Exhibit 2.1

                          AGREEMENT AND PLAN OF MERGER

      THIS AGREEMENT AND PLAN OF MERGER (this "Agreement") is effective as of
December 31, 2003, by and between Barr Laboratories, Inc., a New York
corporation ("Barr-NY" or the "Non-Surviving Company"), and Barr
Pharmaceuticals, Inc., a Delaware corporation ("Barr-DE" or the "Surviving
Company").

      WHEREAS, pursuant to Section 252 of the Delaware General Corporation Law
(the "DGCL") and Section 907 of the New York Business Corporation Law (the
"NYBCL") and the Certificate of Incorporation and Bylaws of Barr-NY and Barr-DE,
the board of directors and shareholders of Barr-NY and Barr-DE have approved the
Merger (as hereinafter defined), whereby Barr-NY will merge with and into
Barr-DE upon the terms and subject to the conditions set forth herein.

      NOW, THEREFORE, in consideration of the premises and of the mutual
covenants, representations, warranties and agreements herein contained, the
parties hereto have agreed as follows:

1.    The Merger.

      (a) The Merger. Subject to the terms and conditions of this Agreement, at
the Effective Time (as such term is defined in Section 1(b)) hereof), Barr-NY
shall be merged with and into Barr-DE (the "Merger") in accordance with Section
252 of the DGCL and Section 907 of the NYBCL, the separate corporate existence
of Barr-NY shall cease and Barr-DE shall continue as the Surviving Company under
the laws of the State of Delaware under the name "Barr Pharmaceuticals, Inc."

      (b) The Effective Time of the Merger. Barr-NY shall file a duly executed
Certificate of Merger with the New York Secretary of State ("NY Certificate of
Merger"). Barr-DE shall file a duly executed Certificate of Merger with the
Delaware Secretary of State ("DE Certificate of Merger"). The "Effective Time"
of the Merger shall be the later of: (i) the date and time of acceptance for
filing with the New York Secretary of State of the NY Certificate of Merger and
(ii) the date and time of acceptance for filing with the Delaware Secretary of
State of the DE Certificate of Merger.

      (c) Effect of the Merger. At the Effective Time, the Surviving Company
shall thereupon and thereafter possess all of the rights, privileges, powers and
franchises, both of a public and private nature, of each of Barr-NY and Barr-DE,
and shall be subject to all of the restrictions, disabilities and duties of each
of Barr-NY and Barr-DE; and all of the rights, privileges, powers and franchises
of each of Barr-NY and Barr-DE, and all property (real, personal and mixed), and
all debts due to either of Barr-NY or Barr-DE on whatever account, for stock
subscriptions as well as all other things in action or belonging to each of
Barr-NY or Barr-DE, shall be vested in the Surviving Company; and all property,
rights, privileges, powers and franchises and all and every other interest shall
thereafter be the property of the Surviving Company as they were of Barr-NY and
Barr-DE; but all rights of creditors and all liens upon any property of either
Barr-NY or Barr-DE shall be preserved unimpaired, and all debts, liabilities and
duties of each of Barr-NY and Barr-DE shall thenceforth attach to the Surviving
Company,

and may be enforced against it to the same extent as if said debts,
liabilities and duties had been incurred or contracted by the Surviving Company.

      (d) Certificate of Incorporation of the Surviving Company. The Certificate
of Incorporation of Barr-DE in effect immediately prior to the Effective Time
shall be the Certificate of Incorporation of the Surviving Company from and
after the Effective Time until otherwise amended or repealed.

      (e) Bylaws of the Surviving Company. The Bylaws of Barr-DE in effect
immediately prior to the Effective Time shall be the Bylaws of the Surviving
Company from and after the Effective Time until otherwise amended or repealed.

      (f) Board of Directors of the Surviving Company. The Board of Directors of
Barr-NY in office immediately prior to the Effective Time, together with such
additional persons as may thereafter be elected, shall serve as the Board of
Directors of the Surviving Company from and after the Effective Time in
accordance with the Certificate of Incorporation and Bylaws of the Surviving
Company.

