As filed with the Securities and Exchange Commission October 5, 2000
                                                     Registration No. 333-27697

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                           ---------------------------
                         POST-EFFECTIVE AMENDMENT NO. 1
                                       TO
                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                      ULTRAMAR DIAMOND SHAMROCK CORPORATION
               (Exact Name of Registrant as Specified in Charter)

Delaware                                              13-3663331
(State of                                            (IRS Employer
Incorporation)                                     Identification No.)

6000 North Loop 1604 West                            78249-1112
(Address of Principal Executive                      (Zip Code)
Offices)

                      ULTRAMAR DIAMOND SHAMROCK CORPORATION
                        NON-EMPLOYEE DIRECTOR EQUITY PLAN
                            (Full title of the Plan)

                           Timothy J. Fretthold, Esq.
                            Executive Vice President,
                     Chief Administrative and Legal Officer
                      Ultramar Diamond Shamrock Corporation
                            6000 North Loop 1604 West
                          San Antonio, Texas 78249-1112
                     (Name and Address of Agent for Service)

                                 (210) 592-2000
                     (Telephone Number, Including Area Code
                              of Agent for Service)

In addition,  pursuant to Rule 416(c)  under the  Securities  Act of 1933,  this
registration  statement also covers an  indeterminate  amount of interests to be
offered or sold pursuant to the employee benefit plan(s) described herein.
<PAGE>
<TABLE>
<CAPTION>
                         CALCULATION OF REGISTRATION FEE
<S>                     <C>                   <C>                  <C>                     <C>
----------------------- --------------------- -------------------- ----------------------- -------------------------
 Title of Securities        Amount to be       Proposed Maximum       Proposed Maximum      Amount of Registration
 to be Registered (1)        Registered       Offering Price Per          Offering                 Fee (2)
                                                   Share (2)       ----------------------
                                                                          Price (2)
----------------------- --------------------- -------------------- ----------------------- -------------------------
----------------------- --------------------- -------------------- ----------------------- -------------------------
  Common Stock, par           250,000               $25.03         $6,257,813                      $401.00
 value $.01 per share
----------------------- --------------------- -------------------- ----------------------- -------------------------
</TABLE>

(1)      Includes  associated  rights  to  purchase  Ultramar  Diamond  Shamrock
         Corporation  common stock exercisable  pursuant to the Rights Agreement
         filed as Exhibit 4.2 hereto.

(2)      Estimated  solely for the purpose of computing the  registration fee in
         accordance  with  Rule 457 (h) and Rule  457 (c),  based on the  market
         price of common stock of Ultramar  Diamond  Shamrock  Corporation  (the
         "Company") of $25.03,  per share,  which is the average of the high and
         low sale  price  thereof  on the  Composite  Tape of the New York Stock
         Exchange on September 26, 2000.

<PAGE>
                                     PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  Incorporation of Documents by Reference.

         The  following   documents  filed  with  the  Securities  and  Exchange
Commission  (the  "Commission")  by  the  Company  are  incorporated  herein  by
reference:

         (a) The Company's  Registration  Statement 333-27697 on Form S-8, filed
with the Commission on May 23, 1997;

         (b) The Company's  Annual Report on Form 10-K for the fiscal year ended
December 31, 1999,  filed pursuant to Section 13(a) of the  Securities  Exchange
Act of 1934, as amended (the "1934 Act");

         (c) The Company's  Quarterly Report on Form 10-Q for the fiscal quarter
ended March 31, 2000 and on Form  10-Q/A for the fiscal  quarter  ended June 30,
2000; and

         (d) The Company's Current Report on Form 8-K dated August 31, 2000;

         All documents filed by the Company pursuant to Sections 13 (a), 13 (c),
14,  or 15(d) of the  1934 Act  subsequent  to the  filing  of this  Form  S-8/A
Registration Statement (the "Registration Statement") and prior to the filing of
a post-effective amendment to the Registration Statement that indicates that all
securities  offered have been sold or that  de-registers  all of the  securities
that remain unsold shall be deemed to be incorporated by reference herein and to
be a part hereof from the respective dates of the filing of such documents.

Item 4.  Description of Securities.

