<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 JUNE 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.)

         444 Market 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 JUNE 30, 2000

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>


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

  Item 1.   Financial Statements


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


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


            Condensed Statements of Cash Flows for the six months ended June 30, 2000 and 1999 (unaudited)                    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
            June 30, 2000 and December 31, 1999, condensed statements of
            operations for the three and six months ended June 30, 2000 and
            1999, and condensed statements of cash flows for the six months
            ended June 30, 2000 and 1999.


                                       19
<PAGE>   4


                             IEA INCOME FUND X, L.P.

                            CONDENSED BALANCE SHEETS

                                   (UNAUDITED)


<TABLE>
<CAPTION>

                                                                                   June 30,          December 31,
                                                                                     2000                1999
                                                                                 -------------       -------------
                        Assets
<S>                                                                              <C>                 <C>
Current assets:
    Cash and cash equivalents, includes $414,984 at June 30, 2000 and
         $356,206 at December 31, 1999 in interest-bearing accounts              $     472,580       $     356,306
    Net lease receivables due from Leasing Company
        (notes 1 and 2)                                                                150,586             177,496
                                                                                 -------------       -------------

             Total current assets                                                      623,166             533,802
                                                                                 -------------       -------------

Container rental equipment, at cost                                                 14,575,043          15,457,224
    Less accumulated depreciation                                                    8,340,471           8,409,983
                                                                                 -------------       -------------
        Net container rental equipment                                               6,234,572           7,047,241
                                                                                 -------------       -------------

             Total assets                                                        $   6,857,738       $   7,581,043
                                                                                 =============       =============

                 Partners' Capital

Partners' capital (deficit):
    General partner                                                              $     (53,494)      $     (45,189)
    Limited partners                                                                 6,911,232           7,626,232
                                                                                 -------------       -------------

             Total partners' capital                                             $   6,857,738       $   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               Six Months Ended
                                                  -------------------------       -------------------------
                                                   June 30,        June 30,        June 30,        June 30,
                                                     2000            1999            2000            1999
                                                  ---------       ---------       ---------       ---------
<S>                                               <C>             <C>             <C>             <C>
Net lease revenue (notes 1 and 3)                 $ 263,594       $ 227,987       $ 507,130       $ 503,588

Other operating expenses:
   Depreciation                                     216,105         233,687         437,909         471,442
   Other general and administrative expenses         18,184           8,269          31,708          22,845
                                                  ---------       ---------       ---------       ---------
                                                    234,289         241,956         469,617         494,287
                                                  ---------       ---------       ---------       ---------

      Income (loss) from operations                  29,305         (13,969)         37,513           9,301

Other income (loss):
   Interest income                                    5,311           6,650           9,164          13,668
   Net loss on disposal of equipment                (56,581)        (17,579)       (107,167)       (101,497)
                                                  ---------       ---------       ---------       ---------
                                                    (51,270)        (10,929)        (98,003)        (87,829)
                                                  ---------       ---------       ---------       ---------

      Net loss                                    $ (21,965)      $ (24,898)      $ (60,490)      $ (78,528)
                                                  =========       =========       =========       =========

Allocation of net (loss):
   General partner                                $   8,500       $  14,021       $  17,410       $  26,040
   Limited partners                                 (30,465)        (38,919)        (77,900)       (104,568)
                                                  ---------       ---------       ---------       ---------

                                                  $ (21,965)      $ (24,898)      $ (60,490)      $ (78,528)
                                                  =========       =========       =========       =========

Limited partners' per unit share of net loss      $   (0.78)      $   (1.00)      $   (1.99)      $   (2.67)
                                                  =========       =========       =========       =========
</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>


                                                                                      Six Months Ended
                                                                                 -------------------------
                                                                                  June 30,        June 30,
                                                                                   2000            1999
                                                                                 ---------       ---------
<S>                                                                              <C>             <C>
Net cash provided by operating activities                                        $ 553,948       $ 558,357

Cash provided by investing activities:
   Proceeds from sale of container rental equipment                                225,141         260,481

Cash used in financing activities:
   Distribution to partners                                                       (662,815)       (905,770)
                                                                                 ---------       ---------


Net increase (decrease) in cash and cash equivalents                               116,274         (86,932)


Cash and cash equivalents at January 1                                             356,306         653,851
                                                                                 ---------       ---------


Cash and cash equivalents at June 30                                             $ 472,580       $ 566,919
                                                                                 =========       =========
</TABLE>

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

                                        6
<PAGE>   7

                             IEA INCOME FUND X, L.P.

                NOTES TO UNAUDITED CONDENSED FINANCIAL STATEMENTS


(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.

                                       7

<PAGE>   8

                             IEA INCOME FUND X, L.P.

                NOTES TO UNAUDITED CONDENSED FINANCIAL STATEMENTS


       (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
            generally accepted accounting procedures 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
            accounting principles generally accepted in the United States (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 June 30,
       2000 and December 31, 1999 were as follows:

<TABLE>
<CAPTION>

                                                                   June 30,        December 31,
                                                                    2000               1999
                                                                -------------      -------------
<S>                                                             <C>                <C>
            Gross lease receivables                             $     575,477      $     518,979
            Less:
            Direct operating payables and accrued expenses            183,646            154,207
            Damage protection reserve                                  70,082             72,336
            Base management fees payable                               45,989             51,184
            Reimbursed administrative expenses                         25,108              8,958
            Allowance for doubtful accounts                           100,066             54,798
                                                                -------------      -------------

            Net lease receivables                               $     150,586      $     177,496
                                                                =============      =============
</TABLE>

                                       8                            (Continued)
<PAGE>   9
                             IEA INCOME FUND X, L.P.

