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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, 2003

                                    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 19.

<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  notes
thereto for the year ended December 31, 2002, which are found in  the
Registrant's Form 10-K Report for 2002 filed with the Securities  and
Exchange  Commission.  The December 31, 2002 balance  sheet  included
herein  has  been taken from the Registrant's 2002 Form 10-K  Report.
Operating results for the three month period ended March 31, 2003 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


                                  March    December
                                   31,       31,
                                   2003      2002
                                   ----      ----
                                 (unaudit
                                   ed)
Assets
----------

Current assets:
 Cash and cash equivalents    $  23,696    20,887
  Receivable  from  Managing     105,033   79,843
General Partner
   Receivable   from   sales     -         7,000
proceeds
                                 --------  --------
                                 ----      ---
   Total current assets          128,729   107,730
                                 --------  --------
                                 ----      ----
Oil  and  gas  properties  -
using the full-
 method of accounting            2,666,16  2,214,66
                                 4         2
       Less      accumulated
depreciation,
         depletion       and     2,282,43  2,093,47
amortization                     5         9
                                 --------  --------
                                 ----      ----
      Net   oil   and    gas     383,729   121,183
properties
                                 --------  --------
                                 ----      ----
                              $  512,458   228,913
                                 =======   =======
Liabilities  and   Partners'
Equity
----------------------------
-----------
Liabilities:
 Other long term liabilities  $  1,042,29  -
                                 4
                                 --------  --------
                                 ----      ----

Partners' equity:
 General partners                (78,957)  (21,978)
 Limited partners                (450,879  250,891
                                 )
                                 --------  --------
                                 ----      ----
                                 (529,836  228,913
                                 )
                                 --------  --------
                                 ----      ----
   Total partners' equity     $  512,458   228,913
                                 =======   =======

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

                         Statements of Operations
                               (unaudited)


                                 Three Months Ended
                                     March 31,
                                   2003      2002
                                   ----      ----

Revenues
-------------

Income   from  net   profits  $  81,182    (12,714)
interests
Interest                         52        34
                                 --------  --------
                                 --        --
                                 81,234    (12,680)
                                 --------  --------
                                 --        --
Expenses
------------

General and administrative       10,235    10,135
Depreciation, depletion  and     6,000     7,000
amortization
Accretion                        20,437    -
                                 --------  --------
                                 --        --
                                 36,672    17,135
                                 --------  --------
                                 --        --
Net   income  (loss)  before     44,562    (29,815)
cumulative effect

Cumulative effect of  change     (753,311  -
in accounting principle          )
                                 --------  --------
                                 --        --
Net income (loss)             $  (708,749  (29,815)
                                 )
                                 ======    ======
Net  income (loss) allocated
to:

 Managing General Partner     $  (46,781)  (2,053)
                                 ======    ======
 General partner              $  (5,198)   (228)
                                 ======    ======
 Limited partners             $  (656,770  (27,534)
                                 )
                                 ======    ======
   Per limited partner unit   $  (109.77)
                                           (4.60)
                                 ======    ======

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

                         Statements of Cash Flows
                               (unaudited)

                                      Three Months Ended
                                          March 31,
                                        2003      2002
                                       -----      ----
Cash    flows   from    operating
activities:

  Cash  received from net profits  $  53,517    6,330
interest
 Cash paid to suppliers               (7,760)   (9,376)
 Interest received                    52        34
                                      --------  --------
                                      --        --
   Net cash provided by (used in)     45,809    (3,012)
operating activities
                                      --------  --------
                                      --        --
Cash  flows provided by investing
activities:

 Sale of oil and gas properties       7,000     -
                                      --------  --------
                                      --        --
Cash   flows  used  in  financing
activities:

 Distributions to partners            (50,000)  -
                                      --------  --------
                                      --        --
Net  increase (decrease) in  cash     2,809     (3,012)
and cash equivalents

 Beginning of period                  20,887    15,300
                                      --------  --------
                                      --        --
 End of period                     $  23,696    12,288
                                      ======    ======
Reconciliation  of   net   income
(loss) to net cash
  provided by (used in) operating
activities:

