FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: January 31, 2005 Estimated average burden hours per response... 0.5

(Print or Type Responses)

1. Name and Address of Reporting Person * HAMMERGREN JOHN H   2. Issuer Name and Ticker or Trading Symbol MCKESSON CORP [MCK] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Chairman, President & CEO (Last) (First) (Middle) ONE POST STREET 3. Date of Earliest Transaction (Month/Day/Year) 09/25/2017 (Street) SAN FRANCISCO, CA 94104 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 09/25/2017   M   100,000 (1) A $ 83.51 165,000 D   Common Stock 09/25/2017   S   100,000 (1) D $ 154.151 65,000 D   Common Stock 09/26/2017   M   100,000 (1) A $ 83.51 165,000 D   Common Stock 09/26/2017   S   100,000 (1) D $ 154.8147 65,000 D   Common Stock 09/27/2017   M   1,000 (1) A $ 83.51 66,000 D   Common Stock 09/27/2017   S   1,000 (1) D $ 155.2973 65,000 D   Common Stock 09/27/2017   M   99,000 (1) A $ 87.24 164,000 D   Common Stock 09/27/2017   S   99,000 (1) D $ 155.2973 65,000 D   Common Stock               400,256 (2) I By Trust Common Stock               4,184.7589 I By Profit-Sharing Investment Plan

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
	Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.		SEC 1474 (9-02)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Employee Stock Option (Right-to-buy)

$ 83.51

09/25/2017

M

100,000 (1)

(3)

05/24/2018

Common Stock

100,000

$ 0

101,000

D

Employee Stock Option (Right-to-buy)

$ 83.51

09/26/2017

M

100,000 (1)

(3)

05/24/2018

Common Stock

100,000

$ 0

1,000

D

Employee Stock Option (Right-to-buy)

$ 83.51

09/27/2017

M

1,000 (1)

(3)

05/24/2018

Common Stock

1,000

$ 0

0

D

Employee Stock Option (Right-to-buy)

$ 87.24

09/27/2017

M

99,000 (1)

(4)

05/22/2019

Common Stock

99,000

$ 0

199,000

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
HAMMERGREN JOHN H ONE POST STREET SAN FRANCISCO, CA 94104	X		Chairman, President & CEO

Signatures

Donna Spinola, Attorney-in-fact		09/27/2017
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Option exercise and sale in accordance with a previously adopted trading plan pursuant to Exchange Act Rule10b5-1.
(2)	Represents 305,341 shares held under the Hammergren Family Trust (5,556 Fidelity Family Trust #585 and 299,785 Goldman Sachs Family Trust #750); 11,876 Fidelity GRAT #999; 11,876 Fidelity GRAT #995; 11,875 Fidelity GRAT #994; 11,875 Fidelity GRAT #993; 11,854 Fidelity Grat #319; 11,853 Fidelity GRAT #312; 11,853 Fidelity GRAT #324; 11,853 Fidelity GRAT #315.
(3)	This stock option was granted 5/24/11 and vested 25% annually commencing on the first anniversary of the grant date.
(4)	This stock option was granted 5/22/12 and vested 25% annually commencing on the first anniversary of the grant date.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.