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                                FORM 10-Q



                    SECURITIES AND EXCHANGE COMMISSION
                         WASHINGTON, D.C.  20549

(Mark One)

(X)  QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d)
     OF THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended March 31, 2001

                                    OR

( )  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d)
     OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from ________________ to ________________

Commission file number 0-18997

         SOUTHWEST ROYALTIES INSTITUTIONAL 1990-91 INCOME PROGRAM
         Southwest Royalties Institutional Income Fund X-A, L.P.
                  (Exact name of registrant as specified
                  in its limited partnership agreement)

Delaware                                75-2310852
(State or other jurisdiction of                (I.R.S. Employer
incorporation or organization)                Identification No.)


                       407 N. Big Spring, Suite 300
                           Midland, Texas 79701
                 (Address of principal executive offices)

                              (915) 686-9927
                      (Registrant's telephone number,
                           including area code)

Indicate  by  check  mark  whether registrant (1)  has  filed  all  reports
required to be filed by Section 13 or 15(d) of the Securities Exchange  Act
of 1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject  to
such filing requirements for the past 90 days:

                            Yes   X   No

        The total number of pages contained in this report is 13.


                     PART I. - FINANCIAL INFORMATION


Item 1.   Financial Statements

The  unaudited  condensed financial statements included  herein  have  been
prepared  by  the Registrant (herein also referred to as the "Partnership")
in  accordance  with generally accepted accounting principles  for  interim
financial information and with the instructions to Form 10-Q and Rule 10-01
of Regulation S-X.  Accordingly, they do not include all of the information
and  footnotes  required  by generally accepted accounting  principles  for
complete   financial  statements.   In  the  opinion  of  management,   all
adjustments necessary for a fair presentation have been included and are of
a  normal  recurring nature.  The financial statements should  be  read  in
conjunction with the audited financial statements and the notes thereto for
the  year ended December 31, 2000 which are found in the Registrant's  Form
10-K  Report  for  2000 filed with the Securities and Exchange  Commission.
The December 31, 2000 balance sheet included herein has been taken from the
Registrant's 2000 Form 10-K Report.  Operating results for the three  month
period  ended March 31, 2001 are not necessarily indicative of the  results
that may be expected for the full year.


         Southwest Royalties Institutional Income Fund X-A, L.P.

                              Balance Sheets


                                                  March 31,     December 31,
                                                     2001           2000
                                                  ---------     ------------
                                                 (unaudited)

  Assets

Current assets:
 Cash and cash equivalents                    $     42,036         61,502
 Receivable from Managing General
  Partner                                           71,103         84,202
                                                 ---------      ---------
    Total current assets                           113,139        145,704
                                                 ---------      ---------
Oil and gas properties - using the
 full-cost method of accounting                  4,239,490      4,239,490
  Less accumulated depreciation,
   depletion and amortization                    4,063,143      4,058,143
                                                 ---------      ---------
    Net oil and gas properties                     176,347        181,347
                                                 ---------      ---------
                                              $    289,486        327,051
                                                 =========      =========
  Liabilities and Partners' Equity

Current liability - Distributions payable     $        312            119
                                                 ---------      ---------
Partners' equity:
 General partners                                  (5,471)        (2,195)
 Limited partners                                  294,645        329,127
                                                 ---------      ---------
    Total partners' equity                         289,174        326,932
                                                 ---------      ---------
                                              $    289,486        327,051
                                                 =========      =========


         Southwest Royalties Institutional Income Fund X-A, L.P.

                         Statements of Operations
                               (unaudited)


                                                        Three Months Ended
                                                            March 31,
                                                          2001      2000
                                                          ----      ----
    Revenues

Income from net profits interests                   $    90,847     67,609
Interest                                                    189         45
                                                        -------    -------
                                                         91,036     67,654
                                                        -------    -------
    Expenses

General and administrative                               23,794     24,064
Depreciation, depletion and amortization                  5,000      4,000
                                                        -------    -------
                                                         28,794     28,064
                                                        -------    -------
Net income                                          $    62,242     39,590
                                                        =======    =======
Net income allocated to:

 Managing General Partner                           $     6,052      3,923
                                                        =======    =======
 General partner                                    $       672        436
                                                        =======    =======
 Limited partners                                   $    55,518     35,231
                                                        =======    =======
  Per limited partner unit                          $      4.91      3.11
                                                        =======    =======


         Southwest Royalties Institutional Income Fund X-A, L.P.

