<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 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.


        TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 (D) OF THE
-----   SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD
        FROM            TO            .



Commission File number:  0-16601 (formerly 33-16164-LA)



                       FMG RITA RANCH LIMITED PARTNERSHIP
                           (Exact name of registrant)


Delaware                                             23-2466343

(State or other jurisdiction of                      (I.R.S. Employer
incorporation or organization)                       Identification No.)

250 King of Prussia Road, Radnor, PA  19087
(Address of Principal Executive Offices)

Issuer's Telephone Number:  (610 964-7234)

Indicate by check mark whether the registrant (a) 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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PART I - FINANCIAL INFORMATION

Item 1 - Financial Statements

         The unaudited financial statements of FMG Rita Ranch Limited
partnership (the "Partnership") at March 31, 1998 are attached hereto as Exhibit
A.

         In the opinion of management, the accompanying unaudited condensed
financial statements include all adjustments, which are of a normal recurring
nature, necessary to present fairly the Partnership's financial position as of
March 31, 1998, and the results of its operations and cash flows for the three
months ended March 31, 1998.

Item 2 - Management's Discussion and Analysis of Financial Condition and Results
of Operations.

         Background

         The Partnership is a Delaware limited partnership. The Partnership was
formed on January 30, 1987 by FMG Western Region Acquisitions, Inc. (the
"General Partner") and the initial limited partner, FM Initial, Inc., with an
initial contribution of $25,000 by the General Partner. The General Partner is
an indirect wholly-owned subsidiary of The Fidelity Mutual Life Insurance
Company (in Rehabilitation) ("Fidelity Mutual"). In accordance with the Amended
and Restated Limited partnership Agreement dated December 17, 1987 (the
"Partnership Agreement"), FM Initial, Inc. withdrew from the partnership upon
admittance of new limited partners. The Partnership was formed to acquire and
realize appreciation in a certain 118 acre parcel of undeveloped land near
Tucson, Arizona (the "Property") by holding it for investment and eventual sale,
although there is no assurance that this will be attained.

         Results of Operations

         The Partnership had no revenues for the first quarter of 1998. Expenses
for the first quarter of 1998 consisted of general and administrative costs of
$3,367, management fees of $3,750, insurance of $30 and real estate taxes of
$2,239.

         The Partnership's revenues for the first quarter of 1997 consisted of
interest income of $2. Expenses for the first quarter of 1997 consisted of
general and administrative costs of $1,255, management fees of $3,750, insurance
of $27 and real estate taxes of $2,367.

         The Partnership's revenues for the first quarter of 1996 consisted of
interest income of $2 and partnership transfer fees of $75. Expenses for the
first quarter of 1996 consisted of general and administrative costs of $1,430,
management fees of $3,750, insurance of $35 and real estate taxes of $2,604.


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<PAGE>   3
         The General Partner has no plans to develop the Property, except for
activities including land planning, market surveys and other activities
necessary to prepare the Property for sale. There can be no assurance that
necessary funds would be available should it be desirable for the Partnership to
improve the Property to facilitate its sale.

         Because of the lack of demand for industrial and commercial land in the
Tucson area and the resulting decline in the Property's value, the Partnership
was required to reduce its carrying value on the Property in 1990 and again in
1992. Class "A" Business Park lots dominate the industrial land sales market.
Sale prices range from $1.00 to $2.15 per square foot for 5 to 20 acre parcels.
There have not been any bulk sale transactions since the RTC was disposing of
it's properties. The General Partner believes that it would be necessary for the
Partnership to hold the property for several years, possibly decades, before the
Partnership may be able to sell the Property at a price which approximates the
price paid by the Partnership for the Property. Thus, it is unlikely that the
Property will be sold for a price which approximates the original price paid by
the Partnership for the Property.

         During 1990 and 1992, the Partnership recorded writedowns of $6,261,041
and $830,000 respectively.

