================================================================================


                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549



                                    FORM 11-K



                     ANNUAL REPORT PURSUANT TO SECTION 15(d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934

                      For the year ended December 31, 2000



                         Commission File Number 1-11154



                      A.   UDS 401(k) Retirement Savings Plan

                      B.   Ultramar Diamond Shamrock Corporation
                           6000 North Loop 1604 West
                           San Antonio, TX  78249-1112




================================================================================








                       UDS 401(k) RETIREMENT SAVINGS PLAN
             Index to Financial Statements and Supplemental Schedule
                           December 31, 2000 and 1999


                                                                        Page
                                                                        ----

Report of Independent Public Accountants................................   3

Financial Statements:

     Statements of Net Assets Available for Plan Benefits
       as of December 31, 2000 and 1999.................................   4

     Statements of Changes in Net Assets Available for Plan Benefits
       for the Years Ended December 31, 2000 and 1999...................   5

     Notes to Financial Statements......................................   6

Supplemental Schedule:

     Schedule I - Schedule of Assets (Held at End of Year)
       as of December 31, 2000..........................................  13

Signature...............................................................  14

Consent of Independent Public Accountants...............................  15




                    REPORT OF INDEPENDENT PUBLIC ACCOUNTANTS


To the Employee Benefits Committee of
Ultramar Diamond Shamrock Corporation:

We have audited the  accompanying  statements  of net assets  available for plan
benefits of the UDS 401(k) Retirement Savings Plan (the Plan) as of December 31,
2000 and 1999, and the related statements of changes in net assets available for
plan  benefits  for the years then ended.  These  financial  statements  and the
schedule referred to below are the responsibility of the Plan's management.  Our
responsibility  is to  express  an opinion  on these  financial  statements  and
schedule based on our audits.

We conducted our audits in accordance with auditing standards generally accepted
in the United States. Those standards require that we plan and perform the audit
to obtain reasonable  assurance about whether the financial  statements are free
of material misstatement. An audit includes examining, on a test basis, evidence
supporting  the amounts and  disclosures in the financial  statements.  An audit
also includes assessing the accounting principles used and significant estimates
made by  management,  as well as  evaluating  the  overall  financial  statement
presentation.  We believe  that our audits  provide a  reasonable  basis for our
opinion.

In our opinion,  the financial  statements  referred to above present fairly, in
all material respects, the net assets available for plan benefits of the Plan as
of December 31, 2000 and 1999, and the changes in net assets  available for plan
benefits  for each of the  years  then  ended,  in  conformity  with  accounting
principles generally accepted in the United States.

Our audits  were  performed  for the  purpose of forming an opinion on the basic
financial statements taken as a whole. The supplemental schedule of assets (held
at end of year) as of December 31, 2000  included as Schedule I is presented for
the  purpose of  additional  analysis  and is not a  required  part of the basic
financial statements but is supplementary information required by the Department
of Labor Rules and Regulations  for Reporting and Disclosure  under the Employee
Retirement  Income  Security  Act of 1974.  The  supplemental  schedule has been
subjected  to the  auditing  procedures  applied  in  the  audits  of the  basic
financial  statements  and, in our  opinion,  is fairly  stated in all  material
respects in relation to the basic financial statements taken as a whole.



San Antonio, Texas
June 20, 2001






                       UDS 401(k) RETIREMENT SAVINGS PLAN
              STATEMENTS OF NET ASSETS AVAILABLE FOR PLAN BENEFITS


                                                    December 31,
                                                    ------------
Assets                                       2000                 1999
                                             ----                 ----
                                                         
Investments, at fair value                $ 236,460,520        $ 198,067,614
                                            -----------          -----------

Contributions receivable:
  Employer                                      783,829              578,270
  Employee                                    2,193,586            1,889,132
                                            -----------          -----------
                                              2,977,415            2,467,402
                                            -----------          -----------

Net assets available for plan benefits    $ 239,437,935        $ 200,535,016
                                            ===========          ===========

                 See accompanying notes to financial statements.









