<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: June 30, 2001

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)


              Nevada                                      98-0127391
  -------------------------------                      ----------------
  (State or other jurisdiction of                      (I.R.S. Employer
   incorporation or organization)                     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


                                 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:


Title of each Class                      Date                 Number Outstanding
---------------------------         ----------------          ------------------
Common Shares, no par value         August 14, 2001               3,427,959

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                                                                     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 -
          June 30, 2001 and December 31, 2000                               3

     Consolidated Condensed Statement of Income and Retained Earnings -
          Six months ended June 30, 2001 and 2000 and
               Three months ended June 30, 2001 and 2000                    4

     Consolidated Condensed Statement of Cash Flows
          Six months ended June 30, 2001 and 2000                           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>


<PAGE>   3
                                                                     Page 3 of 8


CHIEFTAIN INTERNATIONAL FUNDING CORP.

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

BALANCE SHEET

<TABLE>
<CAPTION>
                                                                        JUNE 30    December 31
                                                                         2001          2000
-----------------------------------------------------------------------------------------------
<S>                                                                  <C>             <C>
(US$)
(unaudited)

ASSETS

Current assets:
     Cash                                                            $   179,505     $    27,488
     Due from affiliated companies                                     6,857,174       6,576,734
                                                                     ---------------------------
                                                                       7,036,679       6,604,222
Investment in preferred shares of Chieftain International
     (U.S.) Inc. at cost                                              78,500,000      78,500,000
                                                                     ---------------------------
                                                                     $85,536,679     $85,104,222
                                                                     ===========================

LIABILITIES AND SHAREHOLDERS' EQUITY

Current liabilities:
     Accounts payable and accrued                                    $     3,000     $     6,600

Preferred shares issued (Notes 2,4)                                   63,402,903      63,402,903

Common shareholder's equity:
     Share capital
       Authorized
        10,000,000 common shares, par value $0.01 each
       Issued (Note 4)                                                     2,000           2,000
        200,000 common shares
     Additional paid in capital                                       14,998,000      14,998,000
     Retained earnings                                                 7,130,776       6,694,719
                                                                     ---------------------------
                                                                      22,130,776      21,694,719
                                                                     ---------------------------
                                                                     $85,536,679     $85,104,222
                                                                     ===========================
</TABLE>
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                                                                     Page 4 of 8

CHIEFTAIN INTERNATIONAL FUNDING CORP.

STATEMENT OF INCOME AND RETAINED EARNINGS

<TABLE>
<CAPTION>


                                                   Six months                     Three months
                                          ---------------------------     ----------------------------

 Period ended June 30                         2001            2000             2001            2000
 -----------------------------------------------------------------------------------------------------
<S>                                       <C>             <C>             <C>              <C>
(US$)
(unaudited)

Revenue:
     Dividends                            $ 2,845,625     $ 2,845,625     $ 1,422,812      $ 1,422,812
     Interest                                 227,148         161,629          78,834           90,737
                                           -----------------------------------------------------------
                                            3,072,773       3,007,254       1,501,646        1,513,549
Expense:
     General and administrative               131,644          41,276         115,695           23,254
                                           -----------------------------------------------------------
Income before income taxes and
     dividends on preferred shares          2,941,129       2,965,978       1,385,951        1,490,295
Income tax expense (recovery)
 - (Note 3)                                    34,000          43,000         (13,000)          24,000
                                           -----------------------------------------------------------

Net income before dividends on
  preferred shares                          2,907,129       2,922,978       1,398,951        1,466,295

Dividends on preferred shares              (2,471,072)     (2,471,072)     (1,235,536)      (1,235,536)
                                           -----------------------------------------------------------

Net income applicable to
  common shares for the period                436,057          451,906         163,415         230,759
Retained earnings,
  beginning of period                       6,694,719        5,632,504       6,967,361       5,853,651
                                           -----------------------------------------------------------
Retained earnings, end of period          $ 7,130,776     $  6,084,410    $  7,130,776     $ 6,084,410
                                          ============================================================
</TABLE>


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                                                                     Page 5 of 8

CHIEFTAIN INTERNATIONAL FUNDING CORP.

STATEMENT OF CASH FLOWS

<TABLE>
<CAPTION>

Six months ended June 30                                                        2001         2000
----------------------------------------------------------------------------------------------------
<S>                                                                          <C>           <C>
(US$)
(unaudited)

Operating activities:
     Net income applicable to common shares                                  $ 436,057     $ 451,906
     Change in non-cash working capital -
         Current liabilities                                                    (3,600)       (5,281)
                                                                             -----------------------

                                                                               432,457       446,625
Investing activity:
     Advances to affiliated companies                                         (280,440)     (558,543)
                                                                             -----------------------

Change in cash                                                                 152,017      (111,918)

Beginning cash                                                                  27,488       147,982
                                                                             -----------------------
Ending cash                                                                  $ 179,505     $  36,064
                                                                             =======================
</TABLE>


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                                                                     Page 6 of 8


CHIEFTAIN INTERNATIONAL FUNDING CORP.

NOTES TO FINANCIAL STATEMENTS

June 30, 2001 and 2000

(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 June 30, 2001 and December 31, 2000 and
     the results of operations and cash flows for the six months ended June 30,
     2001 and 2000. 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,
     2000.

     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 six month period ended
     June 30, 2001 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.

4.   Subsequent events:

     Subsequent to June 30, 2001, 2,582,377 $1.8125 convertible redeemable
     preferred shares were converted. This was facilitated by the issuance of
     3,227,959 Funding Corp. common shares to its parent company and also
     resulted in a charge to retained earnings of approximately $33 million.

     Pursuant to its Offer to Purchase dated June 28, 2001, Hunt Oil Company,
     through its wholly-owned subsidiary Hunt Oil Canadian Acquisition III
     Corporation, accepted the 19,025,501 common shares of Chieftain
     International, Inc., Funding Corp's ultimate parent, which were tendered to
     the Offer on August 3, 2001.

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                                                                     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 - Six months ended June 30, 2001 and 2000

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
$2,845,625 for each of the first six months of 2001 and 2000.

Interest earned on short-term notes for the first six months of 2001 was
$227,148, a 41% increase from the amount earned in the comparable 2000 period.
Such increase resulted from a 26% increase in average investment yield and a 14%
increase in the average amount invested compared to the 2000 first six months.

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 decreased to $432,557 for the first six months of
2001 compared with $446,625 for the 2000 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 June 30, 2001 and 2000 were $179,505 and $36,064 respectively.

Subsequent to June 30, 2001, 2,582,377 $1.8125 convertible redeemable preferred
shares were converted. This was facilitated by the issuance of 3,227,959 Funding
Corp. common shares to its parent company and also resulted in a charge to
retained earnings of approximately $33 million.

Pursuant to its Offer to Purchase dated June 28, 2001, Hunt Oil Company, through
its wholly-owned subsidiary Hunt Oil Canadian Acquisition III Corporation,
accepted the 19,025,501 common shares of Chieftain International, Inc., Funding
Corp's ultimate parent, which were tendered to the Offer on August 3, 2001.


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.

<PAGE>   8

                                                                     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/ Donald F. Robillard, Jr.
-------------------------------------------------
Donald F. Robillard, Jr.
Senior Vice President and Chief Financial Officer




Dated: August 14, 2001