         Incorporated  by  reference  to  the  Company's  filing  on Form S-3/A,
Registration Statement No. 333-46775.

Item 5.  Interests of Named Experts and Counsel.

                                     EXPERTS

         The  audited   financial   statements  of  Ultramar   Diamond  Shamrock
Corporation  incorporated  by reference in this  prospectus and elsewhere in the
registration  statement  have been audited by Arthur  Andersen LLP,  independent
public accountants,  as indicated in their reports with respect thereto, and are
included  herein in  reliance  upon the  authority  of said firm as  experts  in
accounting and auditing in giving said reports.

                                  LEGAL MATTERS

         The validity of the shares of the Company's Common Stock being  offered
hereby has been  passed  upon for the  Company by Todd  Walker,  Esq.,  Managing
Attorney and Corporate  Secretary for the Company.  Mr. Walker beneficially owns
shares of the Common Stock of the Company.

Item 6. Indemnification of Directors and Officers.

         The By-laws of the Company provide that the Company shall indemnify its
officers  and  directors  to the  fullest  extent  permitted  or required by the
Delaware  General  Corporation  Law (the "DGCL"),  as amended from time to time,
provided,  however,  that  except  insofar  as  the  Company's  By-laws  provide
indemnification  for  an  officer  or  director  with  respect  to a  proceeding
initiated  by such  officer or  director to enforce  rights to  indemnification,
officers and  directors  will not be entitled to  indemnification  in connection
with  proceedings  initiated by an officer or director if the initiation of such
proceedings was not authorized by the board of directors of the Company. Section
145 of the DGCL  provides,  in  general,  that each  director  and  officer of a
corporation may be indemnified  against  expenses  (including  attorneys'  fees,
judgments,  fines,  and amounts  paid in  settlement)  actually  and  reasonably
incurred  in  connection  with the  defense  or  settlement  of any  threatened,
pending, or completed legal proceedings in which he is involved by reason of the
fact that he is or was a director or officer of the Company, if he acted in good
faith and in a manner that he reasonably believed to be in or not opposed to the
best  interests of the  Company,  and,  with  respect to any criminal  action or
proceeding,  if he had no  reasonable  cause to  believe  that his  conduct  was
unlawful.  If  the  legal  proceeding,  however,  is by or in the  right  of the
Company, the director or officer may not be indemnified in respect of any claim,
issue,  or  matter  as to which he shall  have been  adjudged  to be liable  for
negligence or misconduct in the  performance of his duty to the Company unless a
court determines otherwise.

         The   Company's   By-laws   also   provide  for   advances  in  certain
circumstances  covering  expenses  incurred  by an  officer or  director  of the
Company in connection with the defense of a proceeding for which such officer or
director would be entitled to indemnity under the Company's By-laws.

         The Company's  By-laws further provide that the Company may procure and
maintain insurance covering director's and officer's liability for their actions
in those  capacities,  whether or not the  Company  would be entitled to provide
indemnification for such liability under the DGCL.

         The  Certificate  of  Incorporation  of the Company  provides  that the
personal  liability of the  directors of the Company  shall be eliminated to the
fullest  extent  permitted by applicable  law. The DGCL permits a  corporation's
certificate  of  incorporation  to provide  that no director of the  corporation
shall be personally  liable to the corporation or its  stockholders for monetary
damages for any breach of his fiduciary duty as a director;  provided,  however,
that such  provision  shall not apply to any liability of a director (1) for any
breach of a director's duty of loyalty to the  corporation or its  stockholders,
(2) for acts or  omissions  that are not in good  faith or  involve  intentional
misconduct or a knowing  violation of the law, (3) under Section 174 of the DGCL
or (4) for any transaction from which the director derived an improper  personal
benefit.  The Company  has  entered  into  indemnification  agreements  with the
directors and certain officers of the Company providing for  indemnification  on
the terms set out in the By-laws of the Company.

Item 8. Exhibits.

