PROSPECTUS SUPPLEMENT 
 (TO PROSPECTUS DATED JUNE 18, 1997) 
  

               4,000,000 TRUST CONVERTIBLE PREFERRED SECURITIES 
                           MCKESSON FINANCING TRUST 
                   5% TRUST CONVERTIBLE PREFERRED SECURITIES 
        (LIQUIDATION AMOUNT $50 PER CONVERTIBLE PREFERRED SECURITY) 
                GUARANTEED TO THE EXTENT SET FORTH HEREIN BY, 
                             MCKESSON CORPORATION 
                               ----------------
  
      This prospectus supplement supplements and amends the prospectus dated
 June 18, 1997, relating to the 5% Trust Convertible Preferred Securities of
 McKesson Corporation ("McKesson").  The Convertible Preferred Securities
 represent preferred undivided beneficial interests in the assets of
 McKesson Financing Trust, a statutory business trust formed under the laws
 of the State of Delaware, and the shares of McKesson common stock, par
 value $.01 per share, issuable upon conversion of the Convertible Preferred
 Securities. 
  
      On October 17, 1998, 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 the approval of the stockholders of
 McKesson and HBOC at meetings scheduled to occur on January 12, 1999, 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 president and
 chief executive officer of McKesson, 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 current McKesson board and five members
 from the current HBOC board.  
  
      The table on pages 56 through 58 of the prospectus, which sets forth
 information with respect to the Selling Holders (as defined in the
 prospectus) and the respective amounts of Convertible Preferred Securities
 beneficially owned by each Selling Holder that may be offered pursuant to
 the prospectus (as supplemented and amended), is hereby amended by (i) the
 deletion of item 65 of that table and the substitution therefor of item 65
 below and (ii) the addition of item 93 to that table as follows: 



                                  Convertible Preferred    Number of                Convertible Preferred
                                  Securities Owned         Convertible Preferred    Securities Owned  
                                  Prior to Offering        Securities Offered       After Offering 
                                  ---------------------    ---------------------    ---------------------
 "Selling Holder                  Number        Percent                             Number        Percent
 ---------------                  ------        -------                             ------        -------
                                                                                     
 65. Salomon Smith Barney Inc.    31,620         0.791%         31,620                 0            0.00

 93. Koch Industries, Inc.        10,000         0.250%         10,000                 0            0.00


  
      The Prospectus, together with this Prospectus Supplement, constitutes
 the prospectus required to be delivered by Section 5(b) of the Securities
 Act of 1933, as amended, with respect to offers and sales of the
 Convertible Preferred Securities and McKesson Common Stock issuable upon
 conversion of the Convertible Preferred Securities.  All references in the
 Prospectus to "this Prospectus" are hereby amended to read "this Prospectus
 (as supplemented and amended)". 
  
 CONSIDER CAREFULLY THE RISK FACTORS ABOVE AND BEGINNING ON PAGE 6 IN THIS
 PROSPECTUS. 
  
 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. 
  
 This prospectus supplement is dated December 22, 1998.