                       UDS 401(k) RETIREMENT SAVINGS PLAN
         STATEMENTS OF CHANGES IN NET ASSETS AVAILABLE FOR PLAN BENEFITS


                                                   Years Ended December 31,
                                                  2000                 1999
                                                  ----                 ----
                                                                
Additions to net assets:
  Investment income:
    Interest and dividend income              $  14,137,490        $  10,480,909
    Net appreciation in fair value
     of investments                               4,207,739            4,768,588
                                                -----------          -----------
                                                 18,345,229           15,249,497
                                                -----------          -----------
  Contributions:
    Employer                                      4,724,109            4,038,773
    Employee                                     12,974,092           10,663,142
                                                -----------          -----------
                                                 17,698,201           14,701,915
                                                -----------          -----------

Asset transfers in from other plans              33,733,099           44,553,225
                                                -----------          -----------

     Total additions                             69,776,529           74,504,637
                                                -----------          -----------

Deductions from net assets:
  Benefits paid to participants                  30,873,610           17,534,700
                                                -----------          -----------

Net increase in net assets available for
 plan benefits                                   38,902,919           56,969,937

Net assets available for plan benefits:
  Beginning of year                             200,535,016          143,565,079
                                                -----------          -----------
  End of year                                 $ 239,437,935        $ 200,535,016
                                                ===========          ===========

                 See accompanying notes to financial statements.






                       UDS 401(k) RETIREMENT SAVINGS PLAN

                          NOTES TO FINANCIAL STATEMENTS
                           December 31, 2000 and 1999


NOTE 1: DESCRIPTION OF PLAN

The following  description of the UDS 401(k) Retirement  Savings Plan (the Plan)
provides  only  general  information.  Participants  should  refer  to the  Plan
agreement for a more complete description of the Plan's provisions.

General: The Plan is a defined contribution plan covering all eligible employees
of Ultramar Diamond Shamrock  Corporation (UDS).  Eligible employees include all
non-union  employees and certain union  employees who have completed one year of
service and who are at least 18 years old. The Plan is subject to the provisions
of the Employee Retirement Income Security Act of 1974 (ERISA), as amended.

UDS  is  the  Sponsor  of  the  Plan.  The  Employee  Benefits   Committee  (the
Administrator)  which consists of at least three members  appointed by the Chief
Executive  Officer of UDS administers the Plan. The trustee and  recordkeeper of
the Plan is Vanguard Fiduciary Trust Company.

Plan Mergers and Acquisition:  On August 31, 2000, UDS acquired the Golden Eagle
Refinery from Tosco Corporation.  Effective  September 1, 2000, the employees at
the Golden  Eagle  Refinery  became  eligible  to  participate  in the Plan.  In
connection  with this  acquisition,  UDS agreed to accept the  transfer  of each
Golden  Eagle  employee's  account  balance from the Tosco  Corporation  Capital
Accumulation Plan (the Tosco Plan). Effective October 31, 2000, the Golden Eagle
employee  accounts  in  the  Tosco  Plan  were  transferred  to the  UDS  401(k)
Retirement Savings Plan. These transfers are included in asset transfers in from
other  plans in the  statement  of  changes  in net  assets  available  for plan
benefits for the year ended December 31, 2000.

On September 29, 2000, UDS acquired Valley  Shamrock,  Inc.  Effective with this
acquisition,  employees of Valley Shamrock,  Inc. became eligible to participate
in the Plan.