Exhibit Number                              Description

          4.1              Ultramar  Diamond Shamrock  Corporation  Non-Employee
                           Director  Equity  Plan  (incorporated by reference to
                           the Company's  Report on Schedule 14A filed March 21,
                           2000)

          4.2              Rights  Agreement  dated June 25,  1992  between  the
                           Company  and  Registrar  and  Transfer  Company,   as
                           amended  (incorporated  by reference to  Registration
                           Statement  on Form S-1 (File No.  33-47586),  Exhibit
                           4.2;  Quarterly Report on Form 10-Q for quarter ended
                           September  30, 1992,  Exhibit 4.2;  Annual  Report on
                           Form  10-K  for the year  ended  December  31,  1994,
                           Exhibit 4.3.

          5.1              Opinion regarding legality of securities being issued

         23.1              Consent of Arthur Andersen LLP

         23.2              Consent  of  Todd  Walker,  Esq. (included in Exhibit
                           5.1)

         24.1              Power of Attorney of the Company

         24.2              Powers of  Attorney of Directors  and Officers of the
                           Company

         24.3              Powers of Attorney of members of the Ultramar Diamond
                           Shamrock Corporation Employee Benefits Committee

  Item 9. Undertakings.

  A. The Company hereby undertakes:

  (1) to file  during  any  period in which  offers or sales are being  made,  a
post-effective  amendment  to this  Registration  Statement  (a) to include  any
prospectus  required  by Section  10(a) (3) of the  Securities  Act of 1933,  as
amended (the "1933 Act"),  (b) to reflect in the  prospectus any facts or events
arising after the  effective  date of this  Registration  Statement (or the most
recent post-effective amendment hereof) which, individually or in the aggregate,
represents  a  fundamental   change  in  the   information  set  forth  in  this
Registration  Statement (except to the extent covered by reports filed under the
1934 Act and incorporated herein by reference),  and (c) to include any material
information with respect to the plan of distribution not previously disclosed in
this  Registration  Statement or any material change to such information in this
Registration Statement;

  (2) that,  for the purpose of  determining  any liability  under the 1933 Act,
each such  post-effective  amendment  shall be  deemed to be a new  registration
statement relating to the securities  offered therein,  and the offering of such
securities  at that time shall be deemed to be the  initial  bona fide  offering
thereof; and

  (3) to remove from registration by means of a post-effective  amendment any of
the securities  being  registered  which remain unsold at the termination of the
offering.

B. The Company hereby undertakes that, for purposes of determining any liability
under the 1933 Act,  each  filing of the  Company's  annual  report  pursuant to
Section  13(a) or  Section  15(d) of the 1934 Act and each  filing of the Plan's
annual report pursuant to Section 15(d) of the 1934 Act that are incorporated by
reference in the Registration Statement shall be deemed to be a new registration
statement relating to the securities  offered therein,  and the offering of such
securities  at that time shall be deemed to be the  initial  bona fide  offering
thereof.

C. Insofar as indemnification  for liabilities arising under the 1933 Act may be
permitted  to  directors,  officers,  and  controlling  persons  of the  Company
pursuant to the foregoing provisions or otherwise,  the Company is advised that,
in the opinion of the Commission,  such indemnification is against public policy
as expressed in the 1933 Act and is, therefore, unenforceable. In the event that
a claim for indemnification  against such liabilities (other than the payment by
the Company of expenses  incurred or paid by a director,  officer or controlling
person  of the  Company  in  the  successful  defense  of any  action,  suit  or
proceeding)  is  asserted  by a  director,  officer,  or  controlling  person in
connection with the securities being registered, the Company will, unless in the
opinion of counsel for the Company  the matter has been  settled by  controlling
precedent,  submit to a court of appropriate  jurisdiction  the question whether
such indemnification by it is against public policy as expressed in the 1933 Act
and will be governed by the final adjudication of such issue.

<PAGE>
                                   SIGNATURES

         Pursuant to the  requirements  of the 1933 Act,  the Company  certifies
that it has reasonable  grounds to believe that it meets all of the requirements
for filing on Form S-8/A and has duly caused this  Registration  Statement to be
signed on its behalf by the undersigned,  thereunto duly authorized, in the City
of San Antonio, Texas, on the 3rd day of October, 2000.

