AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON OCTOBER 30, 1998
                                                    REGISTRATION NO. 333-
- -------------------------------------------------------------------------------
- -------------------------------------------------------------------------------
                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549
 
                                ---------------
 
                                   FORM S-3
                            REGISTRATION STATEMENT
                                     UNDER
                          THE SECURITIES ACT OF 1933
 
                                ---------------
 
                             MCKESSON CORPORATION
            (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)


             DELAWARE                                     94-3207296
   (STATE OR OTHER JURISDICTION                       (I.R.S. EMPLOYER
   OF INCORPORATION OR ORGANIZATION)                 IDENTIFICATION NUMBER)


                                MCKESSON PLAZA
                                ONE POST STREET
                        SAN FRANCISCO, CALIFORNIA 94104
                                (415) 983-8300
  (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE, OF
                   REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)
 
                                NANCY A. MILLER
                    VICE PRESIDENT AND CORPORATE SECRETARY
                             MCKESSON CORPORATION
                        MCKESSON PLAZA, ONE POST STREET
                        SAN FRANCISCO, CALIFORNIA 94104
                                (415) 983-8300
(NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                             OF AGENT FOR SERVICE)
 
                                ---------------
 
                                  COPIES TO:

                                              
                 IVAN D. MEYERSON                             GREGG A. NOEL
        VICE PRESIDENT AND GENERAL COUNSEL      SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP
               MCKESSON CORPORATION                 300 SOUTH GRAND AVENUE, SUITE 3400
         MCKESSON PLAZA, ONE POST STREET              LOS ANGELES, CALIFORNIA 90071
         SAN FRANCISCO, CALIFORNIA 94104                     (213) 687-5000
                  (415) 983-8300

 
                                ---------------
 
     APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: From time
to time after this registration statement becomes effective.
     If the only securities being registered on this form are being offered
pursuant to dividend or interest reinvestment plans, please check the
following box. [_]
     If any of the securities being registered on this form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, other than securities being offered only in connection with dividend or
interest reinvestment plans, please check the following box. [X]
     If this form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following
box and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering. [_]
     If this form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. [_] ____________________________________________________
     If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box. [X]
                        CALCULATION OF REGISTRATION FEE


- ------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------
                                                          PROPOSED
                                           PROPOSED        MAXIMUM
 TITLE OF EACH CLASS OF      AMOUNT        MAXIMUM        AGGREGATE      AMOUNT OF
    SECURITIES TO BE         TO BE      OFFERING PRICE     OFFERING     REGISTRATION
       REGISTERED          REGISTERED    PER SHARE(1)      PRICE(1)         FEE
- ------------------------------------------------------------------------------------
                                                           
Common Stock, par value
 $0.01 per share.......    1,869,182        $71.09     $132,880,148.38   $36,941.00
- ------------------------------------------------------------------------------------
Rights to Purchase
 Series A Junior
 Participating Preferred
 Stock of McKesson
 Corporation(2)........                      N/A             N/A            N/A
- ------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------


(1) Estimated solely for the purpose of calculating the registration fee in
    accordance with Rule 457(c) and based on the average of the high and low
    prices for the common stock on October 23, 1998, as reported on the New
    York Stock Exchange.
(2) Associated with the common stock are rights to purchase Series A Junior
    Participating Preferred Stock of McKesson Corporation that will not be
    exercisable or evidenced separately from the Common Stock prior to the
    occurrence of certain events. No separate consideration will be received
    for the rights to purchase the Series A Preferred Stock.
 
                                ---------------
 
THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR DATES
AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(a) OF
THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION
8(a), MAY DETERMINE.
- -------------------------------------------------------------------------------
- -------------------------------------------------------------------------------

 
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+INFORMATION IN THIS PROSPECTUS IS NOT COMPLETE AND MAY BE CHANGED. THE        +
+SELLING STOCKHOLDERS MAY NOT SELL THESE SECURITIES UNTIL THE REGISTRATION     +
+STATEMENT FILED WITH THE SECURITIES AND EXCHANGE COMMISSION IS EFFECTIVE.     +
+THIS PROSPECTUS IS NOT AN OFFER TO SELL THESE SECURITIES AND THE SELLING      +
+STOCKHOLDERS ARE NOT SOLICITING THE OFFER TO BUY THESE SECURITIES IN ANY      +
+STATE WHERE SUCH OFFER OR SALE IS NOT PERMITTED.                              +
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                 SUBJECT TO COMPLETION, DATED OCTOBER 30, 1998
PROSPECTUS
 
                        1,869,182 SHARES OF COMMON STOCK
 
                              MCKESSON CORPORATION
 
                                     -----
 
  The stockholders of McKesson Corporation listed below may offer from time to
time 1,869,182 shares of our common stock under this prospectus. We will not
receive any part of the proceeds from such sales.
 
  Our common stock is listed on the New York Stock Exchange, Inc. and the
Pacific Exchange, Inc. under the trading symbol "MCK." On October 29, 1998, the
closing price of one share of our common stock on the New York Stock Exchange
was $74 7/8.
 
  SEE "RISK FACTORS" BEGINNING ON PAGE 3 OF THIS PROSPECTUS FOR A DESCRIPTION
OF CERTAIN MATTERS THAT YOU SHOULD CONSIDER BEFORE PURCHASING OUR COMMON STOCK.
 
                                     -----
 
  NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR PASSED UPON THE
ADEQUACY OR ACCURACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS
A CRIMINAL OFFENSE.
 
                                     -----
 
                  The date of this prospectus is      , 1998.

 
                             ABOUT THIS PROSPECTUS
 
  This prospectus is part of a registration statement that we filed with the
Securities and Exchange Commission (the "SEC") utilizing a "shelf" registration
process. Under this shelf process, the selling stockholders, may sell up to
1,869,182 shares of our common stock. This prospectus provides you with a
general description of our common stock which the selling stockholders may
offer. When the selling stockholders sell our common stock, we may provide, if
necessary, a prospectus supplement that will contain specific terms of that
offering. The prospectus supplement may also add, update or change information
contained in this prospectus. You should read both this prospectus and any
prospectus supplement together with the additional information described under
the heading "Where You Can Find More Information."
 
               SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS
 
  Certain matters discussed under the captions "Risk Factors" and "The Company"
and elsewhere in this prospectus or in the information incorporated by
reference constitute forward-looking statements within the meaning of Section
27A of the Securities Act of 1933, as amended (the "Securities Act") and
Section 21E of the Securities Exchange Act of 1934, as amended (the "Exchange
Act"). Some of the forward-looking statements can be identified by the use of
forward-looking words such as "believes," "expects," "may," "will," "should,"
"seeks," "approximately," "intends," "plans," "estimates," or "anticipates" or
the negative of those words or other comparable terminology. The discussion of
financial trends, strategy, plans or intentions may also include forward-
looking statements. Forward-looking statements involve risks and uncertainties
that could cause actual results to differ materially from those projected.
These include the speed of the integration of businesses we acquire, the impact
of continued competition in our industry, the success of strategic initiatives,
the implementation of new technologies, continued industry consolidation,
changes in customer mix, changes in pharmaceutical manufacturers' pricing and
distribution policies, the changing United States health care environment and
other factors discussed in this prospectus or incorporated by reference in this
prospectus.
 
                               TABLE OF CONTENTS
 
                                   PROSPECTUS
 


                                                                            PAGE
                                                                            ----
                                                                         
About This Prospectus......................................................   i
Special Note Regarding Forward-Looking Statements..........................   i
The Company................................................................   1
Use of Proceeds............................................................   2
Risk Factors...............................................................   3
Selling Stockholders.......................................................   5
Description of Capital Stock...............................................   6
Plan of Distribution.......................................................  10
Experts....................................................................  12
Legal Matters..............................................................  12
Where You Can Find More Information........................................  13

 
                                       i

 
                                  THE COMPANY
 
  We are the leading health care supply management company in North America. We
also develop and manage innovative marketing programs for pharmaceutical
manufacturers and, through McKesson Water Products Company ("Water Products"),
we process, deliver and sell bottled drinking water.
 
  Our objective is to become the world leader in health care supply and
comprehensive pharmaceutical management across the entire supply chain, from
manufacturer to patient. We conduct our operations through two operating
business segments: the Health Care Services segment and the Water Products
segment.
 
  Our principal executive offices are located at McKesson Plaza, One Post
Street, San Francisco, California 94104, and our telephone number is (415) 983-
8300.
 
  On October 17, 1998, McKesson Corporation ("McKesson") and HBO & Company
("HBOC"), a leading healthcare information company, signed a definitive merger
agreement for McKesson to acquire HBOC. Under the terms of the merger
agreement, stockholders of HBOC would receive 0.37 shares of McKesson common
stock for each share of HBOC common stock in a tax-free exchange. The merger of
the two companies, which is subject to regulatory approval, the approval of our
stockholders and the stockholders of HBOC and other customary conditions, would
be accounted for as a pooling of interests and is anticipated to close in the
first quarter of 1999. The new company would be named McKesson HBOC, and the
corporate headquarters of McKesson HBOC would be located in San Francisco,
California.
 
  Upon completion of the merger, Charles W. McCall, currently president and
chief executive officer of HBOC, would become chairman of McKesson HBOC's board
of directors, and Mark A. Pulido, currently our president and chief executive
officer, would become president and chief executive officer of McKesson HBOC.
Also upon completion of the merger, McKesson HBOC's board of directors would
consist of ten members, which would include five members from the our current
board and five from the current HBOC board.
 
  HBOC provides integrated patient care, clinical, financial, managed care and
strategic management software solutions for the healthcare industry. These open
systems applications facilitate the integration of clinical, financial and
administrative data from a wide range of customer systems and software. HBOC's
broad product portfolio can be implemented in a variety of combinations from
stand-alone to enterprisewide, enabling healthcare organizations to add
incremental capabilities to their existing information systems without making
prior capital investments obsolete. HBOC also provides a full complement of
network communications technologies, including wireless capabilities, as well
as outsourcing services that are offered under contract management agreements
whereby its staff manages and operates data centers, information systems,
medical call centers, organizations and business offices of healthcare
institutions of various sizes and structures. In addition, HBOC offers a wide
range of electronic commerce services, including electronic medical claims and
remittance advice services as well as statement processing.
 
  HBOC markets its products and services to integrated health delivery
networks, hospitals, physicians' offices, home health providers, pharmacies,
reference laboratories, managed care
 
                                       1

 
providers and payors. HBOC also sells its products and services internationally
through subsidiaries and/or distribution agreements in the United Kingdom,
Canada, Ireland, Saudi Arabia, Kuwait, Australia, Puerto Rico and New Zealand.
 
  HBOC has entered into an Agreement of Merger dated July 23, 1998 among HBOC,
HBO & Company of Georgia ("HBOC-GA") and IMNET Systems, Inc. ("IMNET"), which
provides electronic information and document management solutions for the
healthcare industry. Such agreement is subject, among other things, to IMNET
stockholder approval at a meeting scheduled to occur on October 30, 1998. If
the merger is completed, HBOC will issue up to approximately 12.7 million
shares of HBOC Common Stock to IMNET stockholders and optionholders.
 
  HBOC, HBOC-GA and Access Health, Inc. ("Access") entered into an Agreement of
Merger dated as of September 28, 1998, as amended. Access provides clinically
based care management programs and health care information services. The merger
is subject to certain conditions, including the approval by Access
stockholders. If the merger is completed, HBOC will issue up to approximately
38,932,001 shares of HBOC common stock to Access stockholders and
optionholders.
 
                                USE OF PROCEEDS
 
  All net proceeds from the sale of the shares of our common stock will go to
the stockholders who offer and sell their shares. Accordingly, we will not
receive any of the proceeds from the sales of the shares of our common stock.
 
                                       2

 
                                  RISK FACTORS
 
RISKS GENERALLY ASSOCIATED WITH ACQUISITIONS
 
  An element of our growth strategy is to pursue strategic acquisitions that
either expand or complement our business. We routinely review such potential
acquisition opportunities. Acquisitions involve a number of special risks. Such
risks include:
 
  .  the diversion of management's attention to the assimilation of the
     operations of businesses we have acquired;
 
  .  difficulties in the integration of operations and systems;
 
  .  delays or difficulties in opening and operating larger distribution
     centers in a larger and more complex distribution network;
 
  .  the assimilation and retention of the personnel of the acquired
     companies;
 
  .  challenges in retaining the customers of the combined businesses; and
 
  .  potential adverse short-term effects on operating results and the
     ratings assigned to our debt.
 
