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


                                    FORM 10-Q


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

                For the quarterly period ended September 30, 1998

                                       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 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)

303 West Wall, Suite 101, Midland, Texas                       79701     
(Address of principal executive offices)                     (Zip code)


       Registrant's Telephone Number, including area code : (915) 683-4768


                                 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 / /




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

                                TABLE OF CONTENTS


                                                                         Page
                          Part I. Financial Information

Item 1.    Financial Statements

           Balance Sheets as of September 30, 1998 and
              December 31, 1997.........................................    3

           Statements of Operations for the three and nine
             months ended September 30, 1998 and 1997...................    4

           Statement of Partners' Capital for the nine months
             ended September 30, 1998...................................    5

           Statements of Cash Flows for the nine months ended
             September 30, 1998 and 1997................................    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.............................   12

           27.1   Financial Data Schedule

           Signatures...................................................   13



                                        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
                                                 September 30,    December 31,
                                                     1998             1997
                                                 ------------     ------------
                                                   (Unaudited)
                 ASSETS
Current assets:
  Cash                                           $    101,891     $    118,712
  Accounts receivable - oil and gas sales              99,921          126,770
                                                  -----------      -----------
           Total current assets                       201,812          245,482
                                                  -----------      -----------
Oil and gas properties - at cost,  based on
  the successful efforts accounting method          9,596,256        9,582,125
Accumulated depletion                              (7,281,032)      (7,100,097)
                                                  -----------      -----------
           Net oil and gas properties               2,315,224        2,482,028
                                                  -----------      -----------
                                                 $  2,517,036     $  2,727,510
                                                  ===========      ===========
LIABILITIES AND PARTNERS' CAPITAL

Current liabilities:
  Accounts payable - affiliate                   $     51,416     $     34,538

Partners' capital:
  Managing general partner                             24,656           26,929
  Limited partners (11,897 interests)               2,440,964        2,666,043
                                                  -----------      -----------
                                                    2,465,620        2,692,972
                                                  -----------      -----------
                                                 $  2,517,036     $  2,727,510
                                                  ===========      ===========

The financial information included as of September 30, 1998 has been prepared by
          management without audit by independent public accountants.

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

                                        3

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

                            STATEMENTS OF OPERATIONS
                                   (Unaudited)


                                  Three months ended        Nine months ended
                                     September 30,            September 30,
                                ----------------------   ----------------------
                                   1998        1997         1998        1997
                                ----------  ----------   ----------  ----------
Revenues:
  Oil and gas                   $  184,754  $  242,483   $  595,195  $  831,064
  Interest                           1,624       2,014        5,099       6,636
  Gain on disposition of assets        -           -            123         -  
                                 ---------   ---------    ---------   ---------
                                   186,378     244,497      600,417     837,700
                                 ---------   ---------    ---------   ---------
Costs and expenses:
  Oil and gas production           125,327     148,353      399,471     406,338
  General and administrative         5,428       8,177       19,129      26,996
  Depletion                         66,731      56,381      180,935     179,322
                                 ---------   ---------    ---------   ---------
                                   197,486     212,911      599,535     612,656
                                 ---------   ---------    ---------   ---------
Net income (loss)               $  (11,108) $   31,586   $      882  $  225,044
                                 =========   =========    =========   =========
Allocation of net income (loss):
  Managing general partner      $     (111) $      315   $        9  $    2,250
                                 =========   =========    =========   =========
  Limited partners              $  (10,997) $   31,271   $      873  $  222,794
                                 =========   =========    =========   =========
Net income (loss) per limited
  partnership interest          $     (.93) $     2.63   $      .07  $    18.73
                                 =========   =========    =========   =========
Distributions per limited
  partnership interest          $     4.30  $     9.38   $    18.99  $    43.15
                                 =========   =========    =========   =========


         The financial information included herein has been prepared by
           management without audit by independent public accountants.

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

                                        4

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

                         STATEMENT OF PARTNERS' CAPITAL
                                   (Unaudited)




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

Balance at January 1, 1998             $   26,929     $2,666,043     $2,692,972

    Distributions                          (2,282)      (225,952)      (228,234)

    Net income                                  9            873            882
                                        ---------      ---------      ---------
Balance at September 30, 1998          $   24,656     $2,440,964     $2,465,620
                                        =========      =========      =========







         The financial information included herein has been prepared by
           management without audit by independent public accountants.

