<PAGE>
                                                  Filed Pursuant to Rule 424B(3)
                                                  Registration number 333-102090


                                   PROSPECTUS

                          AmerisourceBergen Corporation

                        2,399,091 Shares of Common Stock

      We have prepared this prospectus to allow the selling shareholders we
identify herein to sell from time to time up to 2,399,091 shares of our common
stock. The shares offered by this prospectus were originally offered by us to
the selling shareholders in connection with the merger described in this
prospectus. We will not receive any of the proceeds from the sale of common
stock by the selling shareholders.

      When we use the term "selling shareholders" in this prospectus, it
includes donees, distributees, pledgees and other transferees who are selling
shares received after the date of this prospectus from a selling shareholder
whose name appears under the heading "Selling Shareholders" on page 6. If we are
notified by a selling shareholder that a donee, distributee, pledgee or other
transferee intends to sell more than 500 shares, we will file a supplement to
this prospectus if required by law.

      Our common stock is listed on the New York Stock Exchange under the symbol
"ABC." On January 15, 2003, the last reported price of our common stock was
$54.15 per share.

      INVESTING IN OUR COMMON STOCK INVOLVES A HIGH DEGREE OF RISK. YOU SHOULD
CAREFULLY CONSIDER CERTAIN "RISK FACTORS" IN DETERMINING WHETHER TO BUY ANY OF
OUR COMMON STOCK. SEE PAGE 2.

      NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED THESE SECURITIES OR DETERMINED IF THIS
PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.



                The date of this prospectus is January 17, 2003.

<PAGE>
                                TABLE OF CONTENTS


<TABLE>
<S>                                                                          <C>
Note Regarding Forward-Looking Statements...................................  ii
Our Business................................................................   1
Risk Factors................................................................   2
Use of Proceeds.............................................................   6
Selling Shareholders........................................................   6
Plan of Distribution........................................................   7
Legal Matters...............................................................   8
Experts.....................................................................   8
Information Incorporated by Reference.......................................   8
Where You Can Find More Information.........................................   9
</TABLE>



      This prospectus incorporates important business and financial information
about us that is not included in or delivered with this document. This
information is available without charge upon written or oral request. See
"Information Incorporated by Reference."

      You should rely only on the information contained in this prospectus. We
have not authorized any other person to provide you with different information.
If anyone provides you with different or inconsistent information, you should
not rely on it. The selling shareholders are not making an offer to sell these
securities in any jurisdiction where the offer or sale is not permitted. You
should assume that the information appearing in this prospectus is accurate only
as of the date on the front cover of this prospectus. Our business, financial
condition, results of operations and prospects may have changed since that date.


                                       i

<PAGE>
                    NOTE REGARDING FORWARD-LOOKING STATEMENTS

      This prospectus includes forward-looking statements within the meaning of
the Private Securities Litigation Reform Act of 1995. These statements relate to
analyses and other information that are based on forecasts of future results and
estimates of amounts not yet determinable. These statements also relate to our
future prospects, developments and business strategies. The statements contained
in this prospectus that are not statements of historical fact may include
forward-looking statements that involve a number of risks and uncertainties.

      In some cases, you can identify forward-looking statements by terminology
such as "anticipate," "believe," "could," "estimate," "expect," "intend," "may,"
"plan," "predict," "project," "will" or the negative of such terms or other
similar expressions. Factors that might cause or contribute to discrepancies
include, but are not limited to, those discussed elsewhere in this prospectus
and the risks discussed in our other Securities and Exchange Commission filings
that are incorporated by reference herein. The following factors are among those
that may cause actual results to differ materially from our forward-looking
statements:

      -     acquisitions and dispositions;

      -     changes in general economic, business and industry conditions;

      -     changes in pharmaceutical manufacturer pricing and distribution
            policies;

      -     changes in political and social conditions and corresponding laws
            and regulations;

      -     changes in governmental support of, and reimbursement for,
            pharmaceutical products and healthcare services;

      -     new laws and regulations or changes in laws and regulations
            governing prescription drug pricing, healthcare services or mandated
            benefits;

      -     significant litigation;

      -     changes in sales mix;

      -     competition;

      -     disruptions of established supply channels;

      -     degree of acceptance of new products;

      -     difficulty of forecasting sales at various times in various markets;

      -     the availability, terms and deployment of capital; and

      -     the other factors discussed below under the heading "Risk Factors"
            and elsewhere in this prospectus.