Net income (loss)                  $  (708,749  (29,815)
                                      )

Adjustments   to  reconcile   net
income (loss) to
  net cash provided by (used  in)
operating activities:

   Depreciation,  depletion   and     6,000     7,000
amortization
 Accretion                            20,437    -
  Cumulative effect of change  in     753,311   -
accounting principle
     (Increase)    decrease    in     (27,665)  19,044
receivables
 Increase in payables                 2,475     759
                                      --------  --------
                                      --        --
Net  cash  provided by (used  in)  $  45,809    (3,012)
operating activities
                                      ======    ======
Noncash  investing and  financing
activities:

   Increase   in  oil   and   gas
properties - Adoption              $  268,546   -
        of SFAS No.143
                                      ======    ======

<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    100%       -
capital contributions
Oil and gas sales          90%       10%
All other revenues         90%       10%
Organization        and    100%       -
offering costs (1)
Syndication costs          100%       -
Amortization         of    100%       -
organization costs
Property    acquisition    100%       -
costs
Gain/loss  on  property    90%       10%
disposition
Operating           and    90%       10%
administrative    costs
(2)
Depreciation, depletion
and amortization
   of   oil   and   gas    100%       -
properties
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, 2003, and for
     the  three  months ended March 31, 2003, 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, 2002.

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

                      Notes to Financial Statements

3.   Cumulative effect of change in accounting principle
     On  January  1,  2003,  the  Partnership  adopted  Statement  of
     Financial  Accounting  Standards No. 143, Accounting  for  Asset
     Retirement Obligations ("SFAS No. 143").  Adoption of  SFAS  No.
     143  is  required for all companies with fiscal years  beginning
     after  June 15, 2002.  The new standard requires the Partnership
     to  recognize  a liability for the present value  of  all  legal
     obligations  associated with the retirement  of  tangible  long-
     lived assets and to capitalize an equal amount as a cost of  the
     asset  and  depreciate the additional cost  over  the  estimated
     useful  life  of the asset.  On January 1, 2003, the Partnership
     recorded  additional costs, net of accumulated depreciation,  of
     approximately  $268,547, a long term liability of  approximately
     $1,021,857  and  a  charge  of approximately  $753,311  for  the
     cumulative  effect on depreciation of the additional  costs  and
     accretion   expense  on  the  liability  related   to   expected
     abandonment   costs  of  its  oil  and  natural  gas   producing
     properties.  At March 31, 2003, the asset retirement  obligation
     was $1,042,294, and the increase in the balance from January  1,
     2003  of  $20,437 is due to accretion expense.   The  pro  forma
     amount  of  the  asset retirement obligation was measured  using
     information,  assumptions and interest rates as of the  adoption
     date  of  January 1, 2003.  Assuming the Partnership had applied
     the  provisions of SFAS No. 143 for the three months ended March
     31,  2002 pro forma net income (loss) and related income  (loss)
     per  limited partner unit amounts would have been $(48,617)  and
     $(8.13), respectively.

<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.

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.  The economic life of the
Partnership  thus depends on the period over which the  Partnership's
oil and gas reserves are economically recoverable.

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  no
workovers during 2003 or 2004 to enhance production.  The partnership
will  most likely experience the historical production decline, which
has approximated 10% 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.

Prior to October 1, 2002, the Partnership calculated depletion of oil
and   gas  properties  under  the  units  of  revenue  method.    The
Partnership changed methods of estimating depletion effective October
1,  2002  to the units of production method.  The units of production
method is more predominantly used throughout the oil and gas industry
and  will allow the Partnership to more closely align itself with its
peers.

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. In applying the  units  of  revenue
method  for  the  three  months ended March 31,  2002,  we  have  not
excluded royalty and net profit interest payments from gross revenues
as  all  of  our royalty and net profit interests have been purchased
and  capitalized  to the depletion basis of our proved  oil  and  gas
properties. As of March 31, 2003, the net capitalized costs  did  not
exceed the estimated present value of oil and gas reserves.


