Page 4 of 4
                                 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 0-19585

                SOUTHWEST OIL & GAS 1990-91 INCOME PROGRAM
                Southwest Oil and Gas Income Fund X-B, L.P.
                  (Exact name of registrant as specified
                   in its limited partnership agreement)

Delaware                                          75-2332176
(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, 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.



                Southwest Oil and Gas Income Fund X-B, L.P.

                              Balance Sheets

                                              September 30,   December 31,
                                                   2001           2000
                                              -------------   ------------
                                               (unaudited)
Assets
- ------
Current assets:
 Cash and cash equivalents                    $     21,768         92,659
 Receivable from Managing General Partner          102,513        152,562
                                                 ---------      ---------
    Total current assets                           124,281        245,221
                                                 ---------      ---------
Oil and gas properties - using the
 full-cost method of accounting                  4,478,321      4,443,303
  Less accumulated depreciation,
   depletion and amortization                    4,135,706      4,084,706
                                                 ---------      ---------
    Net oil and gas properties                     342,615        358,597
                                                 ---------      ---------
                                              $    466,896        603,818
                                                 =========      =========
Liabilities and Partners' Equity
- --------------------------------
Current liability - Distributions payable     $        150             58
                                                 ---------      ---------
Partners' equity:
 General partners                                    2,762         11,363
 Limited partners                                  463,984        592,397
                                                 ---------      ---------
    Total partners' equity                         466,746        603,760
                                                 ---------      ---------
                                              $    466,896        603,818
                                                 =========      =========



                Southwest Oil and Gas Income Fund X-B, L.P.

                         Statements of Operations
                                (unaudited)


                                 Three Months Ended    Nine Months Ended
                                   September 30,         September 30,
                                  2001       2000        2001     2000
                                  ----       ----        ----     ----
Revenues
- --------
Oil and gas                  $   196,752   301,676     723,233   827,746
Interest                             455     1,210       2,574     2,725
                                 -------   -------     ------- ---------
                                 197,207   302,886     725,807   830,471
                                 -------   -------     ------- ---------
Expenses
- --------
Production                       148,359   147,281     426,853   437,052
General and administrative        19,149    19,330      57,968    58,267
Depreciation, depletion and
 amortization                     27,000     5,000      51,000    15,000
                                 -------   -------     ------- ---------
                                 194,508   171,611     535,821   510,319
                                 -------   -------     ------- ---------
Net income                   $     2,699   131,275     189,986   320,152
                                 =======   =======     ======= =========

Net income (loss) allocated to:

 Managing General Partner    $     2,673    12,265      21,689    30,163
                                 =======   =======     ======= =========
 General Partner             $       297     1,363       2,410     3,352
                                 =======   =======     ======= =========
 Limited Partners            $     (271)   117,647     165,887   286,637
                                 =======   =======     ======= =========
  Per limited partner unit   $     (.02)     10.80       15.23     26.32
                                 =======   =======     ======= =========



                Southwest Oil and Gas Income Fund X-B, L.P.

                         Statements of Cash Flows
                                (unaudited)


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

 Cash received from oil and gas sales              $  785,323    772,116
 Cash paid to suppliers                             (496,862)  (452,649)
 Interest received                                      2,574      2,725
                                                    ---------  ---------
  Net cash provided by operating activities           291,035    322,192
                                                    ---------  ---------
Cash flows used in investing activities

 Additions to oil and gas properties                 (35,018)   (21,186)
                                                    ---------  ---------
Cash flows used in financing activities

 Distributions to partners                          (326,908)  (255,023)
                                                    ---------  ---------
Net (decrease) increase in cash and cash equivalents            (70,891)
45,983

 Beginning of period                                   92,659     35,345
                                                    ---------  ---------
 End of period                                     $   21,768     81,328
                                                    =========  =========

Reconciliation of net income to net
 cash provided by operating activities

Net income                                         $  189,986    320,152

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

 Depreciation, depletion and amortization              51,000     15,000
 Decrease (increase) in receivables                    62,090   (55,630)
 (Decrease) increase in payables                     (12,041)     42,670
                                                      -------    -------
Net cash provided by operating activities          $  291,035    322,192
                                                      =======    =======



                Southwest Oil & Gas Income Fund X-B, L.P.
                     (a Delaware limited partnership)

