<PAGE>   1

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM 10-Q
(Mark One)

[ 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

[   ]   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: 0-18338

                               I-Flow Corporation
--------------------------------------------------------------------------------
             (Exact name of registrant as specified in its charter)

<TABLE>
<S>                                                     <C>
          California                                        33-0121984
--------------------------------------------------------------------------------
(State or other jurisdiction of                          (I.R.S. Employer
incorporation or organization)                          Identification No.)
</TABLE>

                   20202 Windrow Drive, Lake Forest, CA 92630
--------------------------------------------------------------------------------
               (Address of principal executive offices) (Zip Code)

                                 (949) 206-2700
--------------------------------------------------------------------------------
              (Registrant's telephone number, including area code)


--------------------------------------------------------------------------------
   (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. [ x ] Yes [ ] No


        As of November 10, 2000 there were 15,053,430 shares outstanding of
common stock.



<PAGE>   2

                               I-FLOW CORPORATION
                                    FORM 10-Q
                    FOR THE QUARTER ENDED SEPTEMBER 30, 2000

                                TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                                         Page
                                                                                         ----
<S>                                                                                      <C>
      Part I:    Financial Information

           Item 1.  Financial Statements

                Consolidated Balance Sheets as of September 30, 2000 (Unaudited)
                    and December 31, 1999                                                  3

                Consolidated Statements of Operations for the  three and nine-month
                    periods ended September 30, 2000 and 1999 (Unaudited)                  4

                Consolidated Statements of Cash Flows for the nine-month periods
                    ended September 30, 2000 and 1999 (Unaudited)                          5

                Notes to Consolidated Financial Statements (Unaudited)                     6

           Item 2.  Management's Discussion and Analysis of Financial Condition
                        and Results of Operations                                          9

           Item 3.  Quantitative and Qualitative Disclosures About Market Risk            11

      Part II:  Other Information

           Item 6.  Exhibits and Reports on Form 8-K                                      12

      Signatures                                                                          14
</TABLE>



<PAGE>   3

                               I-FLOW CORPORATION
                          CONSOLIDATED BALANCE SHEETS


<TABLE>
<CAPTION>
                                                                                          September 30,          December 31,
                                                                                              2000                   1999
                                                                                          ------------           ------------
ASSETS                                                                                    (Unaudited)
<S>                                                                                       <C>                    <C>
  CURRENT ASSETS:
    Cash and cash equivalents                                                             $  2,047,000           $  3,192,000
    Accounts receivable, net                                                                10,210,000              8,748,000
    Inventories, net                                                                         4,131,000              3,785,000
    Prepaid expenses and other                                                                 632,000                553,000
    Deferred taxes                                                                           2,837,000              2,837,000

                                                                                          ------------           ------------
       Total current assets                                                                 19,857,000             19,115,000
                                                                                          ------------           ------------


    Property, net                                                                            4,054,000              2,985,000
    Goodwill and other intangibles, net                                                      6,851,000              5,846,000
    Notes receivable and other                                                                 893,000                782,000
    Deferred taxes                                                                           3,040,000              3,040,000

                                                                                          ------------           ------------
TOTAL                                                                                     $ 34,695,000           $ 31,768,000
                                                                                          ============           ============

LIABILITIES AND SHAREHOLDERS' EQUITY

CURRENT LIABILITIES:
    Accounts payable                                                                      $  2,205,000           $  1,800,000
    Accrued payroll and related expenses                                                     1,296,000              1,526,000
    Income taxes payable                                                                     1,182,000                607,000
    Current portion of long-term debt                                                        1,533,000              1,443,000
    Borrowings under line-of-credit                                                            616,000                 88,000
    Other liabilities                                                                           52,000                 86,000

                                                                                          ------------           ------------
       Total current liabilities                                                             6,884,000              5,550,000
                                                                                          ------------           ------------

LONG-TERM DEBT                                                                                 970,000              1,548,000

SHAREHOLDERS' EQUITY:
    Preferred stock - no par value; 5,000,000 shares
      authorized; no shares issued and outstanding at
      September 30, 2000 (unaudited) and December 31, 1999,                                         --                     --
      respectively
    Common stock - no par value; 40,000,000 shares authorized; 15,051,766 and
      14,692,125 shares issued and outstanding at September 30, 2000 (unaudited)
      and December 31, 1999, respectively                                                   40,623,000             39,414,000
    Common stock warrants                                                                      615,000                615,000
    Accumulated other comprehensive income                                                      47,000                 26,000
    Accumulated deficit                                                                    (14,444,000)           (15,385,000)

                                                                                          ------------           ------------
       Net shareholders' equity                                                             26,841,000             24,670,000

                                                                                          ------------           ------------
TOTAL                                                                                     $ 34,695,000           $ 31,768,000
                                                                                          ============           ============
</TABLE>

See accompanying notes to consolidated financial statements.



