<PAGE>

                                  UNITED STATES
                       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, 2004

                                       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 0-13546

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

                     APACHE OFFSHORE INVESTMENT PARTNERSHIP
             ------------------------------------------------------
             (Exact Name of Registrant as Specified in Its Charter)

              Delaware                                         41-1464066
   --------------------------------                      -----------------------
   (State or Other Jurisdiction of                         (I.R.S. Employer
    Incorporation or Organization)                        Identification Number)

   Suite 100, One Post Oak Central                             77056-4400
2000 Post Oak Boulevard, Houston, TX                     -----------------------
----------------------------------------                       (Zip Code)
(Address of Principal Executive Offices)

       Registrant's Telephone Number, Including Area Code: (713) 296-6000

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>

                          PART I-FINANCIAL INFORMATION

ITEM 1 - FINANCIAL STATEMENTS

                     APACHE OFFSHORE INVESTMENT PARTNERSHIP
                               STATEMENT OF INCOME
                                   (UNAUDITED)

<TABLE>
<CAPTION>
                                                              FOR THE QUARTER          FOR THE SIX MONTHS
                                                               ENDED JUNE 30,            ENDED JUNE 30,
                                                          -----------------------   -----------------------
                                                             2004         2003         2004       2003
                                                          ----------   ----------   ----------   ----------
<S>                                                       <C>          <C>          <C>          <C>
REVENUES:
    Oil and gas sales                                     $3,173,969   $3,015,242   $6,424,699   $6,206,650
    Interest income                                            6,165        6,345       12,249        9,783
                                                          ----------   ----------   ----------   ----------
                                                           3,180,134    3,021,587    6,436,948    6,216,433
                                                          ----------   ----------   ----------   ----------
EXPENSES:
    Depreciation, depletion and amortization                 684,091      703,922    1,373,297    1,445,386
    Asset retirement obligation accretion                     12,096        9,332       24,018       18,529
    Lease operating costs                                    227,161      192,007      425,771      449,618
    Gathering and transportation expense                      27,128       51,086       62,120       89,185
    Administrative                                           102,000      105,000      204,000      210,000
                                                          ----------   ----------   ----------   ----------
                                                           1,052,476    1,061,347    2,089,206    2,212,718
                                                          ----------   ----------   ----------   ----------
OPERATING INCOME BEFORE CUMULATIVE
  EFFECT OF CHANGE IN ACCOUNTING PRINCIPLE                 2,127,658    1,960,240    4,347,742    4,003,715
                                                          ----------   ----------   ----------   ----------
    Cumulative effect of change in accounting principle            -            -            -      302,407
                                                          ----------   ----------   ----------   ----------
NET INCOME                                                $2,127,658   $1,960,240   $4,347,742   $4,306,122
                                                          ==========   ==========   ==========   ==========
NET INCOME ALLOCATED TO:
    Managing Partner                                      $  544,883   $  505,080   $1,109,162   $1,041,388
    Investing Partners                                     1,582,775    1,455,160    3,238,580    3,264,734
                                                          ----------   ----------   ----------   ----------
                                                          $2,127,658   $1,960,240   $4,347,742   $4,306,122
                                                          ==========   ==========   ==========   ==========
NET INCOME PER INVESTING PARTNER UNIT                     $    1,494   $    1,348   $    3,055   $    3,016
                                                          ==========   ==========   ==========   ==========
WEIGHTED AVERAGE INVESTING PARTNER
    UNITS OUTSTANDING                                        1,059.6      1,079.8      1,060.2      1,082.3
                                                          ==========   ==========   ==========   ==========
</TABLE>

                 The accompanying notes to financial statements
                    are an integral part of this statement.