         Liquidity and Capital Resources

         The Partnership has no cash reserve remaining at March 31, 1998. As
shown in the accompanying financial statements, the Partnership has incurred
substantial operating losses in each of the past three years. Such losses will
continue until the Partnership begins to sell land parcels. In the partnership
agreement, the General Partner has committed to contribute up to $600,000 to the
capital of the Partnership as the need for additional working capital arises.
Cumulative amounts funded by the General Partner amounted to $305,602 at March
31, 1998. Realization of the partnership's assets is dependent upon the
continued funding of operating deficits by the General Partner and its
affiliate. There can be no assurance, however, that the General Partner or its
affiliate will continue to fund operating deficits.

         During 1997, marketing proposals were solicited from area brokerage
firms. A brokerage firm was selected and the property is currently listed for
sale.

         Impact of Year 2000

         The Partnership's management has assessed the Year 2000 technology
issue, and has developed an action plan to address the issue. Management
believes that its action plan will be implemented and completed in a timely
fashion, and that it will not materially affect the Partnership's future
operating results or future financial condition.


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<PAGE>   4
PART II - OTHER INFORMATION

Item 1 - Legal Proceedings

         The Partnership is not a direct party to, nor is the Partnership's
property directly the subject of, any material legal proceedings. However, on
November 6, 1992, the Commonwealth Court of Pennsylvania issued an order placing
The Fidelity Mutual Life Insurance Company ("Fidelity Mutual"), the indirect
parent of the General Partner of the Partnership, into rehabilitation under the
control and authority of the Pennsylvania Insurance Commissioner pursuant to the
provisions of the Pennsylvania Insurance Department Act, 40 P.S. Section 221.1
et seq. The Partnership is not a direct party to the order, but ownership of the
stock of the General Partner and the stock of the majority Limited Partner is
vested in the Insurance Commissioner pursuant to the Order.

Item 2 - Changes in Securities

         There was no change in the partnership's securities during the first
quarter of 1998.


Item 3 - Defaults Upon Senior Securities

         There was no default in the payment of principal, interest, a sinking
or purchase fund installment or any other default with respect to any
indebtedness of the Partnership. The Partnership has issued no preferred stock;
accordingly, there has been no arrearages or delinquencies with respect to any
such preferred stock.


Item 4 - Submission of Matters to a Vote of Security Holders

         No matters were submitted to the Partners for a vote during the first
quarter of 1998.


Item 5 - Other Information

         None


Item 6 - Exhibits and Reports on Form 8-K

Reports on Form 8-K

         None


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<PAGE>   5
Exhibits (numbered in accordance with Item 601 of Regulation S-K)

Exhibit Numbers            Description                              Page Number
---------------            -----------                              -----------

3.1(a)                     Certificate of Limited                   *
                           Partnership

3.1(b) & (4)               Restated Limited Partnership             **
                           Agreement

9                          not applicable

11                         not applicable

12                         not applicable

13                         not applicable

16                         not applicable

18                         not applicable

19                         not applicable

22                         not applicable

23                         not applicable

24                         not applicable

25                         not applicable

28                         not applicable

29                         not applicable

----------

*Incorporated by reference to Exhibit 3.1 filed as part of the Exhibits to the
Partnership's Registration Statement on Form S-18, Registration No. 33-16164-LA.

** Incorporated by reference to Exhibit 3.2 filed as part of the partnership's
Registration Statement on Form S-18, Registration No. 33-16164-LA.


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<PAGE>   6
                                    SIGNATURE


         Pursuant to the requirements of the Securities Exchange Act of 1934,
this Report has been signed below by the following persons on behalf of the
Registrant and in the capacities and on the date indicated.


Signature                          Title                         Date



/s/ Arthur W. Mullin               President,                 May 13, 1998
-------------------------          Treasurer,
Arthur W. Mullin                   Director of
                                   FMG Western
                                   Region
                                   Acquisitions,
                                   Inc.



/s/ James W. Kelican, Jr.          Vice President,            May 13, 1998
-------------------------          Director of
James W. Kelican, Jr.              FMG Western
                                   Region
                                   Acquisitions,
                                   Inc.