                                       3
<PAGE>   4

                               I-FLOW CORPORATION
                      CONSOLIDATED STATEMENTS OF OPERATIONS
                                   (UNAUDITED)

<TABLE>
<CAPTION>
                                                       Three Months Ended                 Nine Months Ended
                                                          September 30,                    September 30,
                                                  ----------------------------      ----------------------------
                                                      2000             1999             2000             1999
                                                  -----------      -----------      -----------      -----------
<S>                                               <C>              <C>              <C>              <C>
Revenues:
  Net product sales                               $ 7,371,000      $ 7,231,000      $22,578,000      $19,987,000
  Licensing fees                                           --          600,000               --        1,400,000
                                                  -----------      -----------      -----------      -----------

    Net revenues                                    7,371,000        7,831,000       22,578,000       21,387,000

Costs and expenses:
  Cost of sales                                     3,311,000        3,057,000        9,726,000        8,380,000
  Selling and marketing                             1,321,000        1,011,000        3,891,000        3,141,000
  General and administrative                        1,973,000        2,248,000        6,302,000        6,069,000
  Product development                                 285,000          275,000          904,000          801,000

                                                  -----------      -----------      -----------      -----------
    Total costs and expenses                        6,890,000        6,591,000       20,823,000       18,391,000

Operating income                                      481,000        1,240,000        1,755,000        2,996,000

Interest expense, net                                  47,000          115,000          164,000          364,000
Income taxes                                          176,000           29,000          650,000           86,000

                                                  -----------      -----------      -----------      -----------
Net income                                        $   258,000      $ 1,096,000      $   941,000      $ 2,546,000
                                                  ===========      ===========      ===========      ===========


Net income per share

     Basic                                        $      0.02      $      0.08      $      0.06      $      0.18
                                                  ===========      ===========      ===========      ===========
     Diluted                                      $      0.02      $      0.07      $      0.06      $      0.17
                                                  ===========      ===========      ===========      ===========

Comprehensive Operations:
     Net income                                   $   258,000      $ 1,096,000      $   941,000      $ 2,546,000
     Foreign currency translation adjustment           30,000           12,000           21,000           12,000
                                                  -----------      -----------      -----------      -----------
     Comprehensive income                         $   288,000      $ 1,108,000      $   962,000      $ 2,558,000
                                                  ===========      ===========      ===========      ===========
</TABLE>

See accompanying notes to consolidated financial statements.



                                       4
<PAGE>   5

                               I-FLOW CORPORATION
                     CONSOLIDATED STATEMENTS OF CASH FLOWS
                                  (Unaudited)

<TABLE>
<CAPTION>
                                                                           Nine Months Ended
                                                                              September 30,
                                                                    -----------------------------
                                                                        2000              1999
                                                                    -----------       -----------
<S>                                                                 <C>               <C>
CASH FLOWS FROM OPERATING ACTIVITIES:

Net income                                                          $   941,000       $ 2,546,000
Adjustments to reconcile net income
  to net cash provided by operating activities:
  Depreciation and amortization                                       1,949,000         1,812,000
  Compensation expense for stock option grants                           60,000            42,000
  Change in allowance for doubtful accounts                             194,000          (100,000)
  Change in inventory obsolescence reserve                             (353,000)          299,000
  Changes in operating assets and liabilities:
    Accounts receivable                                              (1,457,000)         (928,000)
    Inventories                                                         (65,000)         (460,000)
    Prepaid expenses and other                                           26,000            (6,000)
    Accounts payable, accrued and other liabilities                     474,000           695,000

                                                                    -----------       -----------
Net cash provided by operating activities                             1,769,000         3,900,000
                                                                    -----------       -----------