                                      1
<PAGE>

                     APACHE OFFSHORE INVESTMENT PARTNERSHIP
                             STATEMENT OF CASH FLOWS
                                   (UNAUDITED)

<TABLE>
<CAPTION>
                                                                         FOR THE SIX MONTHS ENDED JUNE 30,
                                                                         -----------------------------------
                                                                             2004                   2003
                                                                         -----------             -----------
<S>                                                                      <C>                     <C>
CASH FLOWS FROM OPERATING ACTIVITIES:
    Net income                                                           $ 4,347,742             $ 4,306,122
    Adjustments to reconcile net income to net cash
         provided by operating activities:
               Depreciation, depletion and amortization                    1,373,297               1,445,386
               Asset retirement obligation accretion                          24,018                  18,529
               Cumulative effect of change in accounting principle                 -                (302,407)
               Dismantlement and abandonment cost                           (140,493)                      -
               Changes in operating assets and liabilities:
                    (Increase) decrease in accrued revenues receivable      (182,368)               (292,210)
                    Increase (decrease) in accrued operating expenses         12,175                  37,093
                    (Increase) decrease in payable to/receivable from
                        Apache Corporation                                   208,679                  87,151
                                                                         -----------             -----------
               Net cash provided by operating activities                   5,643,050               5,299,664
                                                                         -----------             -----------
CASH FLOWS FROM INVESTING ACTIVITIES:
    Additions to oil and gas properties                                     (827,663)               (726,379)
                                                                         -----------             -----------
               Net cash used in investing activities                        (827,663)               (726,379)
                                                                         -----------             -----------
CASH FLOWS FROM FINANCING ACTIVITIES:
    Repurchase of Partnership Units                                          (41,321)               (285,936)
    Distributions to Investing Partners                                   (2,121,466)               (542,445)
    Distributions to Managing Partner                                     (1,093,123)             (1,026,426)
                                                                         -----------             -----------
               Net cash used in financing activities                      (3,255,910)             (1,854,807)
                                                                         -----------             -----------
NET INCREASE IN CASH AND CASH EQUIVALENTS                                  1,559,477               2,718,478

CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR                               2,271,495                 915,891
                                                                         -----------             -----------
CASH AND CASH EQUIVALENTS, END OF PERIOD                                 $ 3,830,972             $ 3,634,369
                                                                         ===========             ===========
</TABLE>

                                       2
<PAGE>

                     APACHE OFFSHORE INVESTMENT PARTNERSHIP
                                  BALANCE SHEET
                                   (UNAUDITED)

<TABLE>
<CAPTION>
                                                                                         JUNE 30,       DECEMBER 31,
                                                                                          2004             2003
                                                                                      --------------   -------------
<S>                                                                                   <C>              <C>
                                 ASSETS

CURRENT ASSETS:
    Cash and cash equivalents                                                         $   3,830,972    $   2,271,495
    Accrued revenues receivable                                                             823,578          641,210
    Receivable from Apache Corporation                                                           --           86,217
                                                                                      -------------    -------------
                                                                                          4,654,550        2,998,922
                                                                                      -------------    -------------
OIL AND GAS PROPERTIES, on the basis of full cost accounting:
    Proved properties                                                                   183,295,637      182,173,899
    Less - Accumulated depreciation, depletion and amortization                        (174,871,986)    (173,498,689)
                                                                                      -------------    -------------
                                                                                          8,423,651        8,675,210
                                                                                      -------------    -------------
                                                                                      $  13,078,201    $  11,674,132
                                                                                      =============    =============
                      LIABILITIES AND PARTNERS' CAPITAL

CURRENT LIABILITIES:
    Accrued development costs                                                         $     488,322    $     334,740
    Accrued operating expenses                                                               64,251           52,076
    Payable to Apache Corporation                                                           122,462               --
                                                                                      -------------    -------------
                                                                                            675,035          386,816
                                                                                      -------------    -------------
ASSET RETIREMENT OBLIGATION                                                                 836,538          812,520
                                                                                      -------------    -------------
PARTNERS' CAPITAL:
    Managing Partner                                                                        183,249          167,210
    Investing Partners (1,057.2 and 1,060.7 units outstanding, respectively)             11,383,379       10,307,586
                                                                                      -------------    -------------
                                                                                         11,566,628       10,474,796
                                                                                      -------------    -------------
                                                                                      $  13,078,201    $  11,674,132
                                                                                      =============    =============
</TABLE>

                 The accompanying notes to financial statements
                    are an integral part of this statement.

