EXHIBIT 5.1


                     [VALERO ENERGY CORPORATION LETTERHEAD]

                                January 31, 2002

Valero Energy Corporation
One Valero Place
San Antonio, Texas  78212

Ladies and Gentlemen:

      I am Vice President and Corporate Secretary of Valero Energy Corporation,
a Delaware corporation (the "Company"), and have acted as counsel for the
Company in connection with the preparation and filing with the Securities and
Exchange Commission (the "Commission") under the Securities Act of 1933, as
amended (the "Securities Act") of a Registration Statement on Form S-8 (the
"Registration Statement") relating to registration under the Securities Act of
3,000,000 shares of Common Stock, par value $0.01 per share, of the Company (the
"Common Stock") issuable in connection with the 2001 Executive Stock Incentive
Plan (the "Plan").

      I have examined the Registration Statement, the Plan and originals or
copies, certified or otherwise identified to my satisfaction, of such other
documents, corporate records, certificates of public officials and other
instruments as I have deemed necessary or advisable for the purpose of rendering
this opinion. I have relied as to certain matters on information obtained from
public officials, officers of the Company and other sources believed by me to be
responsible.

      Based upon and subject to the foregoing, I am of the opinion that the
shares of Common Stock available under the Plan, when issued, delivered and paid
for in accordance with the terms and conditions of the Plan, will be validly
issued, fully paid and nonassessable.

      I am a member of the Bar of the State of Texas and my opinion is limited
to the federal statutory laws of the United States, the laws of the State of
Texas and the Delaware General Corporation Law.

      I hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to me under the heading "Interests
of Named Experts and Counsel" in the Registration Statement. In giving such
opinion, I do not thereby admit that I am in the category of persons whose
consent is required under Section 7 of the Securities Act.

                                    Very truly yours,

                                       /s/ Jay D. Browning
                                    --------------------------------------
                                    Jay D. Browning
                                    Vice President and Corporate Secretary