                                        ULTRAMAR DIAMOND SHAMROCK CORPORATION


                                        By: *Jean Gaulin,  Chairman of the Board
                                        and Chief Executive Officer

         Pursuant  to  the  requirements  of the  1933  Act,  this  Registration
  Statement has been signed by the following  persons in the  capacities  and on
  the date indicated:

Signature                  Title                                 Date

*Jean Gaulin               Chairman of the Board                 October 3, 2000
                           and Chief Executive
                           Officer

*Robert S. Shapard         Executive Vice President              October 3, 2000
                           and Chief Financial officer
                           (Principal Financial Officer
                           and Principal Accounting Officer)

*Byron Allumbaugh          Director                              October 3, 2000

*E. Glenn Biggs            Director                              October 3, 2000

*W. E. Bradford            Director                              October 3, 2000

*H. Frederick Christie     Director                              October 3, 2000

*W. H. Clark               Director                              October 3, 2000

*Russel H. Herman          Director                              October 3, 2000

*Bob Marbut                Director                              October 3, 2000

*Katherine D. Ortega       Director                              October 3, 2000

*Madeleine Saint-Jacques   Director                              October 3, 2000

*C. Barry Schaefer         Director                              October 3, 2000

         Pursuant to the  requirements  of the 1933 Act,  the  Ultramar  Diamond
Shamrock Corporation  Employee Benefits Committee,  as administrator of the Non-
Employee  Director  Equity Plan (the  "Plan"),  have  caused  this  registration
statement to be signed on the Plan's behalf by the  undersigned,  thereunto duly
authorized, in the City of San Antonio, Texas on October 3, 2000.

                                    ULTRAMAR DIAMOND SHAMROCK CORPORATION
                                    NON-EMPLOYEE DIRECTOR EQUITY PLAN

                                    BY:  ULTRAMAR DIAMOND SHAMROCK CORPORATION
                                         EMPLOYEE BENEFITS COMMITTEE

                                    * Timothy J. Fretthold, Member

                                    * Penelope Viteo, Member

                                    * Lorraine Racicot, Member

                                    * Steve Blank, Member

*Todd  Walker,  by signing his name hereto,  does hereby sign this  Registration
Statement on Form S-8/A on behalf of Ultramar Diamond Shamrock Corporation, each
of  the  above-named   officers  and  directors  of  Ultramar  Diamond  Shamrock
Corporation,  and  each of the  above  named  members  of the  Ultramar  Diamond
Shamrock  Corporation Employee Benefits Committee pursuant to powers of attorney
executed  on behalf of the  Company and each of such  officers,  directors,  and
members.

                                                     By: /s/ Todd Walker
                                                     Attorney-in-fact
                                                     October 3, 2000
<PAGE>
                                INDEX TO EXHIBITS

Exhibit
Number      Description

   4.1      Ultramar Diamond Shamrock Corporation  Non-Employee Director  Equity
            Plan (incorporated by reference to the Company's Report on  Schedule
            14A filed March 21, 2000)

   4.2      Rights  Agreement  dated  June  25,  1992  between  the Company  and
            Registrar  and  Transfer  Company,  as  amended   (incorporated   by
            reference to Registration Statement on Form S-1 (File No. 33-47586),
            Exhibit  4.2;  Quarterly  Report  on  Form  10-Q  for  quarter ended
            September 30, 1992, Exhibit 4.2; Annual Report on Form 10-K  for the
            year ended December 31, 1994, Exhibit 4.3.