                         Statements of Cash Flows
                               (unaudited)


                                                        Three Months Ended
                                                            March 31,
                                                          2001      2000
                                                          ----      ----
Cash flows from operating activities:

 Cash received from net profits interests           $   103,203     55,993
 Cash paid to suppliers                                (23,051)   (20,263)
 Interest received                                          189         45
                                                       --------    -------
  Net cash provided by operating activities              80,341     35,775
                                                       --------    -------
Cash flows used in investing activities

 Addition of oil and gas properties                           -        (5)
                                                       --------    -------
Cash flows used in financing activities:

 Distributions to partners                             (99,807)   (50,288)
                                                       --------    -------
Net decrease in cash and cash equivalents              (19,466)   (14,518)

 Beginning of period                                     61,502     32,212
                                                       --------    -------
 End of period                                      $    42,036     17,694
                                                       ========    =======

                                                               (continued)


         Southwest Royalties Institutional Income Fund X-A, L.P.

                   Statements of Cash Flows, continued
                               (unaudited)


                                                        Three Months Ended
                                                            March 31,
                                                          2001      2000
                                                          ----      ----

Reconciliation of net income to net cash
  provided by operating activities:

Net income                                          $    62,242     39,590

Adjustments to reconcile net income to net
 cash provided by operating activities:

  Depreciation, depletion and amortization                5,000      4,000
  Decrease (increase) in receivables                     12,356   (11,616)
  Increase in payables                                      743      3,801
                                                        -------    -------
Net cash provided by operating activities           $    80,341     35,775
                                                        =======    =======


         Southwest Royalties Institutional Income Fund X-A, L.P.
                     (a Delaware limited partnership)

                      Notes to Financial Statements


1.   Organization
     Southwest  Royalties Institutional Income Fund X-A, L.P. was organized
     under  the laws of the state of Delaware on January 29, 1990, for  the
     purpose  of acquiring producing oil and gas properties and to  produce
     and market crude oil and natural gas produced from such properties for
     a  term  of 50 years, unless terminated at an earlier date as provided
     for  in the Partnership Agreement.  The Partnership sells its oil  and
     gas  production to a variety of purchasers with the prices it receives
     being  dependent  upon the oil and gas economy.  Southwest  Royalties,
     Inc. serves as the Managing General Partner and H. H. Wommack, III, as
     the  individual  general partner.  Revenues, costs  and  expenses  are
     allocated as follows:

                                                     Limited      General
                                                     Partners     Partners
                                                     --------     --------

     Interest income on capital contributions        100%            -
     Oil and gas sales                                90%           10%
     All other revenues                               90%           10%
     Organization and offering costs (1)             100%            -
     Amortization of organization costs              100%            -
     Property acquisition costs                      100%            -
     Gain/loss on property disposition                90%           10%
     Operating and administrative costs (2)           90%           10%
     Depreciation, depletion and amortization
      of oil and gas properties                      100%            -
     All other costs                                  90%           10%

          (1)   All  organization costs in excess of 3% of initial  capital
          contributions  will be paid by the Managing General  Partner  and
          will  be treated as a capital contribution.  The Partnership paid
          the  Managing  General Partner an amount equal to 3%  of  initial
          capital contributions for such organization costs.

          (2)   Administrative costs in any year which exceed 2% of capital
          contributions shall be paid by the Managing General  Partner  and
          will be treated as a capital contribution.

2.   Summary of Significant Accounting Policies
     The  interim financial information as of March 31, 2001, and  for  the
     three  months ended March 31, 2001, is unaudited.  Certain information
     and  footnote  disclosures normally included in  financial  statements
     prepared  in accordance with generally accepted accounting  principles
     have been condensed or omitted in this Form 10-Q pursuant to the rules
     and  regulations of the Securities and Exchange Commission.   However,
     in  the  opinion  of  management, these interim  financial  statements
     include all the necessary adjustments to fairly present the results of
     the interim periods and all such adjustments are of a normal recurring
     nature.  The interim consolidated financial statements should be  read
     in  conjunction  with the audited financial statements  for  the  year
     ended December 31, 2000.


Item 2.   Management's  Discussion and Analysis of Financial Condition  and
          Results of Operations

General

Southwest Royalties Institutional Income Fund X-A, L.P. was organized as  a
Delaware  limited  partnership on January 29, 1990. The  offering  of  such
limited  partnership  interests began May 11,  1990  as  part  of  a  shelf
offering registered under the name Southwest Royalties Institutional  1990-
91  Income Program.  Minimum capital requirements for the Partnership  were
met  on  July 30, 1990, with the offering of limited partnership  interests
concluding  on  November 30, 1990, with total limited partner contributions
of $5,658,000.

The Partnership was formed to acquire royalty and net profits interests  in
producing  oil  and  gas properties, to produce and market  crude  oil  and
natural  gas  produced  from such properties, and  to  distribute  the  net
proceeds from operations to the limited and general partners.  Net revenues
from  producing  oil  and gas properties will not be  reinvested  in  other
revenue  producing  assets except to the extent that production  facilities
and wells are improved or reworked or where methods are employed to improve
or enable more efficient recovery of oil and gas reserves.