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<PAGE>   7
EXHIBIT A

                       FMG RITA RANCH LIMITED PARTNERSHIP

                                 BALANCE SHEETS


<TABLE>
<CAPTION>
                                                     MARCH 31,        DECEMBER 31,
                                                       1998               1997
                                                    (UNAUDITED)
                                                    -----------       ------------
           ASSETS

<S>                                                  <C>                <C>     
Land held for sale, net                              $350,000           $350,000

Cash and cash equivalents                                 519                519

Prepaid Insurance                                          59               --
                                                     --------           --------

                                                     $350,578           $350,519
                                                     ========           ========



LIABILITIES AND PARTNERS' EQUITY


   Accrued expenses                                  $ 12,118           $  9,906

   Due to affiliates                                     --                3,750

   Partners' Equity                                   338,460            336,863
                                                     --------           --------

                                                     $350,578           $350,519
                                                     ========           ========
</TABLE>


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<PAGE>   8
                       FMG RITA RANCH LIMITED PARTNERSHIP

                  STATEMENT OF OPERATIONS AND PARTNER'S EQUITY

                                   (UNAUDITED)


<TABLE>
<CAPTION>
                                                FOR THE THREE MONTHS
                                                   ENDED MARCH 31
                                    -------------------------------------------
                                       1998             1997             1996
                                       ----             ----             ----
<S>                                 <C>              <C>              <C>      
REVENUES:
  Interest income                   $    --          $       2        $       2
  Other income                           --               --                 75
                                    ---------        ---------        ---------

                                         --                  2               77
                                    =========        =========        =========


EXPENSES:
  Real estate taxes                     2,239            2,367            2,604
  Management fees                       3,750            3,750            3,750
  General and administrative            3,367            1,255            1,430
  Insurance                                30               27               35
                                    ---------        ---------        ---------

                                        9,386            7,399            7,819
                                    ---------        ---------        ---------


          NET LOSS                  $  (9,386)       $  (7,397)       $  (7,742)

Partners' equity,
   Beginning of period                336,863          336,856          336,613

Captial Contributions                  10,983            8,758            8,738
                                    ---------        ---------        ---------

Partners' equity,
   End of period                    $ 338,460        $ 338,217        $ 337,609
                                    =========        =========        =========


Weighted Average Number of
   Limited Partnership Units
   Outstanding                          6,707            6,707            6,707
                                    =========        =========        =========


Loss from Operations per
   Limited Partnership
   Interest                         $   (1.38)       $   (1.09)       $   (1.14)
                                    =========        =========        =========
</TABLE>


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<PAGE>   9
                       FMG RITA RANCH LIMITED PARTNERSHIP

                            STATEMENTS OF CASH FLOWS

                                   (UNAUDITED)

<TABLE>
<CAPTION>
                                                          FOR THE THREE MONTHS
                                                             ENDED MARCH 31
                                                 ---------------------------------------

                                                    1998           1997           1996
                                                 ---------       --------       --------
<S>                                              <C>             <C>            <C>     
CASH FLOWS FROM OPERATING ACTIVITIES:

         Net income (loss)                       $ (9,386)       $(7,397)       $(7,742)
         Adjustments to reconcile net
            income (loss) to net cash
            used in operating activities:

            Increase in General Partner's
               capital                             10,983          8,758          8,738
           Increase (decrease) in
               accrued expenses                     2,212          2,414          2,870
          (Increase) in prepaid expenses              (59)           (54)           (69)
          Increase (decrease) in due to
               affiliate                           (3,750)        (3,750)        (3,750)
                                                 --------        -------        -------
            Net cash provided by (used in)
               operating activities              $      0        $   (29)       $    47
                                                 --------        -------        -------


            Cash, Beginning of period                 519            267            205
                                                 --------        -------        -------


            Cash, End of period                  $    519        $   238        $   252
                                                 ========        =======        =======
</TABLE>


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