CASH FLOWS FROM INVESTING ACTIVITIES:
  Property acquisitions                                              (1,985,000)         (825,000)
  Cash paid for acquisition                                            (853,000)               --
  Change in other assets                                               (454,000)         (446,000)

                                                                    -----------       -----------
Net cash used in investing activities                                (3,292,000)       (1,271,000)
                                                                    -----------       -----------

CASH FLOWS FROM FINANCING ACTIVITIES:
  Net proceeds (repayments) from line of credit                         527,000        (1,719,000)
  Borrowings on notes payable                                           859,000           356,000
  Payments on notes payable                                          (1,427,000)       (1,643,000)
  Proceeds from exercise of stock options and warrants                  400,000           203,000

                                                                    -----------       -----------
Net cash provided by (used in) financing activities                     359,000        (2,803,000)
                                                                    -----------       -----------

Effect of exchange rates on cash                                         19,000            12,000

NET DECREASE IN CASH AND CASH EQUIVALENTS                            (1,145,000)         (162,000)

CASH AND CASH EQUIVALENTS AT BEGINNING OF
  PERIOD                                                              3,192,000           971,000

                                                                    -----------       -----------
CASH AND CASH EQUIVALENTS AT END OF PERIOD                          $ 2,047,000       $   809,000
                                                                    ===========       ===========


SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid                                                       $   181,000       $   364,000
                                                                    -----------       -----------
Income tax payments                                                 $   195,000       $    86,000
                                                                    -----------       -----------
Conversion of preferred stock to common stock                       $        --       $   662,000
Liabilities issued and assumed in connection with acquisition:
  Fair value of assets acquired (including intangibles)             $ 1,911,000
  Cash outflows for business acquisition                               (853,000)
  Common stock issued                                                  (750,000)
                                                                    -----------
Liabilities issued and assumed                                      $   308,000
                                                                    ===========
</TABLE>

See accompanying notes to consolidated financial statements.



                                       5
<PAGE>   6

                               I-FLOW CORPORATION
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

                                   (Unaudited)

1.      BASIS OF PRESENTATION

        The accompanying unaudited consolidated financial statements contain all
        adjustments (consisting only of normal recurring adjustments) that, in
        the opinion of management, are necessary to present fairly the financial
        position of I-Flow Corporation (the "Company") at September 30, 2000 and
        the results of its operations and its cash flows for the three and
        nine-month periods ended September 30, 2000 and 1999. Certain
        information and footnote disclosures normally included in financial
        statements have been condensed or omitted pursuant to rules and
        regulations of the Securities and Exchange Commission although the
        Company believes that the disclosures in the financial statements are
        adequate to make the information presented not misleading.

        The financial statements included herein should be read in conjunction
        with the financial statements of the Company included in the Company's
        Annual Report on Form 10-K for the year ended December 31, 1999 filed
        with the Securities and Exchange Commission on March 30, 2000.

        Certain amounts previously reported have been reclassified to conform
        with the presentation at September 30, 2000.

2.      INVENTORIES

        Inventories consisted of the following as of September 30, 2000 and
        December 31, 1999:

<TABLE>
<CAPTION>
                                                   September 30,            December 31,
                                                        2000                    1999
                                                        ----                    ----
                <S>                                 <C>                      <C>
                Raw Materials                       $ 4,008,000             $ 3,581,000
                Work in Process                         362,000                 164,000
                Finished Goods                        1,076,000               1,708,000
                Reserve for Obsolescence             (1,315,000)             (1,668,000)
                                                     ----------              ----------

                Total                               $ 4,131,000             $ 3,785,000
                                                     ----------              ----------
</TABLE>

3.      EARNINGS PER SHARE

        Basic net income per share is computed using the weighted average number
        of common shares outstanding during the periods presented.

        Diluted net income per share is computed using the weighted average
        number of common and common equivalent shares outstanding during the
        periods presented assuming the exercise of "all in-the-money" stock
        options and warrants. Common equivalent shares have not been included
        where inclusion would be antidilutive.



