<PAGE>   1

                       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, 2000

                                       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 number 0-18982

                             IEA INCOME FUND X, L.P.
             (Exact name of registrant as specified in its charter)


               California                                    94-3098648
   (State or other jurisdiction of                         (I.R.S. Employer
    incorporation or organization)                        Identification No.)


         One Front Street, 15th Floor, San Francisco, California 94111
               (Address of principal executive offices) (Zip Code)

                                 (415) 677-8990
              (Registrant's telephone number, including area code)


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 [ ].


<PAGE>   2

                             IEA INCOME FUND X, L.P.

                  REPORT ON FORM 10-Q FOR THE QUARTERLY PERIOD
                            ENDED SEPTEMBER 30, 2000

                                TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                                                    PAGE
<S>                                                                                                 <C>
PART I - FINANCIAL INFORMATION

 Item 1. Financial Statements


         Condensed Balance Sheets (unaudited) - September 30, 2000 and December 31, 1999              4


         Condensed Statements of Operations (unaudited) for the three and nine months ended
         September 30, 2000 and 1999                                                                  5


         Condensed Statements of Cash Flows (unaudited) for the nine months ended September
         30, 2000 and 1999                                                                            6


         Notes to Condensed Financial Statements (unaudited)                                          7


 Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations       10


 Item 3. Quantitative and Qualitative Disclosures About Market Risk                                  11



PART II - FINANCIAL INFORMATION


 Item 6. Exhibits and Reports on Form 8-K                                                            12
</TABLE>


                                       2
<PAGE>   3

                         PART I - FINANCIAL INFORMATION


Item 1. Financial Statements

        Presented herein are the Registrant's condensed balance sheets as of
        September 30, 2000 and December 31, 1999, condensed statements of
        operations for the three and nine months ended September 30, 2000 and
        1999, and condensed statements of cash flows for the nine months ended
        September 30, 2000 and 1999.





                                       3
<PAGE>   4

                             IEA INCOME FUND X, L.P.

                            CONDENSED BALANCE SHEETS

                                   (UNAUDITED)



<TABLE>
<CAPTION>
                                                                                 September 30,        December 31,
                                                                                     2000                 1999
                                                                                 -------------        ------------
<S>                                                                              <C>                  <C>
                 Assets

Current assets:
   Cash and cash equivalents, includes $459,621 at September 30, 2000 and
        $356,206 at December 31, 1999 in interest-bearing accounts               $    647,692         $    356,306
   Net lease receivables due from Leasing Company
      (Notes 1 and 2)                                                                 171,403              177,496
                                                                                 ------------         ------------

         Total current assets                                                         819,095              533,802
                                                                                 ------------         ------------

Container rental equipment, at cost                                                13,646,368           15,457,224
   Less accumulated depreciation                                                    8,006,224            8,409,983
                                                                                 ------------         ------------
      Net container rental equipment                                                5,640,144            7,047,241
                                                                                 ------------         ------------

         Total assets                                                            $  6,459,239         $  7,581,043
                                                                                 ============         ============

            Partners' Capital

Partners' capital (deficit):
   General partner                                                               $    (57,479)        $    (45,189)
   Limited partners                                                                 6,516,718            7,626,232
                                                                                 ------------         ------------

         Total partners' capital                                                 $  6,459,239         $  7,581,043
                                                                                 ============         ============
</TABLE>



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


                                       4
<PAGE>   5

                             IEA INCOME FUND X, L.P.