  In addition, in order to fund future acquisitions, we may be required to
borrow money or issue additional equity on terms which may be unfavorable to
us. In some instances, we may not be able to raise funds for future
acquisitions. Our inability to successfully finance, complete and integrate
strategic acquisitions in a timely manner could have an adverse impact on our
results of operations and our ability to effect a portion of our growth
strategy.
 
  In October 1998, we entered into a merger agreement to acquire HBOC. The
merger of the two companies is subject to regulatory approval, the approval of
our stockholders and the stockholders of HBOC and other customary conditions.
It is anticipated that the merger will close in the first quarter of 1999.
However, there can be no assurance that the merger will be completed or that it
will be completed as contemplated or what the results of the merger will be.
 
CHANGING UNITED STATES HEALTH CARE ENVIRONMENT
 
  In recent years, the health care industry has undergone significant change
driven by various efforts to reduce costs. Such efforts include potential
national health care reform, trends toward managed care, cuts in Medicare,
consolidation of pharmaceutical and medical/surgical supply distributors, and
the development of large, sophisticated purchasing groups. This industry is
expected to continue to undergo significant changes for the foreseeable future.
Other healthcare industry factors that could have a material adverse effect on
our results of operations include:
 
  .  changes in governmental support of health care services;
 
  .  the method by which such services are delivered or the prices for such
     services;
 
  .  other legislation or regulations governing such services or mandated
     benefits; or
 
  .  changes in pharmaceutical manufacturers' pricing or distribution
     policies.
 
                                       3

 
COMPUTER TECHNOLOGIES
 
  We rely heavily on computer technologies to operate our business. In 1996, we
began an assessment of our information technology which might be impacted by
the Year 2000 problem. Based on that assessment, we developed an enterprise-
wide Year 2000 project which consists of hundreds of individual projects under
the oversight of a central Year 2000 project office. We currently expect to
complete most of our mission critical projects by December 31, 1998 and all
phases of our identified projects by June 30, 1999. In addition, our business
relies in part on the computer-based systems of our customers and trade
suppliers, and on technology or data purchased from third parties. We are
reviewing the Year 2000 readiness of all of these third parties and are
continuing to develop contingency plans for any Year 2000 problems. We also
plan to conduct systems testing with third parties during calendar year 1999.
We believe that the most reasonably likely worst case Year 2000 scenario would
be a business disruption resulting from an extended and/or extensive
communications failure. We believe that such a disruption is likely to be
localized and of short duration and would therefore not be likely to have a
material adverse effect on us. However, because of the range of possible issues
and the large number of variables involved (including any acquisitions we may
make), we cannot quantify the potential cost of problems should our remediation
efforts or the efforts of those with whom we do business not be successful.
Such costs and any failure of such remediation efforts could result in a loss
of business, damage to McKesson's reputation and legal liability. Consequently
such costs or failures could have a material adverse effect on us.
 
  We expect to incur a total projected cost of less than $40 million in
connection with our Year 2000 remediation efforts. Such costs are difficult to
estimate accurately and the projected cost could change due to unanticipated
technological difficulties, project vendor delays, project vendor cost overruns
and the degree to which systems of newly acquired businesses are compliant. For
a further discussion about our Year 2000 readiness, see our filings with the
SEC made pursuant to the Exchange Act.
 
 
                                       4

 
                              SELLING STOCKHOLDERS
 
  The selling stockholders obtained their shares of our common stock as a
result of the merger of Hawk Medical Supply, Inc. ("Hawk") with and into
McKesson. Under the Registration Rights Agreement, dated as of June 22, 1998,
among McKesson and the stockholders and warrant holders of Hawk (the
"Registration Rights Agreement"), we agreed to register, under certain
circumstances, the shares of our common stock issued to the selling
stockholders and to keep this registration statement effective for at least 120
days, or until all of the registered shares are sold under the registration
statement, whichever comes first. This registration of shares of our common
stock does not necessarily mean that the selling stockholders will sell all or
any of their shares of our common stock.
 
  The following table sets forth certain information about the shares of our
common stock that are owned by the selling stockholders as of the date of this
prospectus:
 


                                       SHARES OWNED               SHARES OWNED
                                       PRIOR TO THE SHARES BEING    AFTER THE
NAME OF SELLING STOCKHOLDER              OFFERING     OFFERED      OFFERING(2)
- ---------------------------            ------------ ------------  ------------
                                                         
Bruce K. Anderson.....................                  8,836(1)        0
Russell L. Carson.....................                  8,836(1)        0
Anthony J. de Nicola..................                    803(1)        0
John R. Hamilton......................                 21,731           0
James B. Hoover.......................                  2,410(1)        0
James B. Hoover-IRA...................                    803(1)        0
David S. Mawhinney....................                 21,731           0
Thomas E. McInerney...................                  2,123(1)        0
Robert A. Minicucci...................                  1,767(1)        0
David A. Nelson.......................                 81,490           0
Andrew M. Paul........................                  8,033(1)        0
Premier Purchasing Partners, L.P. ....                758,373           0
Paul B. Queally.......................                  1,928(1)        0
John G. Rex-Waller and Carlisle Rex-
 Waller, as joint tenants.............                 21,731           0
Rudolph E. Rupert.....................                    321(1)        0
Richard H. Stowe-IRA..................                  1,285(1)        0
Laura M. VanBuren.....................                    803(1)        0
WCAS Healthcare Partners, L.P. .......                 24,098(1)        0
Patrick J. Welsh......................                  8,836(1)        0
Welsh, Carson, Anderson & Stowe VII,
 L.P. ................................                893,244(1)        0

- --------
(1) Pursuant to a pledge agreement dated August 3, 1998, between McKesson and
certain selling stockholders, certain of such selling stockholders' shares are
pledged against the payment by such selling stockholders, to us, when due, of
the principal and interest on certain promissory notes. The selling
stockholders' shares which are pledged to us may not be sold until such notes
are paid in full.
 
