UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D. C. 20549


                                    FORM 10-Q


                Quarterly Report Pursuant to Section 13 or 15(d)
                     of the Securities Exchange Act of 1934

                  For the quarterly period ended June 30, 2001


                         Commission File No. 33-26097-07


                           PARKER & PARSLEY 90-B, L.P.
                          -----------------------------
             (Exact name of Registrant as specified in its charter)


                          Delaware                           75-2329287
          -----------------------------------------     ---------------------
               (State or other jurisdiction of             (I.R.S. Employer
               incorporation or organization)           Identification Number)


     5205 N. O'Connor Blvd., Suite 1400, Irving, Texas          75039
     -------------------------------------------------       ------------
         (Address of principal executive offices)             (Zip code)

       Registrant's Telephone Number, including area code : (972) 444-9001


                                 Not applicable
              (Former name, former address and former fiscal year,
                          if changed since last report)


Indicate by check mark whether the 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 / /









                           PARKER & PARSLEY 90-B, L.P.

                                TABLE OF CONTENTS


                                                                        Page
                          Part I. Financial Information

Item 1.     Financial Statements

            Balance Sheets as of June 30, 2001 and
               December 31, 2000.....................................    3

            Statements of Operations for the three and six
              months ended June 30, 2001 and 2000....................    4

            Statement of Partners' Capital for the six months
              ended June 30, 2001....................................    5

            Statements of Cash Flows for the six months ended
              June 30, 2001 and 2000.................................    6

            Notes to Financial Statements............................    7

Item 2.     Management's Discussion and Analysis of Financial
              Condition and Results of Operations....................    7


                           Part II. Other Information

Item 6.     Exhibits and Reports on Form 8-K.........................   11

            Signatures...............................................   12



                                        2





                           PARKER & PARSLEY 90-B, L.P.
                        (A Delaware Limited Partnership)

                          Part I. Financial Information

Item 1.     Financial Statements

                                 BALANCE SHEETS


                                                     June 30,      December 31,
                                                       2001            2000
                                                   ------------    ------------
                                                   (Unaudited)
                 ASSETS
                                                             
Current assets:
 Cash                                              $  1,006,322    $    364,895
 Accounts receivable - oil and gas sales                454,542         568,283
                                                    -----------     -----------
        Total current assets                          1,460,864         933,178
                                                    -----------     -----------
Oil and gas properties - at cost,  based on the
 successful efforts accounting method                25,938,605      26,110,930
Accumulated depletion                               (21,873,017)    (21,899,717)
                                                    -----------     -----------
        Net oil and gas properties                    4,065,588       4,211,213
                                                    -----------     -----------
                                                   $  5,526,452    $  5,144,391
                                                    ===========     ===========
LIABILITIES AND PARTNERS' CAPITAL

Current liabilities:
 Accounts payable - affiliate                      $     88,337    $     42,091

Partners' capital:
 Managing general partner                                54,385          51,027
 Limited partners (32,264 interests)                  5,383,730       5,051,273
                                                    -----------     -----------
                                                      5,438,115       5,102,300
                                                    -----------     -----------
                                                   $  5,526,452    $  5,144,391
                                                    ===========     ===========




   The financial information included as of June 30, 2001 has been prepared by
  the managing general partner without audit by independent public accountants.

   The accompanying notes are an integral part of these financial statements.

                                        3





                                            PARKER & PARSLEY 90-B, L.P.
                                         (A Delaware Limited Partnership)

                                             STATEMENTS OF OPERATIONS
                                                    (Unaudited)




                                        Three months ended          Six months ended
                                              June 30,                   June 30,
                                     ------------------------    ------------------------
                                        2001          2000          2001          2000
                                     ----------    ----------    ----------    ----------
                                                                   