                       CONDENSED STATEMENTS OF OPERATIONS

                                   (UNAUDITED)


<TABLE>
<CAPTION>
                                                         Three Months Ended                  Nine Months Ended
                                                   -------------------------------    -------------------------------
                                                   September 30,     September 30,    September 30,     September 30,
                                                       2000              1999              2000              1999
                                                   -------------     -------------    -------------     -------------
<S>                                                <C>               <C>              <C>               <C>
Net lease revenue (Notes 1 and 3)                   $ 293,539         $ 245,958         $ 800,669         $ 749,546

Other operating expenses:
  Depreciation                                        210,429           241,380           648,338           712,822
  Other general and administrative expenses            13,829             9,882            45,537            32,727
                                                    ---------         ---------         ---------         ---------
                                                      224,258           251,262           693,875           745,549
                                                    ---------         ---------         ---------         ---------

    Income (loss) from operations                      69,281            (5,304)          106,794             3,997

Other income (loss):
  Interest income                                       4,530             5,508            13,694            19,176
  Net loss on disposal of equipment                  (116,411)           (4,515)         (223,578)         (106,012)
                                                    ---------         ---------         ---------         ---------
                                                     (111,881)              993          (209,884)          (86,836)
                                                    ---------         ---------         ---------         ---------

    Net loss                                        $ (42,600)        $  (4,311)        $(103,090)        $ (82,839)
                                                    =========         =========         =========         =========

Allocation of net loss:
  General partner                                   $   9,932         $  12,337         $  27,342         $  38,377
  Limited partners                                    (52,532)          (16,648)         (130,432)         (121,216)
                                                    ---------         ---------         ---------         ---------

                                                    $ (42,600)        $  (4,311)        $(103,090)        $ (82,839)
                                                    =========         =========         =========         =========


Limited partners' per unit share of net loss        $   (1.34)        $   (0.42)        $   (3.33)        $   (3.09)
                                                    =========         =========         =========         =========
</TABLE>



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


                                       5
<PAGE>   6

                             IEA INCOME FUND X, L.P.

                       CONDENSED STATEMENTS OF CASH FLOWS

                                   (UNAUDITED)


<TABLE>
<CAPTION>
                                                                   Nine Months Ended
                                                            ---------------------------------
                                                            September 30,       September 30,
                                                                2000                1999
                                                            -------------       -------------
<S>                                                         <C>                 <C>
Net cash provided by operating activities                   $   885,970         $   826,559

Cash provided by investing activities:
  Proceeds from sale of container rental equipment              424,130             347,825

Cash used in financing activities:
  Distribution to Partners                                   (1,018,714)         (1,326,674)
                                                            -----------         -----------


Net increase (decrease) in cash and cash equivalents            291,386            (152,290)


Cash and cash equivalents, beginning of period                  356,306             653,851
                                                            -----------         -----------


Cash and cash equivalents, end of period                    $   647,692         $   501,561
                                                            ===========         ===========
</TABLE>



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


                                       6
<PAGE>   7

                             IEA INCOME FUND X, L.P.

               NOTES TO CONDENSED FINANCIAL STATEMENTS (UNAUDITED)


(1) Summary of Significant Accounting Policies

    (a) Nature of Operations

        IEA Income Fund X, L.P. (the "Partnership") is a limited partnership
        organized under the laws of the State of California on July 18, 1989 for
        the purpose of owning and leasing marine cargo containers worldwide to
        ocean carriers. To this extent, the Partnership's operations are subject
        to the fluctuations of world economic and political conditions. Such
        factors may affect the pattern and levels of world trade. The
        Partnership believes that the profitability of, and risks associated
        with, leases to foreign customers is generally the same as those of
        leases to domestic customers. The Partnership's leases generally require
        all payments to be made in United States currency.

        Cronos Capital Corp. ("CCC") is the general partner and, with its
        affiliate Cronos Containers Limited (the "Leasing Company"), manages the
        business of the Partnership. CCC and the Leasing Company also manage the
        container leasing business for other partnerships affiliated with the
        general partner. The Partnership shall continue until December 31, 2010,
        unless sooner terminated upon the occurrence of certain events.

        The Partnership commenced operations on January 17, 1990, when the
        minimum subscription proceeds of $1,000,000 were obtained. The
        Partnership offered 40,000 units of limited partnership interest at $500
        per unit, or $20,000,000. The offering terminated on October 30, 1990,
        at which time 39,206 limited partnership units had been purchased.

