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. 33-26097-10


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


                  Delaware                                   75-2347264       
     (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-C 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-C 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                                           $    80,362      $    87,423
   Accounts receivable - oil and gas sales             51,621           69,891
                                                   ----------       ----------
            Total current assets                      131,983          157,314
                                                   ----------       ----------
Oil and gas properties - at cost, based on the
   successful efforts accounting method             5,763,392        5,751,870
Accumulated depletion                              (4,587,405)      (4,497,380)
                                                   ----------       ----------
            Net oil and gas properties              1,175,987        1,254,490
                                                   ----------       ----------
                                                  $ 1,307,970      $ 1,411,804
                                                   ==========       ==========
LIABILITIES AND PARTNERS' CAPITAL

Current liabilities:
   Accounts payable - affiliate                   $    28,788      $    23,946

Partners' capital:
   Managing general partner                            12,761           13,848
   Limited partners (7,531 interests)               1,266,421        1,374,010
                                                   ----------       ----------
                                                    1,279,182        1,387,858
                                                   ----------       ----------
                                                  $ 1,307,970      $ 1,411,804
                                                   ==========       ==========



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-C 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                  $  103,574  $  145,486   $  332,065  $  490,257
   Interest                          1,108       1,450        3,542       4,389
   Gain on disposition of assets       -             7          -           800
                                 ---------   ---------    ---------   ---------
                                   104,682     146,943      335,607     495,446
                                 ---------   ---------    ---------   ---------
Costs and expenses:
   Oil and gas production           70,626      73,715      239,607     239,766
   General and administrative        3,107       5,888       10,700      16,906
   Depletion                        35,226      26,566       90,025      78,796
                                 ---------   ---------    ---------   ---------
                                   108,959     106,169      340,332     335,468
                                 ---------   ---------    ---------   ---------
Net income (loss)               $   (4,277) $   40,774   $   (4,725) $  159,978
                                 =========   =========    =========   =========
Allocation of net income (loss):
   Managing general partner     $      (43) $      408   $      (47) $    1,600
                                 =========   =========    =========   =========
   Limited partners             $   (4,234) $   40,366   $   (4,678) $  158,378
                                 =========   =========    =========   =========
Net income (loss) per limited
   partnership interest         $     (.56) $     5.36   $     (.62) $    21.03
                                 =========   =========    =========   =========
Distributions per limited
   partnership interest         $     2.39  $    10.27   $    13.66  $    38.16
                                 =========   =========    =========   =========


         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-C CONV., L.P.
                        (A Delaware Limited Partnership)

                         STATEMENT OF PARTNERS' CAPITAL
                                   (Unaudited)




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

Balance at January 1, 1998          $  13,848     $1,374,010     $1,387,858

    Distributions                      (1,040)      (102,911)      (103,951)

    Net loss                              (47)        (4,678)        (4,725)
                                     --------      ---------      ---------

Balance at September 30, 1998       $  12,761     $1,266,421     $1,279,182
                                     ========      =========      =========






         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-C 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 (loss)                                 $   (4,725)   $  159,978
   Adjustments to reconcile net income (loss) to
     net cash provided by operating activities:
        Depletion                                        90,025        78,796
        Gain on disposition of assets                       -            (800)
   Changes in assets and liabilities:
        Accounts receivable                              18,270        61,092
        Accounts payable                                  4,842         9,525
                                                      ---------     ---------
          Net cash provided by operating activities     108,412       308,591
                                                      ---------     ---------
Cash flows from investing activities:
   Additions to oil and gas properties                  (11,522)       (5,911)
   Proceeds from asset dispositions                         -             800
                                                      ---------     ---------
          Net cash used in investing activities         (11,522)       (5,111)
                                                      ---------     ---------
Cash flows from financing activities:
   Cash distributions to partners                      (103,951)     (290,256)
                                                      ---------     ---------
Net increase (decrease) in cash                          (7,061)       13,224
Cash at beginning of period                              87,423        79,564
                                                      ---------     ---------
Cash at end of period                                $   80,362    $   92,788
                                                      =========     =========


         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-C 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-C 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 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, 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 32% to $332,065 from $490,257
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,  18,483

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barrels of oil, 6,214 barrels of natural gas liquids  ("NGLs") and 22,942 mcf of
gas were sold, or 28,521 barrel of oil equivalents ("BOEs"). For the nine months
ended September 30, 1997, 19,209 barrels of oil and 45,111 mcf of gas were sold,
or 26,728 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  $6.20,  or 31%,  from
$19.79  for the nine  months  ended  September  30,  1997 to $13.59 for the same
period in 1998.  The average  price  received per barrel of NGLs during the nine
months ended September 30, 1998 was $7.21. The average price received per mcf of
gas decreased 36% from $2.44 during the nine months ended  September 30, 1997 to
$1.57 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 $800 recognized  during the nine months ended
September 30, 1997 was attributable to credits received from the disposal of oil
and gas equipment on one fully depleted well.