            All of our forward-looking statements should be considered in light
of these factors. We undertake no obligation to update our forward-looking
statements or risk factors to reflect new information, future events or
otherwise.


                                       ii

<PAGE>
                                  OUR BUSINESS

      AmerisourceBergen Corporation is a leading national wholesale distributor
of pharmaceutical products and related healthcare services and solutions with
operating revenue (excluding bulk shipments) of approximately $40 billion and
operating income of approximately $718 million for the fiscal year ended
September 30, 2002.

      We were formed in connection with the merger of AmeriSource Health
Corporation and Bergen Brunswig Corporation, which was consummated in August
2001. As a result of the merger, AmerisourceBergen is the largest pharmaceutical
services company in the United States that is dedicated solely to the
pharmaceutical supply chain. We believe that we are the leading wholesale
distributor of pharmaceutical products and services to hospital systems
(hospitals and acute care facilities), alternate site customers (mail order
facilities, physicians' offices, long-term care institutions, and clinics),
independent community pharmacies, and regional drugstore and food merchandising
chains. Also a leader in the institutional pharmacy marketplace, we provide
outsourced pharmacies to long-term care and workers' compensation programs.

      We are organized based upon the products and services we provide our
customers. We have two operating segments: Pharmaceutical Distribution and
PharMerica.

      The Pharmaceutical Distribution segment includes AmerisourceBergen Drug
Company ("AB Drug") and AmerisourceBergen Specialty Group ("AB Specialty"). AB
Drug includes the full-service pharmaceutical distribution facilities, American
Health Packaging, AutoMed Technologies, and other healthcare related businesses.
AB Drug sells pharmaceuticals, over-the-counter medicines, health and beauty
aids, and other health-related products to hospitals, alternate site and mail
order facilities, and independent and chain retail pharmacies. American Health
Packaging packages oral solid medications for nearly any need in virtually all
settings of patient care. AB Drug also provides promotional, inventory
management, pharmacy automation and information services to its customers. AB
Specialty sells specialty pharmaceutical products and services to physicians,
clinics and other providers in the oncology, nephrology, plasma and vaccines
sectors. AB Specialty also provides third party logistics and reimbursement
consulting services to healthcare product manufacturers.

      The PharMerica segment consists solely of our PharMerica operations.
PharMerica provides institutional pharmacy products and services to patients in
long-term care and alternate site settings, including skilled nursing
facilities, assisted living facilities, and residential living communities.
PharMerica also provides mail order pharmacy services to chronically and
catastrophically ill patients under workers' compensation programs, and provides
pharmaceutical claims administration services for payors.

      We have positioned ourselves in our markets as the only national wholesale
pharmaceutical distributor exclusively focused on pharmaceutical product
distribution, services and solutions. We serve the following major market
segments:

      -     acute care hospitals and health systems;

      -     independent community pharmacies;

      -     alternate site facilities; and

      -     national and regional retail drugstore chains, including departments
            of supermarkets and mass merchandisers.

      We currently serve customers throughout the United States and Puerto Rico
through a geographically diverse network of distribution centers. We are
typically the primary source of supply for pharmaceutical and related products
to our customers. We offer a broad range of solutions to our customers and
suppliers designed to enhance the efficiency and effectiveness of their
operations, allowing them to improve the delivery of healthcare to patients and
customers.

      Our customer base is geographically diverse and balanced with no single
customer representing more than 10% of fiscal 2002 operating revenue. We have
one of the leading market positions in pharmaceutical distribution to the
hospital systems/acute care facilities market and the alternate site facilities
market, which represented approximately 53% of fiscal 2002 operating revenue,
and the independent community pharmacies and national and regional retail
pharmacy chains, which represented approximately 47% of fiscal 2002 operating
revenue.