<PAGE>
The  Partnership's interest in oil and gas properties consists of net
profits interests in proved properties located within the continental
United States.  A net profits interest is created when the owner of a
working  interest in a property enters into an arrangement  providing
that  the net profits interest owner will receive a stated percentage
of  the net profit from the property.  The net profits interest owner
will  not  otherwise participate in additional costs and expenses  of
the property.

The  Partnership recognizes income from its net profits  interest  in
oil  and  gas property on an accrual basis, while the quarterly  cash
distributions of the net profits interest are based on a  calculation
of  actual  cash  received from oil and gas sales,  net  of  expenses
incurred during that quarterly period. The net profits interest is  a
calculated  revenue  interest  that burdens  the  underlying  working
interest in the property, and the net profits interest owner  is  not
responsible  for  the  actual  development  or  production   expenses
incurred.   Accordingly,  if  the net  profits  interest  calculation
results  in  expenses  incurred exceeding  the  oil  and  gas  income
received  during  a  quarter,  no cash distribution  is  due  to  the
Partnership's  net  profits interest until the deficit  is  recovered
from future net profits.  The Partnership accrues a quarterly loss on
its  net  profits interest provided there is a cumulative net  amount
due  for  accrued revenue as of the balance sheet date.  As of  March
31,  2003,  there  were no timing differences, which  resulted  in  a
deficit net profit interest.

Critical Accounting Policies

Full  cost ceiling calculations The Partnership follows the full cost
method  of accounting for its oil and gas properties.  The full  cost
method  subjects companies to quarterly calculations of a  "ceiling",
or  limitation on the amount of properties that can be capitalized on
the  balance  sheet.  If the Partnership's capitalized costs  are  in
excess  of the calculated ceiling, the excess must be written off  as
an expense.

The  Partnership's  discounted present value of its  proved  oil  and
natural gas reserves is a major component of the ceiling calculation,
and  represents  the  component  that requires  the  most  subjective
judgments.   Estimates of reserves are forecasts based on engineering
data,  projected future rates of production and the timing of  future
expenditures.  The process of estimating oil and natural gas reserves
requires substantial judgment, resulting in imprecise determinations,
particularly  for new discoveries.  Different reserve  engineers  may
make  different  estimates of reserve quantities based  on  the  same
data.   The  Partnership's reserve estimates are on an  annual  basis
prepared  by  outside consultants.  Quarterly reserve  estimates  are
prepared  by  the  Managing  General  Partner's  internal  staff   of
engineers.

The  passage of time provides more qualitative information  regarding
estimates  of reserves, and revisions are made to prior estimates  to
reflect updated information.  However, there can be no assurance that
more  significant revisions will not be necessary in the future.   If
future  significant  revisions are necessary that  reduce  previously
estimated reserve quantities, it could result in a full cost property
writedown.   In addition to the impact of these estimates  of  proved
reserves  on calculation of the ceiling, estimates of proved reserves
are also a significant component of the calculation of DD&A.

While the quantities of proved reserves require substantial judgment,
the  associated  prices  of oil and natural  gas  reserves  that  are
included  in  the  discounted present value of the  reserves  do  not
require  judgment.  The ceiling calculation dictates that prices  and
costs  in effect as of the last day of the period are generally  held
constant indefinitely. Because the ceiling calculation dictates  that
prices  in  effect as of the last day of the applicable  quarter  are
held constant indefinitely, the resulting value is not indicative  of
the true fair value of the reserves.  Oil and natural gas prices have
historically been cyclical and, on any particular day at the end of a
quarter,  can  be  either  substantially higher  or  lower  than  the
Partnership's long-term price forecast that is a barometer  for  true
fair value.

Prior to October 1, 2002, the Partnership calculated depletion of oil
and   gas  properties  under  the  units  of  revenue  method.    The
Partnership changed methods of estimating depletion effective October
1,  2002  to the units of production method.  The units of production
method is more predominantly used throughout the oil and gas industry
and  will allow the Partnership to more closely align itself with its
peers.

<PAGE>
Results of Operations

A.  General Comparison of the Quarters Ended March 31, 2003 and 2002

The   following   table   provides  certain   information   regarding
performance factors for the quarters ended March 31, 2003 and 2002.

