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. 33-26097-08


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


                         Delaware                             75-2329284
          -----------------------------------------      ---------------------
              (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 / /





<PAGE>



                        PARKER & PARSLEY 90-B CONV., 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

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

                          Part I. Financial Information

Item 1.      Financial Statements

                                 BALANCE SHEETS
<TABLE>

                                                       June 30,     December 31,
                                                         2001           2000
                                                     -----------    -----------
                                                     (Unaudited)
               ASSETS
<S>                                                  <C>            <C>
Current assets:
   Cash                                              $   369,346    $   132,300
   Accounts receivable - oil and gas sales               166,716        209,552
                                                      ----------     ----------
         Total current assets                            536,062        341,852
                                                      ----------     ----------
Oil and gas properties - at cost, based on the
   successful efforts accounting method                9,564,578      9,628,120
Accumulated depletion                                 (8,066,067)    (8,075,752)
                                                      ----------     ----------
         Net oil and gas properties                    1,498,511      1,552,368
                                                      ----------     ----------
                                                     $ 2,034,573    $ 1,894,220
                                                      ==========     ==========
LIABILITIES AND PARTNERS' CAPITAL

Current liabilities:
   Accounts payable - affiliate                      $    32,466    $    15,580

Partners' capital:
   Managing general partner                               20,020         18,785
   Limited partners (11,897 interests)                 1,982,087      1,859,855
                                                      ----------     ----------
                                                       2,002,107      1,878,640
                                                      ----------     ----------
                                                     $ 2,034,573    $ 1,894,220
                                                      ==========     ==========
</TABLE>



   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

<PAGE>



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

                            STATEMENTS OF OPERATIONS
                                   (Unaudited)



<TABLE>

                                        Three months ended        Six months ended
                                              June 30,                 June 30,
                                     ----------------------    ----------------------
                                        2001         2000         2001        2000
                                     ---------    ---------    ---------    ---------
<S>                                  <C>          <C>          <C>          <C>
Revenues:
  Oil and gas                        $ 338,348    $ 356,486    $ 763,083    $ 687,189
  Interest                               2,579        2,684        5,086        4,777
  Gain on disposition of assets          1,079          -          3,054        2,023
                                      --------     --------     --------     --------
                                       342,006      359,170      771,223      693,989
                                      --------     --------     --------     --------
Costs and expenses:
  Oil and gas production               138,987      143,700      282,193      277,308
  General and administrative             9,322       11,592       22,884       21,724
  Depletion                             27,479       25,752       54,399       52,512
  Abandoned property                     3,059          -          3,059          -
                                      --------     --------     --------     --------
                                       178,847      181,044      362,535      351,544
                                      --------     --------     --------     --------
Net income                           $ 163,159    $ 178,126    $ 408,688    $ 342,445
                                      ========     ========     ========     ========
Allocation of net income:
  Managing general partner           $   1,632    $   1,781    $   4,087    $   3,424
                                      ========     ========     ========     ========
  Limited partners                   $ 161,527    $ 176,345    $ 404,601    $ 339,021
                                      ========     ========     ========     ========
Net income per limited
  partnership interest               $   13,58    $   14.83    $   34.01    $   28.50
                                      ========     ========     ========     ========
</TABLE>



         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

<PAGE>



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

                         STATEMENT OF PARTNERS' CAPITAL
                                   (Unaudited)




<TABLE>

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


<S>                                   <C>            <C>            <C>
Balance at January 1, 2001            $   18,785     $1,859,855     $1,878,640

    Distributions                         (2,852)      (282,369)      (285,221)

    Net income                             4,087        404,601        408,688
                                       ---------      ---------      ---------

Balance at June 30, 2001              $   20,020     $1,982,087     $2,002,107
                                       =========      =========      =========



</TABLE>



         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

<PAGE>



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

                            STATEMENTS OF CASH FLOWS
                                   (Unaudited)


<TABLE>

                                                           Six months ended
                                                               June 30,
                                                      -------------------------
                                                         2001           2000
                                                      ----------     ----------
<S>                                                   <C>            <C>
Cash flows from operating activities:
  Net income                                          $  408,688     $  342,445
  Adjustments to reconcile net income to net
     cash provided by operating activities:
        Depletion                                         54,399         52,512
        Gain on disposition of assets                     (3,054)        (2,023)
  Changes in assets and liabilities:
        Accounts receivable                               42,836        (25,998)
        Accounts payable                                  16,886         12,818
                                                       ---------      ---------
         Net cash provided by operating activities       519,755        379,754
                                                       ---------      ---------
Cash flows from investing activities:
  Additions to oil and gas properties                       (542)       (10,356)
  Proceeds from asset dispositions                         3,054          2,023
                                                       ---------      ---------
         Net cash provided by (used in)
           investing activities                            2,512         (8,333)
                                                       ---------      ---------
Cash flows used in financing activities:
  Cash distributions to partners                        (285,221)      (362,661)
                                                       ---------      ---------
Net increase in cash                                     237,046          8,760
Cash at beginning of period                              132,300        132,031
                                                       ---------      ---------
Cash at end of period                                 $  369,346     $  140,791
                                                       =========      =========


</TABLE>



         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

<PAGE>



                        PARKER & PARSLEY 90-B CONV., 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 Conv., L.P. (the "Partnership") was organized as a general
partnership  in 1990 under the laws of the State of Texas and was converted to a
Delaware limited partnership on August 1, 1991.

