FORM 8-A

                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
                     PURSUANT TO SECTION 12(b) OR (g) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

                          AMERISOURCEBERGEN CORPORATION
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             (Exact name of registrant as specified in its charter)

               DELAWARE                                  23-3079390
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(State of incorporation or organization)    (I.R.S. Employer Identification No.)

                          1300 MORRIS DRIVE, SUITE 100
                                CHESTERBROOK, PA
                                   19087-5594
                                 (610) 727-7000
                    (Address of principal executive offices)

       Securities to be registered pursuant to Section 12(b) of the Act:

         Title of each class                     Name of each exchange on which
         to be so registered                     each class is to be registered

    Preferred Stock Purchase Right                   New York Stock Exchange
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If this form relates to the registration of a class of securities pursuant to
Section 12(b) of the Exchange Act and is effective pursuant to General
Instruction A.(c), check the following box. [X]

If this form relates to the registration of a class of securities pursuant to
Section 12(g) of the Exchange Act and is effective pursuant to General
Instruction A.(d), check the following box. [ ]

Securities Act registration statement file number to which this form relates:
333-61440 (if applicable)

Securities to be registered pursuant to Section 12(g) of the Act:

                                      None
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                                 Title of Class




Item 1.  Description of Registrant's Securities to Be Registered.

         On August 27, 2001, the Board of Directors of AmerisourceBergen
Corporation (the "Company") declared a distribution of one Right for each
outstanding share of Common Stock, par value $0.01 per share (the "Company
Common Stock"), to stockholders of record at the close of business on August 27,
2001 and for each share of Company Common Stock issued (including shares
distributed from Treasury) by the Company thereafter and prior to the
Distribution Date (as defined in the Rights Agreement attached hereto as Exhibit
1). Each Right entitles the registered holder, subject to the terms of the
Rights Agreement (as defined below), to purchase from the Company one
one-hundredth of a share (a "Unit") of Series A Preferred Stock, par value $0.01
per share (the "Preferred Stock"), at a Purchase Price of $275 per Unit, subject
to adjustment. The Purchase Price is payable in cash or by certified or bank
check or money order payable to the order of the Company, or by wire transfer of
immediately available funds to the account of the Company. The description and
terms of the Rights are set forth in a Rights Agreement between the Company and
Mellon Investor Services LLC, as Rights Agent (the "Rights Agreement").

         Initially, the Rights will attach to all certificates representing
shares of outstanding Company Common Stock, and no separate Rights Certificates
will be distributed. The Rights will separate from the Company Common Stock and
the Distribution Date will occur upon the earlier of (i) 10 days following a
public announcement (the date of such announcement being the "Stock Acquisition
Date") that a person or group of affiliated or associated persons (other than
the Company, any Subsidiary of the Company or any employee benefit plan of the
Company or such Subsidiary) (an "Acquiring Person") has acquired, obtained the
right to acquire or otherwise obtained beneficial ownership of 15% or more of
the then-outstanding shares of Company Common Stock, and (ii) 10 business days
(or such later date as may be determined by action of the Board of Directors
prior to such time as any person becomes an Acquiring Person) following the
commencement of a tender offer or exchange offer that would result in a person
or group beneficially owning 15% or more of the then-outstanding shares of
Company Common Stock. Until the Distribution Date, (i) the Rights will be
evidenced by Company Common Stock certificates and will be transferred with and
only with such Company Common Stock certificates, (ii) new Company Common Stock
certificates issued after August 27, 2001 also (including shares distributed
from Treasury) will contain a notation incorporating the Rights Agreement by
reference and (iii) the surrender for transfer of any certificates representing
outstanding Company Common Stock will also constitute the transfer of the Rights
associated with the Company Common Stock represented by such certificates.

         The Rights are not exercisable until the Distribution Date and will
expire at the close of business on the tenth anniversary of the Rights
Agreement, unless earlier redeemed by the Company as described below.

         As soon as practicable after the Distribution Date, Rights Certificates
will be mailed to holders of record of Company Common Stock as of the close of
business on the Distribution Date and, thereafter, the separate Rights
Certificates alone will represent the Rights.