    (b) Leasing Company and Leasing Agent Agreement

        Pursuant to the Limited Partnership Agreement of the Partnership, all
        authority to administer the business of the Partnership is vested in
        CCC. CCC has entered into a Leasing Agent Agreement whereby the Leasing
        Company has the responsibility to manage the leasing operations of all
        equipment owned by the Partnership. Pursuant to the Agreement, the
        Leasing Company is responsible for leasing, managing and re-leasing the
        Partnership's containers to ocean carriers, and has full discretion over
        which ocean carriers and suppliers of goods and services it may deal
        with. The Leasing Agent Agreement permits the Leasing Company to use the
        containers owned by the Partnership, together with other containers
        owned or managed by the Leasing Company and its affiliates, as part of a
        single fleet operated without regard to ownership. Since the Leasing
        Agent Agreement meets the definition of an operating lease in Statement
        of Financial Accounting Standards (SFAS) No. 13, it is accounted for as
        a lease under which the Partnership is lessor and the Leasing Company is
        lessee.

        The Leasing Agent Agreement generally provides that the Leasing Company
        will make payments to the Partnership based upon rentals collected from
        ocean carriers after deducting direct operating expenses and management
        fees to CCC. The Leasing Company leases containers to ocean carriers,
        generally under operating leases which are either master leases or term
        leases (mostly one to five years). Master leases do not specify the
        exact number of containers to be leased or the term that each container
        will remain on hire but allow the ocean carrier to pick up and drop off
        containers at various locations; rentals are based upon the number of
        containers used and the applicable per-diem rate. Accordingly, rentals
        under master leases are all variable and contingent upon the number of
        containers used. Most containers are leased to ocean carriers under
        master leases; leasing agreements with fixed payment terms are not
        material to the financial statements. Since there are no material
        minimum lease rentals, no disclosure of minimum lease rentals is
        provided in these condensed financial statements.


                                                                     (Continued)
                                       7
<PAGE>   8

                             IEA INCOME FUND X, L.P.

               NOTES TO CONDENSED FINANCIAL STATEMENTS (UNAUDITED)


    (c) Basis of Accounting

        The Partnership utilizes the accrual method of accounting. Net lease
        revenue is recorded by the Partnership in each period based upon its
        leasing agent agreement with the Leasing Company. Net lease revenue is
        generally dependent upon operating lease rentals from operating lease
        agreements between the Leasing Company and its various lessees, less
        direct operating expenses and management fees due in respect of the
        containers specified in each operating lease agreement.

    (d) Financial Statement Presentation

        These condensed financial statements have been prepared without audit.
        Certain information and footnote disclosures normally included in
        financial statements prepared in accordance with accounting principles
        generally accepted in The United States of America ("GAAP") have been
        omitted. It is suggested that these condensed financial statements be
        read in conjunction with the financial statements and accompanying notes
        in the Partnership's latest annual report on Form 10-K.

        The preparation of financial statements in conformity with GAAP requires
        the Partnership to make estimates and assumptions that affect the
        reported amounts of assets and liabilities and disclosure of contingent
        assets and liabilities at the date of the financial statements and the
        reported amounts of revenues and expenses during the reported period.
        Actual results could differ from those estimates.

        The interim financial statements presented herewith reflect all
        adjustments of a normal recurring nature which are, in the opinion of
        management, necessary to a fair statement of the financial condition and
        results of operations for the interim periods presented. The results of
        operations for such interim periods are not necessarily indicative of
        the results to be expected for the full year.