(2) Assumes that all of the shares held by the selling stockholders and being
offered under this prospectus are sold, and that the selling stockholders
acquire no additional shares of common stock before the completion of this
offering. After the offering, each selling stockholder will own less than 1% of
the total number of shares of common stock outstanding.
 
                                       5

 
                          DESCRIPTION OF CAPITAL STOCK
 
  The following descriptions of our capital stock and of certain provisions of
Delaware law do not purport to be complete and are subject to and qualified in
their entirety by reference to our Restated Certificate of Incorporation (the
"Certificate") and Restated By-Laws (the "By-Laws") and Delaware law, and, with
respect to certain rights of holders of shares of our common stock, the Rights
Agreement (as defined below under the heading "Rights Plan") and Amendment No.
1 thereto. We have filed copies of such documents with the SEC and have
incorporated such documents as exhibits to the registration statement of which
this prospectus is a part.
 
  As of the date hereof, our capital stock consists of 400,000,000 authorized
shares of common stock and 100,000,000 authorized shares of Series Preferred
Stock, par value $0.01 per share (the "Preferred Stock").
 
COMMON STOCK
 
  As of September 30, 1998, there were 99,271,776 shares of common stock issued
and outstanding.
 
  The holders of outstanding shares of common stock are entitled to receive
dividends out of assets legally available therefor at such times and in such
amounts as our Board of Directors (the "Board") may from time to time
determine. The shares of common stock are neither redeemable nor convertible,
and do not provide their holders with any preemptive or subscription rights to
purchase any of our securities. Upon our liquidation, dissolution or winding
up, the holders of common stock are entitled to receive our assets which are
legally available for distribution, after payment of all debts, other
liabilities and any liquidation preferences of outstanding Preferred Stock.
Each outstanding share of common stock is entitled to one vote on all matters
submitted to a vote of stockholders. There is no cumulative voting.
 
  In February 1997, McKesson Financing Trust issued an aggregate of 4,000,000
5% Trust Convertible Preferred Securities and 123,720 5% Trust Convertible
Common Securities (each, a "Trust Security"). Each Trust Security is
convertible into common stock at any time prior to the close of business on the
business day prior to June 1, 2027 (or prior to the date of redemption of the
Trust Security), at the option of the holder, at the rate of 1.3418 shares of
common stock for each Trust Security (equivalent to a conversion price of
$37.26 per share of common stock), subject to adjustment in certain
circumstances.
 
PREFERRED STOCK
 
  As of the date hereof, there were no shares of Preferred Stock issued and
outstanding. The Board is authorized to issue the Preferred Stock in classes or
series and to fix the designations, preferences, qualifications, limitations,
or restrictions of any class or series with respect to the rate and nature of
dividends, the price and terms and conditions on which shares may be redeemed,
the amount payable in the event of voluntary or involuntary liquidation, the
terms and conditions for conversion or exchange into any other class or series
of the stock, voting rights and other terms. Of the 100,000,000 authorized
shares of Preferred Stock, 10,000,000 shares have been designated Series A
Junior Participating Preferred Stock (the "Series A Preferred Stock") and
reserved for issuance pursuant to our Rights Agreement.
 
                                       6

 
ANTI-TAKEOVER EFFECTS OF PROVISIONS OF OUR RESTATED CERTIFICATE OF
INCORPORATION AND BY-LAWS
 
  Our Certificate and By-Laws contain certain provisions that may be deemed to
have an anti-takeover effect and may delay, deter or prevent a tender offer or
takeover attempt that a stockholder might consider to be in the stockholder's
best interest. Such takeover attempts may include those which would result in a
premium over the market price for the shares held by stockholders.
 
  Pursuant to the Certificate, the Board is divided into three classes serving
staggered three-year terms. Directors can be removed from office only for cause
and only by the affirmative vote of the holders of at least a majority of the
voting power of the then outstanding shares of any class or series of capital
stock of McKesson entitled to vote generally in the election of directors.
Vacancies and newly created directorships on the Board may be filled only by a
majority of the remaining directors or by the plurality vote of the
stockholders.
 
  The Certificate also provides that any action required or permitted to be
taken by the holders of common stock may be effected only at an annual or
special meeting of such holders, and that stockholders may act in lieu of such
meetings only by unanimous written consent. The By-Laws provide that special
meetings of holders of common stock may be called only by our Chairman or
President or the Board. Holders of common stock are not permitted to call a
special meeting or to require that the Board call a special meeting of
stockholders.
 
  The By-Laws establish an advance notice procedure for the nomination, other
than by or at the direction of the Board, of candidates for election as
directors as well as for other stockholder proposals to be considered at annual
meetings of stockholders. In general, we must receive notice of the intent of a
stockholder to nominate a director or to raise business at such meetings not
less than 60 nor more than 90 days prior to the date of the annual meeting and
such notice must contain certain specified information concerning the person to
be nominated or the matters to be brought before the meeting and concerning the
stockholder submitting the proposal.
 
  The Certificate also provides that certain provisions of the By-Laws may only
be amended by the affirmative vote of the holders of 75% of our outstanding
shares entitled to vote. The Certificate also provides that, in addition to any
affirmative vote required by law, the affirmative vote of holders of 80% of our
voting stock and two-thirds of the voting stock other than voting stock held by
an interested stockholder is necessary to approve certain business combinations
proposed by an interested stockholder.
 
  The foregoing summary is qualified in its entirety by the provisions of the
Certificate and By-Laws, copies of which have been filed with the SEC.
 
RIGHTS PLAN
 
  Pursuant to our Rights Agreement, the Board declared a dividend distribution
of one right (a "Right") for each outstanding share of common stock to our
stockholders of record at November 1, 1994 (the "Record Date"). As a result of
the two-for-one stock split effective January 2, 1998, each share of common
stock has attached to it one-half of a Right. Each Right entitles the
registered holder to purchase from us a unit consisting of one one-hundredth of
a share of Series A Preferred Stock at a purchase price of $100 per unit. The
Rights expire on October 21, 2004, unless redeemed
 
                                       7

 
earlier by the Board. The terms of the Rights are set forth in a Rights
Agreement, as amended, between the Company and a rights agent (the "Rights
Agreement"), a copy of which is filed with the SEC. The following summary
outlines certain provisions of the Rights Agreement and is qualified by
reference to the full text of the form of the Rights Agreement.
 