Costs and Expenses:

Total  costs and  expenses  increased  to  $340,332  for the nine  months  ended
September  30,  1998 as compared  to  $335,468  for the same period in 1997,  an
increase of $4,864. This increase was due to an increase in depletion, offset by
declines in general and administrative expenses ("G&A") and production costs.

Production  costs were $239,607 for the nine months ended September 30, 1998 and
$239,766 for the same period in 1997, resulting in a $159 decrease. The decrease
was due to lower  production  taxes,  offset by an increase in well  maintenance
costs incurred in an effort to stimulate well production.

G&A's  components are independent  accounting and engineering  fees and managing
general  partner  personnel  and  operating  costs.   During  this  period,  G&A

                                        8

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decreased,  in aggregate,  37% from $16,906 for the nine months ended  September
30, 1997 to $10,700 for the same period in 1998.

Depletion  was $90,025 for the nine months ended  September 30, 1998 compared to
$78,796 for the same  period in 1997,  representing  an increase of $11,229,  or
14%.  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 oil  production  of 726 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 29% to $103,574 from $145,486
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,  5,909
barrels of oil,  2,477  barrels of NGLs and 8,373 mcf of gas were sold, or 9,782
BOEs.  For the three months ended  September 30, 1997,  6,195 barrels of oil and
15,309 mcf of gas were sold, or 8,747 BOEs.

The average  price  received per barrel of oil  decreased  $5.94,  or 32%,  from
$18.37 for the three  months  ended  September  30,  1997 to $12.43 for the same
period in 1998.  The average price  received per barrel of NGLs during the three
months ended September 30, 1998 was $6.76. The average price received per mcf of
gas decreased 23% from $2.07 during the three months ended September 30, 1997 to
$1.60 in 1998.

Costs and Expenses:

Total costs and  expenses  increased  to  $108,959  for the three  months  ended
September  30,  1998 as compared  to  $106,169  for the same period in 1997,  an
increase of $2,790,  or 3%. This  increase was due to an increase in  depletion,
offset by declines in production costs and G&A.

Production  costs were $70,626 for the three months ended September 30, 1998 and
$73,715 for the same period in 1997, resulting in a $3,089 decrease,  or 4%. The
decrease was due to lower  production  taxes and ad valorem taxes,  offset by an
increase  in well  maintenance  costs  incurred in an effort to  stimulate  well
production.

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,  47% from $5,888 for the three months ended  September
30, 1997 to $3,107 for the same period in 1998.

Depletion was $35,226 for the three months ended  September 30, 1998 compared to
$26,566 for the same period in 1997, representing an increase of $8,660, or 33%.
This increase was primarily  attributable  to a decrease in oil reserves  during

                                        9

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the period  ended  September  30,  1998 as a result of lower  commodity  prices,
offset by a reduction  in oil  production  of 286  barrels for the period  ended
September 30, 1998 compared to the same period in 1997.

Liquidity and Capital Resources

Net Cash Provided by Operating Activities

Net cash provided by operating  activities  decreased  $200,179  during the nine
months ended  September 30, 1998 from the same period ended  September 30, 1997.
This decrease was  primarily due to a decline in oil and gas sales  receipts and
an increase in G&A expenses paid, offset by a decrease in production costs paid.

Net Cash Used in Investing Activities

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

Proceeds from asset  dispositions  of $800 were received  during the nine months
ended  September  30, 1997 from the salvage of equipment  on one fully  depleted
well.

Net Cash Used in Financing Activities

Cash was  sufficient  for the nine  months  ended  September  30,  1998 to cover
distributions to the partners of $103,951 of which $1,040 was distributed to the
managing  general  partner and  $102,911 to the limited  partners.  For the same
period ended  September 30, 1997, cash was sufficient for  distributions  to the
partners of $290,256 of which $2,903 was  distributed  to the  managing  general
partner and $287,353 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.

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

                                       10

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

                                       11

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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-C 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-C CONV., L.P.

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




Dated:  November 9, 1998            By:    /s/ Rich Dealy
                                           ---------------------------------
                                           Rich Dealy, Vice President and
                                             Chief Accounting Officer



                                       13

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