                               Three Months
                                  Ended         Percenta
                                                   ge
                                March 31,       Increase
                              2003      2002    (Decreas
                                                   e)
                             -----     -----    --------
                                                   --
Average    price    per  $   30.61              84%
barrel of oil                         16.68
Average  price per  mcf  $    5.03              157%
of gas                                1.96
Oil    production    in     7,000     6,800     3%
barrels
Gas production in mcf       7,200     8,500     (15%)
Income from net profits  $  81,182    (12,714)  739%
interests
Partnership              $  50,000    -         100%
distributions
Limited         partner  $  45,000    -         100%
distributions
Per  unit  distribution
to limited
 partners                $    7.52         -    100%
Number    of    limited     5,983     5,983
partner units

Revenues

The  Partnership's  income from net profits  interests  increased  to
$81,182  from  $(12,714) for the quarters ended March  31,  2003  and
2002,  respectively,  an  increase of  739%.  The  principal  factors
affecting  the comparison of the quarters ended March  31,  2003  and
2002 are as follows:

1.  The average price for a barrel of oil received by the Partnership
    increased during the quarter ended March 31, 2003 as compared  to
    the  quarter  ended March 31, 2002 by 84%, or $13.93 per  barrel,
    resulting in an increase of approximately $97,500 in income  from
    net  profits interests.  Oil sales represented 86% of  total  oil
    and gas sales during the quarter ended March 31, 2003 as compared
    to 87% during the quarter ended March 31, 2002.

    The  average  price for an mcf of gas received by the Partnership
    increased  during  the same period by 157%,  or  $3.07  per  mcf,
    resulting in an increase of approximately $22,100 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  $119,600.  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 increased approximately 200 barrels or 3%  during
    the quarter ended March 31, 2003 as compared to the quarter ended
    March  31, 2002, resulting in an increase of approximately $3,300
    in income from net profits interests.

    Gas  production decreased approximately 1,300 mcf or  15%  during
    the  same period, resulting in a decrease of approximately $2,500
    in income from net profits interests.

    The  total net increase in income from net profits interests  due
    to the change in production is approximately $800.

3.  Lease  operating costs and production taxes were 19%  higher,  or
    approximately  $26,500 more during the quarter  ended  March  31,
    2003  as  compared  to  the quarter ended March  31,  2002.   The
    increase in lease operating expense and production taxes  is  due
    mainly  to  repairs and maintenance, such as pulling expense,  on
    one  lease,  and the increase in production taxes in relation  to
    the increase in gross revenues received in 2003.

Costs and Expenses

Total  costs and expenses increased to $36,672 from $17,135  for  the
quarters ended March 31, 2003 and 2002, respectively, an increase  of
114%.   The  increase  is  a direct result of the  accretion  expense
associated   with  our  long  term  liability  related  to   expected
abandonment  costs of our oil and natural gas properties and  general
and  administrative  expense,  partially  offset  by  a  decrease  in
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 increased 1% or approximately  $100  during
    the quarter ended March 31, 2003 as compared to the quarter ended
    March 31, 2002.

2.  Depletion expense decreased to $6,000 for the quarter ended March
    31, 2003 from $7,000 for the same period in 2002. This represents
    a  decrease  of  14%.  Prior to October 1, 2002, the  Partnership
    calculated depletion of oil and gas properties under the units of
    revenue  method.  The Partnership changed methods  of  estimating
    depletion  effective October 1, 2002 to the units  of  production
    method.   The  units  of production method is more  predominantly
    used  throughout  the oil and gas industry  and  will  allow  the
    Partnership  to  more closely align itself with its  peers.   The
    effect  of  this  change in estimate if the units  of  production
    method  were applied to 2002 would have increased 2002  depletion
    expense  by $2,000 and decreased 2002 net income by $2,000.   The
    contributing factors to the decrease in depletion expense  is  in
    relation  to  the BOE depletion rate for the quarter ended  March
    31,  2003  was  $.69  applied to 8,200 BOE as compared  to  $1.07
    applied to 8,217 BOE for the same period.