                NOTES TO UNAUDITED CONDENSED FINANCIAL STATEMENTS


(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 six-month periods ended June 30, 2000 and 1999
       was as follows:

<TABLE>
<CAPTION>

                                                    Three Months Ended           Six Months Ended
                                                   ----------------------      ----------------------
                                                   June 30,      June 30,      June 30,      June 30,
                                                     2000          1999          2000          1999
                                                   --------      --------      --------      --------
<S>                                                <C>           <C>           <C>           <C>
          Rental revenue (note 4)                  $433,998      $422,429      $871,756      $885,169
          Less:
          Rental equipment operating expenses       113,650       138,962       249,147       267,565
          Base management fees                       28,767        28,784        56,802        60,955
          Reimbursed administrative expenses         27,987        26,696        58,677        53,061
                                                   --------      --------      --------      --------

                                                   $263,594      $227,987      $507,130      $503,588
                                                   ========      ========      ========      ========
</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 June 30, 2000, the Partnership operated 3,415 twenty-foot, 922
       forty-foot and 83 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 June 30, 2000 and
       December 31, 1999.

       During the first six months of 2000, the Registrant disposed of 269
       containers as part of its ongoing container operations. At June 30, 2000,
       84% 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                    328          186           19
                   Master leases                2,433          531           44
                                              -------      -------      -------
                        Subtotal                2,761          717           63

            Containers off lease                  654          205           20
                                              -------      -------      -------

                   Total container fleet        3,415          922           83
                                              =======      =======      =======
</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                     585         15%        228         20%         17         17%
                                                  -----      -----       -----      -----       -----      -----

            Remaining fleet at June 30, 2000      3,415         85%        922         80%         83         83%
                                                  =====      =====       =====      =====       =====      =====
</TABLE>


       At June 30, 2000, the Registrant had $472,580 in cash and cash
       equivalents, an increase of $116,274 from the cash balances at December
       31, 1999.

       The Registrant's allowance for doubtful accounts increased from $54,798
       at December 31, 1999 to $100,066 at June 30, 2000. This increase was
       attributable to the delinquent account receivable balances of
       approximately 11 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 provided sufficient reserves for all doubtful
       accounts.

       The Registrant disposed of 111 twenty-foot and 26 forty-foot dry cargo
       marine containers, as well as one forty-foot high cube dry cargo marine
       container during the second quarter of 2000, as compared to 82
       twenty-foot and 23 forty-foot dry cargo marine containers during the same
       period in the prior year. These disposals resulted in a loss of $56,581
       for the second quarter of 2000, as compared to a loss of $17,579 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.


                                       10                           (Continued)
<PAGE>   11

       The Registrant's cash distribution from operations for the second quarter
       of 2000 was 4.50% (annualized) of the limited partners' original capital
       contribution, unchanged from the first 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 second quarter of 2000 was 2.50% (annualized) of
       the limited partners' original capital contribution, an increase of 0.50%
       from the first quarter of 2000. Sales proceeds distributed to its
       partners may fluctuate in subsequent periods, reflecting the level of
       container disposals.

       The growth in the volume of world trade, a rise in exports to the Far
       East, and the global effects of a strong U.S. economy have resulted in
       improved market conditions for the container leasing industry. As a
       result of these and other factors, including repositioning initiatives
       implemented earlier in the year, utilization of the Registrant's fleet of
       containers has exhibited steady improvement in recent months. In
       addition, new container prices, as well as interest rates, have been
       rising from historically low levels. During such times, ocean carriers
       tend to reduce their capital spending to supplement their owned fleets of
       containers in favor of leasing. The pressure on per diem rates has
       impacted the Registrant's revenues, but there has been some rate
       stabilization in recent months. The Registrant will continue to take
       advantage of improving market conditions by repositioning equipment to
       locations of greatest demand as well as seeking out leasing opportunities
       that will strengthen utilization and enhance the performance of the
       fleet.


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

       Net lease revenue for the three and six-month periods ended June 30, 2000
       was $263,594 and $507,130, respectively, an increase of 16% and 1%,
       respectively, from the same three and six-month periods in the prior
       year. Gross rental revenue (a component of net lease revenue) for the
       three and six-month periods ended June 30, 2000 was $433,998 and
       $871,756, respectively, an increase of 3% and a decrease of 2% from the
       respective three and six-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
       six-month periods ended June 30, 2000 declined 5% and 9%, respectively,
       when compared to the same periods in the prior year. The Registrant's
       average fleet size and utilization rates for the three and six-month
       periods ended June 30, 2000 and 1999 were as follows:

<TABLE>
<CAPTION>

                                                                          Three Months Ended            Six Months Ended
                                                                        -----------------------       -----------------------
                                                                        June 30,       June 30,       June 30,       June 30,
                                                                          2000           1999           2000           1999
                                                                        --------       --------       --------       --------
<S>                                                                     <C>            <C>            <C>            <C>
            Average fleet size (measured in twenty-foot equivalent
                units (TEU))                                               5,491          5,954          5,602          6,026
            Average Utilization                                               81%            71%            80%            71%
</TABLE>


       The age and declining size of the Registrant's fleet contributed to
       reductions in depreciation expense of 8% and 7%, respectively, when
       compared to the respective three and six-month periods in the prior year.
       Rental equipment operating expenses during the three and six-month
       periods ended June 30, 2000 were 26% and 29%, respectively, of the
       Registrant's gross lease revenue, as compared to 33% and 30%,
       respectively, during the same three and six-month periods ended June 30,
       1999. 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 June 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: August 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)