                                       3
<PAGE>

                     APACHE OFFSHORE INVESTMENT PARTNERSHIP
                          NOTES TO FINANCIAL STATEMENTS
                                   (UNAUDITED)

      The financial statements included herein have been prepared by the Apache
Offshore Investment Partnership (the Partnership), without audit, pursuant to
the rules and regulations of the Securities and Exchange Commission, and reflect
all adjustments which are, in the opinion of management, necessary for a fair
statement of the results for the interim periods, on a basis consistent with the
annual audited financial statements. All such adjustments are of a normal,
recurring nature. Certain information, accounting policies, and footnote
disclosures normally included in financial statements prepared in accordance
with generally accepted accounting principles have been omitted pursuant to such
rules and regulations, although the Partnership believes that the disclosures
are adequate to make the information presented not misleading. These financial
statements should be read in conjunction with the financial statements and the
summary of significant accounting policies and notes thereto included in the
Partnership's latest annual report on Form 10-K.

1.    RECEIVABLE FROM/PAYABLE TO APACHE CORPORATION

      The receivable from/payable to Apache Corporation, the Partnership's
managing partner (Apache or the Managing Partner), represents the net result of
the Investing Partners' revenue and expenditure transactions in the current
month. Generally, cash in this amount will be paid by Apache to the Partnership
or transferred to Apache in the month after the Partnership's transactions are
processed and the net results of operations are determined.

2.    RIGHT OF PRESENTMENT

      As provided in the Partnership Agreement, as amended (the Amended
Partnership Agreement), a first right of presentment offer for 2004 of $11,518
per Unit, plus interest to the date of payment, was made to Investing Partners
in April 2004, based on a valuation date of December 31, 2003. As a result, the
Partnership purchased 3.5 Units in June for a total of $41,321. The Investing
Partners will have a second right of presentment during the fourth quarter of
2004 based on a valuation date of June 30, 2004.

      The Partnership is not in a position to predict how many Units will be
presented for repurchase during the fourth quarter of 2004 and cannot, at this
time, determine if the Partnership will have sufficient funds available to
repurchase any Units. The Partnership has no obligation to purchase any Units
presented to the extent it determines that it has insufficient funds for such
purchases. The Amended Partnership Agreement contains limitations on the number
of Units that the Partnership can repurchase, including a limit of 10 percent of
the outstanding Units on an annual basis.

3.    ASSET RETIREMENT OBLIGATIONS

      Effective January 1, 2003, the Partnership adopted Statement of Financial
Accounting Standards (SFAS) No. 143, "Accounting for Asset Retirement
Obligations," which requires that an asset retirement obligation (ARO)
associated with the retirement of a tangible long-lived asset be recognized as a
liability in the period in which it is incurred and becomes determinable, with
an offsetting increase in the carrying amount of the associated asset. The cost
of the tangible asset, including the initially recognized ARO, is depleted such
that the cost of the ARO is recognized over the useful life of the asset. The
ARO is recorded at fair value, and accretion expense will be recognized over
time as the discounted liability is accreted to its expected settlement value.
The fair value of the ARO is measured using expected future cash outflows
discounted at the company's credit-adjusted risk-free interest rate. The
Partnership's asset retirement obligations primarily relate to the plugging and
abandonment of oil and gas properties.

      Upon adoption, the Partnership recorded an increase to net oil and gas
properties of $1.1 million and additional liabilities related to asset
retirement obligations of $.8 million. These amounts reflect the ARO of the
Partnership had the provisions of SFAS No. 143 been applied since inception and
resulted in a non-cash cumulative effect increase to 2003 earnings of $.3
million.

      The Partnership's increase in ARO liability from December 31, 2003 was
attributable to accretion expense of $24,018.