                                       1

<PAGE>
                                  RISK FACTORS

      An investment in the common stock offered in connection with this
prospectus involves a high degree of risk. You should carefully consider the
risks described below together with all of the other information included in
this prospectus before making an investment decision. If any of the following
risks actually occurs, our business, financial condition or results of
operations could be harmed. In that case, the trading price of our common stock
could decline, and you may lose all or part of your investment.

AMERISOURCEBERGEN MAY NOT REALIZE ALL OF THE ANTICIPATED BENEFITS OF THE MERGER
BETWEEN AMERISOURCE AND BERGEN.

      The success of the merger of AmeriSource Health Corporation and Bergen
Brunswig Corporation will depend in part on our ability to realize the
anticipated synergies of $150 million per year by the end of fiscal 2004 and
growth opportunities from integrating the businesses of AmeriSource and Bergen.
Our success in realizing these synergies and growth opportunities, and the
timing of this realization, depends on the successful integration of
AmeriSource's and Bergen's operations. Even if we are able to integrate the
business operations of AmeriSource and Bergen successfully, we cannot assure you
that this integration will result in the realization of the full benefits of the
synergies and growth opportunities that we currently expect to result from this
integration or that these benefits will be achieved within the anticipated time
frame. For example, the elimination of duplicative costs may not be possible or
may take longer than anticipated and the benefits from the merger may be offset
by costs incurred in integrating the companies.

INTENSE COMPETITION MAY ERODE OUR PROFIT MARGINS.

      The wholesale distribution of pharmaceuticals and related healthcare
services is highly competitive. We compete primarily with the following:

      -     national wholesale distributors of pharmaceuticals such as Cardinal
            Health, Inc. and McKesson Corporation;

      -     regional and local distributors of pharmaceuticals;

      -     chain drugstores that warehouse their own pharmaceuticals;

      -     manufacturers who distribute their products directly to customers;
            and

      -     other specialty distributors.

      Some of our competitors have greater financial resources than we have.
Competitive pressures have contributed to a decline in our pharmaceutical
distribution segment gross profit margins on operating revenue from 4.7% on a
combined basis in fiscal 1997 to 3.9% in fiscal 2002. This trend may continue
and our business could be adversely affected as a result.

      PharMerica, one of our wholly-owned subsidiaries, faces competitive
pressure from other market participants that are significantly larger than it is
and that have significantly greater financial resources than it does. These
competitive pressures could lead to a decline in gross profit margins for
PharMerica in the future. In addition, there are relatively few barriers to
entry in the local markets served by PharMerica, and PharMerica may encounter
substantial competition from new local market entrants. These factors could
adversely affect PharMerica's business in the future.

THE CHANGING UNITED STATES HEALTHCARE ENVIRONMENT MAY IMPACT OUR REVENUE AND
INCOME.

      Our products and services are intended to function within the structure of
the healthcare financing and reimbursement system currently existing in the
United States. In recent years, the healthcare industry has undergone
significant changes in an effort to reduce costs and government spending. These
changes include an increased reliance on managed care, cuts in Medicare funding
affecting our healthcare provider customer base, consolidation


                                       2

<PAGE>
of competitors, suppliers and customers, and the development of large,
sophisticated purchasing groups. We expect the healthcare industry to continue
to change significantly in the future. Some of these potential changes, such as
a reduction in governmental support of healthcare services or adverse changes in
legislation or regulations governing prescription drug pricing, healthcare
services or mandated benefits, may cause healthcare industry participants to
greatly reduce the amount of our products and services they purchase or the
price they are willing to pay for our products and services. Changes in
pharmaceutical manufacturers' pricing or distribution policies could also
significantly reduce our income.

OUR OPERATING REVENUE AND PROFITABILITY MAY SUFFER UPON OUR LOSS OF ONE OR MORE
SIGNIFICANT CUSTOMERS.