                      Notes to Financial Statements


1.   Organization
     Southwest Oil & Gas Income Fund X-B, L.P. was organized under the laws
     of  the  state  of Delaware on November 27, 1990 for  the  purpose  of
     acquiring  producing oil and gas properties and to produce and  market
     crude oil and natural gas produced from such properties for a term  of
     50  years, unless terminated at an earlier date as provided for in the
     Partnership  Agreement.   The  Partnership  sells  its  oil  and   gas
     production  to  a  variety of purchasers with the prices  it  receives
     being  dependent  upon the oil and gas economy.  Southwest  Royalties,
     Inc. serves as the Managing General Partner and H. H. Wommack, III, as
     the  individual  general partner.  Revenues, costs  and  expenses  are
     allocated as follows:

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

     Interest income on capital contributions        100%           -
     Oil and gas sales                                90%          10%
     All other revenues                               90%          10%
     Organization and offering costs (1)             100%           -
     Amortization or 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.


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

General
Southwest  Oil  &  Gas Income Fund X-B, L.P. was organized  as  a  Delaware
limited  partnership  on November 27, 1990. The offering  of  such  limited
partnership interests began on December 1, 1990 as part of a shelf offering
registered  under  the  name Southwest Oil & Gas  1990-91  Income  Program.
Minimum capital requirements for the Partnership were met on March 1, 1991,
with  the offering of limited partnership interests concluding on September
30, 1991, with total limited partner contributions of $5,444,500.

The  Partnership was formed to acquire 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.

Management  does not anticipate performing workovers during the next  year.
The Partnership could possibly experience a steady decline of 10% to 12%.

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.   For  the  quarter ended September  30,  2001,  the  net
capitalized cost did not exceed the estimated present value of oil and  gas
reserves.


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            $   22.81     29.61   (23%)
Average price per mcf of gas               $    2.51      4.65   (46%)
Oil production in barrels                      7,800     8,400    (7%)
Gas production in mcf                         12,800    12,600      2%
Gross oil and gas revenue                  $ 196,752   301,676   (35%)
Net oil and gas revenue                    $  48,393   154,395   (69%)
Partnership distributions                  $  75,000   100,000   (25%)
Limited partner distributions              $  67,500    90,000   (25%)
Per unit distribution to limited partners  $    6.20      8.27   (25%)
Number of limited partner units               10,889    10,889


Revenues

The  Partnership's oil and gas revenues decreased to $196,752 from $301,676
for  the  quarters  ended  September 30, 2001  and  2000,  respectively,  a
decrease  of  35%.  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 23%, or  $6.80  per  barrel,
    resulting  in  a  decrease of approximately $53,000 in  revenues.   Oil
    sales  represented  85% of total oil and gas sales during  the  quarter
    ended  September 30, 2001 as compared to 81% during the  quarter  ended
    September 30, 2000.

    The  average  price  for  a  mcf  of gas received  by  the  Partnership
    decreased  during the quarter ended September 30, 2001 as  compared  to
    the  quarter  ended  September 30, 2000  by  46%,  or  $2.14  per  mcf,
    resulting in a decrease of approximately $27,400 in revenues.

    The  total  decrease in revenues due to the change in  prices  received
    from oil and gas production is approximately $80,400.  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 600 barrels or 7% during the quarter
   ended September 30, 2001 as compared to the quarter ended September  30,
   2000, resulting in a decrease of approximately $17,800 in revenues.

    Gas  production increased approximately 200 mcf or 2% during  the  same
    period, resulting in an increase of approximately $900 in revenues.

    The  net total decrease in revenues due to the change in production  is
    approximately $16,900.

Costs and Expenses

Total  costs  and  expenses increased to $194,508  from  $171,611  for  the
quarters  ended September 30, 2001 and 2000, respectively, an  increase  of
13%.   The  increase  is the result of higher depletion expense  and  lease
operating   costs,  partially  offset  by  a  decrease   in   general   and
administrative expense.

1.    Lease  operating  costs  and production  taxes  were  1%  higher,  or
   approximately $1,100 more during the quarter ended September 30, 2001 as
   compared to the quarter ended September 30, 2000.

2.  General and administrative costs consist 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,  2001  as
    compared to the quarter ended September 30, 2000.

3.  Depletion  expense increased to $27,000 for the quarter ended September
    30,  2001 from $5,000 for the same period in 2000.  This represents  an
    increase  of 440%.  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.