                                       4
<PAGE>

ITEM  2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
          RESULTS OF OPERATIONS

RESULTS OF OPERATIONS

NET INCOME AND REVENUE

      The Partnership earned $2.1 million during the second quarter of 2004,
nine percent above the net income reported in the second quarter a year ago on
the strength of higher prices. Net income per Investing Partner Unit increased
to $1,494 in the second quarter of 2004 from $1,348 in the second quarter of
2003.

      Net income for the first half of 2004, totaled $4.3 million or $3,055 per
Investing Partner Unit. Net income for the same period in 2003 totaled $4.3
million or $3,016 per Investing Partner Unit. As a result of higher oil prices
in 2004, net income in 2004 was nine percent higher than the 2003 net income
before the cumulative effect of a change in accounting principle.

      Total revenues for the second quarter increased five percent from a year
ago, increasing from $3.0 million in 2003 to $3.2 million in 2004. For the six
months ending June 30, 2004, revenues were $6.4 million or four percent above
the revenues for the same period in 2003 on higher oil prices and oil
production.

      The Partnership's oil and gas production volume and price information is
summarized in the following table (gas volumes presented in thousand cubic feet
(Mcf) per day):

<TABLE>
<CAPTION>
                                    FOR THE QUARTER ENDED JUNE 30,     FOR THE SIX MONTHS ENDED JUNE 30,
                                 -----------------------------------   ---------------------------------
                                                            INCREASE                           INCREASE
                                     2004          2003    (DECREASE)    2004       2003      (DECREASE)
                                 ------------    --------  ---------   -------    -------     ----------
<S>                              <C>             <C>       <C>         <C>        <C>         <C>
Gas volume - Mcf per day              3,640         4,189    (13%)       3,695      3,920        (6%)
Average gas price - per Mcf       $    5.97      $   5.60      7%      $  5.98    $  6.21        (4%)
Oil volume - barrels per day            311           333     (7%)         325        321         1%
Average oil price - per barrel    $   37.86      $  28.96     31%      $ 36.50    $  1.00        18%
NGL volume - barrels per day             63             -      -            57          -         -
Average NGL price - per barrel    $   21.28             -      -       $ 23.98          -         -
</TABLE>

OIL AND GAS SALES

      Natural gas production revenues for the second quarter of 2004 totaled
$2.0 million, down seven percent from the second quarter of 2003. Natural gas
volumes on a daily basis decreased 13 percent from a year ago as a result of
natural declines at South Timbalier 295 and Matagorda 681/682. These production
declines were partially offset by new production from the completion of the Ship
Shoal 258 JB-6 well in mid-April and Ship Shoal 259 JA-3 well in late May.
Natural gas prices for the second quarter of 2004 increased seven percent
compared to the year-earlier period. The $.37 per Mcf increase in gas prices
from a year ago impacted sales by approximately $.1 million.

      The Partnership's crude oil production revenues for the second quarter of
2004 totaled $1.1 million, a 22 percent increase from the second quarter of
2003. A $8.90 per barrel, or 31 percent, increase in the Partnership's average
realized oil price increased oil revenues by $.3 million. Oil production was
seven percent lower than a year ago as declines at South Timbalier 295 more than
offset production additions from drilling at Ship Shoal 258/259.

      Gas sales for the first half of 2004 of $4.0 million declined nine
percent, when compared to the same period in 2003. The Partnership's average
realized gas prices decreased $.23 per Mcf, when compared with the first six
months of 2003. Daily gas production for the first half of 2004 also decreased
six percent when compared to the same period in 2003. The lower sales volumes in
2004 reflected natural depletion at South Timbalier 295 and Matagorda 681/682.

      For the six months ended June 30, 2004, oil sales increased 20 percent
from a year ago to $2.2 million. The Partnership's oil sales revenues were
favorably impacted by an 18 percent increase in the average realized oil price
and a one percent increase in daily oil production. The increase in oil
production is a result of recompletions at South Timbalier 295 during the second
half of 2003 and first quarter of 2004. The recompletion of the Ship Shoal 258
JB-5 well in February 2004 also contributed to the increase.