(2) Net Lease Receivables Due from Leasing Company

    Net lease receivables due from the Leasing Company are determined by
    deducting direct operating payables and accrued expenses, base management
    fees payable, and reimbursed administrative expenses payable to CCC and its
    affiliates from the rental billings payable by the Leasing Company to the
    Partnership under operating leases to ocean carriers for the containers
    owned by the Partnership. Net lease receivables at September 30, 2000 and
    December 31, 1999 were as follows:

<TABLE>
<CAPTION>
                                                            September 30,    December 31,
                                                                2000            1999
                                                            -------------    ------------
<S>                                                         <C>              <C>
        Gross lease receivables                               $622,473        $518,979
        Less:
        Direct operating payables and accrued expenses         222,224         154,207
        Damage protection reserve                               65,774          72,336
        Base management fees payable                            46,474          51,184
        Reimbursed administrative expenses                      22,150           8,958
        Allowance for doubtful accounts                         94,448          54,798
                                                              --------        --------

        Net lease receivables                                 $171,403        $177,496
                                                              ========        ========
</TABLE>



                                                                     (Continued)
                                       8
<PAGE>   9

                             IEA INCOME FUND X, L.P.

               NOTES TO CONDENSED FINANCIAL STATEMENTS (UNAUDITED)


(3) Net Lease Revenue

    Net lease revenue is determined by deducting direct operating expenses, base
    management fees and reimbursed administrative expenses to CCC from the
    rental revenue billed by the Leasing Company under operating leases to ocean
    carriers for the containers owned by the Partnership. Net lease revenue for
    the three and nine-month periods ended September 30, 2000 and 1999 was as
    follows:

<TABLE>
<CAPTION>
                                                        Three Months Ended                  Nine Months Ended
                                                  -------------------------------     -------------------------------
                                                  September 30,     September 30,     September 30,     September 30,
                                                      2000              1999              2000              1999
                                                   ----------        ----------        ----------        ----------
<S>                                               <C>               <C>               <C>               <C>
        Rental revenue                             $  406,950        $  418,537        $1,278,706        $1,303,706
        Less:
        Rental equipment operating expenses            72,895           121,075           322,042           388,640
        Base management fees                           28,724            29,064            85,526            90,019
        Reimbursed administrative expenses             11,792            22,440            70,469            75,501
                                                   ----------        ----------        ----------        ----------

                                                   $  293,539        $  245,958        $  800,669        $  749,546
                                                   ==========        ==========        ==========        ==========
</TABLE>


(4) Operating Segment

    The Financial Accounting Standards Board has issued SFAS No. 131,
    "Disclosures about Segments of an Enterprise and Related Information," which
    changes the way public business enterprises report financial and descriptive
    information about reportable operating segments. An operating segment is a
    component of an enterprise that engages in business activities from which it
    may earn revenues and incur expenses, whose operating results are regularly
    reviewed by the enterprise's chief operating decision maker to make
    decisions about resources to be allocated to the segment and assess its
    performance, and about which separate financial information is available.
    Management operates the Partnership's container fleet as a homogenous unit
    and has determined, after considering the requirements of SFAS No. 131, that
    as such it has a single reportable operating segment.

    The Partnership derives its revenues from dry cargo marine containers. As of
    September 30, 2000, the Partnership operated 3,189 twenty-foot, 870
    forty-foot and 77 forty-foot high-cube dry cargo marine containers.

    Due to the Partnership's lack of information regarding the physical location
    of its fleet of containers when on lease in the global shipping trade, it is
    impracticable to provide the geographic area information required by SFAS
    No. 131.

                                     ******



                                       9
<PAGE>   10

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

It is suggested that the following discussion be read in conjunction with the
Registrant's most recent annual report on Form 10-K.


1)  Material changes in financial condition between September 30, 2000 and
    December 31, 1999.