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

                                        5

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

                            STATEMENTS OF CASH FLOWS
                                   (Unaudited)


                                                           Nine months ended
                                                             September 30,
                                                      ------------------------
                                                         1998           1997
                                                      ----------    ----------
Cash flows from operating activities:
   Net income                                         $      882    $  225,044
   Adjustments to reconcile net income to net
      cash provided by operating activities:
        Depletion                                        180,935       179,322
        Gain on disposition of assets                       (123)          -
   Changes in assets and liabilities:
        Accounts receivable                               26,849        91,408
        Accounts payable                                  16,878        18,444
                                                       ---------     ---------
          Net cash provided by operating activities      225,421       514,218
                                                       ---------     ---------
Cash flows from investing activities:
   Additions to oil and gas properties                   (14,131)      (15,893)
   Proceeds from asset dispositions                          123           -  
                                                       ---------     ---------
          Net cash used in investing activities          (14,008)      (15,893)
                                                       ---------     ---------
Cash flows from financing activities:
   Cash distributions to partners                       (228,234)     (518,537)
                                                       ---------     ---------
Net decrease in cash                                     (16,821)      (20,212)
Cash at beginning of period                              118,712       123,797
                                                       ---------     ---------
Cash at end of period                                 $  101,891    $  103,585
                                                       =========     =========


         The financial information included herein has been prepared by
           management 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
                               September 30, 1998
                                   (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  primarily 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  September  30, 1998 and for the three and nine months  ended
September 30, 1998 and 1997 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  information  and  footnote  disclosure  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 results 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, 1997, 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,  1400 Williams Square
West, Irving, Texas 75039-3746.

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

Results of Operations

Nine months ended September 30, 1998 compared with nine months ended
   September 30, 1997

Revenues:

The Partnership's  oil and gas revenues  decreased 28% to $595,195 from $831,064
for the nine  months  ended  September  30,  1998 and  1997,  respectively.  The
decrease in revenues  resulted from lower average prices received,  offset by an
increase in production.   For the nine months ended September 30,  1998,  31,203

                                        7

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barrels of oil, 13,025 barrels of natural gas liquids ("NGLs") and 56,560 mcf of
gas were sold, or 53,655 barrel of oil equivalents ("BOEs"). For the nine months
ended September 30, 1997, 31,575 barrels of oil and 89,474 mcf of gas were sold,
or 46,487 BOEs.

As of September 30, 1997, the Partnership began accounting for processed natural
gas   production  as  processed   natural  gas  liquids  and  dry  residue  gas.
Consequently,  separate  product volumes will not be comparable to periods prior
to September 30, 1997.  Also,  prices for gas products will not be comparable as
the price per mcf for natural gas for the three and nine months ended  September
30,  1998 is the price  received  for dry  residue gas and the price per mcf for
natural gas for the three and nine months  ended  September  30, 1997 is a price
for wet gas (i.e., natural gas liquids combined with dry residue gas).

The average  price  received per barrel of oil  decreased  $6.30,  or 32%,  from
$19.76  for the nine  months  ended  September  30,  1997 to $13.46 for the same
period in 1998.  The average  price  received per barrel of NGLs during the nine
months ended September 30, 1998 was $6.88. The average price received per mcf of
gas  decreased  35% from $2.32 for the nine months ended  September  30, 1997 to
$1.51 for the same  period in 1998.  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 nine months ended September 30, 1998.

During  most of 1997,  the  Partnership  benefitted  from  higher  oil prices as
compared to previous  years.  However,  during the fourth  quarter of 1997,  oil
prices began a downward trend that has continued into 1998. On October 30, 1998,
the market  price for West Texas  intermediate  crude was $13.33 per  barrel.  A
continuation  of the oil price  environment  experienced  during the first three
quarters of 1998 will have an adverse effect on the  Partnership's  revenues and
operating  cash flow and could  result in  additional  decreases in the carrying
value of the Partnership's oil and gas properties.

A gain on disposition  of assets of $123 was  recognized  during the nine months
ended  September 30, 1998 from the sale of equipment on one  saltwater  disposal
well plugged and abandoned in a prior year.

Costs and Expenses:

Total  costs and  expenses  decreased  to  $599,535  for the nine  months  ended
September  30,  1998 as compared  to  $612,656  for the same  period in 1997,  a
decrease  of  $13,121.   The  decrease  was  due  to  declines  in  general  and
administrative  expenses  ("G&A")  and  production  costs,  offset  by a  slight
increase in depletion.

Production  costs were $399,471 for the nine months ended September 30, 1998 and
$406,338  for the same  period  in 1997,  resulting  in a $6,867  decrease.  The
decrease was the result of lower production taxes and workover expenses,  offset
by an increase in well maintenance costs.