                                       6
<PAGE>   7

        The following is a reconciliation between the number of shares used in
        the basic and diluted net income per share calculations:

<TABLE>
<CAPTION>
                                                       Three Months Ended         Nine Months Ended
                                                          September 30,             September 30,
                                                      --------------------      --------------------
(Amounts in thousands)                                 2000         1999         2000         1999
                                                      -------      -------      -------      -------
<S>                                                   <C>          <C>          <C>          <C>
  Net income                                          $   258      $ 1,096      $   941      $ 2,546
Basic net income per  share
   Weighted average number of shares outstanding       15,039       14,442       14,981       14,298
   Effect of dilutive securities:
      Stock options                                       585        1,324          738        1,008
                                                      -------      -------      -------      -------
Diluted net income  per share
   Weighted average number of shares outstanding       15,624       15,766       15,719       15,306
                                                      -------      -------      -------      -------
</TABLE>

4.      BUSINESS SEGMENTS

        The Company operates in two business segments: manufacturing and
        marketing of medical infusion products and rentals of medical infusion
        pumps.

        Business segment information is as follows for the three and nine-month
        periods ended September 30, 2000 and 1999:

<TABLE>
<CAPTION>
                                         Manufacturing
(Amounts in thousands)                   and Marketing   Rentals    Consolidated
----------------------                   -------------   -------    ------------
<S>                                      <C>             <C>        <C>
THREE MONTHS ENDED SEPTEMBER 30, 2000
Revenues                                     5,240         2,131        7,371
Operating income (loss)                        (15)          496          481
Assets                                      23,495        11,200       34,695

NINE MONTHS ENDED SEPTEMBER 30, 2000
Revenues                                    16,212         6,366       22,578
Operating income                               496         1,259        1,755
Assets                                      23,495        11,200       34,695

THREE MONTHS ENDED SEPTEMBER 30, 1999
Revenues                                     5,788         2,043        7,831
Operating income                               814           426        1,240
Assets                                      15,852         8,976       24,828

NINE MONTHS ENDED SEPTEMBER 30, 1999
Revenues                                    15,228         6,159       21,387
Operating income                             1,639         1,357        2,996
Assets                                      15,852         8,976       24,828
</TABLE>



                                       7
<PAGE>   8

5.      ACQUISITION OF SPINAL SPECIALTIES, INC.

        On January 14, 2000, the Company acquired Spinal Specialties, Inc., a
        designer and manufacturer of custom spinal, epidural and nerve block
        infusion kits based in San Antonio, Texas, for $1.5 million. The
        purchase price consisted of $750,000 in cash and 200,000 shares of
        I-Flow common stock plus direct costs of $103,000. The acquisition was
        accounted for under the purchase method of accounting and the purchase
        price has been allocated to the net assets acquired and goodwill.

6.      NEW ACCOUNTING PRONOUNCEMENTS

        In December 1999, the Securities and Exchange Commission issued Staff
        Accounting Bulletin "SAB" 101, "Revenue Recognition in Financial
        Statements." Implementation of SAB 101, which was delayed by the
        issuance of SAB 101A on March 27, 2000 and SAB 101B on June 26, 2000 is
        required by the fourth quarter of 2000. The Company is currently in the
        process of evaluating the impact, if any, SAB 101 will have on its
        consolidated financial position or results of operations.

        In June 1998, the FASB issued Statement of Financial Accounting
        Standards (SFAS) No. 133, "Accounting for Derivative Instruments and
        Hedging Activities." SFAS No. 133 establishes new accounting and
        reporting standards for derivative instruments and for hedging
        activities. SFAS No. 133 requires the Company to measure all derivatives
        at fair value and to recognize them in the balance sheet as an asset or
        liability, depending on the Company's rights or obligations under the
        applicable derivative contract. The Company will adopt SFAS 133 no later
        than the first quarter of fiscal year 2001. Adoption of the new method
        of accounting for derivatives and hedging activities is not expected to
        have a material impact of the Company's financial position.

        In March 2000, the FASB issued Interpretation No. 44 (FIN 44),
        "Accounting for Certain Transactions involving Stock Compensation." FIN
        44 is an interpretation of Accounting Principal Board's Opinion No. 25,
        "Accounting for Stock Issued to Employees" (APB 25). Among other
        matters, FIN 44 clarifies the application of APB 25 regarding the
        definition of an employee for purposes of applying APB 25, the criteria
        for determining whether a plan qualifies as noncompensatory and the
        accounting consequences to the terms of a previously issued stock
        options or similar awards. The Company adopted the provisions of FIN 44
        in the third quarter of 2000. The adoption of FIN 44 did not have a
        material impact of the Company's financial condition or results of
        operations.



