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, 1999


                         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 June 30, 1999 and
              December 31, 1998.......................................    3

           Statements of Operations for the three and six
             months ended June 30, 1999 and 1998......................    4

           Statement of Partners' Capital for the six months
             ended June 30, 1999......................................    5

           Statements of Cash Flows for the six months ended
             June 30, 1999 and 1998...................................    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

                                                    June 30,      December 31,
                                                      1999            1998
                                                  -----------     -----------
                                                  (Unaudited)
                 ASSETS

Current assets:
   Cash                                           $    96,775     $    76,330
   Accounts receivable - oil and gas sales            125,793          83,807
                                                   ----------      ----------
         Total current assets                         222,568         160,137
                                                   ----------      ----------
Oil and gas properties - at cost, based on the
   successful efforts accounting method             9,606,297       9,600,469
Accumulated depletion                              (7,794,127)     (7,703,198)
                                                   ----------      ----------
         Net oil and gas properties                 1,812,170       1,897,271
                                                   ----------      ----------
                                                  $ 2,034,738     $ 2,057,408
                                                   ==========      ==========
LIABILITIES AND PARTNERS' CAPITAL

Current liabilities:
   Accounts payable - affiliate                   $    35,235     $    22,740

Partners' capital:
   Managing general partner                            19,995          20,346
   Limited partners (11,897 interests)              1,979,508       2,014,322
                                                   ----------      ----------
                                                    1,999,503       2,034,668
                                                   ----------      ----------
                                                  $ 2,034,738     $ 2,057,408
                                                   ==========      ==========




   The financial information included as of June 30, 1999 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       Six months ended
                                         June 30,               June 30,
                                 ---------------------   ---------------------
                                    1999        1998        1999        1998
                                 ---------   ---------   ---------   ---------
Revenues:
  Oil and gas                    $ 196,244   $ 203,398   $ 349,651   $ 410,441
  Interest                             960       1,558       1,899       3,475
  Gain on disposition of assets        -           -           -           123
                                  --------    --------    --------    --------
                                   197,204     204,956     351,550     414,039
                                  --------    --------    --------    --------
Costs and expenses:
  Oil and gas production           115,052     134,541     236,655     274,144
  General and administrative         6,427       6,706      12,245      13,701
  Depletion                         29,386      61,424      90,929     114,204
                                  --------    --------    --------    --------
                                   150,865     202,671     339,829     402,049
                                  --------    --------    --------    --------
Net income                       $  46,339   $   2,285   $  11,721   $  11,990
                                  ========    ========    ========    ========
Allocation of net income:
  Managing general partner       $     463   $      23   $     117   $     120
                                  ========    ========    ========    ========
  Limited partners               $  45,876   $   2,262   $  11,604   $  11,870
                                  ========    ========    ========    ========
Net income per limited
  partnership interest           $    3.86   $     .19   $     .98   $    1.00
                                  ========    ========    ========    ========
Distributions per limited
  partnership interest           $    1.80   $    4.76   $    3.90   $   14.69
                                  ========    ========    ========    ========


         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, 1999          $   20,346     $2,014,322     $2,034,668

    Distributions                         (468)       (46,418)       (46,886)

    Net income                             117         11,604         11,721
                                     ---------      ---------      ---------

Balance at June 30, 1999            $   19,995     $1,979,508     $1,999,503
                                     =========      =========      =========







         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)



                                                          Six months ended
                                                               June 30,
                                                      ------------------------
                                                         1999          1998
                                                      ----------    ----------
Cash flows from operating activities:
  Net income                                          $   11,721    $   11,990
  Adjustments to reconcile net income to net
     cash provided by operating activities:
        Depletion                                         90,929       114,204
        Gain on disposition of assets                        -            (123)
  Changes in assets and liabilities:
        Accounts receivable                              (41,986)       31,700
        Accounts payable                                  12,495         6,802
                                                       ---------     ---------
          Net cash provided by operating activities       73,159       164,573
                                                       ---------     ---------
Cash flows from investing activities:
  Additions to oil and gas properties                     (5,828)       (7,888)
  Proceeds from asset dispositions                           -             123
                                                       ---------     ---------
          Net cash used in investing activities           (5,828)       (7,765)
                                                       ---------     ---------
Cash flows used in financing activities:
  Cash distributions to partners                         (46,886)     (176,476)
                                                       ---------     ---------
Net increase (decrease) in cash equivalents               20,445       (19,668)
Cash at beginning of period                               76,330       118,712
                                                       ---------     ---------
Cash at end of period                                 $   96,775    $   99,044
                                                       =========     =========