Effective September 30, 1999, the Ultramar Diamond Shamrock Corporation Employee
Stock  Ownership  Plan  I and  the  Ultramar  Diamond  Shamrock  Employee  Stock
Ownership  Plan II  (collectively  known as the ESOP Plans) were merged with the
Plan.   Participant  account  balances  from  the  respective  ESOP  Plans  were
transferred  from Key Trust Company,  the trustee of the ESOP Plans, to Vanguard
Fiduciary Trust  Company's UDS ESOP1 Stock Fund and UDS ESOP2 Stock Fund.  These
transfers  are included in asset  transfers in from other plans in the statement
of changes in net assets available for plan benefits for the year ended December
31, 1999.  After the  transfers  were  completed,  25% of the common shares were
immediately eligible for diversification by the ESOP Plans'  participants,  with
an  additional  25%  becoming  eligible  on  January 1,  2000,  2001,  and 2002.
Contributions  to the UDS ESOP1  Stock  Fund or the UDS ESOP2  Stock Fund by the
participants are not permitted.

Contributions: Participants can contribute from 1% to 15% of their compensation,
as  defined  in  the  Plan.   In  addition,   any  employee  may  make  rollover
contributions.  For the  years  ended  December  31,  2000  and  1999,  rollover
contributions  were  $1,419,209 and $54,103,  respectively,  and are included in
employee  contributions in the statements of changes in net assets available for
plan  benefits.  UDS  contributes  from  $0.60 to $1.00 for  every  $1.00 of the
participant's   contribution   up  to  6%  of   compensation.   These   matching
contributions  are  invested  in the  same  investment  fund(s)  and in the same
proportion  as the  participant's  current  investment  options.  UDS will  also
contribute 2% of  compensation  for certain  participants  from the Golden Eagle
Refinery.

UDS may make  discretionary  company  contributions to the Plan for a plan year,
subject to certain limitations.  For the years ended December 31, 2000 and 1999,
UDS did not make additional discretionary company contributions to the Plan.

The Internal  Revenue Code  establishes  an annual  limitation  on the amount of
individual pre-tax salary deferral  contributions.  This limit for 2000 and 1999
was $10,500 and $10,000, respectively.

Participant Accounts:  Each participant's account is valued on a daily basis and
is equal to the participant's and company  contributions  plus investment income
less benefits paid to the participant and loans.

Vesting:   Participants  vest  immediately  in  their  contributions,   rollover
contributions  and actual earnings thereon.  Participants  become 100% vested in
company matching and discretionary contributions and related earnings after five
years of service.  Certain  participants are subject to accelerated vesting as a
result of special Plan  provisions  associated  with past  mergers.  However,  a
participant  will be  vested  in 100% of his  account  balance  upon his  death,
disability,  attainment  of  Normal  Retirement  Age,  as  defined  in the Plan,
termination  or  partial  termination  of the Plan or a change  in  control,  as
defined in the Plan. (See Note 10).

Investment  Options:  During  the  years  ended  December  31,  2000  and  1999,
participants  were able to allocate their  contributions  and transfer  existing
account  balances,  except for certain  amounts  restricted  under the UDS ESOP1
Stock Fund and the UDS ESOP2 Stock Fund, among mutual funds, a collective trust,
other  self-directed  investments and the Ultramar Diamond Shamrock  Corporation
Common Stock Fund.

The collective trust is tax-exempt and invests primarily in investment contracts
issued by  insurance  companies  and  commercial  banks,  and  similar  types of
fixed-principal  investments. The contracts are fully benefit responsive and are
recorded at fair value.  The average yield for the years ended December 31, 2000
and 1999 was 6.19% and 5.93%,  respectively.  The crediting  interest rate as of
December 31, 2000 and 1999 was 6.24% and 5.87%, respectively.

Transfers:  Plan participants can transfer the balances in any of the investment
options on a daily basis.

Participant  Loans:  Participants may borrow from their vested account balance a
minimum of $1,000 up to a maximum equal to the lesser of $50,000 or 50% of their
vested account balance. The participant may elect a repayment term of up to five
years for general  purpose loans or up to 10 years for the purchase of a primary
residence.  The loan is secured by a lien on the  participant's  vested  account
balance  and  bears  interest  at  a  reasonable   rate  as  determined  by  the
Administrator.  Principal and interest is repaid through payroll  deductions.  A
participant  can have only one loan  outstanding at any time and must wait three
months after paying off a loan before initiating a new loan.

