Page 1 of 14
                                 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 September 30, 1997

                                    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 14.



                      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 note thereto  for
the  year ended December 31, 1996 which are found in the Registrant's  Form
10-K  Report  for  1996 filed with the Securities and Exchange  Commission.
The December 31, 1996 balance sheet included herein has been taken from the
Registrant's  1996 Form 10-K Report.  Operating results for the  three  and
nine  month periods ended September 30, 1997 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

                                              September 30,   December 31,
                                                   1997           1996
                                              -------------   ------------
                                               (unaudited)
Assets

Current assets
 Cash and cash equivalents                     $    9,683          6,736
 Receivable from Managing General Partner          51,886         99,877
 Other receivable                                       -         14,850
- ---------                                      ---------
     Total current assets                          61,569        121,463
                                                ---------      ---------
Oil and gas properties - using the
 full cost method of accounting                 4,384,642      4,387,142
  Less accumulated depreciation,
   depletion and amortization                   3,827,000      3,789,000
                                                ---------      ---------
     Net oil and gas properties                   557,642        598,142
                                                ---------      ---------
                                               $  619,211        719,605
                                                =========      =========

Liabilities and Partners' Equity

Current liability - Distribution payable       $      234            142
                                                ---------      ---------
Partners' equity
 General partners                                 (5,556)            693
 Limited partners                                 624,533        718,770
                                                ---------      ---------
     Total partners' equity                       618,977        719,463
                                                ---------      ---------
                                               $  619,211        719,605
                                                =========      =========


          Southwest Royalties Institutional Income Fund X-A, L.P.
                                     
                         Statements of Operations
                                (unaudited)


                                Three Months Ended    Nine Months Ended
                                  September 30,         September 30,
                                  1997      1996        1997      1996

Revenues

Income from net profits
 interests                   $    55,603    76,023     190,940   262,487
Interest                             160       278         522       887
Miscellaneous                      6,003         -       7,653         -
                                  ------    ------     -------   -------
                                  61,766    76,301     199,115   263,374
                                  ------    ------     -------   -------
Expenses

General and administrative        22,622    22,832      75,601    76,254
Depreciation, depletion and
 amortization                     12,000    27,000      38,000    94,000
                                  ------    ------     -------   -------
                                  34,622    49,832     113,601   170,254
                                  ------    ------     -------   -------
Net income                   $    27,144    26,469      85,514    93,120
                                  ======    ======     =======   =======



Net income allocated to:

 Managing General Partner    $     3,523     4,812      11,116    16,841
                                  ======    ======     =======   =======
 General Partner             $       391       535       1,235     1,871
                                  ======    ======     =======   =======
 Limited Partners            $    23,230    21,122      73,163    74,408
                                  ======    ======     =======   =======
  Per limited partner unit   $      2.05      1.87        6.47      6.58
                                  ======    ======     =======   =======



          Southwest Royalties Institutional Income Fund X-A, L.P.
                                     
                         Statements of Cash Flows
                                (unaudited)


                                                      Nine Months Ended
                                                        September 30,
                                                       1997       1996
Cash flows from operating activities

 Cash received from income from net
  profits interests                                $  261,434    201,952
 Cash paid to suppliers                              (75,601)   (76,254)
 Interest received                                        522        887
                                                      -------    -------

  Net cash provided by operating activities           186,355    126,585
                                                      -------    -------
Cash flows provided by investing activities

 Cash received from sale of oil and gas
  property interest                                     2,500        791
                                                      -------    -------
Cash flows used in financing activities

 Distributions to partners                          (185,908)  (152,886)
                                                      -------    -------
Net increase (decrease) in cash and cash
 equivalents                                            2,947   (25,510)

 Beginning of period                                    6,736     46,452
                                                      -------    -------
 End of period                                     $    9,683     20,942
=======                                            =======

                                                             (continued)


          Southwest Royalties Institutional Income Fund X-A, L.P.
                                     
                    Statements of Cash Flows, continued
                                (unaudited)


                                                      Nine Months Ended
                                                        September 30,
                                                       1997       1996
Reconciliation of net income to net cash
 provided by operating activities

Net income                                         $   85,514     93,120

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

 Depreciation, depletion and amortization              38,000     94,000
 (Increase) decrease in receivables                    62,841   (60,535)
                                                    ---------    -------
Net cash provided by operating activities          $  186,355    126,585
                                                    =========    =======




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 farmout 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 participating  in  a
farmout  agreement and performing workovers during the next  two  years  to
enhance production.  The Partnership may undergo an increase later in  1997
and   possibly  in  1998.   Thereafter,  the  Partnership  could   possibly
experience a normal decline of 8% to 10% per year.