         In the event that (i) the Company is the surviving corporation in a
merger with an Acquiring Person and shares of Company Common Stock shall remain
outstanding, (ii) a Person

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becomes an Acquiring Person, (iii) an Acquiring Person engages in one or more
"self-dealing" transactions as set forth in the Rights Agreement, or (iv) during
such time as there is an Acquiring Person, an event occurs which results in such
Acquiring Person's ownership interest being increased by more than 1% (e.g., by
means of a reverse stock split or recapitalization) (each such event being a
"Section 11(a)(ii) Event"), then, in each such case, each holder of a Right will
thereafter have the right to receive, upon exercise, Units of Preferred Stock
(or, in certain circumstances, Company Common Stock, cash, property or other
securities of the Company) having a value equal to two times the exercise price
of the Right. The exercise price is the Purchase Price multiplied by the number
of Units of Preferred Stock issuable upon exercise of a Right prior to the
events described in this paragraph. Notwithstanding any of the foregoing,
following the occurrence of any of the events set forth in this paragraph, all
Rights that are, or (under certain circumstances specified in the Rights
Agreement) were, beneficially owned by any Acquiring Person will be null and
void.

         In the event that, at any time following the Stock Acquisition Date,
(i) the Company is acquired in a merger (other than a merger described in the
preceding paragraph) or other business combination transaction and the Company
is not the surviving corporation, (ii) any Person consolidates or merges with
the Company and all or part of the Company Common Stock is converted or
exchanged for securities, cash or property of any other Person or (iii) 50% or
more of the Company's assets or earning power is sold or transferred, each
holder of a Right (except Rights which previously have been voided as described
above) shall thereafter have the right to receive, upon exercise, common stock
of the Acquiring Person (or cash if the Acquiring Person is an individual)
having a value equal to two times the exercise price of the Right.

         The Purchase Price payable, and the number of Units of Preferred Stock
issuable upon exercise of the Rights are subject to adjustment from time to time
to prevent dilution (i) in the event of a stock dividend on, or a subdivision,
combination or reclassification of, the Preferred Stock, (ii) if holders of the
Preferred Stock are granted certain rights or warrants to subscribe for
Preferred Stock or convertible securities at less than the current market price
of the Preferred Stock, or (iii) upon the distribution to the holders of the
Preferred Stock of evidences of indebtedness or assets (excluding regular
quarterly cash dividends) or of subscription rights or warrants (other than
those referred to above).

        With certain exceptions, no adjustment in the Purchase Price will be
required until cumulative adjustments amount to at least 1% of the Purchase
Price. The Company is not required to issue fractional Units. In lieu thereof,
an adjustment in cash may be made based on the market price of the Preferred
Stock prior to the date of exercise.

         At any time prior to the earlier of (i) ten business days following the
Stock Acquisition Date or (ii) the Final Expiration Date, the Company's Board of
Directors may redeem the Rights in whole, but not in part, at a price of $0.01
per Right (the "Redemption Price"), payable, at the election of the Board of
Directors, in cash or shares of Company Common Stock. Immediately upon the
action of the Company's Board of Directors ordering the redemption of the
Rights, the Rights will terminate and the only right of the holders of Rights
will be to receive the Redemption Price.

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         The Board of Directors, at its option, may exchange each Right for (i)
one Unit of Preferred Stock or (ii) such number of Units of Preferred Stock as
will equal (x) the difference between the aggregate market price of the number
of Units of Preferred Stock to be received upon a Section 11(a)(ii) Event and
the Purchase Price divided by (y) the market price per Unit of Preferred Stock
upon the Section 11(a)(ii) Event.

         Until a Right is exercised, the holder thereof, as such, will have no
rights as a stockholder of the Company, including, without limitation, the right
to vote or to receive dividends. While the distribution of the Rights will not
be taxable to stockholders or to the Company, stockholders may, depending upon
the circumstances, recognize taxable income in the event that the Rights become
exercisable for Units of Preferred Stock (or other consideration).