   5.1      Opinion regarding legality of securities being issued

  23.1      Consent of Arthur Andersen LLP

  23.2      Consent of Todd Walker, Esq. (included in Exhibit 5.1)

  24.1      Power of Attorney of the Company

  24.2      Powers of Attorney of Directors and Officers of the Company

  24.3      Powers  of  Attorney  of  members  of the  Ultramar Diamond Shamrock
            Corporation Employee Benefits Committee
[{"type": "S-8", "sequence": "1", "filename": "0001.txt", "description": "NON-EMPLOYEE DIRECTOR EQUITY PLAN S-8", "secsgml_size_bytes": 19698}]
{"company-data": {"conformed-name": "ULTRAMAR DIAMOND SHAMROCK CORP", "cik": "0000887207", "assigned-sic": "2911", "irs-number": "133663331", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-47398", "film-number": "735443"}, "business-address": {"street1": "6000 N. LOOP 1604 W.", "street2": "P O BOX 696000", "city": "SAN ANTONIO", "state": "TX", "zip": "78249-1112", "phone": "2105922000"}, "mail-address": {"street1": "P O BOX 696000", "street2": "THIRD FLOOR", "city": "SAN ANTONIO", "state": "TX", "zip": "78269-6000"}, "former-company": {"former-conformed-name": "ULTRAMAR CORP /DE", "date-changed": "19930328"}}
As filed with the Securities and Exchange Commission October 5, 2000
                                                     Registration No. 333-27697

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                           ---------------------------
                         POST-EFFECTIVE AMENDMENT NO. 1
                                       TO
                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                      ULTRAMAR DIAMOND SHAMROCK CORPORATION
               (Exact Name of Registrant as Specified in Charter)

Delaware                                              13-3663331
(State of                                            (IRS Employer
Incorporation)                                     Identification No.)

6000 North Loop 1604 West                            78249-1112
(Address of Principal Executive                      (Zip Code)
Offices)

                      ULTRAMAR DIAMOND SHAMROCK CORPORATION
                        NON-EMPLOYEE DIRECTOR EQUITY PLAN
                            (Full title of the Plan)

                           Timothy J. Fretthold, Esq.
                            Executive Vice President,
                     Chief Administrative and Legal Officer
                      Ultramar Diamond Shamrock Corporation
                            6000 North Loop 1604 West
                          San Antonio, Texas 78249-1112
                     (Name and Address of Agent for Service)

                                 (210) 592-2000
                     (Telephone Number, Including Area Code
                              of Agent for Service)

In addition,  pursuant to Rule 416(c)  under the  Securities  Act of 1933,  this
registration  statement also covers an  indeterminate  amount of interests to be
offered or sold pursuant to the employee benefit plan(s) described herein.
CALCULATION OF REGISTRATION FEE
----------------------- --------------------- -------------------- ----------------------- -------------------------
 Title of Securities        Amount to be       Proposed Maximum       Proposed Maximum      Amount of Registration
 to be Registered (1)        Registered       Offering Price Per          Offering                 Fee (2)
                                                   Share (2)       ----------------------
                                                                          Price (2)
----------------------- --------------------- -------------------- ----------------------- -------------------------
----------------------- --------------------- -------------------- ----------------------- -------------------------
  Common Stock, par           250,000               $25.03         $6,257,813                      $401.00
 value $.01 per share
----------------------- --------------------- -------------------- ----------------------- -------------------------
(1)      Includes  associated  rights  to  purchase  Ultramar  Diamond  Shamrock
         Corporation  common stock exercisable  pursuant to the Rights Agreement
         filed as Exhibit 4.2 hereto.

(2)      Estimated  solely for the purpose of computing the  registration fee in
         accordance  with  Rule 457 (h) and Rule  457 (c),  based on the  market
         price of common stock of Ultramar  Diamond  Shamrock  Corporation  (the
         "Company") of $25.03,  per share,  which is the average of the high and
         low sale  price  thereof  on the  Composite  Tape of the New York Stock
         Exchange on September 26, 2000.
PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  Incorporation of Documents by Reference.

         The  following   documents  filed  with  the  Securities  and  Exchange
Commission  (the  "Commission")  by  the  Company  are  incorporated  herein  by
reference:

         (a) The Company's  Registration  Statement 333-27697 on Form S-8, filed
with the Commission on May 23, 1997;

         (b) The Company's  Annual Report on Form 10-K for the fiscal year ended
December 31, 1999,  filed pursuant to Section 13(a) of the  Securities  Exchange
Act of 1934, as amended (the "1934 Act");

         (c) The Company's  Quarterly Report on Form 10-Q for the fiscal quarter
ended March 31, 2000 and on Form  10-Q/A for the fiscal  quarter  ended June 30,
2000; and

         (d) The Company's Current Report on Form 8-K dated August 31, 2000;

         All documents filed by the Company pursuant to Sections 13 (a), 13 (c),
14,  or 15(d) of the  1934 Act  subsequent  to the  filing  of this  Form  S-8/A
Registration Statement (the "Registration Statement") and prior to the filing of
a post-effective amendment to the Registration Statement that indicates that all
securities  offered have been sold or that  de-registers  all of the  securities
that remain unsold shall be deemed to be incorporated by reference herein and to
be a part hereof from the respective dates of the filing of such documents.