      During the fiscal year ended September 30, 2002, sales to the federal
government (including sales under separate contracts with different departments
and agencies of the federal government), accounted for approximately 9% of our
operating revenue. In addition, we have contracts with group purchasing
organizations ("GPOs") which represent a concentration of buying power among
multiple healthcare providers. The loss of a major federal government customer
or GPO could lead to a significant reduction in revenue. However, other than the
federal government, we have no individual customer that accounted for more than
5% of our fiscal 2002 operating revenue. Including the federal government, our
top 10 customers represented approximately 32% of operating revenue during
fiscal 2002. Our revenues generated from sales to Merck-Medco Managed Care LLC
in fiscal 2002 were approximately 11% of total revenue and 99% of bulk
deliveries to customers' warehouses.

FAILURE IN OUR INFORMATION TECHNOLOGY SYSTEMS COULD SIGNIFICANTLY DISRUPT OUR
OPERATIONS, WHICH COULD REDUCE OUR CUSTOMER BASE AND RESULT IN LOST REVENUE.

      Our success depends, in part, on the continued and uninterrupted
performance of our information technology, or IT, systems. Our computer systems
are vulnerable to damage from a variety of sources, including telecommunications
failures, malicious human acts and natural disasters. Moreover, despite network
security measures, our servers are potentially vulnerable to physical or
electronic break-ins, computer viruses and similar disruptive problems. Despite
the precautions we have taken, unanticipated problems affecting our systems
could cause failures in our IT systems. Sustained or repeated system failures
that interrupt our ability to process orders or otherwise meet our business
obligations in a timely manner would adversely affect our reputation and result
in a loss of customers and net revenue.

      We operate our full service pharmaceutical distribution facilities on two
different centralized management information systems. One is the former
AmeriSource system and the other is the former Bergen system. We continue to
integrate the systems into the former Bergen system, while maintaining our
customers' ability to access the system through the order-entry system used by
either company. During systems conversions of this type, workflow may be
temporarily interrupted, which may cause interruptions in customer service. In
addition, the implementation process, including the transfer of databases and
master files to new data centers, presents significant conversion risks which
could cause failures in our IT systems and disrupt our operations.

OUR OPERATIONS MAY SUFFER IF GOVERNMENT REGULATIONS REGARDING PHARMACEUTICALS
CHANGE.

      The healthcare industry is highly regulated at the local, state and
federal level. Consequently, we are subject to the risk of changes in various
local, state, federal and international laws, which include the operating and
security standards of the United States Drug Enforcement Administration, or DEA,
the United States Food and Drug Administration, or FDA, various state boards of
pharmacy and comparable agencies. These changes may affect our operations,
including distribution of prescription pharmaceuticals (including certain
controlled substances), operation of pharmacies and packaging of
pharmaceuticals. A review of our business by regulatory authorities may result
in determinations that could adversely affect the operations of the business.

IF WE FAIL TO COMPLY WITH EXTENSIVE LAWS AND REGULATIONS IN RESPECT OF
HEALTHCARE FRAUD, WE COULD SUFFER PENALTIES OR BE REQUIRED TO MAKE SIGNIFICANT
CHANGES TO OUR OPERATIONS.

         We are subject to extensive and frequently changing local, state and
federal laws and regulations relating to healthcare fraud. The federal
government continues to strengthen its position and scrutiny over practices
involving healthcare fraud affecting the Medicare, Medicaid and other government
healthcare programs. Contractual


                                       3

<PAGE>
relationships with pharmaceutical manufacturers and healthcare providers subject
our business to provisions of the federal Social Security Act which, among other
things, (i) preclude persons from soliciting, offering, receiving or paying any
remuneration in order to induce the referral of a patient for treatment or for
inducing the ordering or purchasing of items or services that are in any way
paid for by Medicare, Medicaid or other government-sponsored healthcare programs
and (ii) impose a number of restrictions upon referring physicians and providers
of designated health services under Medicare and Medicaid programs. Legislative
provisions relating to healthcare fraud and abuse give federal enforcement
personnel substantially increased funding, powers and remedies to pursue
suspected fraud and abuse. While we believe that we are in material compliance
with all applicable laws, many of the regulations applicable to us, including
those relating to marketing incentives offered by pharmaceutical suppliers, are
vague or indefinite and have not been interpreted by the courts. They may be
interpreted or applied by a prosecutorial, regulatory or judicial authority in a
manner that could require us to make changes in our operations. If we fail to
comply with applicable laws and regulations, we could suffer civil and criminal
penalties, including the loss of licenses or our ability to participate in
Medicare, Medicaid and other federal and state healthcare programs.

