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 March 31, 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 March 31, 1998 and
              December 31, 1997..........................................    3

           Statements of Operations for the three months
             ended March 31, 1998 and 1997...............................    4

           Statement of Partners' Capital for the three months
             ended March 31, 1998........................................    5

           Statements of Cash Flows for the three months
             ended March 31, 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..............................   10

           27.1    Financial Data Schedule

           Signatures....................................................   11


                                        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
                                                     March 31,      December 31,
                                                       1998             1997
                                                    -----------     -----------
                                                    (Unaudited)
                 ASSETS

Current assets:
   Cash and cash equivalents, including interest
     bearing deposits of $76,613 at March 31
     and $87,310 at December 31                     $    76,726     $    87,423
   Accounts receivable - oil and gas sales               48,634          69,891
                                                     ----------      ----------
         Total current assets                           125,360         157,314
                                                     ----------      ----------
Oil and gas properties - at cost, based on the
   successful efforts accounting method               5,756,703       5,751,870
Accumulated depletion                                (4,525,277)     (4,497,380)
                                                     ----------      ----------
         Net oil and gas properties                   1,231,426       1,254,490
                                                     ----------      ----------
                                                    $ 1,356,786     $ 1,411,804
                                                     ==========      ==========
LIABILITIES AND PARTNERS' CAPITAL

Current liabilities:
   Accounts payable - affiliate                     $    18,933     $    23,946

Partners' capital:
   Managing general partner                              13,348          13,848
   Limited partners (7,531 interests)                 1,324,505       1,374,010
                                                     ----------      ----------
                                                      1,337,853       1,387,858
                                                     ----------      ----------
                                                    $ 1,356,786     $ 1,411,804
                                                     ==========      ==========

  The financial information included as of March 31, 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
                                                          March 31,
                                                 -------------------------
                                                    1998            1997
                                                 ----------     ----------
Revenues:
  Oil and gas                                    $  119,959     $  188,025
  Interest                                            1,284          1,380
                                                  ---------      ---------
                                                    121,243        189,405
                                                  ---------      ---------
Costs and expenses:
  Oil and gas production                             80,969         88,063
  General and administrative                          3,985          6,160
  Depletion                                          27,897         25,441
                                                  ---------      ---------
                                                    112,851        119,664
                                                  ---------      ---------
Net income                                       $    8,392     $   69,741
                                                  =========      =========
Allocation of net income:
  Managing general partner                       $       84     $      697
                                                  =========      =========
  Limited partners                               $    8,308     $   69,044
                                                  =========      =========
Net income per limited partnership interest      $     1.10     $     9.17
                                                  =========      =========
Distributions per limited partnership interest   $     7.68     $    15.85
                                                  =========      =========


         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                        (584)       (57,813)       (58,397)

    Net income                             84          8,308          8,392
                                     --------      ---------      ---------

Balance at March 31, 1998           $  13,348     $1,324,505     $1,337,853
                                     ========      =========      =========





         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)


                                                          Three months ended
                                                               March 31,
                                                       ------------------------
                                                          1998           1997
                                                       ----------    ----------
Cash flows from operating activities:
   Net income                                          $    8,392    $   69,741
   Adjustments to reconcile net income to net
     cash provided by operating activities:
       Depletion                                           27,897        25,441
   Changes in assets and liabilities:
       Accounts receivable                                 21,257        44,155
       Accounts payable                                    (5,013)        1,748
                                                        ---------     ---------
           Net cash provided by operating activities       52,533       141,085
                                                        ---------     ---------
Cash flows used in investing activities:
   Additions to oil and gas properties                     (4,833)       (2,659)

Cash flows used in financing activities:
   Cash distributions to partners                         (58,397)     (120,562)
                                                        ---------     ---------
Net increase (decrease) in cash and cash equivalents      (10,697)       17,864
Cash and cash equivalents at beginning of period           87,423        79,564
                                                        ---------     ---------
Cash and cash equivalents at end of period             $   76,726    $   97,428
                                                        =========     =========




         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
                                 March 31, 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 as of March 31,
1998 of the Partnership  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.  However,  these interim results are not
necessarily indicative of results for a full year.