Item 4.  Description of Securities.

         Incorporated  by  reference  to  the  Company's  filing  on Form S-3/A,
Registration Statement No. 333-46775.

Item 5.  Interests of Named Experts and Counsel.

                                     EXPERTS

         The  audited   financial   statements  of  Ultramar   Diamond  Shamrock
Corporation  incorporated  by reference in this  prospectus and elsewhere in the
registration  statement  have been audited by Arthur  Andersen LLP,  independent
public accountants,  as indicated in their reports with respect thereto, and are
included  herein in  reliance  upon the  authority  of said firm as  experts  in
accounting and auditing in giving said reports.

                                  LEGAL MATTERS

         The validity of the shares of the Company's Common Stock being  offered
hereby has been  passed  upon for the  Company by Todd  Walker,  Esq.,  Managing
Attorney and Corporate  Secretary for the Company.  Mr. Walker beneficially owns
shares of the Common Stock of the Company.

Item 6. Indemnification of Directors and Officers.

         The By-laws of the Company provide that the Company shall indemnify its
officers  and  directors  to the  fullest  extent  permitted  or required by the
Delaware  General  Corporation  Law (the "DGCL"),  as amended from time to time,
provided,  however,  that  except  insofar  as  the  Company's  By-laws  provide
indemnification  for  an  officer  or  director  with  respect  to a  proceeding
initiated  by such  officer or  director to enforce  rights to  indemnification,
officers and  directors  will not be entitled to  indemnification  in connection
with  proceedings  initiated by an officer or director if the initiation of such
proceedings was not authorized by the board of directors of the Company. Section
145 of the DGCL  provides,  in  general,  that each  director  and  officer of a
corporation may be indemnified  against  expenses  (including  attorneys'  fees,
judgments,  fines,  and amounts  paid in  settlement)  actually  and  reasonably
incurred  in  connection  with the  defense  or  settlement  of any  threatened,
pending, or completed legal proceedings in which he is involved by reason of the
fact that he is or was a director or officer of the Company, if he acted in good
faith and in a manner that he reasonably believed to be in or not opposed to the
best  interests of the  Company,  and,  with  respect to any criminal  action or
proceeding,  if he had no  reasonable  cause to  believe  that his  conduct  was
unlawful.  If  the  legal  proceeding,  however,  is by or in the  right  of the
Company, the director or officer may not be indemnified in respect of any claim,
issue,  or  matter  as to which he shall  have been  adjudged  to be liable  for
negligence or misconduct in the  performance of his duty to the Company unless a
court determines otherwise.

         The   Company's   By-laws   also   provide  for   advances  in  certain
circumstances  covering  expenses  incurred  by an  officer or  director  of the
Company in connection with the defense of a proceeding for which such officer or
director would be entitled to indemnity under the Company's By-laws.

         The Company's  By-laws further provide that the Company may procure and
maintain insurance covering director's and officer's liability for their actions
in those  capacities,  whether or not the  Company  would be entitled to provide
indemnification for such liability under the DGCL.

         The  Certificate  of  Incorporation  of the Company  provides  that the
personal  liability of the  directors of the Company  shall be eliminated to the
fullest  extent  permitted by applicable  law. The DGCL permits a  corporation's
certificate  of  incorporation  to provide  that no director of the  corporation
shall be personally  liable to the corporation or its  stockholders for monetary
damages for any breach of his fiduciary duty as a director;  provided,  however,
that such  provision  shall not apply to any liability of a director (1) for any
breach of a director's duty of loyalty to the  corporation or its  stockholders,
(2) for acts or  omissions  that are not in good  faith or  involve  intentional
misconduct or a knowing  violation of the law, (3) under Section 174 of the DGCL
or (4) for any transaction from which the director derived an improper  personal
benefit.  The Company  has  entered  into  indemnification  agreements  with the
directors and certain officers of the Company providing for  indemnification  on
the terms set out in the By-laws of the Company.