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 $763,083 for the six
months  ended June 30, 2001 as compared to $687,189 for the same period in 2000.
The increase in revenues resulted from higher average prices received, offset by

                                        7

<PAGE>



a decrease in production. For the six months ended June 30, 2001, 17,353 barrels
of oil, 6,410 barrels of natural gas liquids ("NGLs") and 35,369 mcf of gas were
sold, or 29,658  barrel of oil  equivalents  ("BOEs").  For the six months ended
June 30, 2000, 17,958 barrels of oil, 8,604 barrel of NGLs and 33,016 mcf of gas
were sold, or 32,065 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 $3,054 and $2,023 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 on 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 $362,535 for the six months ended June 30,
2001 as  compared  to  $351,544  for the same  period in 2000,  an  increase  of
$10,991,  or 3%.  This  increase  was  due to  increases  in  production  costs,
abandoned  property  costs,  depletion and general and  administrative  expenses
("G&A").

Production  costs  were  $282,193  for the six months  ended  June 30,  2001 and
$277,308  for the same period in 2000,  resulting in a $4,885  increase,  or 2%.
This increase was  primarily  due to 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  $21,724 for the six months  ended June 30, 2000 to $22,884 for the same
period in 2001, primarily due to an increase in audit and tax fees.

Depletion  was  $54,399  for the six months  ended June 30,  2001 as compared to
$52,512 for the same period in 2000, an increase of $1,887, or 4%. This increase
was 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 605 barrels for the
six months ended June 30, 2001 as compared to the same period in 2000.

Abandoned  property  costs of $3,059 were  incurred  during the six months ended
June 30, 2001 due to the plugging and abandonment of one well during the current
period.

                                        8

<PAGE>




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 $338,348 for the three
months  ended June 30, 2001 as compared to $356,486 for the same period in 2000.
The decrease in revenues resulted from lower average prices received for oil and
NGLs and a decline in production,  offset by higher average prices  received for
gas.  For the three  months ended June 30,  2001,  8,598  barrels of oil,  3,171
barrels of NGLs and 16,373 mcf of gas were sold,  or 14,498 BOEs.  For the three
months  ended June 30, 2000,  8,968  barrels of oil,  4,625  barrels of NGLs and
17,395 mcf of gas were sold, or 16,492 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 $1,079 was recognized  during the three months
ended June 30,  2001 due to salvage  income  received  on one well  plugged  and
abandoned during the current period.

Costs and Expenses:

Total costs and  expenses  decreased to $178,847 for the three months ended June
30,  2001 as compared  to  $181,044  for the same period in 2000,  a decrease of
$2,197,  or 1%. This decrease was due to declines in  production  costs and G&A,
offset by increases in abandoned property costs and depletion.

Production  costs were  $138,987  for the three  months  ended June 30, 2001 and
$143,700 for the same period in 2000, resulting in a $4,713 decrease, or 3%. The
decrease was primarily due to lower workover expense.

During this period,  G&A  decreased  20% from $11,592 for the three months ended
June 30, 2000 to $9,322 for the same period in 2001,  principally 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 $27,479 for the three  months  ended June 30, 2001 as compared to
$25,752 for the same period in 2000, an increase of $1,727, or 7%. This increase
was due to downward  revisions to proved reserves on several  properties  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 370 barrels for the
three months ended June 30, 2001 as compared to the same period in 2000.


                                        9

<PAGE>



Abandoned  property costs of $3,059 were incurred  during the three months ended
June 30, 2001 due to the plugging and abandonment of one well during the current
period.

Liquidity and Capital Resources

Net Cash Provided by Operating Activities

Net cash  provided by operating  activities  increased  $140,001  during the six
months  ended  June 30,  2001 from the same  period  ended June 30,  2000.  This
increase  resulted from an increase of $76,203 in oil and gas sales receipts and
a reduction in working  capital of $72,902,  offset by  increases in  production
costs of $4,885,  abandoned property costs of $3,059 and G&A expenses of $1,160.
The  increase in oil and gas  receipts  resulted  from the increase in commodity
prices  during  2001 which  contributed  an  additional  $117,367 to oil and gas
receipts, offset by $41,164 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  for  expenditures  related  to oil and gas  equipment
upgrades on active properties.

Proceeds from asset  dispositions  of $3,054 and $2,023 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
derived 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
$285,221,  of which $2,852 was  distributed to the managing  general partner and
$282,369 to the limited partners.  For the same period ended June 30, 2000, cash
distributions to the partners were $362,661,  of which $3,627 was distributed to
the managing general partner and $359,034 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

                                       10

<PAGE>



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
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

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                        PARKER & PARSLEY 90-B CONV., 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 CONV., 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

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