--------------------------------------------------------------------------------
        As filed with the Securities and Exchange Commission May 11, 2001
                           Registration No. 333-27699

                       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
                          1996 LONG TERM INCENTIVE 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.
<TABLE>
<CAPTION>

                         CALCULATION OF REGISTRATION FEE

----------------------- --------------------- -------------------- ----------------------- ------------------
 Title of Securities        Amount to be       Proposed Maximum       Proposed Maximum         Amount of
 to be Registered (1)        Registered       Offering Price Per          Offering         Registration Fee
                                                   Share (2)       ----------------------         (2)
                                                                          Price (2)
----------------------- --------------------- -------------------- ----------------------- ------------------
----------------------- --------------------- -------------------- ----------------------- ------------------
<S>                          <C>                    <C>            <C>                        <C>
  Common Stock, par          5,000,000              $41.73         $208,625,000               $52,157.00
 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 $41.73,  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 May 4, 2001.




<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 333-27699 on Form S-8,
                  filed with the Commission on May 22, 1997;

         (b)      The  Company's  Annual Report on Form 10-K for the fiscal year
                  ended  December 31, 2000,  filed  pursuant to Section 13(a) of
                  the  Securities  Exchange  Act of 1934,  as amended (the "1934
                  Act");and

         (c)      The Company's Current Report on Form 8-K dated May 6, 2001;

     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 December 31, 2000  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 1996 Long Term
          Incentive Plan, as amended and restated (incorporated
          by reference to the company's  Report on Schedule 14A
          filed March 27, 2001)

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.

4.3       Fourth Amendment to Rights Agreement dated May 6, 2001.

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

99.1      Questions and answers relating to conversion of stock options.


  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              May 11, 2001
                           and Chief Executive Officer

*Robert S. Shapard          Executive Vice President          May 11, 2001
                           and Chief Financial Officer
                           (Principal Financial Officer
                           and Principal Accounting Officer)

*Byron Allumbaugh          Director                           May 11, 2001

*E. Glenn Biggs            Director                           May 11, 2001

*W. E. Bradford            Director                           May 11, 2001

*H. Frederick Christie     Director                           May 11, 2001

*W. H. Clark               Director                           May 11, 2001

*Bob Marbut                Director                           May 11, 2001

*Katherine D. Ortega       Director                           May 11, 2001

*Madeleine Saint-Jacques   Director                           May 11, 2001

*C. Barry Schaefer         Director                           May 11, 2001

*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 and
each of the  above-named  officers and  directors of Ultramar  Diamond  Shamrock
Corporation,  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
                            May 11, 2001




<PAGE>
<TABLE>
<CAPTION>


                                INDEX TO EXHIBITS

Exhibit Number                              Description

<S>            <C>
 4.1           Ultramar  Diamond  Shamrock  Corporation  1996 Long Term
               Incentive  Plan,  as  amended  and  restated   (incorporated   by
               reference to the company's Report on Schedule 14A filed March 27,
               2001)

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.

4.3            Fourth Amendment to Rights Agreement dated May 6, 2001.

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

99.1           Questions and answers relating to conversion of stock options
</TABLE>



<PAGE>



EXHIBIT 4.3





                                   May 6, 2001



The Chase Manhattan Bank, successor to
Texas Commerce Bank, N.A., successor to
First City, Texas-Houston, National Association
600 Travis Street, Suite 1150
Houston, Texas 77022
Attention:  Janet Mysinger


         Re:  Amendment No. 4 to Rights Agreement

Ladies and Gentlemen:

     Pursuant to Section 26 of the Rights  Agreement  dated as of June 25, 1992,
as amended on each of October 26, 1992, May 10, 1994 and September 22, 1996 (the
"Rights   Agreement"),   between  Ultramar  Diamond  Shamrock  Corporation  (the
"Company") and First City, Texas-Houston, National Association, as rights agent,
the Company,  by resolution  adopted by its Directors,  hereby amends the Rights
Agreement as follows:

          Section 7(a) of the Rights Agreement is hereby amended and restated in
     its  entirety  as  follows:  "(a)  Subject  to  Section  7(e) and except as
     otherwise  provided herein (including Section 11), each Right shall entitle
     the registered holder thereof, upon exercise thereof as provided herein, to
     purchase for the Purchase  Price, at any time after the  Distribution  Date
     and at or prior to the  Expiration  Date,  one  Common  Share,  subject  to
     adjustment  from  time to time  as  provided  in  Sections  11 and 12.  The
     "Expiration  Date" means the earliest of (i) the Redemption  Date, (ii) the
     Close of  Business  on July 6,  2002,  and (iii)  immediately  prior to the
     Effective Time (as defined in the Merger Agreement)."

<PAGE>

Section 1 of the Rights  Agreement is hereby amended by adding the following new
definition to Section 1:

          "Merger Agreement" means the Agreement and Plan of Merger, dated as of
     May 6, 2001, between the Company and Valero Energy Corporation,  a Delaware
     corporation ("Valero")."

The last  sentence of Section 26 of the Rights  Agreement is hereby  amended and
restated in its entirety as follows:

          "In addition,  notwithstanding  anything to the contrary  contained in
     this Rights Agreement,  no supplement or amendment to this Rights Agreement
     shall be made which (a) reduces the Redemption Price (except as required by
     Section  12(a)) or (b) changes the last two sentences in the  definition of
     Acquiring Person contained in Section 1."

          A new Section 34 of the Rights  Agreement  is hereby added as follows:
     "34. Merger with Valero.  Notwithstanding anything in this Agreement to the
     contrary,  none of Valero,  any of its  Affiliates  or Associates or any of
     their  permitted  assignees  or  transferees  shall be deemed an  Acquiring
     Person  and no  Distribution  Date  shall  be  deemed  to  occur or to have
     occurred,  and  the  Rights  will  not  become  separable,   distributable,
     unredeemable or exercisable, in each such case, by reason of or as a result
     of the  approval,  execution  or  delivery  of the  Merger  Agreement,  the
     consummation  of the Merger (as  defined  in the Merger  Agreement)  or the
     consummation  of  the  other   transactions   contemplated  by  the  Merger
     Agreement."

The Rights Agreement shall not otherwise be supplemented or amended by virtue of
this Amendment No. 4 to the Rights Agreement, but shall remain in full force and
effect. Capitalized terms used without other definitions in this Amendment No. 4
to the Rights Agreement shall be used as defined in the Rights Agreement.
This  Amendment No. 4 to the Rights  Agreement  shall be deemed to be a contract
made under the  internal  substantive  laws of the State of Delaware and for all
purposes  will be governed by and  construed  in  accordance  with the  internal
substantive  laws of such State applicable to contracts to be made and performed
entirely within such State.

This  Amendment  No. 4 to the Rights  Agreement may be executed in any number of
counterparts and each of such  counterparts  shall for all purposes be deemed to
be an original,  and all such counterparts shall together constitute but one and
the same  instrument.  This  Amendment  No. 4 to the Rights  Agreement  shall be
effective as of, and  immediately  prior to, the  execution  and delivery of the
Merger  Agreement,  and all references to the Rights Agreement  shall,  from and
after such time, be deemed to be  references to the Rights  Agreement as amended
hereby.

Exhibit A to the Rights Agreement shall be deemed amended in a manner consistent
with this Amendment No. 4 to the Rights Agreement. Pursuant to Section 26 of the
Rights  Agreement,  the Company  hereby  directs the Rights  Agent to accept and
agree to this Amendment No. 4 to the Rights Agreement.