Increases   or   decreases   in  Partnership   revenues   and,   therefore,
distributions  to partners will depend primarily on changes in  the  prices
received  for  production,  changes in volumes of  production  sold,  lease
operating  expenses, enhanced recovery projects, offset drilling activities
pursuant  to farm-out arrangements, sales of properties, and the  depletion
of  wells.   Since  wells deplete over time, production  can  generally  be
expected to decline from year to year.

Well  operating costs and general and administrative costs usually decrease
with   production   declines;  however,  these  costs  may   not   decrease
proportionately.  Net income available for distribution to the partners  is
therefore expected to fluctuate in later years based on these factors.

Based on current conditions, management anticipates performing a few
workovers during 2001 to enhance production.  The partnership may have an
increase in production volumes for the year 2001, otherwise, the
partnership will most likely experience the historical production decline
of approximately 7% per year.

Oil and Gas Properties

Oil  and  gas  properties  are accounted for at cost  under  the  full-cost
method.  Under this method, all productive and nonproductive costs incurred
in  connection with the acquisition, exploration and development of oil and
gas  reserves  are capitalized.  Gain or loss on the sale of  oil  and  gas
properties  is not recognized unless significant oil and gas  reserves  are
involved.

The  Partnership's policy for depreciation, depletion and  amortization  of
oil  and  gas  properties is computed under the units  of  revenue  method.
Under the units of revenue method, depreciation, depletion and amortization
is  computed  on  the  basis of current gross revenues from  production  in
relation  to future gross revenues, based on current prices, from estimated
production of proved oil and gas reserves.

Should the net capitalized costs exceed the estimated present value of  oil
and gas reserves, discounted at 10%, such excess costs would be charged  to
current  expense.  As of March 31, 2001, the net capitalized costs did  not
exceed the estimated present value of oil and gas reserves.


Results of Operations

A.  General Comparison of the Quarters Ended March 31, 2001 and 2000

The  following  table  provides certain information  regarding  performance
factors for the quarters ended March 31, 2001 and 2000:

                                               Three Months
                                                  Ended         Percentage
                                                         March          31,
Increase
                                              2001      2000    (Decrease)
                                              ----      ----    ----------
Average price per barrel of oil           $   27.18     27.18        -
Average price per mcf of gas              $    7.82      3.09     153%
Oil production in barrels                     3,800     3,900     (3%)
Gas production in mcf                         8,900     7,300      22%
Income from net profits interests         $  90,847    67,609      34%
Partnership distributions                 $ 100,000    49,989     100%
Limited partner distributions             $  90,000    49,989      80%
Per unit distribution to limited
 partners                                 $    7.95      4.42      80%
Number of limited partner units              11,316    11,316

Revenues

The  Partnership's income from net profits interests increased  to  $90,847
from  $67,609 for the quarters ended March 31, 2001 and 2000, respectively,
an  increase of 34%.  The principal factors affecting the comparison of the
quarters ended March 31, 2001 and 2000 are as follows:

1.  The  average  price  for a barrel of oil received  by  the  Partnership
    remained  unchanged during the quarter ended March 31, 2001 as compared
    to  the  quarter  ended March 31, 2000.  Oil sales represented  60%  of
    total  oil  and gas sales during the quarter ended March  31,  2001  as
    compared to 82% during the quarter ended March 31, 2000.

    The  average  price  for  an  mcf of gas received  by  the  Partnership
    increased  during the same period by 153%, or $4.73 per mcf,  resulting
    in  an  increase  of approximately $42,100 in income from  net  profits
    interests.

    The  total  increase in income from net profits interests  due  to  the
    change  in prices received from oil and gas production is approximately
    $42,100.   The market price for oil and gas has been extremely volatile
    over  the  past  decade, and management expects  a  certain  amount  of
    volatility to continue in the foreseeable future.


2.  Oil  production decreased approximately 100 barrels or  3%  during  the
    quarter ended March 31, 2001 as compared to the quarter ended March 31,
    2000,  resulting in a decrease of approximately $2,700 in  income  from
    net profits interests.

    Gas production increased approximately 1,600 mcf or 22% during the same
    period, resulting in an increase of approximately $4,900 in revenues.

    The  net total increase in income from net profit interests due to  the
    change  in  production is approximately $2,200.  The  increase  in  gas
    production  is due to successful workovers in 2000 on one  non-operated
    lease.

3.  Lease  operating  costs  and  production  taxes  were  35%  higher,  or
    approximately $21,100 more during the quarter ended March 31,  2001  as
    compared  to the quarter ended March 31, 2000.  The increase  in  lease
    operating  expense is due to acoustical testing, maintenance and  other
    repairs  being performed in 2001, and the increase in production  taxes
    in relation to the increase in gross revenues received in 2001.