Payment of Benefits:  On  termination  of service,  a  participant  can choose a
lump-sum  distribution equal to the vested interest of his or her account or can
defer receipt of such  distribution,  depending on the terminated  participant's
vested account balance.  If the vested account balance is less than $5,000,  the
distribution  can not be deferred.  If the vested  account  balance is more than
$5,000, the participant can consent to the distribution, or can defer to a later
date, but not later than the normal retirement date. If the participant takes no
action,  the distribution is made at normal  retirement date.  Optional forms of
payments  are  available  to  certain  participants  as  described  in the  Plan
agreement.

In the event of hardship,  participants can elect to withdraw a portion of their
vested account  balance,  subject to tax penalties and the cessation of elective
deferral contributions under certain circumstances.

Forfeitures:  In the event a participant  terminates before becoming 100% vested
in the employer contributions,  the nonvested employer contribution amounts held
in the participant's  account will be forfeited.  If the terminated  participant
receives a distribution  from the vested  portion of his account,  the nonvested
amounts  remaining  in the  participant's  account are treated as a  forfeiture.
Forfeited  amounts are used to reduce future  employer  contributions  or defray
Plan administrative  costs.  During 2000 and 1999,  employer  contributions were
reduced  by  $230,659   and  $159,893   from   forfeited   nonvested   accounts,
respectively. At December 31, 2000 and 1999, $20,102 and $30,036,  respectively,
in unused forfeitures were available for future use under the Plan.

NOTE 2: SUMMARY OF ACCOUNTING POLICIES

Basis of Accounting: The Plan's financial statements are prepared on the accrual
basis of accounting. Benefits paid to participants are recorded when paid.

Use of Estimates:  The  preparation of financial  statements in conformity  with
United States' generally accepted  accounting  principles requires management to
make  estimates  and  assumptions  that affect the  reported  amounts of assets,
liabilities,  and changes  therein,  and  disclosure  of  contingent  assets and
liabilities. Actual results could differ from those estimates.

Investment  Valuation and Income  Recognition:  Investments  in mutual funds are
valued at quoted  market  prices which  represent  the net asset value of shares
held by the Plan as of the balance  sheet  date.  The Plan's  investment  in the
collective trust is valued at fair value.  Self-directed  investments are valued
at quoted  market  prices as of the balance  sheet date.  Participant  loans are
valued at cost which  approximates fair value. UDS common stock is valued at its
quoted market price as of the balance sheet date.

Purchases and sales of investments are recorded on a trade-date basis.  Interest
income  is  recorded  on  the  accrual  basis.  Dividends  are  recorded  on the
ex-dividend  date.  Capital  gain  distributions  are  included in interest  and
dividend income.

Net Appreciation in Fair Value of Investments: Net appreciation in fair value of
investments  includes net realized  gains and losses on the sale of  investments
and net unrealized appreciation (depreciation) of investments in accordance with
the rules enacted by the Department of Labor.  The computation of realized gains
and losses on the sale of  investments  is based on the fair value  (rather than
historical  cost) of Plan assets at the  beginning of the year or at the time of
purchase  if  purchased  during  the  year,  compared  to the sale  price of the
investment.  The  computation  of  unrealized  appreciation   (depreciation)  of
investments  is based  on the  difference,  if any,  between  fair  value at the
beginning of the year plus current year purchases  compared to fair value at the
end of the year.

Derivative Instruments: Effective January 1, 2001, the Plan adopted Statement of
Financial  Accounting Standard No. 133,  "Accounting for Derivative  Instruments
and Hedging Activities",  as amended. This statement established  accounting and
reporting standards for derivative  instruments and for hedging  activities.  It
requires  that all  derivative  instruments  be  recognized  as either assets or
liabilities  in the  statement of net assets  available for plan benefits and be
measured  at their  fair  value.  The  Statement  requires  that  changes in the
derivative  instrument's fair value be recognized  currently in the statement of
changes  in net  assets  available  for  plan  benefits  unless  specific  hedge
accounting  criteria are met. There was no impact in adopting Statement No. 133,
as amended, as the Plan does not hold or trade derivative instruments.