                                        8

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G&A's  components are independent  accounting and engineering  fees and managing
general  partner  personnel  and  operating  costs.   During  this  period,  G&A
decreased,  in aggregate,  29% from $26,996 for the nine months ended  September
30, 1997 to $19,129 for the same period in 1998.

Depletion was $180,935 for the nine months ended  September 30, 1998 compared to
$179,322 for the same period in 1997,  representing an increase of $1,613.  This
increase was  primarily  attributable  to a decrease in oil reserves  during the
period ended September 30, 1998 as a result of lower commodity prices, 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 1997 and a  reduction  in oil
production  of 372 barrels for the period ended  September  30, 1998 compared to
the same period in 1997.

Three months ended September 30, 1998 compared with three months ended
   September 30, 1997

Revenues:

The Partnership's  oil and gas revenues  decreased 24% to $184,754 from $242,483
for the three  months  ended  September  30,  1998 and 1997,  respectively.  The
decrease in revenues  resulted from lower average prices received,  offset by an
increase in production.  For the three months ended  September 30, 1998,  10,050
barrels of oil, 4,915 barrels of NGLs and 19,838 mcf of gas were sold, or 18,271
BOEs.  For the three months ended  September 30, 1997,  9,805 barrels of oil and
30,045 mcf of gas were sold, or 14,813 BOEs.

The average  price  received per barrel of oil  decreased  $5.96,  or 33%,  from
$18.32  during the three months ended  September 30, 1997 to $12.36 for the same
period in 1998.  The average price  received per barrel of NGLs during the three
months ended September 30, 1998 was $6.24. The average price received per mcf of
gas decreased 28% from $2.09 during the three months ended September 30, 1997 to
$1.51 for the same period in 1998.

Costs and Expenses:

Total costs and  expenses  decreased  to  $197,486  for the three  months  ended
September  30,  1998 as compared  to  $212,911  for the same  period in 1997,  a
decrease of $15,425,  or 7%. This decrease was due to lower production costs and
G&A, offset by an increase in depletion.

Production costs were $125,327 for the three months ended September 30, 1998 and
$148,353 for the same period in 1997,  resulting in a $23,026 decrease,  or 16%.
The decrease was the result of lower  workover  costs,  production  taxes and ad
valorem taxes.

G&A's  components are independent  accounting and engineering  fees and managing
general  partner  personnel  and  operating  costs.   During  this  period,  G&A
decreased,  in aggregate,  34%, from $8,177 for the three months ended September
30, 1997 to $5,428 for the same period in 1998.

                                        9

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Depletion was $66,731 for the three months ended  September 30, 1998 compared to
$56,381 for the same  period in 1997,  representing  an increase of $10,350,  or
18%.  This  increase  was  primarily attributable  to a decrease in oil reserves
during the period ended September 30, 1998 as a result of lower commodity prices
and an increase in oil production of 245 barrels for the period ended  September
30,  1998  compared to the same  period in 1997,  offset by a  reduction  in the
Partnership's  net depletable  basis from charges taken in accordance  with SFAS
121 during the fourth quarter of 1997.

Liquidity and Capital Resources

Net Cash Provided by Operating Activities

Net cash provided by operating  activities  decreased  $288,797  during the nine
months ended  September 30, 1998 from the same period ended  September 30, 1997.
This decrease was primarily due to a decrease in oil and gas sales receipts.

Net Cash Used in Investing Activities

The  Partnership's  investing  activities during the nine months ended September
30, 1998 and 1997  included  expenditures  related to equipment  replacement  on
various oil and gas properties.

Proceeds from asset  dispositions  of $123 were received  during the nine months
ended  September 30, 1998 from the sale of equipment on one  saltwater  disposal
well abandoned in a prior year.

Net Cash Used in Financing Activities

Cash was  sufficient  for the nine  months  ended  September  30,  1998 to cover
distributions to the partners of $228,234 of which $2,282 was distributed to the
managing  general  partner and  $225,952 to the limited  partners.  For the same
period ended  September 30, 1997, cash was sufficient for  distributions  to the
partners of $518,537 of which $5,185 was  distributed  to the  managing  general
partner and $513,352 to the limited partners.

It is expected  that future net cash  provided by operating  activities  will be
sufficient for any capital expenditures and any distributions. As the production
from the properties declines, distributions are also expected to decrease.

