Page 14 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, 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 0-20298

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

Delaware                                          75-2374449
(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.

<PAGE>

                      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, 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  and
nine  month periods ended September 30, 2001 are not necessarily indicative
of the results that may be expected for the full year.

<PAGE>

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

                              Balance Sheets

                                              September 30,   December 31,
                                                   2001           2000
                                              -------------   ------------
                                               (unaudited)
Assets
------
Current assets:
 Cash and cash equivalents                    $     20,226         87,960
 Receivable from Managing General Partner           50,891        111,036
                                                 ---------      ---------
    Total current assets                            71,117        198,996
                                                 ---------      ---------
Oil and gas properties - using the
 full-cost method of accounting                  2,221,662      2,221,662
  Less accumulated depreciation,
   depletion and amortization                    2,045,479      1,960,479
                                                 ---------      ---------
    Net oil and gas properties                     176,183        261,183
                                                 ---------      ---------
                                              $    247,300        460,179
                                                 =========      =========

Liabilities and Partners' Equity
--------------------------------
Partners' equity:
 General partners                             $   (24,937)       (12,149)
 Limited partners                                  272,237        472,328
                                                 ---------      ---------
    Total partners' equity                         247,300        460,179
                                                 ---------      ---------
                                              $    247,300        460,179
                                                 =========      =========

<PAGE>

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

                         Statements of Operations
                                (unaudited)


                                Three Months Ended    Nine Months Ended
                                  September 30,         September 30,
                                  2001      2000        2001      2000
                                  ----      ----        ----      ----
Revenues
--------
Income from net
 profits interests           $    39,868   112,639     209,750   273,888
Interest                             538     1,014       2,585     2,168
                                 -------   -------     -------   -------
                                  40,406   113,653     212,335   276,056
                                 -------   -------     -------   -------
Expenses
--------
General and administrative        10,225    10,265      30,214    30,858
Depreciation, depletion and
 amortization                     49,000    10,000      85,000    25,000
                                 -------   -------     -------   -------
                                  59,225    20,265     115,214    55,858
                                 -------   -------     -------   -------
Net income (loss)            $  (18,819)    93,388      97,121   220,198
                                 =======   =======     =======   =======

Net income (loss) allocated to:

 Managing General Partner    $     2,716     9,305      16,391    22,068
                                 =======   =======     =======   =======
 General Partner             $       302     1,034       1,821     2,452
                                 =======   =======     =======   =======
 Limited Partners            $  (21,837)    83,049      78,909   195,678
                                 =======   =======     =======   =======
  Per limited partner unit   $    (3.65)     13.88       13.19     32.71
                                 =======   =======     =======   =======

<PAGE>

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

                         Statements of Cash Flows
                                (unaudited)


                                                      Nine Months Ended
                                                        September 30,
                                                       2001       2000
                                                       ----       ----
Cash flows from operating activities

 Cash received from income from net
  profits interests                                $  268,812    264,570
 Cash paid to suppliers                              (29,131)   (18,235)
 Interest received                                      2,585      2,168
                                                      -------    -------
  Net cash provided by operating activities           242,266    248,503
                                                      -------    -------
Cash flow used in investing activities

 Additions to oil and gas properties                        -        (5)
                                                      -------    -------
Cash flows used in financing activities

 Distributions to partners                          (310,000)  (190,002)
                                                      -------    -------
Net (decrease) increase in cash and cash equivalents            (67,734)
58,496

 Beginning of period                                   87,960     22,098
                                                      -------    -------
 End of period                                     $   20,226     80,594
                                                      =======    =======
Reconciliation of net income to net
 cash provided by operating activities

Net income                                         $   97,121    220,198

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

 Depreciation, depletion and amortization              85,000     25,000
 Decrease (increase) receivables                       59,060    (9,318)
 Increase in payables                                   1,085     12,623
                                                      -------    -------
Net cash provided by operating activities          $  242,266    248,503
                                                      =======    =======


<PAGE>

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

                      Notes to Financial Statements


1.   Organization
     Southwest  Royalties Institutional Income Fund X-C, L.P. was organized
     under the laws of the state of Delaware on September 20, 1991, 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 several 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%             -
     Syndication costs                              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 September 30, 2001,  and  for
     the  three  and  nine months ended September 30, 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.

<PAGE>

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

General
Southwest Royalties Institutional Income Fund X-C, L.P. was organized as  a
Delaware limited partnership on September 20, 1991.  The offering  of  such
limited  partnership interests began October 1, 1991 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 January 28, 1992, with the offering of limited partnership interests
concluding April 30, 1992, with 340 limited partners purchasing 5,983 units
for $2,991,500.

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 does not  anticipate  performing
workovers  during the next twelve months.  The Partnership  could  possibly
experience a normal decline of 8% 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 September 30, 2001, the net capitalized costs  did
not exceed the estimated present value of oil and gas reserves.

