<PAGE>   1
                                                                     Page 1 of 8


                                    FORM 10-Q
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


[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: 33-51630
                        --------

                      CHIEFTAIN INTERNATIONAL FUNDING CORP.
                     --------------------------------------
             (Exact name of registrant as specified in its charter)

<TABLE>
<S>                                                                    <C>
                     Nevada                                                        98-0127391
--------------------------------------------------------------         -----------------------------------
(State or other jurisdiction of incorporation or organization)         (I.R.S. Employer Identification No.)

           1201 TD Tower, 10088 - 102 Avenue
              Edmonton, Alberta, Canada                                              T5J  2Z1
      --------------------------------------------                             ---------------------
        (Address of principal executive offices)                               (Zip Code/Postal Code)

    Registrants' telephone number, including area code:                            (780) 425-1950
</TABLE>

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

Indicate the number of shares outstanding of each of the issuer's classes of
common stock, as of the latest practicable date:

<TABLE>
<CAPTION>
Title of each Class                                        Date                                  Number Outstanding
-------------------                                  -----------------                           ------------------
<S>                                                  <C>                                            <C>
Common Shares, no par value                          October 17 , 2000                              200,000
</TABLE>

<PAGE>   2
                                                                     Page 2 of 8


                      CHIEFTAIN INTERNATIONAL FUNDING CORP.

                                      INDEX
<TABLE>
<CAPTION>
                                                                               Page No.
<S>                                                                            <C>

PART I: FINANCIAL STATEMENTS

Item 1. Financial Statements

        Chieftain International Funding Corp.

        Consolidated  Condensed  Balance Sheet -
              September 30, 2000 and December 31, 1999                         3

        Consolidated Condensed Statement  of Income  and  Retained Earnings
              Nine months  ended  September  30, 2000 and 1999 and
              Three months ended September  30, 2000 and 1999                  4

        Consolidated Condensed Statement of Cash Flows
              Nine months ended September 30, 2000 and 1999                    5

Notes to Consolidated Condensed Financial Statements                           6

Item 2. Management's Discussion and Analysis of
              Financial Condition and Results of Operations                    7


        Signatures                                                             8

</TABLE>
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                                                                     Page 3 of 8


CHIEFTAIN INTERNATIONAL FUNDING CORP.

(a subsidiary of Chieftain International (U.S.) Inc.)

BALANCE SHEET
<TABLE>
<CAPTION>

                                                            SEPTEMBER 30  December 31
                                                                2000         1999
                                                            -----------   -----------
<S>                                                         <C>           <C>
(US$)
(unaudited)
ASSETS

Current assets:
     Cash                                                   $    62,236   $   147,982
     Due from affiliated companies                            6,170,863     5,392,730
                                                            -----------   -----------
                                                              6,233,099     5,540,712
Investment in preferred shares of Chieftain International
     (U.S.) Inc. at cost                                     78,500,000    78,500,000
                                                            -----------   -----------
                                                            $84,733,099   $84,040,712
                                                            ===========   ===========

LIABILITIES AND SHAREHOLDERS' EQUITY

Current liabilities:
     Accounts payable and accrued                           $        23   $     5,305

Preferred shares issued (Note 2)                             63,402,903    63,402,903

Common shareholder's equity:
     Share capital
       Authorized
        10,000,000 common shares, par value $0.01 each
       Issued                                                     2,000         2,000
        200,000 common shares
     Additional paid in capital                              14,998,000    14,998,000
     Retained earnings                                        6,330,173     5,632,504
                                                            -----------   -----------
                                                             21,330,173    20,632,504
                                                            -----------   -----------
                                                            $84,733,099   $84,040,712
                                                            ===========   ===========
</TABLE>

<PAGE>   4

                                                                     Page 4 of 8


CHIEFTAIN INTERNATIONAL FUNDING CORP.

STATEMENT OF INCOME AND RETAINED EARNINGS
<TABLE>
<CAPTION>


                                           Nine months                  Three months
                                    --------------------------   ---------------------------
Period ended September 30              2000             1999           2000           1999
-------------------------           -----------   ------------   ------------   ------------
<S>                                <C>             <C>           <C>            <C>

(US$)
(unaudited)
Revenue:
   Dividends                        $ 4,268,438    $ 4,268,438    $ 1,422,813    $ 1,422,813
   Interest                             266,654        150,302        105,025         52,943
                                    -----------    -----------    -----------    -----------

                                      4,535,092      4,418,740      1,527,838      1,475,756
Expense:
   General and administrative            56,815         48,973         15,539         23,108
                                    -----------    -----------    -----------    -----------
Income before income taxes and
   dividends on preferred shares      4,478,277      4,369,767      1,512,299      1,452,648
 Income tax expense  - (Note 3)          74,000         36,000         31,000         11,000
                                    -----------    -----------    -----------    -----------
Net income before dividends on
   preferred shares                   4,404,277      4,333,767      1,481,299      1,441,648

Dividends on preferred shares        (3,706,608)    (3,706,608)    (1,235,536)    (1,235,536)
                                    -----------    -----------    -----------    -----------
Net income applicable to
   common shares for the period         697,669        627,159        245,763        206,112
Retained earnings,
   beginning of period                5,632,504      4,784,505      6,084,410      5,205,552
                                    -----------    -----------    -----------    -----------

Retained earnings, end of period    $ 6,330,173    $ 5,411,664    $ 6,330,173    $ 5,411,664
                                    ===========    ===========    ===========    ===========
</TABLE>

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                                                                     Page 5 of 8


CHIEFTAIN INTERNATIONAL FUNDING CORP.