Revenues:
  Oil and gas                        $  917,666    $  966,583    $2,069,524    $1,863,518
  Interest                                7,073         7,402        14,158        13,142
  Gain on disposition of assets           2,926           -           8,283         5,487
                                      ---------     ---------     ---------     ---------
                                        927,665       973,985     2,091,965     1,882,147
                                      ---------     ---------     ---------     ---------
Costs and expenses:
  Oil and gas production                376,953       389,681       765,323       752,025
  General and administrative             25,284        31,430        61,934        58,911
  Depletion                              74,458        69,726       147,093       142,347
  Abandoned property                      8,296           -           8,296           -
                                      ---------     ---------     ---------     ---------
                                        484,991       490,837       982,646       953,283
                                      ---------     ---------     ---------     ---------
Net income                           $  442,674    $  483,148    $1,109,319    $  928,864
                                      =========     =========     =========     =========
Allocation of net income:
  Managing general partner           $    4,427    $    4,832    $   11,093    $    9,289
                                      =========     =========     =========     =========
  Limited partners                   $  438,247    $  478,316    $1,098,226    $  919,575
                                      =========     =========     =========     =========
Net income per limited
  partnership interest               $    13.58    $    14.82    $    34.04    $    28.50
                                      =========     =========     =========     =========




         The financial information included herein has been prepared by
  the managing general partner without audit by independent public accountants.

   The accompanying notes are an integral part of these financial statements.

                                        4





                           PARKER & PARSLEY 90-B, L.P.
                        (A Delaware Limited Partnership)

                         STATEMENT OF PARTNERS' CAPITAL
                                   (Unaudited)





                                          Managing
                                          general      Limited
                                          partner      partners       Total
                                         ---------    ----------    ----------


                                                           
Balance at January 1, 2001               $  51,027    $5,051,273    $5,102,300

    Distributions                           (7,735)     (765,769)     (773,504)

    Net income                              11,093     1,098,226     1,109,319
                                          --------     ---------     ---------

Balance at June 30, 2001                 $  54,385    $5,383,730    $5,438,115
                                          ========     =========     =========






         The financial information included herein has been prepared by
  the managing general partner without audit by independent public accountants.

   The accompanying notes are an integral part of these financial statements.

                                        5





                           PARKER & PARSLEY 90-B, L.P.
                        (A Delaware Limited Partnership)

                            STATEMENTS OF CASH FLOWS
                                   (Unaudited)




                                                            Six months ended
                                                                 June 30,
                                                        ------------------------
                                                           2001          2000
                                                        ----------    ----------
                                                                
Cash flows from operating activities:
  Net income                                            $1,109,319    $  928,864
  Adjustments to reconcile net income to net
     cash provided by operating activities:
        Depletion                                          147,093       142,347
        Gain on disposition of assets                       (8,283)       (5,487)
  Changes in assets and liabilities:
        Accounts receivable                                113,741       (19,535)
        Accounts payable                                    46,246        35,060
                                                         ---------     ---------
          Net cash provided by operating activities      1,408,116     1,081,249
                                                         ---------     ---------
Cash flows from investing activities:
  Additions to oil and gas properties                       (1,468)      (28,083)
  Proceeds from asset dispositions                           8,283         5,487
                                                         ---------     ---------
          Net cash provided by (used in)
             investing activities                            6,815       (22,596)
                                                         ---------     ---------
Cash flows used in financing activities:
  Cash distributions to partners                          (773,504)     (983,517)
                                                         ---------     ---------
Net increase in cash                                       641,427        75,136
Cash at beginning of period                                364,895       311,017
                                                         ---------     ---------
Cash at end of period                                   $1,006,322    $  386,153
                                                         =========     =========





         The financial information included herein has been prepared by
  the managing general partner without audit by independent public accountants.

   The accompanying notes are an integral part of these financial statements.

                                        6





                           PARKER & PARSLEY 90-B, L.P.
                        (A Delaware Limited Partnership)

                          NOTES TO FINANCIAL STATEMENTS
                                  June 30, 2001
                                   (Unaudited)

Note 1.     Organization and nature of operations

Parker &  Parsley  90-B,  L.P.  (the  "Partnership")  is a  limited  partnership
organized in 1990 under the laws of the State of Delaware.

The  Partnership  engages in oil and gas development and production in Texas and
is not involved in any industry segment other than oil and gas.