Cumulative effect of change in accounting principle

On  January  1, 2003, the Partnership adopted Statement of  Financial
Accounting   Standards  No.  143,  Accounting  for  Asset  Retirement
Obligations  ("SFAS No. 143").  Adoption of SFAS No. 143 is  required
for  all  companies with fiscal years beginning after June 15,  2002.
The  new  standard requires the Partnership to recognize a  liability
for  the  present value of all legal obligations associated with  the
retirement of tangible long-lived assets and to capitalize  an  equal
amount as a cost of the asset and depreciate the additional cost over
the  estimated  useful life of the asset.  On January  1,  2003,  the
Partnership   recorded   additional   costs,   net   of   accumulated
depreciation,  of  approximately $268,547, a long term  liability  of
approximately $1,021,857 and a charge of approximately  $753,311  for
the  cumulative  effect on depreciation of the additional  costs  and
accretion  expense  on the liability related to expected  abandonment
costs of its oil and natural gas producing properties.  At March  31,
2003,  the  asset  retirement  obligation  was  $1,042,294,  and  the
increase  in the balance from January 1, 2003 of $20,437  is  due  to
accretion  expense.   The pro forma amount of  the  asset  retirement
obligation  was measured using information, assumptions and  interest
rates  as  of  the  adoption date of January 1, 2003.   Assuming  the
Partnership had applied the provisions of SFAS No. 143 for the  three
months  ended March 31, 2002 pro forma net income (loss) and  related
income  (loss)  per  limited partner unit  amounts  would  have  been
$(48,617) and $(8.13), respectively.

<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  (used  in)  operating  activities   were
approximately $45,800 in the quarter ended March 31, 2003 as compared
to  approximately $(3,000) in the quarter ended March 31, 2002.   The
primary  source  of the 2003 cash flow from operating activities  was
from profitable operations.

Cash flows provided by investing activities were approximately $7,000
in  the quarter ended March 31, 2003.  There were no cash flows  used
in  investing  activities in the quarter ended March 31,  2002.   The
principle source of the 2003 cash flow from investing activities  was
the sale of an oil and gas property.

Cash  flows  provided  by  financing  activities  were  approximately
$50,000  in  the quarter ended March 31, 2003.  There  were  no  cash
flows  used  in financing activities in the quarter ended  March  31,
2002.

Total  distributions  during the quarter ended March  31,  2003  were
$50,000 of which $45,000 was distributed to the limited partners  and
$5,000 to the general partners.  The per unit distribution to limited
partners  during the quarter ended March 31, 2003 was  $7.52.   There
were no distributions during the quarter ended March 31, 2002.

The  primary sources for the 2003 distributions of $50,000  were  oil
and gas operations of approximately $45,800 and the change in oil and
gas  properties of approximately $7,000, resulting in excess cash for
contingencies or subsequent distribution to partners.

Since   inception  of  the  Partnership,  cumulative   monthly   cash
distributions  of $3,314,059 have been made to the partners.   As  of
March  31, 2003, $2,996,137 or $500.78 per limited partner  unit  has
been  distributed to the limited partners, representing a 100% return
of the capital contributed.

As  of March 31, 2003, the Partnership had approximately $128,700  in
working  capital.  The Managing General Partner knows of  no  unusual
contractual  commitments.  Although the partnership held  many  long-
lived  properties  at  inception,  because  of  the  restrictions  on
property  development  imposed  by  the  partnership  agreement,  the
Managing  General Partner anticipates that at some point in the  near
future,  the partnership will need to be liquidated.  Maintenance  of
properties  and  administrative expenses are increasing  relative  to
production.   As  the properties continue to deplete, maintenance  of
properties  and  administrative costs as a percentage  of  production
will continue to increase.

As  the partnerships properties have matured, the net cash flows from
operations  for  the partnership have generally declined,  except  in
periods  of  substantially increased commodity  pricing.   Since  the
partnership  cannot develop their properties, the producing  reserves
continue to deplete causing cash flow to steadily decline.