Results of Operations

A.  General Comparison of the Quarters Ended September 30, 1997 and 1996

The  following  table  provides certain information  regarding  performance
factors for the quarters ended September 30, 1997 and 1996:

                                                 Three Months
                                                    Ended        Percentage
                                                September 30,     Increase
                                                1997      1996   (Decrease)

Average price per barrel of oil            $   17.42     20.97    (17%)
Average price per mcf of gas               $    2.36      2.09      13%
Oil production in barrels                      6,800     8,500    (20%)
Gas production in mcf                         11,900    12,000     (1%)
Income from net profits interests          $  55,603    76,023    (27%)
Partnership distributions                  $  49,000    63,000    (22%)
Limited partner distributions              $  44,100    56,700    (22%)
Per unit distribution to limited partners  $    3.90      5.01    (22%)
Number of limited partner units               11,316    11,316

Revenues

The  Partnership's income from net profits interests decreased  to  $55,603
from   $76,023  for  the  quarters  ended  September  30,  1997  and  1996,
respectively,  a  decrease  of 27%.  The principal  factors  affecting  the
comparison  of  the  quarters ended September 30,  1997  and  1996  are  as
follows:

1.   The  average  price  for a barrel of oil received by  the  Partnership
     decreased  during the quarter ended September 30, 1997 as compared  to
     the  quarter  ended  September 30, 1996 by 17%, or $3.55  per  barrel,
     resulting  in a decrease of approximately $30,200 in income  from  net
     profits  interests.  Oil sales represented 81% of total  oil  and  gas
     sales  during the quarter ended September 30, 1997 as compared to  88%
     during the quarter ended September 30, 1996.

     The  average  price  for  an mcf of gas received  by  the  Partnership
     increased during the same period by 13%, or $.27 per mcf, resulting in
     an  increase  of  approximately $3,200  in  income  from  net  profits
     interests.

     The net total decrease in income from net profits interests due to the
     change in prices received from oil and gas production is approximately
     $27,000.  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 1,700 barrels or 20% during the
    quarter  ended  September 30, 1997 as compared  to  the  quarter  ended
    September 30, 1996, resulting in a decrease of approximately $29,600 in
    income from net profits interests.

    Gas  production decreased approximately 100 mcf or 1% during  the  same
    period,  resulting in a decrease of approximately $200 in  income  from
    net profits interests.

    The  total  decrease in income from net profits interests  due  to  the
    change  in  production is approximately $29,800.  The decrease  in  oil
    production  is  primarily  attributable to a farm-out  agreement  which
    lowered  the Partnership's interest in the Ballard Grayburg San  Andres
    Unit.

3.  Lease  operating  costs  and  production  taxes  were  28%  lower,   or
    approximately $35,900 less during the quarter ended September 30,  1997
    as  compared to the quarter ended September 30, 1996.  The decrease  is
    primarily  attributable  to  a  farm-out agreement  which  lowered  the
    Partnership's interest in the Ballard Grayburg San Andres Unit.


Costs and Expenses

Total costs and expenses decreased to $34,622 from $49,832 for the quarters
ended  September 30, 1997 and 1996, respectively, a decrease of  31%.   The
decrease  is  the  result of lower general and administrative  expense  and
depletion 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 $200 during the quarter ended September 30,  1997  as
    compared to the quarter ended September 30, 1996.

2.  Depletion  expense decreased to $12,000 for the quarter ended September
    30,  1997 from $27,000 for the same period in 1996.  This represents  a
    decrease  of 56%.  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.  Two contributing
    factors  to  the  decline in depletion expense between the  comparative
    periods  were  the increase in the price of oil used to  determine  the
    Partnership's reserves for January 1, 1997 as compared to 1996 and  the
    decline in gross oil and gas revenues.



















B.  General Comparison of the Nine Month Periods Ended September 30, 1997
and 1996

The  following  table  provides certain information  regarding  performance
factors for the nine month periods ended September 30, 1997 and 1996:

                                                 Nine Months
                                                    Ended        Percentage
                                                September 30,     Increase
                                                1997      1996   (Decrease)

Average price per barrel of oil            $   18.24     19.02     (4%)
Average price per mcf of gas               $    2.54      2.33       9%
Oil production in barrels                     21,500    31,700    (32%)
Gas production in mcf                         36,900    38,200     (3%)
Income from net profits interests          $ 190,940   262,487    (27%)
Partnership distributions                  $ 186,000   153,000      22%
Limited partner distributions              $ 167,400   137,700      22%
Per unit distribution to limited partners  $   14.79     12.17      22%
Number of limited partner units               11,316    11,316

Revenues

The  Partnership's income from net profits interests decreased to  $190,940
from  $262,487  for  the nine months ended September  30,  1997  and  1996,
respectively,  a  decrease  of 27%.  The principal  factors  affecting  the
comparison  of  the nine months ended September 30, 1997 and  1996  are  as
follows:

1.  The  average  price  for a barrel of oil received  by  the  Partnership
    decreased  during the nine months ended September 30, 1997 as  compared
    to  the nine months ended September 30, 1996 by 4%, or $.78 per barrel,
    resulting  in  a decrease of approximately $24,700 in income  from  net
    profits  interests.  Oil sales represented 81% of  total  oil  and  gas
    sales  during the nine months ended September 30, 1997 as  compared  to
    87% during the nine months ended September 30, 1996.

