
           --------------------
           Joel F. Gemunder
           President and Chief Executive Officer