Item 8. Exhibits.

Exhibit Number                              Description

          4.1              Ultramar  Diamond Shamrock  Corporation  Non-Employee
                           Director  Equity  Plan  (incorporated by reference to
                           the Company's  Report on Schedule 14A filed March 21,
                           2000)

          4.2              Rights  Agreement  dated June 25,  1992  between  the
                           Company  and  Registrar  and  Transfer  Company,   as
                           amended  (incorporated  by reference to  Registration
                           Statement  on Form S-1 (File No.  33-47586),  Exhibit
                           4.2;  Quarterly Report on Form 10-Q for quarter ended
                           September  30, 1992,  Exhibit 4.2;  Annual  Report on
                           Form  10-K  for the year  ended  December  31,  1994,
                           Exhibit 4.3.

          5.1              Opinion regarding legality of securities being issued

         23.1              Consent of Arthur Andersen LLP

         23.2              Consent  of  Todd  Walker,  Esq. (included in Exhibit
                           5.1)

         24.1              Power of Attorney of the Company

         24.2              Powers of  Attorney of Directors  and Officers of the
                           Company

         24.3              Powers of Attorney of members of the Ultramar Diamond
                           Shamrock Corporation Employee Benefits Committee

  Item 9. Undertakings.

  A. The Company hereby undertakes:

  (1) to file  during  any  period in which  offers or sales are being  made,  a
post-effective  amendment  to this  Registration  Statement  (a) to include  any
prospectus  required  by Section  10(a) (3) of the  Securities  Act of 1933,  as
amended (the "1933 Act"),  (b) to reflect in the  prospectus any facts or events
arising after the  effective  date of this  Registration  Statement (or the most
recent post-effective amendment hereof) which, individually or in the aggregate,
represents  a  fundamental   change  in  the   information  set  forth  in  this
Registration  Statement (except to the extent covered by reports filed under the
1934 Act and incorporated herein by reference),  and (c) to include any material
information with respect to the plan of distribution not previously disclosed in
this  Registration  Statement or any material change to such information in this
Registration Statement;

  (2) that,  for the purpose of  determining  any liability  under the 1933 Act,
each such  post-effective  amendment  shall be  deemed to be a new  registration
statement relating to the securities  offered therein,  and the offering of such
securities  at that time shall be deemed to be the  initial  bona fide  offering
thereof; and

  (3) to remove from registration by means of a post-effective  amendment any of
the securities  being  registered  which remain unsold at the termination of the
offering.

B. The Company hereby undertakes that, for purposes of determining any liability
under the 1933 Act,  each  filing of the  Company's  annual  report  pursuant to
Section  13(a) or  Section  15(d) of the 1934 Act and each  filing of the Plan's
annual report pursuant to Section 15(d) of the 1934 Act that are incorporated by
reference in the Registration Statement shall be deemed to be a new registration
statement relating to the securities  offered therein,  and the offering of such
securities  at that time shall be deemed to be the  initial  bona fide  offering
thereof.

C. Insofar as indemnification  for liabilities arising under the 1933 Act may be
permitted  to  directors,  officers,  and  controlling  persons  of the  Company
pursuant to the foregoing provisions or otherwise,  the Company is advised that,
in the opinion of the Commission,  such indemnification is against public policy
as expressed in the 1933 Act and is, therefore, unenforceable. In the event that
a claim for indemnification  against such liabilities (other than the payment by
the Company of expenses  incurred or paid by a director,  officer or controlling
person  of the  Company  in  the  successful  defense  of any  action,  suit  or
proceeding)  is  asserted  by a  director,  officer,  or  controlling  person in
connection with the securities being registered, the Company will, unless in the
opinion of counsel for the Company  the matter has been  settled by  controlling
precedent,  submit to a court of appropriate  jurisdiction  the question whether
such indemnification by it is against public policy as expressed in the 1933 Act
and will be governed by the final adjudication of such issue.
SIGNATURES

         Pursuant to the  requirements  of the 1933 Act,  the Company  certifies
that it has reasonable  grounds to believe that it meets all of the requirements
for filing on Form S-8/A and has duly caused this  Registration  Statement to be
signed on its behalf by the undersigned,  thereunto duly authorized, in the City
of San Antonio, Texas, on the 3rd day of October, 2000.