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            $   24.23     27.57    (12%)
Average price per mcf of gas               $    4.18      3.67      14%
Oil production in barrels                     23,400    25,200     (7%)
Gas production in mcf                         37,400    36,200       3%
Gross oil and gas revenue                  $ 723,233   827,746    (13%)
Net oil and gas revenue                    $ 296,380   390,694    (24%)
Partnership distributions                  $ 327,000   255,000      28%
Limited partner distributions              $ 294,300   229,500      28%
Per unit distribution to limited partners  $   27.03     21.08      28%
Number of limited partner units               10,889    10,889

Revenues

The  Partnership's oil and gas revenues decreased to $723,233 from $827,746
for  the  nine  months ended September 30, 2001 and 2000,  respectively,  a
decrease  of  13%.  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  12%,  or  $3.34  per
    barrel,  resulting in a decrease of approximately $78,200 in  revenues.
    Oil  sales represented 78% of total oil and gas sales during  the  nine
    months  ended  September 30, 2001 as compared to 84%  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 14%, or $.51 per mcf, resulting  in
    an increase of approximately $19,100 in revenues.

    The net total decrease in revenues due to the change in prices received
    from oil and gas production is approximately $59,100.  The market price
    for  oil  and gas has been extremely volatile over the past decade  and
    management  expects a certain amount of volatility to continue  in  the
    foreseeable future.



2.    Oil production decreased approximately 1,800 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
   $49,600 in revenues.

    Gas  production increased approximately 1,200 mcf or 3% during the same
    period, resulting in an increase of approximately $4,400 in revenues.

    The  net total decrease in revenues due to the change in production  is
    approximately $45,200.

Costs and Expenses

Total  costs and expenses increased to $535,821 from $510,319 for the  nine
months ended September 30, 2001 and 2000, respectively, an increase of  5%.
The increase is the result of higher depletion expense, partially offset by
a decrease general and administrative expense and lease operating costs.

1. Lease   operating  costs  and  production  taxes  were  2%   lower,   or
   approximately  $10,200 less during the nine months ended  September  30,
   2001 as compared to the nine months ended September 30, 2000.

2.  General and administrative costs consist of independent accounting  and
    engineering  fees,  computer services, postage,  and  Managing  General
    Partner personnel costs.  General and administrative costs decreased 1%
    or  approximately $300 during the nine months ended September 30,  2001
    as compared to the nine months ended September 30, 2000.

3.  Depletion  expense  increased to $51,000  for  the  nine  months  ended
    September  30,  2001 from $15,000 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.


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 $291,000  in
the  nine  months  ended  September 30, 2001 as compared  to  approximately
$322,200  in the nine months ended September 30, 2000.  The primary  source
of the 2001 cash flow from operating activities was profitable operations.

Cash  flows used in investing activities were approximately $35,000 in  the
nine  months ended September 30, 2001 as compared to approximately  $21,200
in the nine months ended September 30, 2000.  The principle use of the 2001
cash  flow  from  investing  activities was  the  change  in  oil  and  gas
properties.

Cash flows used in financing activities were approximately $326,900 in  the
nine  months ended September 30, 2001 as compared to approximately $255,000
in  the  nine  months ended September 30, 2000.  The only use of  financing
activities was in relation to distributions to partners.

Total  distributions during the nine months ended September 30,  2001  were
$327,000  of  which  $294,300 was distributed to the limited  partners  and
$32,700  to  the  general partners.  The per unit distribution  to  limited
partners during the nine months ended September 30, 2001 was $27.03.  Total
distributions during the nine months ended September 30, 2000 were $255,000
of  which  $229,500 was distributed to the limited partners and $25,500  to
the general partners.  The per unit distribution to limited partners during
the nine months ended September 30, 2000 was $21.08.

The  sources  for  the  2001 distributions of $327,000  were  oil  and  gas
operations of approximately $291,000 and the change in oil and gas property
of approximately $(35,000), with the balance from available cash on hand at
the  beginning  of  the period. The sources for the 2000  distributions  of
$255,000  were  oil and gas operations of approximately  $322,200  and  the
change  in  oil and gas property of approximately $(21,200),  resulting  in
excess cash for contingencies or subsequent distributions.

Since  inception of the Partnership, cumulative monthly cash  distributions
of  $5,377,939 have been made to the partners.  As of September  30,  2001,
$4,866,600 or $446.93 per limited partner unit has been distributed to  the
limited partners, representing a 89% return of the capital contributed.

As  of  September 30, 2001, the Partnership had approximately  $124,100  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.



                        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.





                                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 Oil and Gas Income Fund X-B,
                                   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