    During the first nine months of 2000, the Registrant disposed of 553
    containers as part of its ongoing container operations. At September 30,
    2000, 79% of the original equipment remained in the Registrant's fleet, as
    compared to 89% at December 31, 1999, and was comprised of the following:

<TABLE>
<CAPTION>
                                                                   40-Foot
                                         20-Foot      40-Foot     High-Cube
                                         -------      -------     ---------
<S>                                      <C>          <C>         <C>
        Containers on lease:
             Term leases                    318          173           18
             Master leases                2,264          504           44
                                          -----        -----        -----
                Subtotal                  2,582          677           62

        Containers off lease                607          193           15
                                          -----        -----        -----

             Total container fleet        3,189          870           77
                                          =====        =====        =====
</TABLE>


<TABLE>
<CAPTION>
                                                                                                     40-Foot
                                                        20-Foot                40-Foot              High-Cube
                                                   ----------------       ----------------       ----------------
                                                   Units        %         Units        %         Units        %
                                                   -----      -----       -----      -----       -----      -----
<S>                                                <C>        <C>         <C>        <C>         <C>        <C>
        Total purchases                            4,000        100%      1,150        100%        100        100%
            Less disposals                           811         20%        280         24%         23         23%
                                                   -----      -----       -----      -----       -----      -----

        Remaining fleet at September 30, 2000      3,189         80%        870         76%         77         77%
                                                   =====      =====       =====      =====       =====      =====
</TABLE>


    At September 30, 2000, the Registrant had $647,692 in cash and cash
    equivalents, an increase of $291,386 from the cash balances at December 31,
    1999.

    The Registrant's allowance for doubtful accounts increased from $54,798 at
    December 31, 1999 to $94,448 at September 30, 2000. This increase was
    attributable to the delinquent account receivable balances of approximately
    16 lessees. The Leasing Company has either negotiated specific payment terms
    with these lessees or is pursuing other alternatives to collect the
    outstanding balances. In each instance, the Registrant believes it has
    recorded appropriate allowance.

    The Registrant disposed of 226 twenty-foot and 52 forty-foot dry cargo
    marine containers, as well as six forty-foot high cube dry cargo marine
    container during the third quarter of 2000, as compared to 25 twenty-foot
    and 15 forty-foot dry cargo marine containers during the same period in the
    prior year. These disposals resulted in a loss of $223,578 for the third
    quarter of 2000, as compared to a loss of $106,012 for the same period in
    the prior year. The Registrant does not believe that the carrying amount of
    its containers has been permanently impaired or that events or changes in
    circumstances have indicated that the carrying amount of its containers may
    not be fully recoverable. The Registrant believes that the loss on container
    disposals was a result of various factors including the age, condition,
    suitability for continued leasing, as well as the geographical location of
    the containers when disposed. These factors will continue to influence the
    amount of sales proceeds received and the related gain or loss on container
    disposals, which may fluctuate in subsequent periods.


                                                                     (Continued)
                                       10
<PAGE>   11

    The Registrant's cash distribution from operations for the third quarter of
    2000 was 4.50% (annualized) of the limited partners' original capital
    contribution, unchanged from the second quarter of 2000. These distributions
    are directly related to the Registrant's results from operations and may
    fluctuate accordingly. The cash distribution from sales proceeds for the
    third quarter of 2000 was 4.00% (annualized) of the limited partners'
    original capital contribution, an increase of 1.50% from the second quarter
    of 2000. Sales proceeds distributed to its partners may fluctuate in
    subsequent periods, reflecting the level of container disposals.

2)  Material changes in the results of operations between the three and
    nine-month periods ended September 30, 2000 and the three and nine-month
    periods ended September 30, 1999.

