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                                                Filed Pursuant to Rule 424(b)(3)
                                                           File Number 333-45825

PROSPECTUS SUPPLEMENT NO. 9
(To Prospectus dated February 13, 1998,
as Supplemented)


                                 OMNICARE, INC.
                 $345,000,000 PRINCIPAL AMOUNT OF 5% CONVERTIBLE
                        SUBORDINATED DEBENTURES DUE 2007
                    (Interest payable June 1 and December 1)

                         ------------------------------

                        8,976,222 SHARES OF COMMON STOCK

                         ------------------------------

         This Prospectus Supplement supplements the Prospectus dated February
13, 1998 and the Prospectus Supplements Nos. 1, 2, 3, 4, 5, 6, 7 and 8 dated
February 26, 1998, March 6, 1998, April 1, 1998, April 17, 1998, April 27, 1998,
May 5, 1998, May 15, 1998 and May 27, 1998, respectively (together, the
"Prospectus"), relating to (i) $345,000,000 aggregate principal amount of 5%
Convertible Subordinated Debentures due 2007 (the "Debentures") of Omnicare,
Inc., a Delaware corporation (the "Company"), (ii) 8,712,121 shares of common
stock, par value $1.00 per share (the "Common Stock"), of the Company which are
initially issuable upon conversion of the Debentures plus such additional
indeterminate number of shares of Common Stock as may become issuable upon
conversion of the Debentures as a result of adjustments to the conversion price
(the "Conversion Shares") and (iii) 264,101 additional shares of Common Stock.
The Debentures and the Conversion Shares are being offered for the account of
the holders thereof or by their transferees, pledgees, donees or successors. The
Debentures were initially acquired from the Company by Morgan Stanley & Co.
Incorporated, Credit Suisse First Boston Corporation, Merrill Lynch, Pierce,
Fenner & Smith Incorporated, NationsBanc Montgomery Securities, Inc., Smith
Barney Inc. and William Blair & Company, L.L.C. in December 1997 in connection
with a private offering. This Prospectus Supplement is not complete without, and
may not be delivered or utilized except in connection with, the Prospectus.
Capitalized terms used herein but not defined shall have the meaning assigned to
such terms in the Prospectus.

         The Common Stock is traded on the NYSE under the symbol "OCR." On June
11, 1998 the closing price of the Common Stock on the NYSE Composite Tape was
$39.562.


         The following table sets forth certain information concerning Indiana
Lumbermens Mutual Insurance Company, Service Life and Casualty Insurance 
Company, Service Lloyd Insurance Company and The Class IC Company, Ltd. (the
"Selling Securityholders") who have provided the Company with notice as of the
date of this Prospectus Supplement pursuant to the Registration Rights
Agreement of such Selling Securityholders' intent to sell or otherwise dispose
of Debentures and/or Conversion Shares pursuant to the Registration Statement.
This information supplements the information contained in the Prospectus under
the caption "Selling Securityholders." Neither the Selling Securityholders nor
any of their affiliates have held any position or office with, been employed by
or otherwise have had any material relationship with, the Company or any of its
affiliates during the three years prior to the date of this Prospectus
Supplement. Because the Selling Securityholders may offer all or some portion
of the Debentures and Conversion Shares,

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no estimate can be given as to the percentage of Debentures or Common Stock that
will be held by the Selling Securityholders upon termination of sales pursuant
to this Prospectus Supplement.




                               Principal Amount     Percentage of Debentures                            Percentage of Common
                                 of Debentures      Outstanding Beneficially    Conversion Shares        Stock Beneficially
            Name               that May be Sold      Owned Before Offering      That May Be Sold**      Owned Before Offering
            ----               ----------------    -------------------------    ------------------      ---------------------
                                                                                                    
Indiana Lumbermens Mutual             $320,000                *                      8,080                      *
Insurance Company

Service Life and Casualty                20,000               *                        505                      *
Insurance Company

Service Lloyd Insurance                  20,000               *                        505                      *
Company

The Class IC Company, Ltd.              500,000               *                     12,626                      *




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*        Less than 1%.

**       Assumes conversion of full amount of Debentures held by such holder at
         the initial rate of $39.60 in principal amount of Debentures per share
         of Common Stock.

             The date of this Prospectus Supplement is June 12, 1998





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