                                Very truly yours,

                                ULTRAMAR DIAMOND SHAMROCK CORPORATION




                                By:   /s/ Timothy J. Fretthold
                                      -------------------------------
                                      Name:  Timothy J. Fretthold
                                      Title:    Executive Vice President

Accepted and agreed to as of the effective time specified above:

THE CHASE MANHATTAN BANK, SUCCESSOR TO
TEXAS COMMERCE BANK, N.A., SUCCESSOR TO
First City, Texas-Houston, National Association



By:   /s/Janet Mysinger
   -------------------------
        Name:  Janet Mysinger
        Title:    Vice President and Trust Officer





<PAGE>


Exhibit 5.1

May 11, 2001

Ultramar Diamond Shamrock Corporation
P.O. Box 696000
San Antonio, Texas 78269-6000

Re:  Ultramar  Diamond Shamrock  Corporation  1996 Long-Term  Incentive Plan, as
     Amended and Restated (the "Plan").

Ladies and Gentlemen:

     I  am  counsel  for  Ultramar  Diamond  Shamrock  Corporation,  a  Delaware
corporation (the "Company"). The Company expects to file with the Securities and
Exchange  Commission  on or May 11, 2001 under the  Securities  Act of 1933,  as
amended, a Registration  Statement on Form S-8/A (the "Registration  Statement")
for the purpose of registering  5,000,000 shares of common stock, $.01 par value
of the Company ("Common Stock") issuable under the Plan .

     In  connection  with such filing,  I have  examined the Plan and such other
documents,  records,  and  matters  of law as I have  deemed  necessary  for the
purpose of this opinion and based thereupon, I am of the opinion that the shares
of Common  Stock that may be issued and sold or  delivered  pursuant to the Plan
will be, when issued in accordance with the Plan,  legally  issued,  fully paid,
and  nonassessable  and the rights to purchase  common  stock (the  "Rights") in
accordance with the Rights Agreement dated June 25, 1992 between the Company and
The Chase Manhattan Bank, when duly issued, will be legally issued.

     I hereby  consent  to the  filing  of this  opinion  as an  exhibit  to the
Registration  Statement  filed by the Company with the  Securities  and Exchange
Commission  to register the Common Stock under the  Securities  Act of 1933,  as
amended.

Sincerely,

/S/ Todd Walker



<PAGE>


Exhibit 23.1

                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS

         As   independent   public   accountants,   we  hereby  consent  to  the
incorporation  by reference in this  registration  statement of our report dated
March 14, 2001 included in Ultramar Diamond Shamrock Corporation's Form 10-K for
the year ended  December 31, 2000 and to all  references to our firm included in
this registration statement.

                                             /S/  Arthur Andersen LLP

San Antonio, Texas
May 11, 2001



<PAGE>


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 R. Gaulin
                                              -----------------------
                                              Chairman, President, and
                                              Chief Executive Officer


Dated: May 7, 2001



<PAGE>


Exhibit 24.2

                                POWER OF ATTORNEY

     The  undersigned  directors  and/or officers of Ultramar  Diamond  Shamrock
Corporation, hereby constitute and appoint Timothy J. Fretthold and Todd Walker,
or either of them,  as the true and lawful  attorneys-in-fact  and agents of the
undersigned, each with full power of substitution and resubstitution,  to do any
and all acts and things in their names and in their  respective  capacities as a
director  and/or an officer of Ultramar  Diamond  Shamrock  Corporation,  and to
execute any and all  instruments  for them and in their names in the  capacities
indicated above, which 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  covering up to  5,000,000  shares of common
stock of the company,  $.01 par value,  including  without  limitation power and
authority to sign for them,  in their name in the  capacities  indicated  above,
such Registration Statement 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.

/S/ Jean R. Gaulin                    /S/Bob Marbut
-------------------------             ------------------------
    Jean Gaulin                          Bob Marbut

/S/ Byron Allumbaugh                  /S/Katherine D. Ortega
-------------------------             -------------------------
    Byron Allumbaugh                    Katherine D. Ortega


/S/ E. Glenn Biggs                   /S/Madeleine Saint-Jacques
-------------------------            ---------------------------
    E. Glenn Biggs                      Madeleine Saint-Jacques


/S/ W. E. Bradford                   /S/ C. Barry Schaefer
-------------------------            --------------------------
    W. E. Bradford                       C. Barry Schaefer