    Net lease revenue for the three and nine-month periods ended September 30,
    2000 was $293,539 and $800,669, respectively, an increase of 19% and 7%,
    respectively, from the same three and nine-month periods in the prior year.
    Gross rental revenue (a component of net lease revenue) for the three and
    nine-month periods ended September 30, 2000 was $406,950 and $1,278,706,
    respectively, a decrease of 3% and 2% from the respective three and
    nine-month periods in the prior year. Gross rental revenue was primarily
    impacted by higher utilization levels and lower per-diem rental rates.
    Average per-diem rental rates for the three and nine-month periods ended
    September 30, 2000 declined 2% and 7%, respectively, when compared to the
    same periods in the prior year. The Registrant's average fleet size and
    utilization rates for the three and nine-month periods ended September 30,
    2000 and 1999 were as follows:

<TABLE>
<CAPTION>
                                                        Three Months Ended          Nine Months Ended
                                                   ---------------------------   ----------------------------
                                                   September 30,  September 30,  September 30,  September 30,
                                                        2000          1999          2000            1999
                                                   -------------  -------------  -------------  -------------
<S>                                                <C>            <C>            <C>            <C>
        Average fleet size (measured in twenty-        5,208         5,860         5,484           5,973
           foot equivalent units (TEU))
        Average Utilization                               81%           76%           80%             72%
</TABLE>

    The age and declining size of the Registrant's fleet contributed to
    reductions in depreciation expense of 13% and 9%, respectively, when
    compared to the respective three and nine-month periods in the prior year.
    Rental equipment operating expenses during the three and nine-month periods
    ended September 30, 2000 were 18% and 25%, respectively, of the Registrant's
    gross lease revenue, as compared to 29% and 30%, respectively, during the
    same three and nine-month periods ended September 30, 1999. The large
    decrease for the three-month period ended September 30, 2000 was
    attributable to the recovery of doubtful accounts. The Registrant's
    declining fleet size and related operating results contributed to a decline
    in base management fees.


Item 3. Quantitative and Qualitative Disclosures About Market Risk

        Not applicable.



                                       11
<PAGE>   12

                           PART II - OTHER INFORMATION


Item 6. Exhibits and Reports on Form 8-K

(a) Exhibits

<TABLE>
<CAPTION>
      Exhibit
        No.                       Description                                   Method of Filing
      -------                     -----------                                   ----------------
<S>              <C>                                                            <C>
       3(a)      Limited Partnership Agreement of the Registrant,               *
                 amended and restated as of November 7, 1989

       3(b)      Certificate of Limited Partnership of the Registrant           **


       27        Financial Data Schedule                                        Filed with this
                                                                                document
</TABLE>


(b) Reports on Form 8-K

    No reports on Form 8-K were filed by the Registrant during the quarter ended
    September 30, 2000.






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

*   Incorporated by reference to Exhibit "A" to the Prospectus of the Registrant
    dated November 7, 1989, included as part of Registration Statement on Form
    S-1 (No. 33-30245)

**  Incorporated by reference to Exhibit 3.2 to the Registration Statement on
    Form S-1 (No. 33-30245)


                                       12
<PAGE>   13

                                   SIGNATURES


        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.




                                     IEA INCOME FUND X, L.P.


                                     By   Cronos Capital Corp.
                                          The General Partner




                                     By   /s/ Dennis J. Tietz
                                          --------------------------------------
                                          Dennis J. Tietz
                                          President and Director of Cronos
                                          Capital Corp. ("CCC")
                                          Principal Executive Officer of CCC


Date: November 14, 2000


                                       13
<PAGE>   14

                                  EXHIBIT INDEX


<TABLE>
<CAPTION>
      Exhibit
        No.                       Description                                   Method of Filing
      -------                     -----------                                   ----------------
<S>              <C>                                                            <C>
       3(a)      Limited Partnership Agreement of the Registrant,               *
                 amended and restated as of November 7, 1989

       3(b)      Certificate of Limited Partnership of the Registrant           **


       27        Financial Data Schedule                                        Filed with this
                                                                                document
</TABLE>







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

*   Incorporated by reference to Exhibit "A" to the Prospectus of the Registrant
    dated November 7, 1989, included as part of Registration Statement on Form
    S-1 (No. 33-30245)

**  Incorporated by reference to Exhibit 3.2 to the Registration Statement on
    Form S-1 (No. 33-30245)