                                        ULTRAMAR DIAMOND SHAMROCK CORPORATION

                                        By: *Jean Gaulin,  Chairman of the Board
                                        and Chief Executive Officer

         Pursuant  to  the  requirements  of the  1933  Act,  this  Registration
  Statement has been signed by the following  persons in the  capacities  and on
  the date indicated:

Signature                  Title                                 Date

*Jean Gaulin               Chairman of the Board                 October 3, 2000
                           and Chief Executive
                           Officer

*Robert S. Shapard         Executive Vice President              October 3, 2000
                           and Chief Financial officer
                           (Principal Financial Officer
                           and Principal Accounting Officer)

*Byron Allumbaugh          Director                              October 3, 2000

*E. Glenn Biggs            Director                              October 3, 2000

*W. E. Bradford            Director                              October 3, 2000

*H. Frederick Christie     Director                              October 3, 2000

*W. H. Clark               Director                              October 3, 2000

*Russel H. Herman          Director                              October 3, 2000

*Bob Marbut                Director                              October 3, 2000

*Katherine D. Ortega       Director                              October 3, 2000

*Madeleine Saint-Jacques   Director                              October 3, 2000

*C. Barry Schaefer         Director                              October 3, 2000

         Pursuant to the  requirements  of the 1933 Act,  the  Ultramar  Diamond
Shamrock Corporation  Employee Benefits Committee,  as administrator of the Non-
Employee  Director  Equity Plan (the  "Plan"),  have  caused  this  registration
statement to be signed on the Plan's behalf by the  undersigned,  thereunto duly
authorized, in the City of San Antonio, Texas on October 3, 2000.

                                    ULTRAMAR DIAMOND SHAMROCK CORPORATION
                                    NON-EMPLOYEE DIRECTOR EQUITY PLAN

                                    BY:  ULTRAMAR DIAMOND SHAMROCK CORPORATION
                                         EMPLOYEE BENEFITS COMMITTEE

                                    * Timothy J. Fretthold, Member

                                    * Penelope Viteo, Member

                                    * Lorraine Racicot, Member

                                    * Steve Blank, Member

*Todd  Walker,  by signing his name hereto,  does hereby sign this  Registration
Statement on Form S-8/A on behalf of Ultramar Diamond Shamrock Corporation, each
of  the  above-named   officers  and  directors  of  Ultramar  Diamond  Shamrock
Corporation,  and  each of the  above  named  members  of the  Ultramar  Diamond
Shamrock  Corporation Employee Benefits Committee pursuant to powers of attorney
executed  on behalf of the  Company and each of such  officers,  directors,  and
members.

                                                     By: /s/ Todd Walker
                                                     Attorney-in-fact
                                                     October 3, 2000
INDEX TO EXHIBITS

Exhibit
Number      Description

   4.1      Ultramar Diamond Shamrock Corporation  Non-Employee Director  Equity
            Plan (incorporated by reference to the Company's Report on  Schedule
            14A filed March 21, 2000)

   4.2      Rights  Agreement  dated  June  25,  1992  between  the Company  and
            Registrar  and  Transfer  Company,  as  amended   (incorporated   by
            reference to Registration Statement on Form S-1 (File No. 33-47586),
            Exhibit  4.2;  Quarterly  Report  on  Form  10-Q  for  quarter ended
            September 30, 1992, Exhibit 4.2; Annual Report on Form 10-K  for the
            year ended December 31, 1994, Exhibit 4.3.

   5.1      Opinion regarding legality of securities being issued

  23.1      Consent of Arthur Andersen LLP

  23.2      Consent of Todd Walker, Esq. (included in Exhibit 5.1)

  24.1      Power of Attorney of the Company

  24.2      Powers of Attorney of Directors and Officers of the Company

  24.3      Powers  of  Attorney  of  members  of the  Ultramar Diamond Shamrock
            Corporation Employee Benefits Committee