EXHIBIT 24.1

                                POWER OF ATTORNEY

         Ultramar Diamond Shamrock  Corporation  hereby constitutes and appoints
Timothy J.  Fretthold  and Todd Walker,  or either of them,  its true and lawful
attorneys-in-fact   and  agents,  each  with  full  power  of  substitution  and
resubstitution, to do any and all acts and things in its name and behalf, and to
execute  any  and  all  instruments  for  it  and in its  name  which  the  said
attorneys-in-fact and agents, or either of them, may deem necessary or advisable
to enable Ultramar  Diamond  Shamrock  Corporation to comply with the Securities
Act of 1933, as amended,  and any rules,  regulations  and  requirements  of the
Securities and Exchange  Commission in connection with a Registration  Statement
on Form S-8,  including  without  limitation  power and authority to sign for it
such  Registration  Statement  and power and any and all  amendments  (including
post-effective  amendments)  thereto,  and to file the same,  with all  exhibits
thereto,  and other  documents in connection  therewith  with the Securities and
Exchange  Commission,   hereby  ratifying  and  confirming  all  that  the  said
attorneys-in-fact and agents, or their substitute or substitutes,  or any one of
them, shall do or cause to be done by virtue hereof.

                                       ULTRAMAR DIAMOND SHAMROCK CORPORATION



                                       By:  /s/ Jean Gaulin
                                                Jean Gaulin
                                       Chairman, President, and
                                       Chief Executive Officer

Dated: October 3, 2000