Year 2000 Project Readiness

Historically,  many computer programs have been developed that use only the last
two digits in a date to refer to a year.  As the year 2000 nears,  the inability
of such  computer  programs and embedded  technologies  to  distinguish  between
"1900" and "2000" has given rise to the "Year 2000" problem. Theoretically, such
computer  programs and related  technology  could fail outright,  or communicate
inaccurate  data,  if not  remediated  or replaced.  With the  proliferation  of
electronic  data  interchange,  the Year 2000 problem  represents a  significant
exposure to the entire  global  community,  the full  extent of which  cannot be
accurately assessed.
                                       10

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In proactive  response to the Year 2000 problem,  the managing  general  partner
established  a "Year  2000"  project to  assess,  to the  extent  possible,  the
Partnership's and the managing general partner's internal Year 2000 problem;  to
take remedial  actions  necessary to minimize the Year 2000 risk exposure to the
managing  general  partner and  significant  third parties with whom it has data
interchange;  and, to test its systems and processes once remedial  actions have
been taken. The managing general partner has contracted with IBM Global Services
to perform the assessment and remedial phases of its Year 2000 project.

The assessment phase of the managing general  partner's Year 2000 project is 85%
complete and has included, but is not limited to, the following procedures:

o      the identification of  necessary remediation,  upgrade and/or replacement
       of existing information technology applications and systems;

o      the   assessment  of  non-information   technology  exposures,   such  as
       telecommunications  systems,  security  systems,  elevators  and  process
       control equipment;

o      the  initiation  of inquiry and  dialogue  with  significant  third party
       business partners, customers and suppliers in an effort to understand and
       assess their Year 2000  problems,  readiness and potential  impact on the
       managing general partner and its Year 2000 problem;

o      the   implementation  of  processes   designed  to  reduce  the  risk  of
       reintroduction  of Year 2000 problems into the managing general partner's
       systems and business processes; and,

o      the  formulation of  contingency plans for  mission-critical  information
       technology systems.

The managing  general  partner  expects to complete the assessment  phase of its
Year 2000 project by the end of the first  quarter of 1999 but is being  delayed
by limited responses  received on inquiries made of third party  businesses.  To
date, the managing general partner has distributed  Year 2000 problem  inquiries
to over 500 entities and has received  responses on  approximately  10% of those
inquiries.

The  remedial  phase of the  managing  general  partner's  Year 2000  project is
approximately  40%  complete,  subject to the results of the third party inquiry
assessments  and the testing phase.  The remedial phase has included the upgrade
and/or  replacement of certain  application and hardware  systems.  The managing
general  partner has  upgraded its Artesia  general  ledger  accounting  systems
through  remedial  coding and is  currently  testing  this  system for Year 2000
compliance.  The  remediation  of  non-information  technology is expected to be
completed by mid-1999. The managing general partner's Year 2000 remedial actions
have not delayed other information technology projects or upgrades.

The testing  phase of the  managing  general  partner's  Year 2000 project is on
schedule.  The managing  general  partner expects to complete the testing of the
Artesia  system  upgrades  by March 1999 and  all other  information  technology

                                       11

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systems by May 1999. The testing of the non-information  technology  remediation
is scheduled to be completed by the end of September 1999.

The managing  general  partner  expects that its total costs related to the Year
2000 problem will approximate $3.5 million, of which approximately $500 thousand
will have been incurred to replace non-compliant information technology systems.
As of September 30, 1998, the managing general partner's total costs incurred on
the Year 2000 problem were $1.5 million, of which $200 thousand were incurred to
replace  non-compliant  systems.  The managing  general  partner will allocate a
portion of the costs of the year 2000  programming  charges  to the  Partnership
when they are incurred, along with recurring general and administrative expenses
and such allocation should not be significant to the Partnership.

The risks  associated with the Year 2000 problem are  significant.  A failure to
remedy a critical  Year 2000 problem could have a materially  adverse  affect on
the Partnership's  results of operations and financial  condition.  The problems
which  may be  encountered  as a result  of a Year 2000  problem  could  include
information and non-information  system failures, the receipt or transmission of
erroneous  data,  lost data or a combination of similar  problems of a magnitude
that cannot be accurately  assessed at this time. In the assessment phase of the
managing  general  partner's  Year  2000  project,  contingency  plans are being
designed to mitigate the exposures noted above. However, given the uncertainties
regarding the scope of the Year 2000 problem and the  compliance of  significant
third  parties,  there can be no  assurance  that  contingency  plans  will have
anticipated all Year 2000 scenarios.

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

(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

       27.1   Financial Data Schedule

(b)    Reports on Form 8-K - none

                                       12

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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:  November 6, 1998             By:   /s/ Rich Dealy
                                           -----------------------------------
                                           Rich Dealy, Vice President and
                                             Chief Accounting Officer



                                       13

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