                                       8
<PAGE>   9

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

        Certain disclosures made by the Company in this report and in other
        reports and statements released by the Company are and will be
        forward-looking in nature, such as comments that express the Company's
        opinions about trends and factors that may impact future operating
        results. Disclosures that use words such as the Company "believes,"
        "anticipates," or "expects" or use similar expressions are intended to
        identify forward-looking statements. Such statements are subject to
        certain risks and uncertainties that could cause actual results to
        differ from those expected. Readers are cautioned not to place undue
        reliance on these forward-looking statements. The Company undertakes no
        obligation to publish revised forward-looking statements to reflect the
        occurrence of unanticipated events. Readers are also urged to carefully
        review and consider the various disclosures made by the Company in this
        report that seek to advise interested parties of the risks and other
        factors that affect the Company's business, as well as in the Company's
        periodic reports on Forms 10-K, 10-Q, and 8-K filed with the Securities
        and Exchange Commission. The risks affecting the Company's business
        include reliance on the clinical and commercial acceptance of the
        Company's products, the ability to penetrate hospital accounts, the
        health care reimbursement system in place now and in the future,
        competition in the industry, demand in foreign countries, customer
        credit risks, technological changes and product availability. Any such
        forward-looking statements, whether made in this report or elsewhere,
        should be considered in context with the various disclosures made by the
        Company about its business.

RESULTS OF OPERATIONS

        Net revenues during the three and nine-month periods ended September 30,
        2000 were $7,371,000 and $22,578,000 compared to $7,831,000 and
        $21,387,000 for the same periods in the prior year, representing a
        decrease of 6% and an increase of 6%, respectively.

        Net product sales increased from $19,987,000 for the nine months ended
        September 30, 1999 to $22,578,000 for the same period in 2000, an
        increase of 13%. In January 2000, the Company acquired a new subsidiary,
        Spinal Specialties, Inc., a designer and manufacturer of custom spinal,
        epidural and nerve block infusion kits based in San Antonio, Texas
        ("Spinal Specialties"). Product sales generated by Spinal Specialties of
        $465,000 and $1,377,000 were included in product sales for the three and
        nine-month periods ended September 30, 2000. The remaining increase in
        product sales, year to date, is primarily due to increased sales to
        major distributors.

        The Company incurred cost of sales of $3,311,000 and $9,726,000 during
        the three and nine-month periods ended September 30, 2000, compared to
        $3,057,000 and $8,380,000 in the prior year. As a percentage of net
        product sales, cost of sales was relatively unchanged compared to the
        same periods in the prior year.

        Selling and marketing expenses for the three and nine-month periods
        ended September 30, 2000 increased over the same periods in the prior
        year by $310,000 or 31% and $750,000 or 24%, respectively. The increase
        is due in significant part to the addition of $146,000 and $360,000 in
        selling expenses for Spinal Specialties for the three and nine-month
        periods ended September 30, 2000, and partly due to increased sales
        compensation and outside sales commissions. For the three and nine-month
        periods ended September 30, 2000 selling and marketing expenses as a
        percent of net product sales increased by 4% and 2%, respectively.

        General and administrative expenses decreased for the three months ended
        September 30, 2000 by $275,000 or 12% and increased year to date by
        $233,000 or 4% from the same periods in the prior year. The increase
        year to date is due primarily to the addition of the Spinal Specialties
        operation. For the three and nine-month periods ended September 30, 2000
        general and administrative expenses as a percent of net product sales
        decreased by 4% and 1%, respectively. The decrease for the three-month
        period ended September 30, 2000 was due to a reduction in total
        compensation.



                                       9
<PAGE>   10

        Product development expenses for the three and nine-months ended
        September 30, 2000 increased $10,000 or 4% and $103,000 or 13% over the
        same periods in the prior year, due primarily to increased efforts on
        the new pain management products. The Company will continue to incur
        product development expenses as it continues its efforts to introduce
        new and improved technology and cost-efficient products into the market.