IF KEY MANAGERS LEAVE AMERISOURCEBERGEN, OUR OPERATING RESULTS MAY BE ADVERSELY
AFFECTED.

      We depend on our senior management. If some of these employees leave us,
operating results could be adversely affected. We cannot be assured that we will
be able to retain these or any other key employees.

FEDERAL AND STATE LAWS THAT PROTECT PATIENT HEALTH INFORMATION MAY INCREASE OUR
COSTS AND LIMIT OUR ABILITY TO COLLECT AND USE THAT INFORMATION.

      Our activities subject us to numerous federal and state laws and
regulations governing the collection, dissemination, use, security and
confidentiality of patient-identifiable health information, including the
federal Health Insurance Portability and Accountability Act of 1996, or HIPAA,
and related rules and regulations, or Privacy Laws. For example, as part of
PharMerica's pharmaceutical dispensing, medical record keeping, third party
billing and other services, we collect and maintain patient-identifiable health
information, which activities may trigger certain requirements under the Privacy
Laws. The costs associated with our efforts to comply with the Privacy Laws
could be substantial. Moreover, if we fail to comply with certain Privacy Laws,
we could suffer civil and criminal penalties. We can provide no assurance that
the costs incurred in complying or penalties we may incur for failure to comply
with the Privacy Laws will not have a material effect on us.

OUR OPERATING RESULTS AND/OR FINANCIAL CONDITION MAY BE ADVERSELY AFFECTED IF WE
UNDERTAKE ACQUISITIONS OF BUSINESSES THAT DO NOT PERFORM AS WE EXPECT.

      We expect to continue to acquire companies as an element of our growth
strategy. Acquisitions are among the ways by which we seek to expand our
presence in strategically important markets and to expand the breadth and scope
of our ancillary businesses and service offerings. At any particular time, we
may be in various stages of assessment, discussion and negotiation with regard
to one or more potential acquisitions, many of which will not proceed beyond the
assessment, discussion and/or negotiation stages. We make public disclosure of
pending and completed acquisitions when appropriate and required by applicable
securities laws and regulations.

      Acquisitions involve numerous risks and uncertainties. If we complete one
or more acquisitions, our business, results of operations and financial
condition may be adversely affected by a number of factors, including:

      -     the failure of the acquired businesses to achieve the results we
            have projected in either the near term or the longer term;

      -     the assumption of unknown liabilities;

      -     difficulties in the integration of the operations, technologies,
            services and products of the acquired companies;

      -     the failure to achieve the strategic objectives of these
            acquisitions; and

      -     other unforeseen difficulties.


                                       4

<PAGE>
      We anticipate that we will finance acquisitions in the foreseeable future
at least partly by the issuance of additional AmerisourceBergen common stock.
The use of equity financing for acquisitions will dilute the ownership
percentage of our then current shareholders.

WE HAVE IN PLACE ANTI-TAKEOVER DEVICES THAT MAY DISCOURAGE A THIRD-PARTY FROM
ACQUIRING CONTROL OF AMERISOURCEBERGEN AND AFFECT THE ABILITY OF SHAREHOLDERS TO
REMOVE OUR MANAGEMENT.

      We have adopted a shareholders' rights plan that is intended to encourage
persons who may seek to acquire control to initiate negotiations with our board
of directors. If exercised, the rights granted under the plan will cause
substantial dilution to a person or group that attempts to acquire us on terms
not approved by our board of directors.

      In addition, Section 203 of the Delaware General Corporation Law imposes
restrictions on mergers and other business combinations between us and any
holder of 15% or more of our common stock.

      Some provisions of our amended and restated certificate of incorporation,
as amended, and amended and restated bylaws could have the effect of delaying,
discouraging or preventing the removal of management. These provisions include
the following: a classified board (with each board member serving a three-year
term), no authorization for shareholders to call a special meeting, limited
ability of shareholders to remove directors, prohibition of action by written
consent of shareholders, an advance notice requirement for nomination of
directors and for shareholder proposals and a limitation on shareholders'
ability to amend the certificate of incorporation.