  The Rights are attached to all common stock certificates representing shares
outstanding at the Record Date and shares issued between the Record Date and
the Distribution Date (as defined below), and no separate rights certificates
(the "Rights Certificates") have been distributed. The Rights will separate
from the common stock, separate Rights Certificates will be issued and a
distribution date (the "Distribution Date") will occur when the first of the
following events takes place:
 
  .  ten business days following the date of a public announcement that there
     is an Acquiring Person (as defined below) (such date, the "Stock
     Acquisition Date"),
 
  .  ten business days (or such later date as the Board may determine)
     following commencement of a tender or exchange offer that would result
     in the offeror beneficially owning 15% or more of the common stock, or
 
  .  ten business days after the Board determines that the ownership of 10%
     or more of our outstanding common stock by a person is (A) intended to
     cause us to repurchase the common stock beneficially owned by such
     person or (B) is causing, or is reasonably likely to cause, a material
     adverse impact on us.
 
  The term "Acquiring Person" means any person who, together with affiliates
and associates, acquires beneficial ownership of shares of common stock
representing 15% or more of the common stock, but shall not include us, any of
our subsidiaries, any of our employee benefit plans or any of our subsidiaries'
employee benefits plans, or any person or entity we organized, appointed or
established for or pursuant to the terms of such plans.
 
  In the event that a person becomes an Acquiring Person (except pursuant to an
offer for all outstanding shares of common stock which the independent
directors determine to be fair to and otherwise in our best interests and that
of our stockholders), following a Distribution Date each holder of a Right will
thereafter have the right to receive, upon exercise, common stock (or, in
certain circumstances, cash, property or other of our securities) having a
calculated value equal to two times the exercise price of the Right.
Notwithstanding the foregoing, following the occurrence of such event, all
Rights that are, or (under certain circumstances specified in the Rights
Agreement) were, beneficially owned by an Acquiring Person and certain related
persons and transferees will be null and void. However, Rights are not
exercisable following the occurrence of such event until such time as the
Rights are no longer redeemable as set forth below.
 
  At any time prior to the tenth day following the Stock Acquisition Date, we
may redeem the Rights, in whole, but not in part, at a price of $.01 per Right.
 
  Until a Right is exercised, the holder of the Right, as such, will have no
rights as our stockholder, including without limitation, the right to vote or
to receive dividends.
 
                                       8

 
  In general, the Rights Agreement may be amended by the Board (1) prior to the
Distribution Date in any manner and (2) on or after the Distribution Date in
certain respects including (A) to shorten or lengthen any time period and (B)
in a manner not adverse to the interests of Rights holders. However, amendments
extending the redemption period must be made while the Rights are still
redeemable.
 
  The Rights have certain anti-takeover effects and will cause substantial
dilution to a person or group that attempts to acquire us on terms not approved
by the Board. The Rights should not interfere with any merger or other business
combination approved by the Board, since the Board may redeem the Rights as
provided above.
 
  In connection with the definitive merger agreement (the "HBOC Merger
Agreement") by and among McKesson, a wholly owned subsidiary of McKesson and
HBOC, McKesson and the rights agent entered into Amendment No. 1 to the Rights
Agreement (the "Rights Agreement Amendment"). The Rights Agreement Amendment
provides, among other things, that HBOC shall not be deemed to be an "Acquiring
Person" as defined in the Rights Agreement as a result of the execution of the
HBOC Merger Agreement or the associated stock option agreement.
 
SECTION 203 OF DELAWARE GENERAL CORPORATION LAW
 
  We are subject to the "business combination" statute of the Delaware General
Corporation Law (Section 203). In general, such statute prohibits a publicly
held Delaware corporation from engaging in a "business combination" with any
"interested stockholder" for a period of three years after the date of the
transaction in which the person became an "interested stockholder," unless:
 
  .  such transaction is approved by the board of directors prior to the date
     the interested stockholder obtains such status,
 
  .  upon consummation of such transaction, the "interested stockholder"
     beneficially owned at least 85% of the voting stock of the corporation
     outstanding at the time the transaction commenced, excluding for
     purposes of determining the number of shares outstanding those shares
     owned by (1) persons who are directors and also officers and (2)
     employee stock plans in which employee participants do not have the
     right to determine confidentially whether shares held subject to the
     plan will be tendered in a tender or exchange offer, or
 
  .  the "business combination" is approved by the board of directors and
     authorized at an annual or special meeting of stockholders by the
     affirmative vote of at least 66% of the outstanding voting stock which
     is not owned by the "interested stockholder."
 
  A "business combination" includes mergers, asset sales and other transactions
resulting in financial benefit to the "interested stockholder." An "interested
stockholder" is a person who, together with affiliates and associates, owns (or
within three years, did own) beneficially 15% or more of a corporation's voting
stock. The statute could prohibit or delay mergers or other takeover or change
in control attempts with respect to us and, accordingly, may discourage
attempts to acquire us.
 
CERTAIN EFFECTS OF AUTHORIZED BUT UNISSUED STOCK
 
  Our authorized but unissued shares of common stock and Preferred Stock may be
issued without additional stockholder approval and may be utilized for a
variety of corporate purposes, including future offerings to raise additional
capital or to facilitate corporate acquisitions.
 
                                       9

 
  The issuance of Preferred Stock could have the effect of delaying or
preventing a change in control of McKesson. The issuance of Preferred Stock
could decrease the amount of earnings and assets available for distribution to
the holders of our common stock or could adversely affect the rights and
powers, including voting rights, of the holders of our common stock. In certain
circumstances, such issuance could have the effect of decreasing the market
price of our common stock.
 
  One of the effects of the existence of unissued and unreserved common stock
or Preferred Stock may be to enable the Board to issue shares to persons
friendly to current management which could render more difficult or discourage
an attempt to obtain control of us by means of a merger, tender offer, proxy
contest or otherwise, and thereby protect the continuity of management. Such
additional shares could also be used to dilute the stock ownership of persons
seeking to obtain control of us.
 