         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

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

                          NOTES TO FINANCIAL STATEMENTS
                                  June 30, 1999
                                   (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 June 30, 1999 and for the three and six months ended June 30,
1999 and 1998 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 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, 1998, 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

Six months ended June 30, 1999 compared with six months ended
   June 30, 1998

Revenues:

The Partnership's  oil and gas revenues  decreased 15% to $349,651 from $410,441
for the six months ended June 30, 1999 and 1998,  respectively.  The decrease in
revenues  resulted  from  lower  average  prices  received  and  a  decrease  in
production. For the six months ended June 30, 1999, 18,107 barrels of oil, 8,670
barrels  of natural  gas liquids  ("NGLs") and  36,322 mcf of gas were sold,  or

                                        7

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32,831  barrel of oil  equivalents  ("BOEs").  For the six months ended June 30,
1998,  21,153  barrels of oil,  8,110  barrel of NGLs and 36,722 mcf of gas were
sold, or 35,383 BOEs.

The average  price  received per barrel of oil decreased 6%, from $13.99 for the
six  months  ended  June 30,  1998 to $13.22  for the same  period in 1999.  The
average  price  received per barrel of NGLs  decreased 6%, from $7.27 during the
six months ended June 30, 1998 to $6.81 for the same period in 1999. The average
price  received per mcf of gas  decreased 7% from $1.51 for the six months ended
June 30, 1998 to $1.41 for the same period in 1999. 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,
1999.

The volatility of commodity prices has had, and continues to have, a significant
impact on the Partnership's revenues and operating cash flow and could result in
additional  decreases to the  carrying  value of the  Partnership's  oil and gas
properties.

A gain on disposition of assets of $123 was received during the six months ended
June 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 $339,829 for the six months ended June 30,
1998 as compared to $402,049 for the same period in 1998, a decrease of $62,220,
or 15%.  This decrease was due to declines in  production  costs,  depletion and
general and administrative expenses ("G&A").

Production  costs  were  $236,655  for the six months  ended  June 30,  1999 and
$274,144 for the same period in 1998,  resulting in a $37,489 decrease,  or 14%.
This decrease was due to declines in well  maintenance  costs,  production taxes
and workover expenses.

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, 11% from $13,701 for the six months ended June 30, 1998
to $12,245 for the same period in 1999.

Depletion  was  $90,929  for the six months  ended  June 30,  1999  compared  to
$114,204 for the same period in 1998,  a decrease in  depletion  of $23,275,  or
20%. This  decrease was primarily due to a reduction in oil  production of 3,046
barrels for the six months  ended June 30,  1999  compared to the same period in
1998, an increase in proved  reserves  during the period ended June 30, 1999 due
to higher commodity prices and 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
1998.

                                        8

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Three months ended June 30, 1999 compared with three months ended
   June 30, 1998

Revenues:

The  Partnership's  oil and gas revenues  decreased 4% to $196,244 from $203,398
for the three months ended June 30, 1999 and 1998, respectively. The decrease in
revenues resulted from a decrease in production, offset by higher average prices
received.  For the three months ended June 30, 1999, 8,675 barrels of oil, 4,896
barrels of NGLs and 18,753 mcf of gas were sold,  or 16,697 BOEs.  For the three
months ended June 30, 1998,  10,684  barrels of oil,  4,429  barrels of NGLs and
18,359 mcf of gas were sold, or 18,173 BOEs.

The average  price  received per barrel of oil  increased  $1.56,  or 12%,  from
$13.25 for the three months ended June 30, 1998 to $14.81 for the same period in
1999.  The average  price  received  per barrel of NGLs  increased 4% from $7.62
during  the three  months  ended June 30,  1998 to $7.90 for the same  period in
1999.  The average price  received per mcf of gas increased  slightly from $1.53
during  the three  months  ended June 30,  1998 to $1.55 for the same  period in
1999.

Costs and Expenses:

Total costs and  expenses  decreased to $150,865 for the three months ended June
30,  1999 as compared  to  $202,671  for the same period in 1998,  a decrease of
$51,806,  or 26%.  This  decrease was due to declines in  depletion,  production
costs and G&A.

Production  costs were  $115,052  for the three  months  ended June 30, 1999 and
$134,541 for the same period in 1998,  resulting in a $19,489 decrease,  or 14%.
The decrease was due to lower well  maintenance  costs,  production taxes and ad
valorem taxes.