THE MARKET PRICE OF OUR COMMON STOCK MAY FLUCTUATE SIGNIFICANTLY, WHICH MAY
RESULT IN LOSSES FOR INVESTORS.

      The stock market and the price of our common stock may be subject to
volatile fluctuations based on general economic and market conditions, industry
trends and company performance. The market price for our common stock may also
be affected by our ability to meet analysts' expectations. Failure to meet such
expectations, even slightly, could have an adverse effect on the market price of
our common stock. In the past, following periods of volatility in the market
price of a company's securities, securities class action litigation has often
been instituted against such a company. If similar litigation were instituted
against us, it could result in substantial costs and diversion of our
management's attention and resources, which could have an adverse effect on our
business. Because of the volatility, we may fail to meet the expectations of our
shareholders or of securities analysts at some time in the future, and our stock
price could decline as a result.


                                       5

<PAGE>
                                 USE OF PROCEEDS

      We will not receive any proceeds from the sale of shares of common stock
by the selling shareholders. We have paid the costs relating to the registration
of these shares, which we estimate to be $44,261.

                              SELLING SHAREHOLDERS

      The shares of our common stock covered by this prospectus are shares that
the selling shareholders have agreed to acquire in connection with the
acquisition of US Bioservices Corporation ("US Bioservices") by
AmerisourceBergen through a merger between a wholly-owned subsidiary of
AmerisourceBergen and US Bioservices. In connection therewith, we have agreed to
register such shares for resale by the selling shareholders.

      The following table sets forth, for the selling shareholders, the number
of shares of our common stock that will be beneficially owned prior to the
offering, the number of shares of common stock offered hereby and the number of
shares of common stock to be held and the percentage of outstanding common stock
to be beneficially owned after completion of this offering. Except as disclosed
in this section, we are not aware of any material relationship between any of
the selling shareholders and us in the past three years other than as a result
of the ownership of the shares of our common stock and as a result of the
merger. The information regarding the selling shareholders may change from time
to time. If required, we will set forth these changes in one or more prospectus
supplements.


<TABLE>
<CAPTION>
                                                                                                  PERCENTAGE BENEFICIAL
                                  NUMBER OF SHARES    NUMBER OF SHARES    NUMBER OF SHARES TO        OWNERSHIP AFTER
                                   OWNED PRIOR TO      OFFERED IN THE           BE OWNED            COMPLETION OF THE
                                   THE OFFERING(1)       OFFERING(2)      AFTER THE OFFERING(2)         OFFERING(2)
                                   ---------------       -----------      ---------------------         -----------
<S>                               <C>                 <C>                 <C>                     <C>
Whitney V, L.P.                       1,408,597            1,408,597                       0                         0
Other selling shareholders(3)           990,494              990,494                       0                         0
</TABLE>


      (1) We have been advised by the selling shareholders that they have no
present intention to acquire any additional shares prior to the effectiveness of
the registration statement to which this prospectus relates.

      (2) Because the selling shareholders may sell all or a portion of the
shares of common stock that may be offered pursuant to this prospectus, the
number of shares that will be owned by the selling shareholders upon termination
of this offering cannot be determined. For purposes of preparing this table, we
have assumed the sale of all shares offered under this prospectus.

      (3) Collectively, the selling shareholders other than Whitney V, L.P., all
of whom are officers or employees of US Bioservices or affiliates of such
persons, will own less than 1% of our outstanding common stock.


                                       6

<PAGE>
                              PLAN OF DISTRIBUTION

      The selling shareholders may sell the shares of common stock from time to
time in separate transactions or in a single transaction. When we use the term
"selling shareholders" in this prospectus, it includes the former shareholders
of US Bioservices referenced in "Selling Shareholders" and donees, distributees,
pledgees and other transferees who are selling shares received after the date of
this prospectus from such former shareholders of US Bioservices. If we are
notified by a selling shareholder that a donee, distributee, pledgee or other
transferee intends to sell more than 500 shares, we will file a supplement to
this prospectus if required by law. The selling shareholders will act
independently of us in making decisions regarding the timing, manner and size of
each sale.