    The  average  price  for  an  mcf of gas received  by  the  Partnership
    increased  during the same period by 9%, or $.21 per mcf, resulting  in
    an  increase  of  approximately  $8,000  in  income  from  net  profits
    interests.

    The  net total decrease in income from net profits interests due to the
    change  in prices received from oil and gas production is approximately
    $16,700.   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 10,200 barrels or 32% during the
    nine  months  ended September 30, 1997 as compared to the  nine  months
    ended  September  30,  1996, resulting in a decrease  of  approximately
    $186,000 in income from net profits interests.

    Gas  production decreased approximately 1,300 mcf or 3% during the same
    period, resulting in a decrease of approximately $3,300 in income  from
    net profits interests.

    The  total  decrease in income from net profits interests  due  to  the
    change  in  production  is  approximately $189,300.   The  decrease  is
    primarily attributable to eleven months of revenue, on one lease, being
    held in suspense during litigation between a third party operator,  the
    lease's  pumper and the Managing General Partner.  Upon  conclusion  of
    the  litigation, all revenues, approximately 5,900 barrels of oil, were
    released  during the first quarter of 1996.  Also contributing  to  the
    decline  is  a  farm-out  agreement, which  lowered  the  Partnership's
    interest in the Ballard Grayburg San Andres Unit.

3.  Lease  operating  costs  and  production  taxes  were  31%  lower,   or
    approximately $133,700 less during the nine months ended September  30,
    1997  as  compared to the nine months ended September  30,  1996.   The
    decrease   is  primarily  attributable  to  the  litigation  costs   of
    approximately $56,000 incurred during the first quarter of 1996  and  a
    farm-out  agreement, which lowered the Partnership's  interest  in  the
    Ballard Grayburg San Andres Unit.

Costs and Expenses

Total  costs and expenses decreased to $113,601 from $170,254 for the  nine
months ended September 30, 1997 and 1996, respectively, a decrease of  33%.
The  decrease is the result of lower general and administrative expense and
depletion 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 $700 during the nine months ended September 30,  1997
    as compared to the nine months ended September 30, 1996.

2.  Depletion  expense  decreased to $38,000  for  the  nine  months  ended
    September  30,  1997 from $94,000 for the same period  in  1996.   This
    represents a decrease of 60%.  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.   Two
    contributing  factors to the decline in depletion expense  between  the
    comparative  periods  were the increase in the price  of  oil  used  to
    determine the Partnership's reserves for January 1, 1997 as compared to
    1996 and the decline in gross oil and gas revenues.



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, nor does it anticipate any such change.

Cash flows provided by operating activities were approximately $186,400  in
the  nine  months  ended  September 30, 1997 as compared  to  approximately
$126,600  in the nine months ended September 30, 1996.  The primary  source
of the 1997 cash flow from operating activities was profitable operations.

Cash  flows provided by investing activities were approximately  $2,500  in
the  nine months ended September 30, 1997 as compared to approximately $800
in  the nine months ended September 30, 1996.  The principle source of  the
1997  cash  flow from investing activities was the change in  oil  and  gas
properties.

Cash flows used in financing activities were approximately $185,900 in  the
nine  months ended September 30, 1997 as compared to approximately $152,900
in  the  nine  months ended September 30, 1996.  The only use in  financing
activities was the distributions to partners.

Total  distributions during the nine months ended September 30,  1997  were
$186,000  of  which  $167,400 was distributed to the limited  partners  and
$18,600  to  the  general partners.  The per unit distribution  to  limited
partners during the nine months ended September 30, 1997 was $14.79.  Total
distributions during the nine months ended September 30, 1996 were $153,000
of  which  $137,700 was distributed to the limited partners and $15,300  to
the general partners.  The per unit distribution to limited partners during
the nine months ended September 30, 1996 was $12.17.

The  sources  for  the  1997 distributions of $186,000  were  oil  and  gas
operations  of  approximately  $186,400 and  the  change  in  oil  and  gas
properties   of  approximately  $2,500,  resulting  in  excess   cash   for
contingencies  or  subsequent distributions.   The  sources  for  the  1996
distributions  of  $153,000  were oil and gas operations  of  approximately
$126,600,  and the change in oil and gas properties of approximately  $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  $2,939,122 have been made to the partners.  As of September  30,  1997,
$2,693,561 or $238.03 per limited partner unit has been distributed to  the
limited partners, representing a 48% return of the capital contributed.

As  of  September  30, 1997, the Partnership had approximately  $61,300  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.



                        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)Exhibits:

             27 Financial Data Schedule

         (b) 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:     November 15, 1997