<PAGE>
Liquidity - Managing General Partner
The Managing General Partner has a highly leveraged capital structure
with  approximately $124.0 million of principal due between  December
31,  2002  and  December 31, 2004.  The Managing General  Partner  is
constantly monitoring its cash position and its ability to  meet  its
financial  obligations as they become due, and  in  this  effort,  is
continually  exploring various strategies for addressing its  current
and  future liquidity needs.  The Managing General Partner  regularly
pursues  and  evaluates recapitalization strategies  and  acquisition
opportunities   (including  opportunities  to  engage   in   mergers,
consolidations or other business combinations) and at any given  time
may be in various stages of evaluating such opportunities.

Based  on  current production, commodity prices and  cash  flow  from
operations,  the Managing General Partner has adequate cash  flow  to
fund  debt service, developmental projects and day to day operations,
but  it  is not sufficient to build a cash balance which would  allow
the  Managing  General Partner to meet its debt principal  maturities
scheduled  for  2004.   Therefore the Managing General  Partner  must
renegotiate the terms of its various obligations or seek new  lenders
or  equity  investors  in  order to meet its  financial  obligations,
specifically  those maturing in 2004.  The Managing  General  Partner
may  be  required to dispose of certain assets in order to  meet  its
obligations.

There  can  be no assurance that the Managing General Partner's  debt
restructuring  efforts will be successful or that  the  debt  holders
will agree to a course of action consistent with the Managing General
Partner's    requirements   in   restructurings   the    obligations.
Furthermore, there can be no assurance that the sales of  assets  can
be  successfully  accomplished on terms acceptable  to  the  Managing
General Partner.

Recent Accounting Pronouncements

The   FASB  has  issued  Statement  No.  143  "Accounting  for  Asset
Retirement  Obligations"  which  establishes  requirements  for   the
accounting  of removal-type costs associated with asset  retirements.
The  standard is effective for fiscal years beginning after June  15,
2002,  with  earlier  application encouraged.  The  Managing  General
Partner  is  currently  assessing  the  impact  on  the  partnerships
financial  statements.  This  statement  has  been  adopted  by   the
Partnership  effective  January 1, 2003.  The  transition  adjustment
resulting  from the adoption of SFAS No. 143 has been reported  as  a
cumulative effect of a change in accounting principle.

In  April  2004,  the  FASB issued Statement of Financial  Accounting
Standards  No.  149,  Amendment of Statement No.  133  on  Derivative
Instruments  and Hedging Activities ("SFAS No. 149").  SFAS  No.  149
amendments require that contracts with comparable characteristics  be
accounted  for similarly, clarifies when a contract with  an  initial
investment  meets  the characteristic of a derivative  and  clarifies
when a derivative requires special reporting in the statement of cash
flows.    SFAS   No.  149  is  effective  for  hedging  relationships
designated and for contracts entered into or modified after June  30,
2003,  except  for provisions that relate to SFAS No.  133  Statement
Implementation  Issues that have been effective for  fiscal  quarters
prior  to  June 15, 2003, should be applied in accordance with  their
respective effective dates and certain provisions relating to forward
purchases or sales of when-issued securities or other securities that
do  not yet exist, should be applied to existing contracts as well as
new  contracts entered into after June 30, 2003.  Assessment  by  the
Managing  General  Partner  revealed this pronouncement  to  have  no
impact on the partnership.

Item 3.   Quantitative and Qualitative Disclosures About Market Risk

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

Item 4.   Controls and Procedures

(a)  Evaluation  of  Disclosure Controls and Procedures.   The  chief
executive  officer  and chief financial officer of the  Partnership's
managing  general  partner have evaluated the  effectiveness  of  the
design  and  operation of the Partnership's disclosure  controls  and
procedures (as defined in Exchange Act Rule 13a-14(c)) as of  a  date
within 90 days of the filing date of this quarterly report. Based  on
that  evaluation,  the chief executive officer  and  chief  financial
officer have concluded that the Partnership's disclosure controls and
procedures are effective to ensure that material information relating
to the Partnership and the Partnership's consolidated subsidiaries is
made  known  to  such  officers  by  others  within  these  entities,
particularly during the period this quarterly report was prepared, in
order to allow timely decisions regarding required disclosure.