      The selling shareholders may make these sales on the New York Stock
Exchange or otherwise, at prices and terms that are then-prevailing or at prices
related to the then-current market price, at fixed prices or in privately
negotiated transactions. The selling shareholders may use one or more of the
following methods to sell the shares of common stock:

      -     a block trade in which a selling shareholder's broker or dealer will
            attempt to sell the shares as agent, but may position and resell all
            or a portion of the block as a principal to facilitate the
            transaction;

      -     a broker or dealer may purchase the common stock as a principal and
            then resell the common stock for its own account pursuant to this
            prospectus;

      -     an exchange or over-the-counter distribution in accordance with the
            rules of the applicable exchange or automated interdealer quotation
            system;

      -     ordinary brokerage transactions and transactions in which the broker
            solicits purchasers;

      -     sales through underwriters or dealers who may receive compensation
            in the form of underwriting discounts, concessions or commissions
            from the selling shareholders or such successors in interest and/or
            from the purchasers of shares for whom they act as agent; and

      -     the pledge of the shares as security for any loan or obligation,
            including pledges to brokers or dealers who may, from time to time,
            themselves effect distribution of the shares or interests therein.

      The selling shareholders may enter into hedging transactions with
broker-dealers in connection with distributions of the shares or otherwise. In
these transactions, broker-dealers may engage in short sales of the shares in
the course of hedging the positions they assume with the selling shareholders.
The selling shareholders also may sell shares short and redeliver the shares to
close out short positions. The selling shareholders may enter into option or
other transactions with broker-dealers that require the delivery to the
broker-dealer of the shares. The broker-dealer may then resell or otherwise
transfer the shares under this prospectus. The selling shareholders also may
loan or pledge the shares to a broker-dealer. The broker-dealer may sell the
loaned shares, or upon a default the broker-dealer may sell the pledged shares
under this prospectus.

      In effecting sales, broker-dealers engaged by the selling shareholders may
arrange for other broker-dealers to participate in the resales. To the extent
required, this prospectus will be amended and supplemented from time to time to
describe a specific plan of distribution.

      Broker-dealers or agents may receive compensation in the form of
commissions, discounts or concessions from selling shareholders. Broker-dealers
or agents may also receive compensation from the purchasers of the shares for
whom they act as agents or to whom they sell as principal, or both. Compensation
as to a particular broker-dealer might be in excess of customary commissions and
will be in amounts to be negotiated in connection with the sale. Broker-dealers
or agents and any other participating broker-dealers or the selling shareholders
may be deemed to be "underwriters" within the meaning of section 2(a)(11) of the
Securities Act in connection with sales of the shares. Accordingly, any such
commission, discount or concession received by them and any profit on the resale
of the shares purchased by them may be deemed to be underwriting discounts or
concessions under the Securities Act.


                                       7

<PAGE>
Because selling shareholders may be deemed "underwriters" within the meaning of
section 2(a)(11) of the Securities Act, the selling shareholders will be subject
to the prospectus delivery requirements of the Securities Act.

      Any shares covered by this prospectus which qualify for sale pursuant to
Rule 144 under the Securities Act may be sold under Rule 144 rather than
pursuant to this prospectus.

      The selling shareholders and any other person participating in such
distribution will be subject to applicable provisions of the Exchange Act and
the rules and regulations there under, including, without limitation, Regulation
M, which may limit the timing of purchases and sales of any of the shares by the
selling shareholders and any other such person. Furthermore, under Regulation M
under the Exchange Act, any person engaged in the distribution of the shares may
not simultaneously engage in market-making activities with respect to the
particular shares being distributed for certain periods prior to the
commencement of such distribution. All of the foregoing may affect the
marketability of the shares and the ability of any person or entity to engage in
market-making activities with respect to the shares.

      There is no assurance that any selling shareholder will sell any or all of
the shares offered by it hereunder or that any such selling shareholder will not
transfer, devise or gift such shares by other means not described herein.