         The Rights Agreement may be amended in any way by the Board at any time
prior to the Distribution Date. After the Distribution Date, the Company may
supplement or amend the Rights Agreement without the approval of Rights holders
in order (a) to cure any ambiguity, (b) to correct or supplement any defective
or inconsistent provision, (c) to shorten or lengthen any time period as
permitted by the Rights Agreement or (d) to change or supplement the Rights
Agreement in any manner which would not adversely affect the interests of Rights
holders.

         A total of 3,000,000 shares of Preferred Stock will be reserved for
issuance upon exercise of the Rights. The Units of Preferred Stock that may be
acquired upon exercise of the Rights will be nonredeemable and subordinate to
any other shares of preferred stock that may be issued by the Company.

         Each Unit of Preferred Stock will have a minimum preferential quarterly
dividend rate of $0.01 per Unit but will, in any event, be entitled to a
dividend equal to the per share dividend declared on the Company Common Stock.

         In the event of liquidation, the holder of a Unit of Preferred Stock
will receive a preferred liquidation payment equal to the greater of the per
Unit and the per share amount paid in respect of a share of Company Common
Stock.

         Each Unit of Preferred Stock will have one vote, voting together with
the Company Common Stock. The holders of Units of Preferred Stock, voting as a
separate class, shall be entitled to elect two directors if dividends on the
Preferred Stock are in arrears for six consecutive fiscal quarters.

         In the event of any merger, consolidation or other transaction in which
shares of Company Common Stock are exchanged, each Unit of Preferred Stock will
be entitled to receive the per share amount paid in respect of each share of
Company Common Stock.

         The rights of holders of the Preferred Stock to dividends, liquidation
and voting, and in the event of mergers and consolidations, are protected by
customary antidilution provisions.

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         Because of the nature of the Preferred Stock's dividend, liquidation
and voting rights, the economic value of one Unit of Preferred Stock that may be
acquired upon the exercise of each Right should approximate the economic value
of one share of Company Common Stock.

         The Rights may have certain anti-takeover effects. The Rights will
cause substantial dilution to a person or group that attempts to acquire the
Company on terms not approved by the Company's Board of Directors. However, the
Rights should not interfere with any merger or other business combination
approved by the Company's Board of Directors because the Rights may be redeemed
by the Board at a nominal price of $0.01 per Right at any time on or prior to
the tenth day after a public announcement made by either the Company or the
acquiring person or group that such person or group has acquired beneficial
ownership of 15% or more of the Company's Common Stock (subject to extension by
the Company's Board of Directors). Thus, the Rights are intended to encourage
persons who may seek to acquire control of the Company to initiate such an
acquisition through negotiations with the Board of Directors. However, the
effect of the Rights may be to discourage a third party from making a partial
tender offer or otherwise attempting to obtain a substantial equity position in
the equity securities of, or seeking to obtain control of, the Company. To the
extent any potential acquirors are deterred by the Rights, the Rights may have
the effect of preserving incumbent management in office.

         The Rights Agreement between the Company and the Rights Agent
specifying the terms of the Rights, which includes as Exhibit A the Form of
Rights Certificate, is attached hereto as Exhibit 1 and is incorporated herein
by reference. The foregoing description of the Rights does not purport to be
complete and is qualified in its entirety by reference to such Exhibit 1.

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Item 2.  Exhibits.

         1. Rights Agreement, dated as of August 27, 2001, between
AmerisourceBergen Corporation and Mellon Investor Services LLC.

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                                    SIGNATURE


         Pursuant to the requirements of Section 12 of the Securities Exchange
Act of 1934, the registrant has duly caused this registration statement to be
signed on its behalf by the undersigned, thereto duly authorized.

                                          AMERISOURCEBERGEN CORPORATION



                                          By:    /s/ William D. Sprague
                                              ----------------------------------
                                              Name:  William D. Sprague
                                              Title: Secretary

Date:    August 28, 2001

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                                  EXHIBIT INDEX



 Exhibit No.                        Description
 -----------                        -----------
      1              Rights Agreement, dated as of August 27,
                     2001, between AmerisourceBergen
                     Corporation and Mellon Investor Services
                     LLC.

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