      (g) Tax Treatment of the Merger. The parties hereto intend that the Merger
shall be treated as a tax-free a reorganization within the meaning of Section
368(a) of the United States Internal Revenue Code of 1986, as amended, and each
party shall file all tax returns, and take all other actions for tax purposes,
in a manner consistent therewith.

2.    Conversion of Shares.

      (a) Exchange Ratio. At the Effective Time, by virtue of the Merger and
without any action on the part of the holder thereof:

            (i) All shares of the common stock, par value $.01 per share, of
      Barr-DE ("Barr-DE Common Stock") issued and outstanding immediately prior
      to the Effective Time shall no longer be outstanding and shall
      automatically be canceled and retired and shall cease to exist.

            (ii) Each share of the common stock, par value $.01 per share, of
      Barr-NY ("Barr-NY Common Stock") issued and outstanding immediately prior
      to the Effective Time shall be converted into and represent the right to
      receive, and shall be exchangeable for, one validly issued, fully paid and
      non-assessable share of Barr-DE Common Stock.

      (b) Exchange of Shares.

            (i) Prior to the Effective Time, Barr-DE shall select and enter into
      an agreement with a bank or trust company to act as Exchange Agent
      hereunder (the "Exchange Agent"). No later than the Effective Time,
      Barr-DE shall cause the Exchange Agent, pursuant to irrevocable
      instructions, to make available and deliver, and each holder of Barr-NY
      Common Stock shall be entitled to receive, upon surrender to the Exchange
      Agent of one or more certificates representing such shares of Barr-NY
      Common Stock for cancellation, certificates representing the number of
      shares of Barr-DE Common Stock into which such shares of Barr-NY Common
      Stock are converted in


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      the Merger. The shares of Barr-DE Common Stock into which the shares of
      Barr-NY Common Stock shall be converted in the Merger shall be deemed to
      have been issued at the Effective Time.

            (ii) As soon as reasonably practicable after the Effective Time, the
      Exchange Agent shall mail to each holder of record of a certificate or
      certificates which immediately prior to the Effective Time represented
      outstanding shares of Barr-NY Common Stock (the "Certificates"), (A) a
      letter of transmittal (which shall specify that delivery shall be
      effected, and risk of loss and title to the Certificates shall pass, only
      upon delivery of the Certificates to the Exchange Agent and shall be in
      such form and have such other provisions as Barr-DE may reasonably
      specify) and (B) instructions for use in effecting the surrender of the
      Certificates in exchange for certificates representing shares of Barr-DE
      Common Stock. Upon surrender of a Certificate for cancellation to the
      Exchange Agent together with such letter of transmittal, duly executed,
      the holder of such Certificate shall be entitled to receive in exchange
      therefor a certificate representing that number of whole shares of Barr-DE
      Common Stock which such holder has the right to receive in respect of the
      Certificates surrendered pursuant to the provisions of this Section 2.

            (iii) In the event that any Certificate shall have been lost,
      stolen, or destroyed, upon the making of an affidavit of that fact by the
      person claiming such Certificate to be lost, stolen, or destroyed, Barr-DE
      shall issue or cause to be issued in exchange for such lost, stolen, or
      destroyed Certificate the number of shares of Barr-DE Common Stock into
      which such shares are converted in the Merger in accordance with this
      Section 2. When authorizing such issuance in exchange therefor, the Board
      of Directors of Barr-DE may, in its sole discretion and as a condition
      precedent to the issuance thereof, require the owner of such lost, stolen,
      or destroyed certificate to deliver a bond to Barr-DE (in such amount as
      the Board of Directors of Barr-DE may direct) as an indemnity against any
      claim that may be made against Barr-DE with respect to the Certificate
      alleged to have been lost, stolen, or destroyed.