During this period,  G&A decreased,  in aggregate,  4% from $6,706 for the three
months ended June 30, 1998 to $6,427 for the same period in 1999.

Depletion  was $29,386  for the three  months  ended June 30,  1999  compared to
$61,424  for the same  period in 1997,  a  decrease  of  $32,038,  or 52%.  This
decrease was primarily attributable to an increase in proved reserves during the
period ended June 30, 1999 as a result of higher commodity prices, a decrease in
oil  production  of 2,009  barrels  for the three  months  ended  June 30,  1999
compared  to the same period in 1998 and a reduction  in the  Partnership's  net
depletable  basis  from  charges  taken in  accordance  with SFAS 121 during the
fourth quarter of 1998.

Liquidity and Capital Resources

Net Cash Provided by Operating Activities

Net cash  provided by  operating  activities  decreased  $91,414  during the six
months  ended  June 30,  1999 from the same  period  ended June 30,  1998.  This
decrease was primarily due to a decline in oil and gas sales receipts, offset by
a decrease in production costs paid.

                                        9

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Net Cash Used in Investing Activities

The Partnership's  principal investing  activities for the six months ended June
30, 1999 and 1998  included  expenditures  related to equipment  replacement  on
various oil and gas properties.

Proceeds from asset  dispositions  of $123 were  received  during the six months
ended June 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  six  months  ended  June  30,  1999  to  cover
distributions  to the partners of $46,886 of which $468 was  distributed  to the
managing  general  partner  and $46,418 to the  limited  partners.  For the same
period  ended  June 30,  1998,  cash was  sufficient  for  distributions  to the
partners of $176,476 of which $1,765 was  distributed  to the  managing  general
partner and $174,711 to the limited partners.

From the third  quarter of 1997 through the first  quarter of 1999,  there was a
declining  trend in oil and gas levels.  During the first  quarter of 1999,  the
Organization  of  Petroleum  Exporting  Countries  and  certain  other crude oil
exporting  nations announced  reductions in their planned export volumes.  These
announcements,  together with early  indications that the nations have initiated
their planned  reductions,  have had some stabilizing effect on commodity prices
during  the  latter  part of the first  quarter  of 1999 and into  August  1999.
However,  no  assurances  can be given  that  the  stabilizing  effect  of these
actions,  or the planned reductions in export volumes,  will be sustained for an
extended period of time.

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.

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.

As of June 30, 1999, the managing general partner  estimates that the assessment
phase is approximately 99% complete and has included, but is not limited to, the
following procedures:

                                       10

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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.

Through June 30, 1999, the managing  general partner had  distributed  Year 2000
problem   inquiries  to  over  500  entities  and  has  received   responses  to
approximately 52% of the inquiries.

The remedial  phase of the managing  general  partner's  Year 2000 project is in
varying  stages of completion as it pertains to the  remediation  of information
technology and non-information technology applications and systems in the United
States, Canada and Argentina.  As of June 30, 1999, the managing general partner
estimates that the remedial phase is approximately 83% complete,  on a worldwide
basis,  subject  to  continuing  evaluations  of the  responses  to third  party
inquiries and to the testing phase results.  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 has completed the testing of the system for
Year 2000 compliance.  The remediation of non-information technology is expected
to be  completed  by October  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
information   technology   systems  by  October   1999.   The   testing  of  the
non-information  technology  remediation is scheduled to be completed by the end
of November 1999.

The managing  general  partner  expects that its total costs related to the Year
2000 problem will approximate $3.6 million, of which approximately $500 thousand
will have been incurred to replace non-compliant information technology systems.
As of June 30, 1999, the managing general  partner's total costs incurred on the
Year 2000 problem were $2.3 million,  of which  approximately $200 thousand were
incurred to replace non-compliant systems.

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 most likely
worst case scenario  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.

                                       11

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In the  business  continuity  and  contingency  planning  phase of the  managing
general partner's Year 2000 project, contingency plans were designed to mitigate
the exposures to mission critical  information  technology systems,  such as oil
and gas sales receipts, vendor and royalty cash distributions,  debt compliance,
accounting,  and employee  compensation.  Such contingency  plans anticipate the
extensive utilization of third-party data processing services, personal computer
applications  and the  substitution  of courier  and mail  services  in place of
electronic data interchange.  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)     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:  August 9, 1999          By:      /s/ Rich Dealy
                                         ---------------------------------
                                         Rich Dealy, Vice President and
                                         Chief Accounting Officer




                                       13

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