                                       5
<PAGE>

      During the fourth quarter of 2003, the Partnership began processing a
portion of its natural gas production through onshore plants operated by third
parties. The Partnership sold an average of 63 barrels per day of natural gas
liquids from processing gas during the second quarter of 2004 and 57 barrels per
day of natural gas liquids during the first six months of 2004.

      Declines in oil and gas production can be expected in future periods due
to natural depletion. Given the small number of producing wells owned by the
Partnership, and their natural depletion, the Partnership's future production
will be subject to more volatility than those companies with greater reserves
and longer-lived properties.

OPERATING EXPENSES

      The Partnership's depreciation, depletion and amortization (DD&A) rate,
expressed as a percentage of oil and gas sales, was approximately 22 percent
during the second quarter of 2004 compared to 23 percent during the same period
in 2003. This decline in rate reflected the impact of higher oil and gas prices
in the current year. The Partnership recognized $12,096 of accretion expense on
the asset retirement obligation during the second quarter of 2004 and $24,018
for the first six months of 2004.

      Lease operating expense (LOE) in the second quarter of 2004 increased 18
percent from the second quarter of 2003 as a result of higher overall repair and
maintenance costs in 2004 and higher costs at North Padre Island 969 compared to
2003. During the first half of 2004, LOE totaled $.4 million, down five percent
from the same period in 2003.

      Gathering and transportation costs include amounts paid by the Partnership
to third parties to transport oil and gas to a purchaser-specified delivery
point. Such costs vary based on the volume and distance shipped, and the fee
charged by the transporter, which may be price sensitive. The transportation
cost may also vary from period to period based on marketing and delivery options
utilized by the Partnership to realize the highest net price (gross price less
transportation) for either oil or gas. Gathering and transportation costs during
the second quarter and first six months of 2004 decreased from the comparable
periods in 2003 primarily as a result of decreased volumes from Matagorda
681/682.

CASH FLOW, LIQUIDITY AND CAPITAL RESOURCES

CAPITAL RESOURCES AND LIQUIDITY

      The Partnership's primary capital resource is net cash provided by
operating activities, which totaled $5.6 million for the first six months of
2004. Net cash provided by operating activities in 2004 was six percent above
$5.3 million reported a year ago, reflecting increases in oil prices and
production from 2003. Future cash flows will be influenced by fluctuations in
product prices, production levels and operating costs.

      The Partnership's future financial condition, results of operations and
cash from operating activities will largely depend upon prices received for its
oil and natural gas production. A substantial portion of the Partnership's
production is sold under market-sensitive contracts. Prices for oil and natural
gas are subject to fluctuations in response to changes in supply, market
uncertainty and a variety of factors beyond the Partnership's control. These
factors include worldwide political instability (especially in the Middle East),
the foreign supply of oil and natural gas, the price of foreign imports, the
level of consumer demand, and the price and availability of alternative fuels.
With natural gas accounting for 62 percent of the Partnership's production for
the first half of 2004 and 62 percent of total proved reserves at December 31,
2003, on an energy equivalent basis, the Partnership is affected more by
fluctuations in natural gas prices than in oil prices.

      The Partnership's oil and gas reserves and production will also
significantly impact future results of operations and cash from operating
activities. The Partnership's production is subject to fluctuations in response
to remaining quantities of oil and gas reserves, weather, pipeline capacity,
consumer demand, mechanical performance and workover, recompletion and drilling
activities. Declines in oil and gas production can be expected in future years
as a result of normal depletion and the Partnership not participating in
acquisition or exploration activities. Based on production estimates from
independent engineers and current market conditions, the Partnership expects it
will be able to meet its liquidity needs for routine operations in the
foreseeable future. The Partnership will reduce capital expenditures and
distributions to partners as cash from operating activities declines.

                                       6
<PAGE>

      In the event that future short-term operating cash requirements are
greater than the Partnership's financial resources, the Partnership may seek
short-term, interest-bearing advances from the Managing Partner as needed. The
Managing Partner, however, is not obligated to make loans to the Partnership.