<PAGE>
Results of Operations

A.  General Comparison of the Quarters Ended September 30, 2001 and 2000

The  following  table  provides certain information  regarding  performance
factors for the quarters ended September 30, 2001 and 2000:

                                                 Three Months
                                                    Ended        Percentage
                                                September 30,     Increase
                                                2001      2000   (Decrease)
                                                ----      ----   ---------
Average price per barrel of oil            $   21.85     29.16    (25%)
Average price per mcf of gas               $    2.09      4.25    (51%)
Oil production in barrels                      7,300     7,600     (4%)
Gas production in mcf                         11,200     9,100      23%
Income from net profits interests          $  39,868   112,639    (65%)
Partnership distributions                  $  90,000    80,000      13%
Limited partner distributions              $  81,000    72,000      13%
Per unit distribution to limited partners  $   13.54     12.03      13%
Number of limited partner units                5,983     5,983

Revenues

The  Partnership's income from net profits interests decreased  to  $39,868
from  $112,639  for  the  quarters  ended  September  30,  2001  and  2000,
respectively,  a  decrease  of 65%.  The principal  factors  affecting  the
comparison  of  the  quarters ended September 30,  2001  and  2000  are  as
follows:

1.   The  average  price  for a barrel of oil received by  the  Partnership
     decreased  during the quarter ended September 30, 2001 as compared  to
     the  quarter  ended  September 30, 2000 by 25%, or $7.31  per  barrel,
     resulting  in a decrease of approximately $53,400 in income  from  net
     profits  interests.  Oil sales represented 87% of total  oil  and  gas
     sales  during the quarter ended September 30, 2001 as compared to  85%
     during the quarter ended September 30, 2000.

     The  average  price  for  an mcf of gas received  by  the  Partnership
     decreased  during the same period by 51%, or $2.16 per mcf,  resulting
     in  a  decrease  of approximately $24,200 in income from  net  profits
     interests.

     The  total  decrease in income from net profits interests due  to  the
     change in prices received from oil and gas production is approximately
     $77,600.  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.

<PAGE>

2. Oil  production  decreased approximately 300 barrels or  4%  during  the
   quarter  ended  September  30, 2001 as compared  to  the  quarter  ended
   September  30, 2000, resulting in a decrease of approximately $8,700  in
   income from net profits interests.

    Gas production increased approximately 2,100 mcf or 23% during the same
    period, resulting in an increase of approximately $8,900 in income from
    net profits interests.

    The  net total increase in income from net profits interests due to the
    change  in  production  is approximately $200.   The  increase  in  gas
    production  is  in  relation  to an unsuccessful  workover,  which  was
    performed on a non-operated lease during 2000.  The workover caused the
    well  to shut down and was determined to be unrecoverable.  During  the
    nine months ended September 30, 2001, a new well on the same lease  was
    brought  on  line  and  has proven successful  in  replacing  the  lost
    production of the old well.

3.  Lease   operating  costs  and  production  taxes  were  3%  lower,   or
    approximately $4,300 less during the quarter ended September  30,  2001
    as compared to the quarter ended September 30, 2000.

Costs and Expenses

Total costs and expenses increased to $59,225 from $20,265 for the quarters
ended September 30, 2001 and 2000, respectively, an increase of 192%.   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
    less  than  1% or approximately $40 during the quarter ended  September
    30, 2001 as compared to the quarter ended September 30, 2000.

2.  Depletion  expense  increased to $49,000  for  the  nine  months  ended
    September  30,  2001 from $10,000 for the same period  in  2000.   This
    represents  an  increase of 390%.  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. Contributing factors to the increase in depletion  expense
    between the comparative periods were the decrease in the price  of  oil
    and  gas  used to determine the Partnership's reserves for  October  1,
    2001  as  compared  to 2000, and the decrease in oil and  gas  revenues
    received by the Partnership during 2001 as compared to 2000.


<PAGE>

B.   General Comparison of the Nine Month Periods Ended September 30,  2001
and 2000

The  following  table  provides certain information  regarding  performance
factors for the nine month periods ended September 30, 2001 and 2000:

                                                 Nine Months
                                                    Ended        Percentage
                                                September 30,     Increase
                                                2001      2000   (Decrease)
                                                ----      ----   ---------
Average price per barrel of oil            $   23.13     27.26   (15%)
Average price per mcf of gas               $    3.89      3.58      9%
Oil production in barrels                     21,400    23,000    (7%)
Gas production in mcf                         33,900    20,740     63%
Income from net profits interests          $ 209,750   273,888   (23%)
Partnership distributions                  $ 310,000   190,000     63%
Limited partner distributions              $ 279,000   171,000     63%
Per unit distribution to limited partners  $   46.63     28.58     63%
Number of limited partner units                5,983     5,983