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

Revenues:

The Partnership's  oil and gas revenues  decreased 36% to $119,959 from $188,025
for the three months ended March 31, 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 March 31, 1998, 6,439 barrels of oil,
1,823 barrels of natural gas liquids ("NGLs") and 7,827 mcf of gas were sold, or
9,567 barrel of oil equivalents  ("BOEs").  For the three months ended March 31,
1997, 6,596 barrels of oil and 14,606 mcf of gas were sold, or 9,030 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 for periods prior
to September 30, 1997. Also, prices for gas products will not be comparable as

                                        7

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the price per mcf for natural gas for the three  months  ended March 31, 1998 is
the price received for dry residue gas and the price per mcf for natural gas for
the three months ended March 31, 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  $7.19,  or 33%,  from
$21.99 for the three  months  ended March 31, 1997 to $14.80 for the same period
in 1998.  The average price  received per barrel of NGLs during the three months
ended  March 31,  1998 was $7.03.  The  average  price  received  per mcf of gas
decreased  49% from $2.94  during the three months ended March 31, 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 three months ended March 31, 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 March 1998. On April 23,
1998, the market price for West Texas  intermediate crude was $13.80 per barrel.
A continuation of the oil price environment experienced during the first quarter
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.

Costs and Expenses:

Total costs and expenses  decreased to $112,851 for the three months ended March
31,  1998 as compared  to  $119,664  for the same period in 1997,  a decrease of
$6,813,  or 6%.  This  decrease  was due to a decline  in  production  costs and
general and administrative expenses ("G&A"), offset by an increase in depletion.

Production  costs were  $80,969  for the three  months  ended March 31, 1998 and
$88,063 for the same period in 1997,  resulting in a decrease of $7,094,  or 8%.
The decrease was due to less well maintenance  costs and a decline in production
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,  35% from $6,160 for the three months ended March 31,
1997 to $3,985 for the same period in 1998.

Depletion  was $27,897  for the three  months  ended March 31, 1998  compared to
$25,441 for the same period in 1997.  This  represented an increase in depletion
of $2,456,  or 10%,  primarily  attributable to a decline in oil reserves during
the three  months  ended March 31, 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.

                                        8

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Liquidity and Capital Resources

Net Cash Provided by Operating Activities

Net cash provided by operating  activities  decreased  $88,552  during the three
months ended March 31, 1998 from the same period in 1997.  This decrease was due
to declines in oil and gas sales  receipts,  offset by a decline in G&A expenses
paid.

Net Cash Used in Investing Activities

The Partnership's  principal investing  activities during the three months ended
March 31,  1998 and 1997  related to the  addition of oil and gas  equipment  on
active properties.

Net Cash Used in Financing Activities

Cash  was  sufficient  for the  three  months  ended  March  31,  1998 to  cover
distributions  to the partners of $58,397 of which $584 was  distributed  to the
managing  general  partner  and $57,813 to the  limited  partners.  For the same
period  ended March 31,  1997,  cash was  sufficient  for  distributions  to the
partners of $120,562 of which $1,205 was  distributed  to the  managing  general
partner and $119,357 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.

Information systems for the year 2000

The managing general partner will be required to modify its information  systems
in order to  accurately  process  Partnership  data  referencing  the year 2000.
Because of the importance of occurrence  dates in the oil and gas industry,  the
consequences of not pursuing these  modifications  could be very  significant to
the Partnership's ability to manage and report operating activities.  Currently,
the managing general partner plans to contract with third parties to perform the
software  programming  changes  necessary to correct any existing  deficiencies.
Such programming  changes are anticipated to be completed and tested by March 1,
1999. 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.  Although the costs are not
estimable at this time, they should not be significant to the Partnership.

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

(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.

                                        9

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                           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

        (1)  On April 2, 1998,  the  Partnership  filed a Current Report on Form
             8-K dated  March 31,  1998,  reporting  under  Item 4  (Changes  in
             Registrant's  Certifying  Accountants)  the  engagement  of Ernst &
             Young  LLP  as  the  Partnership's  independent  auditors  and  the
             dismissal of KPMG Peat Marwick LLP effective upon the completion of
             the audit of the  Partnership  for the fiscal year ending  December
             31, 1997.



                                       10

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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:  May 5, 1998                 By:     /s/ Rich Dealy
                                            -----------------------------------
                                            Rich Dealy, Vice President
                                              and Chief Accounting Officer



                                       11

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