      On an ongoing basis, the Partnership reviews the possible sale of lower
value properties prior to incurring associated dismantlement and abandonment
cost.

CAPITAL COMMITMENTS

      The Partnership's primary needs for cash are for operating expenses,
drilling and recompletion expenditures, future dismantlement and abandonment
costs, distributions to Investing Partners, and the purchase of Units offered by
Investing Partners under the right of presentment. The Partnership had no
outstanding debt or lease commitments at June 30, 2004.

      During the first six months of 2004, the Partnership invested $1.1 million
in oil and gas properties as the Partnership participated in drilling activities
at Ship Shoal 258/259. The Partnership participated in the successful completion
of the Ship Shoal 259 JA-3, which was brought on production in late May, and the
Ship Shoal 258 JB-6 well, which was brought on production in mid-April. During
the first quarter, the Partnership participated in the recompletion of the South
Timbalier 295 A-13 and Ship Shoal 258 JB-5 wells. The Partnership is
participating in the drilling of the Ship Shoal 259 JA-7 and the JA-8 wells,
which were in progress at June 30, 2004.

      On March 17, 2004, the Partnership paid distributions to Investing
Partners totaling $2.1 million, or $2,000 per Investing Partner unit. The
Partnership made a cash distribution to Investing Partners during the first half
of 2003 of $500 per Investing Partner Unit. The amount of future distributions
will be dependent on actual and expected production levels, realized and
expected oil and gas prices, expected drilling and recompletion expenditures,
and prudent cash reserves for future dismantlement and abandonment costs that
will be incurred after the Partnership's reserves are depleted. Based on
available cash balances and projections of the above items for the second half
of 2004, the Partnership anticipates it will make a distribution to Investing
Partners in the fourth quarter of 2004.

      As provided in the Amended Partnership Agreement, a first right of
presentment offer for 2004 of $11,518 per Unit, plus interest to the date of
payment, was made to Investing Partners in April 2004, based on a valuation date
of December 31, 2003. As a result, the Partnership purchased 3.5 Units in June
2004 for a total of $41,321. The Investing Partners will have second right of
presentment during the fourth quarter of 2004 based on a valuation date of June
30, 2004.

      The Partnership is not in a position to predict how many Units will be
presented for repurchase during the fourth quarter of 2004 and cannot, at this
time, determine if the Partnership will have sufficient funds available to
repurchase any Units. The Partnership has no obligation to purchase any Units
presented to the extent it determines that it has insufficient funds for such
purchases. The Amended Partnership Agreement contains limitations on the number
of Units that the Partnership can repurchase, including a limit of 10 percent of
the outstanding Units on an annual basis.

ITEM 3 - QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

      The Partnership's major market risk exposure is in the pricing applicable
to its oil and gas production. Realized pricing is primarily driven by the
prevailing worldwide price for crude oil and spot prices applicable to its
natural gas production. Prices received for oil and gas production have been and
remain volatile and unpredictable. The Partnership has not used derivative
financial instruments or otherwise engaged in hedging activities during 2003 or
the first six months of 2004.

      The information set forth under "Commodity Risk" in Item 7A of the
Partnership's Form 10-K for the year ended December 31, 2003, is incorporated by
reference. Information about market risks for the current quarter is not
materially different.

                                       7
<PAGE>

ITEM 4 - CONTROLS AND PROCEDURES

      G. Steven Farris, the Managing Partner's President, Chief Executive
Officer and Chief Operating Officer, and Roger B. Plank, the Managing Partner's
Executive Vice President and Chief Financial Officer, evaluated the
effectiveness of the Partnership's disclosure controls and procedures as of the
end of the period covered by this report. Based on that evaluation and as of the
date of that evaluation, these officers concluded that the Partnership's
disclosure controls to be effective, providing effective means to insure that
information it is required to disclose under applicable laws and regulations is
recorded, processed, summarized and reported in a timely manner. Also, no
significant changes were made in the Partnership's internal controls over
financial reporting during the fiscal quarter ending June 30, 2004 that have
materially affected, or are reasonably likely to materially affect, the
Partnership's internal control over financial reporting.