      The shares will be sold only through registered or licensed brokers or
dealers if required under applicable state securities laws. In addition, in
certain states the shares may not be sold unless they have been registered or
qualified for sale in the applicable state or an exemption from the registration
or qualification requirement is available and is complied with.

      We will bear all costs, expenses and fees in connection with the
registration of the shares. The selling shareholders will bear all commissions
and discounts, if any, attributable to the sale of the shares. The selling
shareholders may agree to indemnify any broker-dealer or agent that participates
in transactions involving sales of the shares against certain liabilities,
including liabilities arising under the Securities Act. We have agreed to
indemnify the selling shareholders against certain liabilities in connection
with their offering of the shares, including liabilities arising under the
Securities Act.

                                  LEGAL MATTERS

      The validity of our common stock offered hereby will be passed upon for us
by Dechert, Philadelphia, Pennsylvania. A partner of Dechert beneficially owns
10,500 shares of our common stock.

                                     EXPERTS

      Ernst & Young LLP, independent auditors, have audited our consolidated
financial statements and schedule included in our Annual Report on Form 10-K for
the year ended September 30, 2001, as set forth in their report, which is
incorporated by reference in this prospectus and elsewhere in the registration
statement. Our financial statements and schedule are incorporated by reference
in reliance on Ernst & Young LLP's report, given on their authority as experts
in accounting and auditing.

      The consolidated financial statements of Bergen Brunswig Corporation
incorporated in this prospectus by reference from Bergen Brunswig Corporation's
Annual Report on Form 10-K for the year ended September 30, 2000 have been
audited by Deloitte & Touche LLP, independent auditors, as stated in their
report, which is incorporated herein by reference, and have been so incorporated
in reliance upon the report of such firm given upon their authority as experts
in accounting and auditing.

                      INFORMATION INCORPORATED BY REFERENCE

      The Commission allows us to "incorporate by reference" the information in
certain of our publicly-filed documents, which means that we can disclose
important information to you by referring you to those documents. The
information incorporated by reference is considered to be a part of this
prospectus, and information that we file with the Commission after the date of
this prospectus will automatically update and supercede previously filed
information, including information contained in this prospectus.


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<PAGE>
      We incorporate by reference the documents listed below and any future
filings we will make with the Commission under Sections 13(a), 13(c), 14 or
15(d) of the Securities Exchange Act of 1934 until this offering has been
completed or until we terminate the effectiveness of this registration
statement:

                        (1)   Current Report on Form 8-K, filed on January 6,
                              2003

                        (2)   Annual Report on Form 10-K, filed on December 24,
                              2002

                        (3)   The "Description of AmerisourceBergen Capital
                              Stock" section from the Registration Statement on
                              Form S-4/A, filed on July 27, 2001

                        (4)   Annual Report of Bergen on Form 10-K, filed on
                              December 29, 2000

                        (5)   Quarterly Reports of Bergen on Form 10-Q, filed on
                              February 14, 2001, May 14, 2001 and August 14,
                              2001

      Upon written or oral request, we will provide you with a copy of any of
the incorporated documents without charge (not including exhibits to the
documents unless the exhibits are specifically incorporated by reference into
the documents). You may submit such a request for this material at the following
address and telephone number:

                               Investor Relations
                          AmerisourceBergen Corporation
                          1300 Morris Drive, Suite 100
                        Chesterbrook, Pennsylvania 19087
                                 (610) 727-7000

                       WHERE YOU CAN FIND MORE INFORMATION

      We are currently subject to the informational reporting requirements of
the Securities Exchange Act of 1934, as amended, and file periodic reports and
other information with the SEC. These documents include specific information
about us. You may read and copy any document we file with the SEC at the public
reference room at 450 Fifth Street, N.W., Washington, D.C. 20549. Please call
the SEC at 1-800-SEC-0330 to obtain information on the operation of the public
reference room. Our SEC filings are also available over the Internet at the
SEC's website at www.sec.gov. Copies of such material can also be obtained from
us upon request.

      Our common stock is traded on the New York Stock Exchange and, therefore,
the information we file with the Commission may also be inspected at the offices
of the New York Stock Exchange, located at 20 Broad Street, New York, NY 10005.



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