/S/ H. Frederick Christie            /S/Robert S. Shapard
-------------------------            --------------------------
    H. Frederick Christie               Robert S. Shapard

/S/W. H. Clark
-------------------------
   W. H. Clark


Dated: May 7, 2001
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--------------------------------------------------------------------------------
        As filed with the Securities and Exchange Commission May 11, 2001
                           Registration No. 333-27699

                       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
                          1996 LONG TERM INCENTIVE 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
 to be Registered (1)        Registered       Offering Price Per          Offering         Registration Fee
                                                   Share (2)       ----------------------         (2)
                                                                          Price (2)
----------------------- --------------------- -------------------- ----------------------- ------------------
----------------------- --------------------- -------------------- ----------------------- ------------------
Common Stock, par          5,000,000              $41.73         $208,625,000               $52,157.00
 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 $41.73,  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 May 4, 2001.
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 333-27699 on Form S-8,
                  filed with the Commission on May 22, 1997;

         (b)      The  Company's  Annual Report on Form 10-K for the fiscal year
                  ended  December 31, 2000,  filed  pursuant to Section 13(a) of
                  the  Securities  Exchange  Act of 1934,  as amended (the "1934
                  Act");and

         (c)      The Company's Current Report on Form 8-K dated May 6, 2001;

     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 December 31, 2000  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 1996 Long Term
          Incentive Plan, as amended and restated (incorporated
          by reference to the company's  Report on Schedule 14A
          filed March 27, 2001)

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.

4.3       Fourth Amendment to Rights Agreement dated May 6, 2001.

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

99.1      Questions and answers relating to conversion of stock options.

  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              May 11, 2001
                           and Chief Executive Officer

*Robert S. Shapard          Executive Vice President          May 11, 2001
                           and Chief Financial Officer
                           (Principal Financial Officer
                           and Principal Accounting Officer)

*Byron Allumbaugh          Director                           May 11, 2001

*E. Glenn Biggs            Director                           May 11, 2001

*W. E. Bradford            Director                           May 11, 2001

*H. Frederick Christie     Director                           May 11, 2001

*W. H. Clark               Director                           May 11, 2001

*Bob Marbut                Director                           May 11, 2001

*Katherine D. Ortega       Director                           May 11, 2001

*Madeleine Saint-Jacques   Director                           May 11, 2001

*C. Barry Schaefer         Director                           May 11, 2001

*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 and
each of the  above-named  officers and  directors of Ultramar  Diamond  Shamrock
Corporation,  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
                            May 11, 2001
INDEX TO EXHIBITS

Exhibit Number                              Description
4.1           Ultramar  Diamond  Shamrock  Corporation  1996 Long Term
               Incentive  Plan,  as  amended  and  restated   (incorporated   by
               reference to the company's Report on Schedule 14A filed March 27,
               2001)

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.

4.3            Fourth Amendment to Rights Agreement dated May 6, 2001.

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

99.1           Questions and answers relating to conversion of stock options
EXHIBIT 4.3

                                   May 6, 2001

The Chase Manhattan Bank, successor to
Texas Commerce Bank, N.A., successor to
First City, Texas-Houston, National Association
600 Travis Street, Suite 1150
Houston, Texas 77022
Attention:  Janet Mysinger

         Re:  Amendment No. 4 to Rights Agreement

Ladies and Gentlemen:

     Pursuant to Section 26 of the Rights  Agreement  dated as of June 25, 1992,
as amended on each of October 26, 1992, May 10, 1994 and September 22, 1996 (the
"Rights   Agreement"),   between  Ultramar  Diamond  Shamrock  Corporation  (the
"Company") and First City, Texas-Houston, National Association, as rights agent,
the Company,  by resolution  adopted by its Directors,  hereby amends the Rights
Agreement as follows:

          Section 7(a) of the Rights Agreement is hereby amended and restated in
     its  entirety  as  follows:  "(a)  Subject  to  Section  7(e) and except as
     otherwise  provided herein (including Section 11), each Right shall entitle
     the registered holder thereof, upon exercise thereof as provided herein, to
     purchase for the Purchase  Price, at any time after the  Distribution  Date
     and at or prior to the  Expiration  Date,  one  Common  Share,  subject  to
     adjustment  from  time to time  as  provided  in  Sections  11 and 12.  The
     "Expiration  Date" means the earliest of (i) the Redemption  Date, (ii) the
     Close of  Business  on July 6,  2002,  and (iii)  immediately  prior to the
     Effective Time (as defined in the Merger Agreement)."
Section 1 of the Rights  Agreement is hereby amended by adding the following new
definition to Section 1:

          "Merger Agreement" means the Agreement and Plan of Merger, dated as of
     May 6, 2001, between the Company and Valero Energy Corporation,  a Delaware
     corporation ("Valero")."

The last  sentence of Section 26 of the Rights  Agreement is hereby  amended and
restated in its entirety as follows:

          "In addition,  notwithstanding  anything to the contrary  contained in
     this Rights Agreement,  no supplement or amendment to this Rights Agreement
     shall be made which (a) reduces the Redemption Price (except as required by
     Section  12(a)) or (b) changes the last two sentences in the  definition of
     Acquiring Person contained in Section 1."

          A new Section 34 of the Rights  Agreement  is hereby added as follows:
     "34. Merger with Valero.  Notwithstanding anything in this Agreement to the
     contrary,  none of Valero,  any of its  Affiliates  or Associates or any of
     their  permitted  assignees  or  transferees  shall be deemed an  Acquiring
     Person  and no  Distribution  Date  shall  be  deemed  to  occur or to have
     occurred,  and  the  Rights  will  not  become  separable,   distributable,
     unredeemable or exercisable, in each such case, by reason of or as a result
     of the  approval,  execution  or  delivery  of the  Merger  Agreement,  the
     consummation  of the Merger (as  defined  in the Merger  Agreement)  or the
     consummation  of  the  other   transactions   contemplated  by  the  Merger
     Agreement."

The Rights Agreement shall not otherwise be supplemented or amended by virtue of
this Amendment No. 4 to the Rights Agreement, but shall remain in full force and
effect. Capitalized terms used without other definitions in this Amendment No. 4
to the Rights Agreement shall be used as defined in the Rights Agreement.
This  Amendment No. 4 to the Rights  Agreement  shall be deemed to be a contract
made under the  internal  substantive  laws of the State of Delaware and for all
purposes  will be governed by and  construed  in  accordance  with the  internal
substantive  laws of such State applicable to contracts to be made and performed
entirely within such State.

This  Amendment  No. 4 to the Rights  Agreement may be executed in any number of
counterparts and each of such  counterparts  shall for all purposes be deemed to
be an original,  and all such counterparts shall together constitute but one and
the same  instrument.  This  Amendment  No. 4 to the Rights  Agreement  shall be
effective as of, and  immediately  prior to, the  execution  and delivery of the
Merger  Agreement,  and all references to the Rights Agreement  shall,  from and
after such time, be deemed to be  references to the Rights  Agreement as amended
hereby.

Exhibit A to the Rights Agreement shall be deemed amended in a manner consistent
with this Amendment No. 4 to the Rights Agreement. Pursuant to Section 26 of the
Rights  Agreement,  the Company  hereby  directs the Rights  Agent to accept and
agree to this Amendment No. 4 to the Rights Agreement.

                                Very truly yours,

                                ULTRAMAR DIAMOND SHAMROCK CORPORATION

                                By:   /s/ Timothy J. Fretthold
                                      -------------------------------
                                      Name:  Timothy J. Fretthold
                                      Title:    Executive Vice President

Accepted and agreed to as of the effective time specified above:

THE CHASE MANHATTAN BANK, SUCCESSOR TO
TEXAS COMMERCE BANK, N.A., SUCCESSOR TO
First City, Texas-Houston, National Association

By:   /s/Janet Mysinger
   -------------------------
        Name:  Janet Mysinger
        Title:    Vice President and Trust Officer
Exhibit 5.1

May 11, 2001

Ultramar Diamond Shamrock Corporation
P.O. Box 696000
San Antonio, Texas 78269-6000

Re:  Ultramar  Diamond Shamrock  Corporation  1996 Long-Term  Incentive Plan, as
     Amended and Restated (the "Plan").