  We have reserved for issuance shares of common stock for the exercise of
options which have been granted or which may be granted in the future to our
directors, officers and employees and the conversion of the Trust Securities.
We do not currently have any plans to issue shares of Preferred Stock, although
10,000,000 shares have been designated Series A Preferred Stock pursuant to our
Rights Agreement.
 
LIMITATION OF DIRECTORS LIABILITY
 
  The Certificate contains a provision that limits the liability of our
directors for monetary damages for breach of fiduciary duty as a director to
the fullest extent permitted by the Delaware General Corporation Law. Such
limitation does not, however, affect the liability of a director for:
 
  .  any breach of the director's duty of loyalty to us or our stockholders,
 
  .  acts or omissions not in good faith or that involve intentional
     misconduct or a knowing violation of law,
 
  .  in respect of certain unlawful dividend payments or stock redemptions or
     purchases, and
 
  .  for any transaction from which the director derives an improper personal
     benefit.
 
  The effect of this provision is to eliminate our rights and the rights of our
stockholders (through stockholders' derivative suits on our behalf) to recover
monetary damages against a director for breach of the fiduciary duty of care as
a director (including breaches resulting from negligent or grossly negligent
behavior) except in the situations described above. This provision does not
limit or eliminate our rights or rights of any stockholder to seek non-monetary
relief such as an injunction or rescission in the event of a breach of a
director's duty of care. In addition, our directors and officers have
indemnification protection.
 
                              PLAN OF DISTRIBUTION
 
  We are registering shares of our common stock on behalf of the selling
stockholders. As used herein, "selling stockholders" includes donees and
pledgees selling shares received from a named selling stockholder after the
date of this prospectus. The selling stockholders or their respective
successors in interest may offer their shares of our common stock at various
times, depending on market conditions and other factors, in one or more
transactions on any of the United States
 
                                       10

 
securities exchanges where our capital stock is listed, including the New York
Stock Exchange, Inc. and the Pacific Exchange, Inc., in the over-the-counter
market or in transactions other than on such exchanges or in the over-the-
counter market. The selling stockholders may sell their shares at market prices
prevailing at the time of the sale, at negotiated prices or at fixed prices.
The selling stockholders may offer their shares of our common stock in any
manner permitted by law, including through underwriters, brokers, dealers or
agents and directly to one or more purchasers. Sales of the shares of our
common stock may involve:
 
  .  sales to underwriters who will acquire the shares of our common stock
     for their own account and resell them in one or more transactions at
     fixed prices or at varying prices determined at the time of sale;
 
  .  block transactions in which the broker or dealer engaged will attempt to
     sell the shares of our common stock as an agent but may position and
     resell a portion of the block as a principal to facilitate the
     transaction;
 
  .  purchases by a broker or dealer as principal and resale by such broker
     or dealer for its account;
 
  .  an exchange distribution in accordance with the rules of any such
     exchange; and
 
  .ordinary brokerage transactions and transactions in which a broker
  solicits purchasers.
 
  Brokers and dealers may receive compensation in the form of underwriting
discounts, concessions or commission from the selling stockholders and/or
purchasers of shares of our common stock for whom they may act as agents (which
compensation may be in excess of customary commissions). The selling
stockholder and any broker or dealer that participates in the distribution of
shares of our common stock may be deemed to be underwriters and any commissions
received by them and any profit on the resale of shares of our common stock
positioned by a broker or dealer may be deemed to be underwriting discounts and
commissions under the Securities Act. In the event any selling stockholder
engages an underwriter in connection with the sale of the shares of our common
stock, to the extent required, a prospectus supplement will be distributed,
which will set forth the number of shares of our common stock being offered and
the terms of the offering, including the names of the underwriters, any
discounts, commissions and other items constituting compensation to
underwriters, dealers or agents, the public offering price and any discounts,
commissions or concessions allowed or reallowed or paid by underwriters to
dealers. In addition, upon our being notified by a selling stockholder that a
donee or pledgee intends to sell more than 500 shares, a supplement to this
prospectus will be filed. Unless this prospectus is accompanied by a prospectus
supplement stating otherwise, offers and sales may be made pursuant to this
prospectus only in ordinary broker's transactions made on the New York Stock
Exchange, Inc. or the Pacific Exchange, Inc. in transactions involving ordinary
and customary brokerage commissions.
 
  In addition, the selling stockholders may from time to time sell shares of
our common stock in transactions under Rule 144 promulgated under the
Securities Act.
 
  Pursuant to the Registration Rights Agreement, we will pay all registration
expenses in connection with the registration of the shares of our common stock.
We and the selling stockholders have agreed to indemnify each other against
certain civil liabilities, including certain liabilities under the Securities
Act.
 
                                       11

 
                                    EXPERTS
 
  The consolidated financial statements of McKesson and the related financial
statement schedule incorporated in this prospectus and elsewhere in the
registration statement by reference from McKesson's Annual Report on Form 10-K
for the fiscal year ended March 31, 1998 and the consolidated financial
statements of FoxMeyer Corporation ("FoxMeyer") for the year ended March 31,
1996 incorporated in this prospectus and elsewhere in the registration
statement by reference from McKesson's Current Report on Form 8-K/A filed with
the SEC on April 28, 1997 have been audited by Deloitte & Touche LLP,
independent auditors, as stated in their reports incorporated herein by
reference, (which report dated May 18, 1998 on McKesson's consolidated
financial statements expresses an unqualified opinion and which report on a
FoxMeyer's consolidated financial statements dated June 28, 1996, (March 18,
1997 as to paragraph seven of Note Q), expresses an unqualified opinion and
includes an explanatory paragraph relating to the sale of the principal assets
of FoxMeyer and its Chapter 7 bankruptcy filing). Such consolidated financial
statements and financial statement schedule have been so incorporated in
reliance upon the reports of such firm given upon their authority as experts in
accounting and auditing.
 
  The audited financial statements and schedule of HBOC incorporated by
reference in this prospectus and elsewhere in the registration statement of
which this prospectus is a part, to the extent and for the periods indicated in
their reports, have been audited by Arthur Andersen LLP, independent public
accountants, and are included herein in reliance upon the authority of said
firm as experts in giving said reports.
 