Plan  Expenses:  UDS pays the  administrative  expenses of the Plan and provides
certain other services at no cost to the Plan.

Risks and  Uncertainties:  The Plan's  investments,  in general,  are exposed to
various risks, such as interest rate, credit and overall market volatility risk.
Due to the level of risk associated with certain  investment  securities,  it is
reasonably  possible  that changes in the value of  investment  securities  will
occur  in  the  near  term  and  that  such  changes  could  materially   affect
participants'  account  balances and amounts  presented in the statements of net
assets available for plan benefits.

NOTE 3: INVESTMENTS

Investments that represent 5% or more of the Plan's net assets are as follows:


                                                         December 31,
                                                    2000               1999
                                                    ----               ----
                                                              
     Vanguard 500 Index Fund                    $ 28,700,428      $ 24,842,696
     Vanguard PRIMECAP Fund                       57,159,426        35,806,727
     Vanguard U.S. Growth Fund**                  10,362,159        11,227,487
     Vanguard Wellington Fund                     29,783,466        27,767,821
     Vanguard Windsor II Fund**                    7,798,735         8,035,535
     Vanguard Retirement Savings Trust            27,341,012        30,768,546
     UDS ESOP1 Stock Fund   *                     36,290,707        31,731,479
     --------------
     * Nonparticipant-directed.
     **This  investment  at December  31, 2000 is less than 5% of the Plan's
       net  assets but is shown in the  schedule  for  comparative  purposes
       only.






During  2000 and 1999,  the Plan's  investments  (including  gains and losses on
investments  bought  and sold,  as well as held  during  the  year)  appreciated
(depreciated) in value as follows:


                                                 Years Ended December 31,
                                              2000                  1999
                                              ----                  ----

                                                            
     Mutual funds                           $(10,746,926)         $ 9,961,767
     Self-directed investments                       944                  375
     Common shares of
       Ultramar Diamond Shamrock
        Corporation                           14,953,721           (5,193,554)
                                              ----------            ---------

         Net appreciation in fair
          value of investments              $  4,207,739         $  4,768,588
                                              ==========           ==========

NOTE 4: NONPARTICIPANT-DIRECTED INVESTMENTS

The net assets and the changes in net assets relating to nonparticipant-directed
investments  (comprised of the UDS ESOP1 Stock Fund and UDS ESOP2 Stock Fund) as
of and for the years ended December 31, 2000 and 1999 are shown below.


                                                          December 31,
                                                          -----------
                                                  2000                  1999
                                                  ----                  ----
                                                              
     Net assets:
           Common shares of
            Ultramar Diamond Shamrock
             Corporation                       $ 45,170,172         $ 39,541,988
                                                 ==========           ==========





                                                    Years Ended December 31,
                                                    -----------------------
                                                 2000                 1999
                                                 ----                 ----
                                                             
     Changes in net assets:
          Interest and dividend income         $  1,710,261      $      480,498
          Net appreciation (depreciation) in
            fair value of investments            12,456,093          (4,953,413)
          Asset transfers in from other plans             -          44,553,225
          Benefits paid to participants          (3,809,393)                  -
          Transfers to participant-directed
            investments                          (4,728,777)           (538,322)
                                                 ----------          -----------
     Net increase in net assets                   5,628,184          39,541,988
     Net assets, beginning of year               39,541,988                   -
                                                 ----------          -----------
     Net assets, end of year                   $ 45,170,172        $ 39,541,988
                                                 ==========          ===========

NOTE 5: PLAN TERMINATION

Although it has not  expressed  any intent to do so, UDS has the right under the
Plan to discontinue or reduce its contributions and to terminate the Plan at any
time subject to the provisions of ERISA.