Ladies and Gentlemen:

     I  am  counsel  for  Ultramar  Diamond  Shamrock  Corporation,  a  Delaware
corporation (the "Company"). The Company expects to file with the Securities and
Exchange  Commission  on or May 11, 2001 under the  Securities  Act of 1933,  as
amended, a Registration  Statement on Form S-8/A (the "Registration  Statement")
for the purpose of registering  5,000,000 shares of common stock, $.01 par value
of the Company ("Common Stock") issuable under the Plan .

     In  connection  with such filing,  I have  examined the Plan and such other
documents,  records,  and  matters  of law as I have  deemed  necessary  for the
purpose of this opinion and based thereupon, I am of the opinion that the shares
of Common  Stock that may be issued and sold or  delivered  pursuant to the Plan
will be, when issued in accordance with the Plan,  legally  issued,  fully paid,
and  nonassessable  and the rights to purchase  common  stock (the  "Rights") in
accordance with the Rights Agreement dated June 25, 1992 between the Company and
The Chase Manhattan Bank, when duly issued, will be legally issued.

     I hereby  consent  to the  filing  of this  opinion  as an  exhibit  to the
Registration  Statement  filed by the Company with the  Securities  and Exchange
Commission  to register the Common Stock under the  Securities  Act of 1933,  as
amended.

Sincerely,

/S/ Todd Walker
Exhibit 23.1

                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS

         As   independent   public   accountants,   we  hereby  consent  to  the
incorporation  by reference in this  registration  statement of our report dated
March 14, 2001 included in Ultramar Diamond Shamrock Corporation's Form 10-K for
the year ended  December 31, 2000 and to all  references to our firm included in
this registration statement.

                                             /S/  Arthur Andersen LLP

San Antonio, Texas
May 11, 2001
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 R. Gaulin
                                              -----------------------
                                              Chairman, President, and
                                              Chief Executive Officer

Dated: May 7, 2001
Exhibit 24.2

                                POWER OF ATTORNEY

     The  undersigned  directors  and/or officers of Ultramar  Diamond  Shamrock
Corporation, hereby constitute and appoint Timothy J. Fretthold and Todd Walker,
or either of them,  as the true and lawful  attorneys-in-fact  and agents of the
undersigned, each with full power of substitution and resubstitution,  to do any
and all acts and things in their names and in their  respective  capacities as a
director  and/or an officer of Ultramar  Diamond  Shamrock  Corporation,  and to
execute any and all  instruments  for them and in their names in the  capacities
indicated above, which 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  covering up to  5,000,000  shares of common
stock of the company,  $.01 par value,  including  without  limitation power and
authority to sign for them,  in their name in the  capacities  indicated  above,
such Registration Statement 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.

/S/ Jean R. Gaulin                    /S/Bob Marbut
-------------------------             ------------------------
    Jean Gaulin                          Bob Marbut

/S/ Byron Allumbaugh                  /S/Katherine D. Ortega
-------------------------             -------------------------
    Byron Allumbaugh                    Katherine D. Ortega

/S/ E. Glenn Biggs                   /S/Madeleine Saint-Jacques
-------------------------            ---------------------------
    E. Glenn Biggs                      Madeleine Saint-Jacques

/S/ W. E. Bradford                   /S/ C. Barry Schaefer
-------------------------            --------------------------
    W. E. Bradford                       C. Barry Schaefer

/S/ H. Frederick Christie            /S/Robert S. Shapard
-------------------------            --------------------------
    H. Frederick Christie               Robert S. Shapard

/S/W. H. Clark
-------------------------
   W. H. Clark

Dated: May 7, 2001