Note 2.     Basis of presentation

In  the  opinion  of  management,  the  unaudited  financial  statements  of the
Partnership  as of June 30, 2001 and for the three and six months ended June 30,
2001 and 2000 include all  adjustments  and accruals  consisting  only of normal
recurring accrual adjustments which are necessary for a fair presentation of the
results for the  interim  period.  These  interim  results  are not  necessarily
indicative of results for a full year. Certain  reclassifications  may have been
made to the June 30, 2000  financial  statements to conform to the June 30, 2001
financial statement presentations.

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.  The financial statements
should  be read in  conjunction  with the  financial  statements  and the  notes
thereto  contained in the  Partnership's  Report on Form 10-K for the year ended
December 31, 2000, as filed with the Securities and Exchange Commission,  a copy
of which is available upon request by writing to Rich Dealy,  Vice President and
Chief Accounting  Officer,  5205 North O'Connor  Boulevard,  Suite 1400, Irving,
Texas 75039-3746.

Item 2.     Management's Discussion and Analysis of Financial Condition
               and Results of Operations (1)

Results of Operations

Six months ended June 30, 2001 compared with six months ended
   June 30, 2000

Revenues:

The Partnership's  oil and gas revenues  increased 11% to $2,069,524 for the six
months  ended June 30,  2001 as compared  to  $1,863,518  for the same period in
2000. The increase in revenues  resulted from higher  average  prices  received,
offset by a decrease  in  production.  For the six months  ended June 30,  2001,
47,052 barrels of oil, 17,412 barrels of natural gas liquids ("NGLs") and 95,918


                                        7





mcf of gas were sold, or 80,450 barrel of oil equivalents ("BOEs").  For the six
months ended June 30, 2000,  48,699  barrels of oil,  23,339 barrels of NGLs and
89,536 mcf of gas were sold, or 86,961 BOEs.

The average price received per barrel of oil increased  $.54, or 2%, from $27.72
for the six months  ended June 30,  2000 to $28.26 for the same  period in 2001.
The average  price  received per barrel of NGLs  increased  $2.09,  or 15%, from
$14.00  during the six months  ended June 30, 2000 to $16.09 for the same period
in 2001. The average price received per mcf of gas increased 130% from $2.08 for
the six months  ended June 30,  2000 to $4.79 for the same  period in 2001.  The
market price for oil and gas has been extremely  volatile in the past decade and
management expects a certain amount of volatility to continue in the foreseeable
future.  The Partnership may therefore sell its future oil and gas production at
average  prices lower or higher than that  received  during the six months ended
June 30, 2001.

Gains on disposition of assets of $8,283 and $5,487 were  recognized  during the
six  months  ended June 30,  2001 and 2000,  respectively.  The gain  recognized
during  the  period in 2001 was due to  salvage  income  received  from one well
plugged and abandoned  during the current year. The gain  recognized  during the
period in 2000 was from the sale of equipment on one fully depleted well.

Costs and Expenses:

Total costs and expenses increased to $982,646 for the six months ended June 30,
2001 as  compared  to  $953,283  for the same  period in 2000,  an  increase  of
$29,363, or 3%. The increase was due to increases in production costs, abandoned
property costs, depletion and general and administrative expenses ("G&A").

Production  costs  were  $765,323  for the six months  ended  June 30,  2001 and
$752,025 for the same period in 2000,  resulting in a $13,298  increase,  or 2%.
The increase was primarily the result of higher production taxes associated with
higher oil and gas prices.

G&A's  components are independent  accounting and engineering  fees and managing
general partner personnel and operating costs. During this period, G&A increased
5% from  $58,911 for the six months  ended June 30, 2000 to $61,934 for the same
period in 2001, primarily due to an increase in tax and audit fees.

Depletion  was  $147,093  for the six months  ended June 30, 2001 as compared to
$142,347  for the same  period in 2000,  an  increase  of  $4,746,  or 3%.  This
increase was primarily due to downward  revisions to proved  reserves on several
wells  during  the period  ended June 30,  2001,  offset by a  reduction  in the
Partnership's  net  depletable  basis  from  charges  taken in  accordance  with
Statement  of  Financial  Accounting  Standards  No.  121,  "Accounting  for the
Impairment of  Long-Lived  Assets and for  Long-Lived  Assets to be Disposed Of"
("SFAS 121") during the fourth  quarter of 2000 and a decline in oil  production
of 1,647  barrels for the six months ended June 30, 2001 as compared to the same
period in 2000.