Costs and Expenses

Total costs and expenses increased to $28,794 from $28,064 for the quarters
ended  March  31,  2001 and 2000, respectively, an  increase  of  3%.   The
increase is the result of higher depletion expense, partially offset  by  a
decrease in general and administrative expense.

1.  General and administrative costs consists of independent accounting and
    engineering  fees,  computer services, postage,  and  Managing  General
    Partner personnel costs.  General and administrative costs decreased 1%
    or  approximately  $300  during the quarter ended  March  31,  2001  as
    compared to the quarter ended March 31, 2000.

2.  Depletion  expense increased to $5,000 for the quarter ended March  31,
    2001  from  $4,000  for the same period in 2000.   This  represents  an
    increase  of 25%.  Depletion is calculated using the units  of  revenue
    method  of  amortization based on a percentage of current period  gross
    revenues  to  total future gross oil and gas revenues, as estimated  by
    the  Partnership's independent petroleum consultants.  The contributing
    factors  to  the increase of depletion expense between the  comparative
    periods  were the increase in oil and gas revenue and the  increase  in
    the price of gas used to determine the Partnership's reserves.

Liquidity and Capital Resources

The  primary source of cash is from operations, the receipt of income  from
interests in oil and gas properties.  The Partnership knows of no  material
change,  other than the ones noted above, nor does it anticipate  any  such
change.

Cash  flows provided by operating activities were approximately $80,300  in
the  quarter ended March 31, 2001 as compared to approximately  $35,800  in
the quarter ended March 31, 2000.  The primary source of the 2001 cash flow
from operating activities was operations.

There  were no cash flows used in investing activities in the quarter ended
March 31, 2001.
Cash  flows  used  in investing activities were $(5) in the  quarter  ended
March 31, 2000.

Cash  flows used in financing activities were approximately $99,800 in  the
quarter  ended March 31, 2001 as compared to approximately $50,300  in  the
quarter ended March 31, 2000.  The only use in financing activities was the
distributions to partners.

Total  distributions during the quarter ended March 31, 2001 were  $100,000
of which $90,000 was distributed to the limited partners and $10,000 to the
general partner.  The per unit distribution to limited partners during  the
quarter  ended  March 31, 2001 was $7.95.  Total distributions  during  the
quarter  ended March 31, 2000 were $49,989 of which $49,989 was distributed
to  the  limited  partners.  The per unit distribution to limited  partners
during the quarter ended March 31, 2000 was $4.42.

The  primary source for the 2001 distributions of $100,000 was oil and  gas
operations  of approximately $80,300, with the balance from available  cash
on  hand  at the beginning of the period.  The primary source for the  2000
distributions  of  $49,989  was  oil and gas  operations  of  approximately
$35,800,  with the balance from available cash on hand at the beginning  of
the period.

Since  inception of the Partnership, cumulative monthly cash  distributions
of  $3,288,444  have  been made to the partners.  As  of  March  31,  2001,
$3,017,401 or $266.65 per limited partner unit has been distributed to  the
limited partners, representing a 53% return of the capital contributed.

As of March 31, 2001, the Partnership had approximately $112,800 in working
capital.   The  Managing  General Partner knows of no  unusual  contractual
commitments  and  believes  the  revenues  generated  from  operations  are
adequate to meet the needs of the Partnership.

Item 3.   Quantitative and Qualitative Disclosures About Market Risk

The  Partnership  is  not a party to any derivative or embedded  derivative
instruments.


                       PART II. - OTHER INFORMATION


Item 1.   Legal Proceedings

          None

Item 2.   Changes in Securities

          None

Item 3.   Defaults Upon Senior Securities

          None

Item 4.   Submission of Matter to a Vote of Security Holders

          None

Item 5.   Other Information

          None

Item 6.   Exhibits and Reports on Form 8-K

               (a)  Reports on Form 8-K:

                     No  reports on Form 8-K were filed during the  quarter
               for which this report is filed.


                                SIGNATURES


Pursuant  to the requirements of the Securities Exchange Act of  1934,  the
registrant  has duly caused this report to be signed on its behalf  by  the
undersigned thereunto duly authorized.


                              SOUTHWEST ROYALTIES INSTITUTIONAL
                              INCOME FUND X-A, L.P.
                              a Delaware limited partnership


                              By:  Southwest Royalties, Inc.
                                   Managing General Partner


                              By:  /s/ Bill E. Coggin
                                   ------------------------------
                                   Bill E. Coggin, Vice President
                                   and Chief Financial Officer



Date:  May 15, 2001