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                                                                     EXHIBIT 5.1


[DECHERT LETTERHEAD]

July 26, 2001


AmerisourceBergen Corporation
1300 Morris Drive, Suite 100
Chesterbrook, PA  19087-5594

Re:  Registration Statement on Form S-4 of AmerisourceBergen Corporation

Gentlemen and Ladies:

We have acted as counsel to AmerisourceBergen Corporation, a Delaware
corporation (the "Company"), in connection with the Registration Statement (No.
333-61440) on Form S-4 (the "Registration Statement") filed by the Company with
the Securities and Exchange Commission under the Securities Act of 1933, as
amended (the "Securities Act"). The Registration Statement relates to the
proposed issuance by the Company of up to 108,625,865 shares (the "Shares") of
Common Stock of the Company, $0.01 par value per share, pursuant to the
Agreement and Plan of Merger, dated as of March 16, 2001 (the "Merger
Agreement"), among the Company, AmeriSource Health Corporation, a Delaware
corporation ("AmeriSource"), Bergen Brunswig Corporation, a New Jersey
corporation ("Bergen"), A-Sub Acquisition Corp., a Delaware corporation, and
B-Sub Acquisition Corp, a New Jersey corporation. The Merger Agreement provides
for the mergers (the "Mergers") whereby AmeriSource and Bergen will each become
a wholly owned subsidiary of the Company, as described in the Joint Proxy
Statement/Prospectus (the "Joint Proxy Statement/Prospectus") that is a part of
the Registration Statement.

We have participated in the preparation and filing of the Registration Statement
and have made such legal and factual examination and inquiry as we have deemed
necessary for the rendering of this opinion. We have reviewed the Merger
Agreement, the Registration Statement and the exhibits thereto, and have
examined originals or copies, certified or otherwise identified to our
satisfaction, of such corporate records, agreements, instruments and other
documents as we have deemed relevant and necessary in connection with this
opinion.

In making our examination, we have assumed the genuineness of all signatures and
the authenticity of all documents submitted to us as originals, the conformity
to all authentic original documents of all documents submitted to us as copies
and the authenticity of the originals of such copies, the legal capacity of
natural persons, and the truth, accuracy and completeness (without independent
investigation or verification) of the information, representations, warranties
and statements contained in the records, agreements, instruments and other
documents we have reviewed. In our examination of documents executed by
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July 26, 2001
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parties other than the Company, we have assumed that such parties had, have or
will have all requisite power and authority to enter into and perform all
obligations thereunder and also have assumed the due authorization by all
requisite action, the due execution and delivery by such parties of all such
agreements, instruments and other documents and the validity and binding effect
thereof. As to any facts material to this opinion which we have not
independently established or verified, we have relied upon statements and
representations of officers and other representatives of the Company and others.

Our opinion is limited to applicable provisions of the General Corporation Law
of the State of Delaware ("Delaware Law") and judicial decisions interpreting
Delaware Law. We express no opinion with respect to the laws of any other
jurisdiction and no opinion is expressed herein with respect to the
qualifications of the Shares under the securities or blue sky laws of any state
or any foreign jurisdiction.

Based upon and subject to the foregoing, we are of the opinion that following
(i) effectiveness of the Registration Statement under the Securities Act, (ii)
effectiveness of the Mergers pursuant to applicable corporate law, and (iii)
issuance of the Shares in accordance with the Merger Agreement, the Shares will
be validly issued, fully paid and non-assessable.

We hereby consent to the filing of this opinion with the Securities and Exchange
Commission as an exhibit to the Registration Statement and to the reference to
our firm under the caption "Legal Matters" in the Joint Proxy
Statement/Prospectus contained therein. In giving this consent, we do not
thereby admit that we are in the category of persons whose consent is required
under Section 7 of the Securities Act.

This opinion is provided by us, as counsel to the Company, in accordance with
the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act,
and, except as provided herein, is not to be used, circulated or quoted for any
other purpose or otherwise referred to or relied upon by any other person
without the express written consent of the Company.

Very truly yours,


/s/ Dechert Price & Rhoads
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Dechert Price & Rhoads