October 9 , 2012

Mr. Andrew D. Mew

Accounting Branch Chief

Securities and Exchange Commission

Division of Corporation Finance

100 F Street, N.E.

Washington, D.C. 20549

Re: Core-Mark Holding Company, Inc.

Form 10-K for the Fiscal Year Ended December 31, 2011

Filed March 8, 2012

Response dated September 10, 2012

File No. 0-51515

Dear Mr. Mew:

This letter confirms my telephone conversation with Robert Babula on October 9, 2012 regarding our request for an extension of time to respond to your letter dated October 3, 2012. We intend to submit our response to your letter by October 31, 2012.

Thank you for your consideration in this matter.

Please contact us at (650) 589-9445 with any follow up questions you may have.

Sincerely,

CORE-MARK HOLDING COMPANY, INC.

by:

/s/ Christopher Miller

Christopher Miller

Chief Accounting Officer