  With respect to the unaudited interim financial information of HBOC for the
three and nine months ended September 30, 1997 and 1998, which are incorporated
by reference herein, Arthur Andersen LLP has applied limited procedures in
accordance with professional standards for a review of that information.
However, their separate report thereon states that they did not audit and they
do not express an opinion on that interim financial information. Accordingly,
the degree of reliance on their report on that information should be restricted
in light of the limited nature of the review procedure applied. In addition,
the accountants are not subject to the liability provisions of Section 11 of
the Securities Act, for their report on the unaudited interim financial
information because that report is not a "report" or a "part" of the
registration statement prepared or certified by the accountants within the
meaning of Sections 7 and 11 of the Securities Act.
 
                                 LEGAL MATTERS
 
  Ivan D. Meyerson, Vice President and General Counsel of McKesson will issue
an opinion about the validity of the shares of our common stock. Mr. Meyerson
owns shares of, and holds options to purchase, in the aggregate, less than 1%
of our common stock.
 
                                       12

 
                      WHERE YOU CAN FIND MORE INFORMATION
 
  We file annual, quarterly and special reports, proxy statements and other
information with the SEC. You may read and copy any documents we file at the
SEC's public reference rooms in Washington, D.C., New York, New York and
Chicago, Illinois. Please call the SEC at 1- 800-SEC-0330 for further
information on the public reference rooms. Our SEC filings are also available
to the public from the SEC's Website at "http://www.sec.gov."
 
  The SEC allows us to "incorporate by reference" the information we file with
them, 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 part of this prospectus, and information we later file with
the SEC will automatically update and supersede this information. We
incorporate by reference the documents listed below and any future filings we
will make with the SEC under Sections 13(a), 13(c), 14 and 15(d) of the
Exchange Act:
 
    1. Annual Report on Form 10-K for the fiscal year ended March 31, 1998,
  as amended by Amendment No. 1 to Form 10-K, filed with the SEC on July 29,
  1998;
 
    2. Quarterly Reports on Form 10-Q for the quarters ended June 30, 1998
  and September 30, 1998; and
 
    3. Current Reports on Form 8-K dated November 22, 1996 (as amended by
  Amendment No. 1 on Form 8-K/A filed on January 21, 1997 as further amended
  by Amendment No. 2 on Form 8-K/A, filed on April 28, 1997) and October 19,
  1998 (as amended by Amendment No. 1 on Form 8-K/A, filed on October 30,
  1998).
 
  You may request a copy of these filings, at no cost by writing or telephoning
us at the following address:
 
  Nancy A. Miller
  Vice President and Corporate Secretary
  McKesson Corporation
  McKesson Plaza
  One Post Street
  San Francisco, California 94104
  (415) 983-8300
 
  You should rely only on the information incorporated by reference or provided
in this prospectus or any prospectus supplement. We have not authorized anyone
else to provide you with different information. The selling stockholders will
not make an offer of the shares of our common stock in any state where the
offer is not permitted. You should not assume that the information in this
prospectus or any prospectus supplement is accurate as of any date other than
the date on the front of those documents.
 
                                       13

 
 
 
                              [LOGO OF MCKESSON] 
 

 
                                    PART II
 
                    INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.
 
  The following expenses (other than the SEC filing fee) are estimated.
 

                                                                       
   SEC registration fee.................................................. $
   Printing and engraving expenses.......................................
   Accountants' fees and expenses........................................
   Attorneys' fees and expenses..........................................
   Miscellaneous.........................................................
                                                                          -----
     Total...............................................................
                                                                          =====

 
  The Company will pay all registration expenses in connection with the
registration of the shares of our common stock.
 
ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS.
 
  Article VIII of the Restated By-Laws (the "Bylaws") of McKesson Corporation
(the "Company"), in accordance with the provisions of Section 145 of the
General Corporation Law of Delaware (the "Delaware Corporation Law"), provides
that the Company shall indemnify any person in connection with any threatened,
pending or completed legal proceeding (other than a legal proceeding by or in
the right of the Company) by reason of the fact that such person is or was a
director or officer of the Company or is or was serving at the request of the
Company as a director, officer, employee or agent of another corporation,
partnership or other enterprise against expenses (including attorneys' fees),
judgments, fines and amounts paid in settlement actually and reasonably
incurred in connection with such legal proceeding if such person acted in good
faith and in a manner that such person reasonably believed to be in or not
opposed to the best interests of the Company, and, with respect to any
criminal action or proceeding, if such person had no reasonable cause to
believe that his or her conduct was unlawful. If the legal proceeding is by or
in the right of the Company, the director or officer may be indemnified by the
Company against expenses (including attorneys' fees) actually and reasonably
incurred in connection with the defense or settlement of such legal proceeding
if such person acted in good faith and in a manner such person reasonably
believed to be in or not opposed to the best interests of the Company, except
that such person may not be indemnified in respect of any claim, issue or
matter as to which such person shall have been adjudged to be liable to the
Company unless a court determines otherwise.
 
  Article VIII of the Company's Restated By-Laws allows the Company to
maintain director and officer liability insurance on behalf of any person who
is or was a director or officer of the Company or such person who serves or
served as director, officer, employee or agent of another corporation,
partnership or other enterprise at the request of the Company.
 
  Article VI of the Company's Restated Certificate of Incorporation, in
accordance with Section 102(b)(7) of the Delaware Corporation Law, provides
that no director of the Company shall be personally liable to the Company or
its stockholders for monetary damages for any breach of such director's
fiduciary duty as a director; provided, however, that such clause shall not
apply to any liability of a director (1) for any breach of such director's
duty of loyalty to the Company or its stockholders, (2) for acts or omissions
that are not in good faith or involve intentional misconduct or a knowing
violation of the law, (3) under Section 174 of the Delaware Corporation Law,
or (4) for any transaction from which the director derived an improper
personal benefit.
 
                                     II-1

 
ITEM 16. LIST OF EXHIBITS.
 


