FIRST AMENDMENT TO $2,500,000,000 5-YEAR REVOLVING CREDIT AGREEMENT

Exhibit 10.24

FIRST AMENDMENT

TO

$2,500,000,000 5-YEAR REVOLVING CREDIT AGREEMENT

dated as of

July 24, 2006

among

VALERO ENERGY CORPORATION,
as Borrower ,

JPMORGAN CHASE BANK, N.A.,
as Administrative Agent and Global Administrative Agent ,

and

The Lenders Party Hereto

FIRST AMENDMENT TO
$2,500,000,000 5-YEAR REVOLVING CREDIT AGREEMENT

      THIS FIRST AMENDMENT TO $2,5000,000,000 5-YEAR REVOLVING CREDIT AGREEMENT (this “ First Amendment ”) dated as of July 24, 2006, is among VALERO ENERGY CORPORATION , a Delaware corporation (the “ Borrower ”); JPMORGAN CHASE BANK, N.A. , as administrative agent (in such capacity, together with its successors in such capacity, the “ Administrative Agent ”) and global administrative agent (in such capacity, together with its successors in such capacity, the “ Global Administrative Agent ”) for the lenders party to the Credit Agreement referred to below (collectively, the “ Lenders ”); and the undersigned Lenders.

R E C I T A L S

     A. The Borrower, the Administrative Agent, the Global Administrative Agent and the Lenders are parties to that certain $2,500,000,000 5-Year Revolving Credit Agreement dated as of August 17, 2005 (the “ Credit Agreement ”), pursuant to which the Lenders have made certain extensions of credit available to the Borrower.

     B. The Borrower has requested and the Administrative Agent and the Lenders have agreed to amend certain provisions of the Credit Agreement.

     C. NOW, THEREFORE, in consideration of the premises and the mutual covenants herein contained, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto agree as follows:

     Section 1. Defined Terms . Each capitalized term used herein but not otherwise defined herein has the meaning given such term in the Credit Agreement. Unless otherwise indicated, all references to Sections in this First Amendment refer to Sections of the Credit Agreement.

     Section 2. Amendments to Credit Agreement .

     2.1 Amendments to Section 1.01 .

     (a) The definition of “ Agreement ” is hereby amended in its entirety to read as follows:

     “ Agreement ” means this $2,500,000,000 5-Year Revolving Credit Agreement, as amended by the First Amendment, as the same may from time to time be amended, modified, supplemented or restated.

     (b) The definition of “ Arrangers ” is hereby amended in its entirety to read as follows:

     “ Arrangers ” means, collectively, J.P. Morgan Securities Inc. and Banc of America Securities LLC, each in its capacities as co-lead arranger and joint bookrunner hereunder.

     (c) The definition of “ Maturity Date ” is hereby amended in its entirety to read as follows:

     “ Maturity Date ” means August 17, 2011.

     (d) The following definition is hereby added where alphabetically appropriate to read as follows:

     “ First Amendment ” means the First Amendment to $2,500,000,000 5-Year Revolving Credit Agreement dated as of July 24, 2006 among the Borrower, the Administrative Agent, the Global Administrative Agent and the Lenders party thereto.

     (e) The definitions of “ Consolidated EBITDA ”, “ Consolidated Interest Coverage Ratio ”, “ Consolidated Interest Expense ”, “ Consolidated Net Income ”, “ Rolling Period ” and “ Transfer ” are hereby deleted.

     2.2 Amendment to Section 2.06(c) . Section 2.06(c) is hereby amended in its entirety to read as follows:

     “(c) Expiration Date . Each Letter of Credit shall expire at or prior to the close of business on the date that is five Business Days prior to the Maturity Date.”

     2.3 Amendment to Section 2.12(b) . Section 2.12(b) is hereby amended in its entirety to read as follows:

     “(b) The Borrower agrees to pay to the Administrative Agent for the account of each Lender