NOTE 6: TAX STATUS

The Internal  Revenue  Service has determined and informed UDS by a letter dated
September  22, 1995,  that the Plan and related trust are designed in accordance
with  applicable  sections of the Internal  Revenue Code.  Although the Plan has
been amended since  receiving the  determination  letter,  UDS believes that the
Plan is  designed  and is  currently  being  operated  in  compliance  with  the
applicable requirements of the Internal Revenue Code.

NOTE 7: PARTY-IN-INTEREST TRANSACTIONS

Certain  Plan  investments  are shares of mutual  funds and a  collective  trust
managed  by an  affiliate  of the  Trustee  and  shares of common  stock of UDS.
Transactions in these investments qualify as party-in-interest transactions.

NOTE 8: RECONCILIATION OF FINANCIAL STATEMENTS TO FORM 5500

The following is a reconciliation  of net assets available for plan benefits per
the  financial  statements  to the Form 5500  Annual  Return/Report  of Employee
Benefit Plan:

The  following is a  reconciliation  of benefits  paid to  participants  per the
financial statements to the Form 5500:


                                                                       Years Ended December 31,
                                                                       2000                1999
                                                                       ----                ----
                                                                                  
Benefits paid to participants per the financial statements           $ 30,873,610       $ 17,534,700
    Add: Amounts allocated to withdrawing participants
    at end of year                                                          1,167            221,857
    Less: Amounts allocated to withdrawing participants
       at beginning of year                                              (221,857)        (1,151,538)
                                                                      -----------         ----------
Benefits paid to participants per the Form 5500                      $ 30,652,920       $ 16,605,019
                                                                       ==========         ==========

NOTE 9: NONEXEMPT TRANSACTIONS

For the year ended December 31, 2000, there were no nonexempt transactions.  For
the year ended December 31, 1999, UDS failed to remit participant  contributions
totaling  $971,756  to the Plan  within  the  required  period as  specified  by
applicable Department of Labor regulations. These late contributions resulted in
prohibited extensions of credit to UDS and represent nonexempt transactions. The
late  contributions plus interest of $5,503 were contributed to the Plan in July
2000.  In May  2001,  UDS  paid  interest  of  $8,838  for  late  remittance  of
contributions  for the years ended December 31, 1998 and 1997 as assessed by the
Department of Labor.

NOTE 10: SUBSEQUENT EVENT

On May 7, 2001, UDS announced that it had agreed to be acquired by Valero Energy
Corporation  for total  consideration  of  approximately  $4.0  billion plus the
assumption of all  outstanding  debt of  approximately  $2.0 billion.  Under the
terms of the agreement and plan of merger, shareholders of UDS common stock will
receive  1.228  shares  of Valero  common  stock  for  approximately  50% of the
outstanding  shares  of UDS  common  stock,  and $55 per  share  in cash for the
remaining  50%.  The merger has been  approved by the board of directors of both
companies;  however, closing of the transaction is subject to regulatory reviews
and the approval of the  shareholders of both companies.  The merger is expected
to close in the fourth quarter of 2001.

Valero Energy Corporation owns and operates six refineries in Texas,  Louisiana,
New Jersey and California with a combined  throughput  capacity of more than 1.0
million barrels per day.  Valero markets its gasoline,  diesel and other refined
products  in 34  states  through  a bulk  and rack  marketing  network  and,  in
California, through approximately 350 retail locations.

As noted above, the UDS board of directors approved the merger which constitutes
a change in control as defined by the Plan agreement.  At closing of the merger,
participants  will be 100%  vested  in their  account  balances  which  includes
company matching and discretionary contributions.

Shares of UDS common stock held under the Plan,  whether in the Ultramar Diamond
Shamrock  Corporation  Common  Stock  Fund,  the UDS ESOP1 Stock Fund or the UDS
ESOP2 Stock Fund, will not be subject to the proration of cash and Valero common
stock as described  above.  These shares will be  converted  into Valero  common
stock based on the exchange ratio.