(b)   Changes  in  Internal  Controls.   There  have  not  been   any
significant  changes  in the Partnership's internal  controls  or  in
other   factors  that  could  significantly  affect  these   controls
subsequent to the date of their evaluation.
<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)  Exhibits:

                     99.1 Certification pursuant to 18 U.S.C. Section
               1350
               99.2 Certification pursuant to 18 U.S.C. Section 1350

               (b)  Reports on Form 8-K:

                     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:  May 15, 2003

<PAGE>

                           CERTIFICATIONS

          I, H.H. Wommack, III, certify that:

          1.   I have reviewed this quarterly report on Form 10-Q of Southwest
Royalties Institutional Income Fund X-C, L.P.;

          2.   Based on my knowledge, this quarterly report does not contain
any  untrue statement of a material fact or omit to state a  material
fact  necessary  to  make  the  statements  made,  in  light  of  the
circumstances  under which such statements were made, not  misleading
with respect to the period covered by this quarterly report;

          3.   Based on my knowledge, the financial statements, and other
financial  information  included in  this  quarterly  report,  fairly
present in all material respects the financial condition, results  of
operations  and  cash flows of the registrant as  of,  and  for,  the
periods presented in this quarterly report;

          4.   The registrant's other certifying officers and I are responsible
for  establishing and maintaining disclosure controls and  procedures
(as  defined  in  Exchange  Act Rules  13a-14  and  15d-14)  for  the
registrant and we have:

          a)   designed such disclosure controls and procedures to ensure that
          material information relating to the registrant, including its
          consolidated subsidiaries, is made known to us by others within those
          entities, particularly during the period in which this quarterly
          report is being prepared;

          b)   evaluated the effectiveness of the registrant's disclosure
          controls and procedures as of a date within 90 days prior to the
          filing date of this quarterly report (the "Evaluation Date"); and

          c)   presented in this quarterly report our conclusions about the
          effectiveness of the disclosure controls and procedures based on our
          evaluation as of the Evaluation Date;

          5.   The registrant's other certifying officers and I have disclosed,
based on our most recent evaluation, to the registrant's auditors and
the  audit  committee of registrant's board of directors (or  persons
performing the equivalent functions):

          a)   all significant deficiencies in the design or operation of
          internal controls which could adversely affect the registrant's
          ability to record, process, summarize and report financial data and
          have identified for the registrant's auditors any material weaknesses
          in internal controls; and

          b)   any fraud, whether or not material, that involves management or
          other employees who have a significant role in the registrant's
          internal controls; and

          6.   The registrant's other certifying officers and I have indicated
in  this  quarterly  report  whether or not  there  were  significant
changes  in  internal  controls  or  in  other  factors  that   could
significantly affect internal controls subsequent to the date of  our
most  recent evaluation, including any corrective actions with regard
to significant deficiencies and material weaknesses.

Date:  May 15, 2003



/s/ H.H. Wommack, III
H. H. Wommack, III
Chairman, President and Chief Executive Officer
  of Southwest Royalties, Inc., the Managing
  General Partner of Southwest Royalties
  Institutional Income Fund X-C, L.P.

<PAGE>
                           CERTIFICATIONS

          I, Bill E. Coggin, certify that:

          1.   I have reviewed this quarterly report on Form 10-Q of Southwest
     Royalties Institutional Income Fund X-C, L.P.;

          2.   Based on my knowledge, this quarterly report does not contain
     any untrue statement of a material fact or omit to state a material
     fact  necessary  to make the statements made, in  light  of  the
     circumstances under which such statements were made, not misleading
     with respect to the period covered by this quarterly report;

          3.   Based on my knowledge, the financial statements, and other
     financial information included in this quarterly report,  fairly
     present in all material respects the financial condition, results of
     operations and cash flows of the registrant as of, and for,  the
     periods presented in this quarterly report;