 EXHIBIT
 NUMBER                                DESCRIPTION
 -------                               -----------
      
  3.1    Restated Certificate of Incorporation of the Company (Exhibit 3.2(1)).
  3.2    Restated Bylaws of the Company, as amended through May 30, 1997 (Ex-
          hibit 3.1(2)).
  3.3    Rights Agreement, dated as of October 21, 1994, by and between the
          Company and First Chicago Trust Company of New York as Rights Agent
          (Exhibit 4.1(3)).
  3.4    Amendment No. 1 to Rights Agreement, dated as of October 19, 1998, by
          and between the Company and First Chicago Trust Company of New York
          as Rights Agent (Exhibit 99.1(4)).
  5.1    Opinion of Ivan D. Meyerson, Vice President and General Counsel of the
          Company.
 10.1*   Registration Rights Agreement, dated as of June 22, 1998, among the
          Company and the Selling Stockholders.
 23.1    Consent of Ivan D. Meyerson (included in Exhibit 5.1).
 23.2*   Independent Auditors' Consent--Deloitte & Touche LLP.
 23.3*   Consent of Independent Public Accountants--Arthur Andersen LLP.
 24.1*   Power of Attorney.

- --------
 * Filed herewith
 
(1) Incorporated by reference to designated exhibit to the Company's Quarterly
    Report on Form 10-Q for the quarter ended June 30, 1998.
 
(2) Incorporated by reference to designated exhibit to the Company's Current
    Report on Form 8-K as filed with the Commission on June 24, 1997.
 
(3) Incorporated by reference to designated exhibit to Amendment No. 3 to the
    Company's Registration Statement on Form 10 filed with the Commission on
    October 27, 1994.
 
(4) Incorporated by reference to designated exhibit to the Company's Quarterly
    Report on Form 10-Q for the quarter ended September 30, 1998.
 
ITEM 17. UNDERTAKINGS.
 
  (a) The undersigned registrant hereby undertakes:
 
    (1) To file, during any period in which offers or sales are being made, a
  post-effective amendment to this registration statement:
 
      (i) To include any prospectus required by section 10(a)(3) of the
    Securities Act of 1933;
 
      (ii) To reflect in the prospectus any facts or events arising after
    the effective date of this registration statement (or the most recent
    post-effective amendment thereof) which, individually or in the
    aggregate, represent a fundamental change in the information set forth
    in the registration statement. Notwithstanding the foregoing, any
    increase or decrease in volume of securities offered (if the total
    dollar value of securities offered would not exceed that which was
    registered) and any deviation from the low or high end of the estimated
    maximum offering range may be reflected in the form of prospectus filed
    with the Commission pursuant to Rule 424(b) if, in the aggregate, the
    changes in volume and price represent no more than 20 percent change in
    the maximum aggregate offering price set forth in the "Calculation of
    Registration Fee" table in the effective Registration Statement.
 
      (iii) To include any material information with respect to the plan of
    distribution not previously disclosed in the registration statement or
    any material change to such information in the registration statement.
 
    (2) That, for the purpose of determining any liability under the
  Securities Act of 1933, each such post-effective amendment shall be deemed
  to be a new registration statement relating to the securities offered
  therein, and the offering of such securities at the time shall be deemed to
  be the initial bona fide offering thereof.
 
    (3) To remove from registration by means of a post-effective amendment
  any of the securities being registered which remain unsold at the
  termination of the offering.
 
                                     II-2

 
  (b) The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
Company's annual report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in this
registration statement shall be deemed to be a new registration statement
relating to the securities offered thereby, and the offering of such
securities at the time shall be deemed to be the initial bona fide offering
thereof.
 
  (c) Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers and controlling persons of
the registrant pursuant to the provisions referred to in Item 15 of this
registration statement, or otherwise, the registrant has been advised that in
the opinion of the Securities and Exchange Commission such indemnification is
against public policy as expressed in the Securities Act of 1933 and is,
therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the registrant of expenses
incurred or paid by a director, officer or controlling person of the
registrant in the successful defense of any action, suit or proceeding) is
asserted by such director, officer or controlling person in connection with
the securities being registered, the registrant will, unless in the opinion of
its counsel the matter has been settled by controlling precedent, submit to a
court of appropriate jurisdiction the question whether such indemnification by
it is against public policy as expressed in the Act and will be governed by
the final adjudication of such issue.
 
                                     II-3

 
                                  SIGNATURES
 
  Pursuant to the requirements of the Securities Act of 1933, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-3 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of San Francisco, State of California, on the 30th day
of October, 1998.
 
                                          McKESSON CORPORATION
 
                                                /s/  Richard H. Hawkins
                                          By: _________________________________
                                          Name:Richard H. Hawkins
                                          Title:Vice President and Chief
                                           Financial Officer
 
  Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed below by the following persons in the
capacities and on the date indicated.
 


              SIGNATURE                        TITLE                  DATE
              ---------                        -----                  ----
 
                                                          
        /s/ Mark A. Pulido              President and Chief     October 30, 1998
 ____________________________________  Executive Officer and
            Mark A. Pulido                    Director
                                        (principal executive
                                              officer)
 
      /s/ Richard H. Hawkins             Vice President and     October 30, 1998
 ____________________________________ Chief Financial Officer
          Richard H. Hawkins            (principal financial
                                              officer)
 
      /s/ Heidi E. Yodowitz                  Controller         October 30, 1998
 ____________________________________  (principal accounting
          Heidi E. Yodowitz                   officer)
 
                  *                           Director          October 30, 1998
 ____________________________________
         Mary G.F. Bitterman
 
                                              Director
 ____________________________________
          Tully M. Friedman
 
                  *                           Director          October 30, 1998
 ____________________________________
          John M. Pietruski
 
 ____________________________________         Director
          David S. Pottruck
 
 ____________________________________         Director
          Carl E. Reichardt
 
                  *                          Director;          October 30, 1998
 ____________________________________  Chairman of the Board
          Alan Seelenfreund

 
                                     II-4

 


              SIGNATURE                 TITLE          DATE
              ---------                 -----          ----
 
                                           
                  *                   Director   October 30, 1998
 ____________________________________
             Jane E. Shaw
 
                  *                   Director   October 30, 1998
 ____________________________________
       Robert H. Waterman, Jr.

 
    /s/ Nancy A. Miller
*By: __________________________
        Nancy A. Miller
       Attorney-in-fact
 
                                      II-5