Abandoned  property  costs of $8,296 were  incurred  during the six months ended
June 30, 2001 due to the plugging and abandonment of one well during the current
year.

                                        8





Three months ended June 30, 2001 compared with three months ended June 30, 2000

Revenues:

The  Partnership's  oil and gas revenues  decreased 5% to $917,666 for the three
months  ended June 30, 2001 as compared to $966,583 for the same period in 2000.
The decrease in revenues resulted from a decline in production and lower average
prices  received for oil and NGLs,  offset by higher average prices received for
gas.  For the three months ended June 30,  2001,  23,315  barrels of oil,  8,603
barrels of NGLs and 44,414 mcf of gas were sold,  or 39,320 BOEs.  For the three
months ended June 30, 2000,  24,312  barrels of oil,  12,529 barrels of NGLs and
47,154 mcf of gas were sold, or 44,700 BOEs.

The average price received per barrel of oil decreased  $.51, or 2%, from $27.75
for the three  months ended June 30, 2000 to $27.24 for the same period in 2001.
The average price received per barrel of NGLs decreased $.22, or 2%, from $14.10
during the three  months  ended June 30,  2000 to $13.88 for the same  period in
2001.  The average price received per mcf of gas increased 50% from $2.44 during
the three months ended June 30, 2000 to $3.67 for the same period in 2001.

Gain on disposition  of assets of $2,926 was recognized  during the three months
ended June 30, 2001 due to salvage  income  received  from one well  plugged and
abandoned during the current period.

Costs and Expenses:

Total costs and  expenses  decreased to $484,991 for the three months ended June
30,  2001 as compared  to  $490,837  for the same period in 2000,  a decrease of
$5,846,  or 2%. This decrease was due to declines in  production  costs and G&A,
offset by increases in abandoned property costs and depletion.

Production  costs were  $376,953  for the three  months  ended June 30, 2001 and
$389,681  for the same period in 2000  resulting in a $12,728  decrease,  or 3%.
This decrease was primarily due to lower workover expense.

During this period,  G&A  decreased  20% from $31,430 for the three months ended
June 30, 2000 to $25,284 for the same period in 2001,  primarily  due to a lower
percentage of the managing general partner's G&A being allocated  (limited to 3%
of oil and gas  revenues)  as a result of  decreased  oil and gas revenues and a
decline in audit and tax fees.

Depletion  was $74,458 for the three  months  ended June 30, 2001 as compared to
$69,726 for the same period in 2000, an increase of $4,732, or 7%. This increase
was  primarily  due to downward  revisions to proved  reserves on several  wells
during  the  period  ended  June  30,  2001,   offset  by  a  reduction  in  the
Partnership's  net depletable  basis from charges taken in accordance  with SFAS
121  during the fourth  quarter of 2000 and a decline in oil  production  of 997
barrels for the three  months ended June 30, 2001 as compared to the same period
in 2000.

Abandoned  property costs of $8,296 were incurred  during the three months ended
June 30, 2001 due to the plugging and abandonment of one well during the current
period.

                                        9





Liquidity and Capital Resources

Net Cash Provided by Operating Activities

Net cash  provided by operating  activities  increased  $326,867  during the six
months  ended  June 30,  2001 from the same  period  ended June 30,  2000.  This
increase resulted from an increase of $207,022 in oil and gas sales receipts and
a reduction in working  capital of $144,462,  offset by increases in  production
costs of $13,298, abandoned property costs of $8,296 and G&A expenses of $3,023.
The  increase in oil and gas  receipts  resulted  from the increase in commodity
prices  during  2001 which  contributed  an  additional  $318,339 to oil and gas
receipts,  offset by $111,317  resulting  from the decline in production  during
2001 as compared to the same period in 2000.  The increase in  production  costs
was primarily due to increased  production  taxes associated with higher oil and
gas prices.  The increase in G&A was  primarily  due to an increase in audit and
tax fees.

Net Cash Provided by (Used in) Investing Activities

The Partnership's  principal investing  activities for the six months ended June
30,  2001 and 2000 were  related to  expenditures  for  upgrades  of oil and gas
equipment on active properties.

