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PROSPECTUS SUPPLEMENT NO. 1                     Filed Pursuant to Rule 424(b)(3)
(To Prospectus dated February 13, 1998)         File Number 333-45825


                                 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 (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
February 24, 1998, the closing price of the Common Stock on the NYSE Composite
Tape was $35.188.

         The following table sets forth certain information concerning Argent
Classic Convertible Arbitrage Fund (Bermuda) L.P., Argent Classic Convertible
Arbitrage Fund L.P., Bear, Sterns & Co., Inc., Chrysler Corporation Master
Retirement Trust, Combined Insurance Company of America, Hughs Aircraft Company
Master Retirement Trust, Partner Reinsurance Company Ltd., The Lutheran Church -
Missouri Synod, and Vanguard Convertible Securities Fund, Inc. (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 has 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, 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.


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                                                        Percentage of       
                            Principal Amount       Debentures Outstanding                             Percentage of Common
                             of Debentures           Beneficially Owned       Conversion Shares        Stock Beneficially
            Name            that May be Sold           Before Offering        That May Be Sold**      Owned Before Offering
            ----             ---------------         ------------------       ------------------      ---------------------
                                                                                                   
Argent Classic Convertible        $3,500,000                1.01%                   88,383                      *
Arbitrage Fund (Bermuda)
L.P.


Argent Classic Convertible        $1,500,000                  *                     37,878                      *
Arbitrage Fund L.P.

Bear, Sterns & Co., Inc.          $1,000,000                  *                     25,252                      *

Chrysler Corporation Master       $3,255,000                  *                     82,196                      *
Retirement Trust

Combined Insurance Company          $860,000                  *                     21,717                      *
of America

Hughs Aircraft Company            $1,690,000                  *                     42,676                      *
Master Retirement Trust

Partner Reinsurance Company         $340,000                  *                      8,585                      *
Ltd.

The Lutheran Church  -            $2,000,000                  *                     50,505                      *
Missouri Synod

Vanguard Convertible              $3,010,000                  *                     76,010                      *
Securities Fund, Inc.


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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 February 26, 1998



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