POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that Ultramar Diamond Shamrock
Corporation (the "Corporation") hereby constitutes and appoints
Patrick J. Guarino, Todd Walker, and Gregory Robbins, and each of
them, its true and lawful attorney or attorneys-in-fact, with full
power of substitution and revocation, to sign a Registration
Statement on Form S-8 for the Corporation for the purpose of
registering, pursuant to the Securities Act of 1933, up to
1,000,000 shares of Common Stock (and associated stock purchase
rights) of the Corporation for issuance pursuant to the
Corporation's obligations under the Long-Term Incentive Plan
assumed by operation of the merger of Diamond Shamrock, Inc. with
and into the Corporation effective December 3, 1996, and to sign
any or all amendments and any or all post-effective amendments to
such Registration Statement, and to file the same, with all
exhibits thereto, and other documents in connection therewith, with
the Securities and Exchange Commission granting unto said attorney
or attorneys-in-fact, and each of them, full power and authority to
do and perform each and every act and thing requisite and necessary
to be done in and about the premises, hereby ratifying and
confirming all that said attorney or attorneys-in-fact or any of
them or their substitute or substitutes, may lawfully do or cause
to be done by virtue hereof.

ULTRAMAR DIAMOND SHAMROCK CORPORATION
                                   

/s/ R. R. HEMMINGHAUS


R. R. HEMMINGHAUS, CHAIRMAN
AND CHIEF EXECUTIVE OFFICER                            



Dated: December 30, 1996                              
W5012.TW