Proceeds from asset  dispositions  of $8,283 and $5,487 were received during the
six months ended June 30, 2001 and 2000,  respectively.  The proceeds recognized
during the period in 2001 were due to salvage  income from one well  plugged and
abandoned during the current year. The proceeds recognized during 2000 were from
the sale of equipment on one fully depleted well.

Net Cash Used in Financing Activities

For the six months ended June 30, 2001, cash  distributions to the partners were
$773,504,  of which $7,735 was  distributed to the managing  general partner and
$765,769 to the limited partners.  For the same period ended June 30, 2000, cash
distributions to the partners were $983,517,  of which $9,835 was distributed to
the managing general partner and $973,682 to the limited partners.

For the three  months  ended June 30, 2001,  no  distributions  were made by the
partnership to its partners.  Subsequent to June 30, 2001 the cash  distribution
that  otherwise  would  have been  mailed to  partners  in late June was made to
holders  of  record  as of July 9, 2001 and was  mailed  on July 13,  2001.  For
further information, see "Proposal to acquire partnerships" below.

Proposal to acquire partnerships

On June 29, 2001,  Pioneer Natural Resources Company  ("Pioneer") filed with the
Securities and Exchange Commission  Amendment No. 1 to the Form S-4 Registration
Statement (File No. 333-59094) (the "preliminary  proxy  statement/prospectus"),
which  proposes an agreement and plan of merger among Pioneer,  Pioneer  Natural
Resources USA, Inc. ("Pioneer USA"), a wholly-owned  subsidiary of Pioneer,  and
46 Parker & Parsley limited  partnerships.  Each  partnership  that approves the
agreement and plan of merger and the other related  merger  proposals will merge
with and into Pioneer USA upon the closing of the transactions  described in the
preliminary proxy  statement/prospectus,  and the partnership  interests of each
such  partnership  will be converted  into the right to receive  Pioneer  common
stock.  The Partnership is one of the 46 Parker & Parsley  limited  partnerships


                                       10





that will be asked to approve the agreement and plan of merger.  The preliminary
proxy statement/prospectus is non-binding and is subject to, among other things,
consideration  of offers from third parties to purchase any  partnership  or its
assets and the majority  approval of the limited  partnership  interests in each
partnership.

Pioneer USA will solicit  proxies  from limited  partners to approve the mergers
only when the proxy  statement/prospectus  is final and declared  effective.  No
solicitation will be made using preliminary  materials.  Nonetheless,  copies of
the preliminary proxy  statement/prospectus  may be obtained without charge upon
request from Pioneer Natural Resources Company, 5205 North O'Connor Blvd., Suite
1400, Irving, Texas 75039, Attention: Investor Relations.

The limited partners are urged to read the proxy statement/prospectus of Pioneer
filed with the Securities and Exchange Commission, when it is finalized, because
it  contains  important  information  about  the  proposed  mergers,   including
information  about the direct and indirect  interests of Pioneer USA and Pioneer
in the mergers.  The limited  partners may also obtain the preliminary and (when
filed) final proxy statement/prospectus and other relevant documents relating to
the proposed  mergers free through the internet web site that the Securities and
Exchange Commission maintains at www.sec.gov.

- --------------

(1)  "Item 2.  Management's  Discussion and Analysis of Financial  Condition and
     Results of Operations"  contains  forward  looking  statements that involve
     risks and uncertainties.  Accordingly,  no assurances can be given that the
     actual  events  and  results  will  not be  materially  different  than the
     anticipated results described in the forward looking statements.

                           Part II. Other Information


Item 6.     Exhibits and Reports on Form 8-K

(a)    Exhibits - none

(b)    Form 8-K - none


                                       11




                           PARKER & PARSLEY 90-B, L.P.
                        (A Delaware Limited Partnership)



                               S I G N A T U R E S



     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.

                                           PARKER & PARSLEY 90-B, L.P.

                                  By:      Pioneer Natural Resources USA, Inc.,
                                             Managing General Partner





Dated:  August 6, 2001            By:      /s/ Rich Dealy
                                           ----------------------------------
                                           Rich Dealy, Vice President and
                                           Chief Accounting Officer




                                       12