          4.   The registrant's other certifying officers and I are responsible
     for establishing and maintaining disclosure controls and procedures
     (as  defined  in Exchange Act Rules 13a-14 and 15d-14)  for  the
     registrant and we have:

          a)   designed such disclosure controls and procedures to ensure that
          material information relating to the registrant, including its
          consolidated subsidiaries, is made known to us by others within those
          entities, particularly during the period in which this quarterly
          report is being prepared;

          b)   evaluated the effectiveness of the registrant's disclosure
          controls and procedures as of a date within 90 days prior to the
          filing date of this quarterly report (the "Evaluation Date"); and

          c)   presented in this quarterly report our conclusions about the
          effectiveness of the disclosure controls and procedures based on our
          evaluation as of the Evaluation Date;

          5.   The registrant's other certifying officers and I have disclosed,
     based on our most recent evaluation, to the registrant's auditors and
     the audit committee of registrant's board of directors (or persons
     performing the equivalent functions):

          a)   all significant deficiencies in the design or operation of
          internal controls which could adversely affect the registrant's
          ability to record, process, summarize and report financial data and
          have identified for the registrant's auditors any material weaknesses
          in internal controls; and

          b)   any fraud, whether or not material, that involves management or
          other employees who have a significant role in the registrant's
          internal controls; and

          6.   The registrant's other certifying officers and I have indicated
     in  this  quarterly report whether or not there were significant
     changes  in  internal controls or in other  factors  that  could
     significantly affect internal controls subsequent to the date of our
     most recent evaluation, including any corrective actions with regard
     to significant deficiencies and material weaknesses.

Date:  May 15, 2003



/s/ Bill E. Coggin
Bill E. Coggin
Executive Vice President
  and Chief Financial Officer of
  Southwest Royalties, Inc., the Managing
  General Partner of Southwest Royalties
  Institutional Income Fund X-C, L.P.

<PAGE>
                      CERTIFICATION PURSUANT TO
                       19 U.S.C. SECTION 1350,
                       AS ADOPTED PURSUANT TO
            SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002


      In  connection with the Quarterly Report of Southwest Royalties
Institutional Income Fund X-C, Limited Partnership (the "Company") on
Form  10-Q  for  the period ending March 31, 2003 as filed  with  the
Securities and Exchange Commission on the date hereof (the "Report"),
I, H.H. Wommack, III, Chief Executive Officer of the Managing General
Partner  of  the  Company, certify, pursuant to 18 U.S.C.   1350,  as
adopted pursuant to  906 of the Sarbanes-Oxley Act of 2002, that:

     (1)  The Report fully complies with the requirements of section 13(a)
       or 15(d) of the Securities Exchange Act of 1934; and

     (2)  The information contained in the Report fairly presents, in all
       material respects, the financial condition and results of operation
       of the Company.


Date:  May 15, 2003




/s/ H.H. Wommack, III
H. H. Wommack, III
Chairman, President, Director and Chief Executive Officer
  of Southwest Royalties, Inc., the
  Managing General Partner of
  Southwest Royalties Institutional Income Fund X-C, L.P.

<PAGE>
                      CERTIFICATION PURSUANT TO
                       19 U.S.C. SECTION 1350,
                       AS ADOPTED PURSUANT TO
            SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002


   In  connection  with  the Quarterly Report of Southwest  Royalties
Institutional Income Fund X-C, Limited Partnership (the "Company") on
Form  10-Q  for  the period ending March 31, 2003 as filed  with  the
Securities and Exchange Commission on the date hereof (the "Report"),
I,  Bill  E. Coggin, Chief Financial Officer of the Managing  General
Partner  of  the  Company, certify, pursuant to 18 U.S.C.   1350,  as
adopted pursuant to  906 of the Sarbanes-Oxley Act of 2002, that:

     (3)  The Report fully complies with the requirements of section 13(a)
       or 15(d) of the Securities Exchange Act of 1934; and

     (4)  The information contained in the Report fairly presents, in all
       material respects, the financial condition and results of operation
       of the Company.


Date:  May 15, 2003




/s/ Bill E. Coggin
Bill E. Coggin
Executive Vice President
  and Chief Financial Officer of
  Southwest Royalties, Inc., the
  Managing General Partner of
  Southwest Royalties Institutional Income Fund X-C, L.P.


<PAGE>