                                   SCHEDULE I

                       UDS 401(k) RETIREMENT SAVINGS PLAN

                    Schedule of Assets (Held at End of Year)
                                December 31, 2000

                                                                                                              Current
      Identity of Issue                         Description of Investment                    Cost              Value

                                                                                                   
*  The Vanguard Group                 Vanguard 500 Index Fund                                     **        $  28,700,428
*  The Vanguard Group                 Vanguard Extended Market Index Fund                         **            1,267,441
*  The Vanguard Group                 Vanguard Federal Money Market Fund                          **            5,907,088
*  The Vanguard Group                 Vanguard International Growth Fund                          **            2,229,466
*  The Vanguard Group                 Vanguard International Value Fund                           **              990,897
*  The Vanguard Group                 Vanguard Long Term Corporate Fund                           **            1,546,359
*  The Vanguard Group                 Vanguard Long Term Treasury Fund                            **              440,727
*  The Vanguard Group                 Vanguard PRIMECAP Fund                                      **           57,159,426
*  The Vanguard Group                 Vanguard Total Bond Market Index Fund                       **            2,143,956
*  The Vanguard Group                 Vanguard U.S. Growth Fund                                   **           10,362,159
*  The Vanguard Group                 Vanguard Wellington Fund                                    **           29,783,466
*  The Vanguard Group                 Vanguard Windsor II Fund                                    **            7,798,735
   Credit Suisse                      Warburg Pincus Value Fund                                   **              150,066
*  The Vanguard Group                 Vanguard Retirement Savings Trust                           **           27,341,012

*  Ultramar Diamond                   Ultramar Diamond Shamrock Corporation
      Shamrock Corporation                ESOP1 Common Stock Fund                          $ 22,213,528        36,290,707

*  Ultramar Diamond                   Ultramar Diamond Shamrock Corporation
      Shamrock Corporation                ESOP2 Common Stock Fund                             6,209,366         8,879,465

*  Ultramar Diamond                   Ultramar Diamond Shamrock Corporation
      Shamrock Corporation             Common Stock Fund                                          **            8,712,974

*  UDS 401(k) Retirement              Participant loans --
      Savings Plan                      Interest rates range from 7% - 11.5%                      **            6,703,578

   Self-directed investments:
    Salomon Smith Barney Inc.         Smith Barney Money Funds                                    **                7,660
    Salomon Smith Barney Inc.         Smith Barney Appreciation Fund                              **               18,638
    Salomon Smith Barney Inc.         Government Backed Trust CL T-1                              **                8,770
    Salomon Smith Barney Inc.         Government Backed Trust CTF                                 **                7,821
    Salomon Smith Barney Inc.         Government Trust CTF CL 3-C-REG                             **                9,681
                                                                                                              -----------
                                                                                                            $ 236,460,520
                                                                                                              ===========

*    Parties-in-interest to the Plan.
** Historical cost information is omitted as it is  participant-directed  and is
   not required to be disclosed.






                                    SIGNATURE

The Plan.  Pursuant to the requirements of the Securities  Exchange Act of 1934,
the trustees (or other persons who  administer  the employee  benefit plan) have
duly  caused this  annual  report to be signed on its behalf by the  undersigned
hereunto duly authorized as of June 20, 2001.



UDS 401(k) Retirement Savings Plan

By:       /s/     Penelope Viteo
    ------------------------------------
     Penelope Viteo
     Member, Employee Benefits Committee and
     Vice President, Ultramar Diamond Shamrock Corporation








                                  Exhibit 23.1

                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS

As independent public accountants, we hereby consent to the incorporation of our
report  dated  June 20,  2001,  included  in this Form 11-K,  into the  Ultramar
Diamond Shamrock Corporation's  previously filed Registration Statement File No.
333-47322.

                                                          /s/ARTHUR ANDERSEN LLP


San Antonio, Texas
June 20, 2001