      (c) Stock Options, Warrants, Debentures, Preferred Stock and other
Agreements. As of the Effective Time, any stock options, warrants, convertible
securities or other contractual commitments or agreements of any kind to
purchase or issue shares of Barr-NY Common Stock that are outstanding
immediately prior to the Effective Time (whether or not contingent or otherwise
requiring further shareholder approval) shall be converted into a stock option,
warrant, convertible security or other contractual commitment or agreement to
purchase or issue shares of Barr-DE Common Stock on the same terms as prior to
the Effective Time, except that any rights or obligations therein relating to
shares of Barr-NY Common Stock shall be converted to rights or obligations
relating to shares of Barr-DE Common Stock.

      (d) Closing of Transfer Books. At the Effective Time, the stock transfer
books of Barr-NY shall be closed and no transfer of shares of Barr-NY Common
Stock shall thereafter be made. If, after the Effective Time, certificates
representing shares of Barr-NY Common Stock are presented to the Surviving
Company, they shall be canceled and exchanged for certificates representing
shares of Barr-DE Common Stock in accordance with the terms hereof. At and after
the Effective Time, the holders of shares of Barr-NY Common Stock to be
exchanged for


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shares of Barr-DE Common Stock pursuant to this Agreement shall cease to have
any rights as shareholders of Barr-NY except for the right to surrender such
stock certificates in exchange for shares of Barr-DE Common Stock as provided
hereunder.

3.    Miscellaneous.

      (a) Fees and Expenses. Whether or not the Merger is consummated, each
party hereto shall pay its own costs and expenses incident to the preparation of
this Agreement, the consummation of the Merger, and the performance of and
compliance with all of the agreements and conditions contained herein.

      (b) Notices. All notices, requests, demands, waivers and other
communications required or permitted to be given under this Agreement shall be
in writing and shall be deemed to have been duly given if delivered personally
or mailed by overnight delivery service or by first class mail postage prepaid,
or sent by telecopier, to the parties at the following address (or at such other
address of a party as shall be specified by like notice):

          Barr Laboratories, Inc.
          2 Quaker Road
          Pomona, New York  10970

      (c) Binding Effect; Benefit. This Agreement shall inure to the benefit of
and be binding upon the parties hereto and their respective successors and
assigns, but neither this Agreement nor any of the rights, interests or
obligations hereunder shall be assigned by any party hereto without the prior
written consent of the other party. Nothing in this Agreement, express or
implied, is intended to confer on any person other than the parties hereto or
their respective successors and assigns, any rights, remedies, obligations or
liabilities under or by reason of this Agreement.

      (d) Amendment, Modification and Termination. Subject to applicable law,
this Agreement may be amended, modified and supplemented in any and all
respects, or terminated in part or in its entirety, by written agreement of
Barr-NY and Barr-DE at any time prior to the Effective Time.

      (e) Section Headings. The Section headings contained in this Agreement are
inserted for reference purposes only and shall not affect the meaning or
interpretation of this Agreement.

      (f) Applicable Law. This Agreement and the legal relations among the
parties hereto shall be governed by and construed in accordance with the laws of
the State of Delaware without regard to the conflict of laws principles or rules
thereof.

      (g) Integration. This Agreement sets forth and is intended to be an
integration of all of the promises, agreements, conditions, understandings,
covenants, warranties and representations among the parties with respect to the
Merger and there are no promises, agreements, conditions, understandings,
covenants, warranties or representations, oral or written, express or implied,
among the parties with respect to the transactions contemplated other than as
set forth herein. Any and all prior agreements among the parties with respect to
the Merger are hereby revoked.


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      IN WITNESS WHEREOF, the parties hereto have executed this Merger Agreement
effective as of the date first above written.

                                        BARR LABORATORIES, INC.,

                                        A NEW YORK CORPORATION

                                        By: /s/ Bruce L. Downey
                                           -------------------------------------
                                           Name:  Bruce L. Downey
                                           Title: Chief Executive Officer

                                        BARR PHARMACEUTICALS, INC.,

                                        A DELAWARE CORPORATION

                                        By: /s/ Bruce L. Downey
                                           -------------------------------------
                                           Name:  Bruce L. Downey
                                           Title:  Chief Executive Officer