Revenues

The  Partnership's income from net profits interests decreased to  $209,750
from  $273,888  for  the nine months ended September  30,  2001  and  2000,
respectively,  a  decrease  of 23%.  The principal  factors  affecting  the
comparison  of  the nine months ended September 30, 2001 and  2000  are  as
follows:

1.  The  average  price  for a barrel of oil received  by  the  Partnership
    decreased  during the nine months ended September 30, 2001 as  compared
    to  the  nine  months ended September 30, 2000 by  15%,  or  $4.13  per
    barrel, resulting in a decrease of approximately $88,400 in income from
    net  profits interests.  Oil sales represented 79% of total oil and gas
    sales  during the nine months ended September 30, 2001 as  compared  to
    89% during the nine months ended September 30, 2000.

    The  average  price  for  an  mcf of gas received  by  the  Partnership
    increased  during the same period by 9%, or $.31 per mcf, resulting  in
    an  increase  of  approximately $10,500  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
    $77,900.   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.

<PAGE>

2.  Oil  production decreased approximately 1,600 barrels or 7% during  the
    nine  months  ended September 30, 2001 as compared to the  nine  months
    ended  September  30,  2000, resulting in a decrease  of  approximately
    $43,600 in income from net profits interests.

    Gas  production  increased approximately 13,160 mcf or 63%  during  the
    same  period,  resulting  in an increase of  approximately  $47,100  in
    income from net profits interests.

    The  net total increase in income from net profits interests due to the
    change  in  production is approximately $3,500.  The  increase  in  gas
    production  is  in  relation  to an unsuccessful  workover,  which  was
    performed on a non-operated lease during 2000.  The workover caused the
    well  to shut down and was determined to be unrecoverable.  During  the
    nine months ended September 30, 2001, a new well on the same lease  was
    brought  on  line  and  has proven successful  in  replacing  the  lost
    production of the old well.

3.  Lease   operating  costs  and  production  taxes  were  2%  lower,   or
    approximately  $10,300 less during the nine months ended September  30,
    2001 as compared to the nine months ended September 30, 2000.

Costs and Expenses

Total  costs and expenses increased to $115,214 from $55,858 for  the  nine
months  ended  September 30, 2001 and 2000, respectively,  an  increase  of
106%.   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 2%
    or  approximately $600 during the nine months ended September 30,  2001
    as compared to the nine months ended September 30, 2000.

2.  Depletion  expense  increased to $85,000  for  the  nine  months  ended
    September  30,  2001 from $25,000 for the same period  in  2000.   This
    represents  an  increase of 240%.  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. Contributing factors to the increase in depletion  expense
    between the comparative periods were the decrease in the price  of  oil
    and  gas  used to determine the Partnership's reserves for  October  1,
    2001  as  compared  to 2000, and the decrease in oil and  gas  revenues
    received by the Partnership during 2001 as compared to 2000.
<PAGE>

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 $242,300  in
the  nine  months  ended  September 30, 2001 as compared  to  approximately
$248,500  in the nine months ended September 30, 2000.  The primary  source
of the 2001 cash flow from operating activities was profitable operations.

There  were no cash flows used in investing activities for the nine  months
ended  September  30, 2001 as compared to approximately $(5)  in  the  nine
months ended September 30, 2000.

Cash flows used in financing activities were approximately $310,000 in  the
nine  months ended September 30, 2001 as compared to approximately $190,000
in  the  nine  months ended September 30, 2000.  The only use in  financing
activities was the distributions to partners.

Total  distributions during the nine months ended September 30,  2001  were
$310,000  of  which  $279,000 was distributed to the limited  partners  and
$31,000  to  the  general partners.  The per unit distribution  to  limited
partners during the nine months ended September 30, 2001 was $46.63.  Total
distributions during the nine months ended September 30, 2000 were $190,000
of  which  $171,000 was distributed to the limited partners and $19,000  to
the general partners.  The per unit distribution to limited partners during
the nine months ended September 30, 2000 was $28.58.

The  source  for  the  2001  distributions of  $310,000  was  oil  and  gas
operations of approximately $242,300, with the balance from available  cash
on  hand  at  the  beginning  of  the period.  The  sources  for  the  2000
distributions  of  $190,000  were oil and gas operations  of  approximately
$248,500,   resulting  in  excess  cash  for  contingencies  or  subsequent
distributions.

Since  inception of the Partnership, cumulative monthly cash  distributions
of  $3,243,295 have been made to the partners.  As of September  30,  2001,
$2,932,450 or $490.13 per limited partner unit has been distributed to  the
limited partners, representing a 98% return of the capital contributed.

As  of  September  30, 2001, the Partnership had approximately  $71,100  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.

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


<PAGE>
                                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-C, 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 14, 2001

<PAGE>