FORWARD-LOOKING STATEMENTS AND RISK

      Certain statements in this report, including statements of the future
plans, objectives, and expected performance of the Partnership, are
forward-looking statements that are dependent on certain events, risks and
uncertainties that may be outside the Partnership's control, and which could
cause actual results to differ materially from those anticipated. Some of these
include, but are not limited to, the market prices of oil and gas, economic and
competitive conditions, inflation rates, legislative and regulatory changes,
financial market conditions, political and economic uncertainties of foreign
governments, future business decisions, and other uncertainties, all of which
are difficult to predict.

      There are numerous uncertainties inherent in estimating quantities of
proved oil and gas reserves and in projecting future rates of production and
timing of development expenditures. The total amount or timing of actual future
production may vary significantly from reserves and production estimates. The
drilling of exploratory wells can involve significant risks, including those
related to timing, success rates and cost overruns. Lease and rig availability,
complex geology and other factors can affect these risks. Fluctuations in oil
and gas prices, or a prolonged period of low prices, may substantially adversely
affect the Partnership's financial position, results of operations and cash
flows.

                                       8
<PAGE>

                           PART II - OTHER INFORMATION

ITEM 1. LEGAL PROCEEDINGS

       None.

ITEM 2. CHANGES IN SECURITIES, USE OF PROCEEDS AND ISSUER PURCHASES OF EQUITY
       SECURITIES

<TABLE>
<CAPTION>
                     ISSUER PURCHASES OF EQUITY SECURITIES
-----------------------------------------------------------------------------
                                          TOTAL                      AVERAGE
                                          NUMBER                      PRICE
                                         OF UNITS                   PAID PER
          PERIOD                         PURCHASED                    UNIT
-------------------------                ---------                  ---------
<S>                                      <C>                        <C>
April 1 to April 30, 2004                     None                        N/A
May 1 to May 31, 2004                         None                        N/A
June 1 to June 30, 2004                        3.5                  $11,518 (1)
</TABLE>

(1)     Before interest

      Shares are purchased under terms of Amended Partnership Agreement which
      had previously been announced to Investing Partners in the Partnership.
      The Amended Partnership Agreement contains limitations on the number of
      units that can be repurchased including a limit of 10 percent of the
      Outstanding Units on an annual basis. See Note 2 (Right of Presentment) to
      the Consolidated Financial Statements for total cash outlays for unit
      purchases during the quarter and additional limitations.

ITEM  3. DEFAULTS UPON SENIOR SECURITIES

        None.

ITEM  4. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

      None.

ITEM  5. OTHER INFORMATION

      None.

ITEM  6. EXHIBITS AND REPORTS ON FORM 8-K

      a.    Exhibits

          31.1  -   Certification of Chief Executive Officer

          31.2  -   Certification of Chief Financial Officer

          32.1  -   Certification of Chief Executive Officer and Chief Financial
                    Officer

      b.    Reports filed on Form 8-K - None.

                                       9
<PAGE>

                                   SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) 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.

                           APACHE OFFSHORE INVESTMENT PARTNERSHIP
                           By:   Apache Corporation, General Partner

Dated: August 6, 2004      /s/ Roger B. Plank
                           -----------------------------------------------------
                           Roger B. Plank
                           Executive Vice President and Chief Financial Officer

Dated: August 6, 2004      /s/ Thomas L. Mitchell
                           -----------------------------------------------------
                           Thomas L. Mitchell
                           Vice President and Controller
                           (Chief Accounting Officer)

<PAGE>

                                  EXHIBIT INDEX

<TABLE>
<S>       <C>
31.1  -   Certification of Chief Executive Officer

31.2  -   Certification of Chief Financial Officer

32.1  -   Certification of Chief Executive Officer and Chief Financial
          Officer
</TABLE>