STATEMENT OF CASH FLOWS
<TABLE>
<CAPTION>

Nine months ended September 30                  2000          1999
-------------------------------------------  ----------    ---------
<S>                                           <C>          <C>
(US$)
(unaudited)

Operating activities:
     Net income applicable to common shares   $ 697,669    $ 627,159
     Change in non-cash working capital -
         Current liabilities                     (5,282)      (6,343)
                                              ---------    ---------
                                                692,387      620,816

Investing activity:
     Advances to affiliated companies          (778,133)    (640,020)
                                              ---------    ---------
Change in cash                                  (85,746)     (19,204)

Beginning cash                                  147,982      121,495
                                              ---------    ---------
Ending cash                                   $  62,236    $ 102,291
                                              =========    =========

</TABLE>

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                                                                     Page 6 of 8


CHIEFTAIN INTERNATIONAL FUNDING CORP.

NOTES TO FINANCIAL STATEMENTS

September 30, 2000 and 1999

(unaudited)

1.   Basis of Presentation:

     In the opinion of Chieftain International Funding Corp. ("Funding Corp."),
     the accompanying unaudited financial statements contain all adjustments
     (consisting of only normal recurring adjustments) necessary to present
     fairly the financial position as at September 30, 2000 and December 31,
     1999 and the results of operations and cash flows for the nine months ended
     September 30, 2000 and 1999. Certain information and notes normally
     included in Funding Corp.'s financial statements prepared in accordance
     with Canadian generally accepted accounting principles have been condensed
     or omitted for interim reporting pursuant to the rules and regulations of
     the Securities and Exchange Commission. These financial statements should
     be read in conjunction with the financial statements and the notes thereto
     included in Funding Corp.'s Annual Report on Form 10-K for the year ended
     December 31, 1999.

     Preparation of financial statements in conformity with generally accepted
     accounting principles requires management to make informed judgements and
     estimates. Actual results may differ from those estimates.

     The results of operations and cash flows for the nine month period ended
     September 30, 2000 are not necessarily indicative of the results to be
     expected for the full year.

2.   Preferred Shares:

     The  Articles  of Funding  Corp.  authorize  the  issuance  of a maximum of
     10,000,000 preferred shares with a par value of $1.00 each.

     In 1992, Funding Corp. sold 2,726,700 shares of $1.8125 convertible
     redeemable preferred stock at $25.00 per share through an underwritten
     public offering in the United States. Proceeds of the issuance of preferred
     shares, net of offering costs of $4.7 million, were $63.4 million.

3.   Income Taxes:

     Funding Corp. and its parent company file corporate income tax returns on a
     consolidated  basis. As a result,  income taxes payable have been offset by
     the parent  company's  tax losses and are  reflected in the amount due from
     the parent company.

<PAGE>   7
                                                                     Page 7 of 8


         MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
                              RESULTS OF OPERATIONS


Chieftain International Funding Corp., a special purpose subsidiary of Chieftain
International  (U.S.)  Inc.,  was  formed  in 1992 for the  primary  purpose  of
financing the U.S. business operations of its parent.

Analysis of Operating Results - Nine months ended September 30, 2000 and 1999

Funding Corp.'s income is derived from dividends on preferred shares and
interest on short-term notes, all of which are issued by its parent company,
Chieftain International (U.S.) Inc.

Dividends received on 3,140,000 redeemable Class B preferred shares amounted to
$4,268,438 for each of the first nine months of 2000 and 1999.

Interest earned on short-term notes for the first nine months of 2000 was
$266,654, a 77% increase from the amount earned in the comparable 1999 period.
Such increase resulted from a 44% increase in average investment yield and a 24%
increase in the average amount invested compared to the 1999 first nine months.
Future dividend income is expected to remain constant while interest income
should increase, subject to rate fluctuations, reflecting increases in
short-term investment amounts.

Income taxes are calculated on interest income less general and administrative
costs. Dividends received from the parent are tax exempt.

Capital Resources and Liquidity

Funding  Corp.  is dependent  upon the dividend  income from its  investment  in
preferred shares of its parent company to provide funds for payment of dividends
on its publicly-held preferred shares.

Funds provided from operations increased to $692,387 for the first nine months
of 2000 compared with $620,816 for the 1999 comparable period. Funds not
required for current working capital were invested in short-term notes issued
and payable by the parent company.

Cash balances at September 30, 2000 and 1999 were $62,236 and $102,291,
respectively.

Information Regarding Forward Looking Financial Statements

This 10-Q contains forward-looking statements that are subject to risk factors
associated with the Company's business. The Company believes that the
expectations reflected in these statements are reasonable, but may be affected
by a variety of factors affecting the Company's business.

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                                                                     Page 8 of 8


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.

Chieftain International Funding Corp.
-------------------------------------
          (Registrant)





/s/ STANLEY A. MILNER
--------------------------------
Stanley A. Milner, A.O.E., LL.D.
President and Chief Executive Officer
Principal Executive and Financial Officer

Dated: October 17, 2000