LIQUIDITY AND CAPITAL RESOURCES

        During the nine-month period ended September 30, 2000, funds of
        $1,769,000 were provided by operating activities consisting of net
        income of $941,000 plus non-cash expenses of $1,850,000 less net changes
        in operating assets and liabilities of $1,022,000. These changes in
        operating assets and liabilities consisted of: (1) an increase in
        accounts receivable of $1,457,000, (2) an increase in inventories of
        $65,000, (3) a decrease in prepaid expenses and other of $26,000, plus
        (4) an increase in accounts payable, accrued expenses, and other
        liabilities of $474,000. The increase in accounts receivable is
        substantially attributable to slower collection of Medicare receivables
        by the Company's InfuSystem subsidiary. Steps have been taken which
        management believes will improve the timeliness of these collections.

        The Company used funds for investing activities during the nine-month
        period ended September 30, 2000 aggregating $3,319,000. These
        expenditures consisted of $1,985,000 for acquiring furniture, fixtures
        and equipment for use in its operations and an increase in other assets
        of $454,000. Additionally, in January 2000, the Company used $853,000 in
        connection with the acquisition of Spinal Specialties (see Note 5 of
        Notes to Consolidated Financial Statements).

        During the nine-month period ended September 30, 2000, funds of $359,000
        were provided by financing activities consisting of $527,000 net
        proceeds from line of credit, $859,000 additional borrowings on notes
        payable less payments on notes payable of $1,427,000 (including $80,000
        notes payable assumed through the acquisition of Spinal Specialties),
        and $400,000 in proceeds from the exercise of stock options and
        warrants.

        As of September 30, 2000, the Company had cash and cash equivalents of
        $2,047,000 and net receivables of $10,210,000. Management believes the
        Company's funds are sufficient to provide for its projected needs for
        operations for the next twelve months. However, the Company may decide
        to sell additional equity or increase its borrowings in order to fund
        increased product development or for other purposes.

NEW ACCOUNTING PRONOUNCEMENTS

        In December 1999, the Securities and Exchange Commission issued Staff
        Accounting Bulletin "SAB" 101, "Revenue Recognition in Financial
        Statements." Implementation of SAB 101, which was delayed by the
        issuance of SAB 101A on March 27, 2000 and SAB 101B on June 26, 2000 is
        required by the fourth quarter of 2000. The Company is currently in the
        process of evaluating the impact, if any, SAB 101 will have on its
        consolidated financial position or results of operations.

        In June 1998, the FASB issued Statement of Financial Accounting
        Standards (SFAS) No. 133, "Accounting for Derivative Instruments and
        Hedging Activities." SFAS No. 133 establishes new accounting and
        reporting standards for derivative instruments and for hedging
        activities. SFAS No. 133 requires the Company to measure all derivatives
        at fair value and to recognize them in the balance sheet as an asset or
        liability, depending on the Company's rights or obligations under the
        applicable derivative contract. The Company will adopt SFAS 133 no later
        than the first quarter of fiscal year 2001. Adoption of the new method
        of accounting for derivatives and hedging activities is not expected to
        have a material impact of the Company's financial position.

        In March 2000, the FASB issued Interpretation No. 44 (FIN 44),
        "Accounting for Certain Transactions involving Stock Compensation." FIN
        44 is an interpretation of Accounting Principal Board's Opinion No. 25,
        "Accounting for Stock Issued to Employees" (APB 25). Among other
        matters, FIN 44 clarifies the application of APB 25 regarding the
        definition of an employee for purposes of applying APB 25, the criteria
        for determining whether a plan qualifies as noncompensatory and the
        accounting consequences to



                                       10
<PAGE>   11

        the terms of a previously issued stock options or similar awards. The
        Company adopted the provisions of FIN 44 in the third quarter of 2000.
        The adoption of FIN 44 did not have a material impact of the Company's
        financial condition or results of operations.

YEAR 2000 COMPLIANCE

        The Company did not experience any significant malfunctions or errors in
        its operating or business systems when the date changed from 1999 to
        2000. Based on operations since January 1, 2000, the Company does not
        expect any significant impact to its ongoing business as a result of the
        "Year 2000 issue." However, it is possible that the full impact of the
        date change, which was of concern due to computer programs that use two
        digits instead of four digits to define years, has not been fully
        recognized. For example, it is possible that Year 2000 or similar issues
        such as leap year-related problems may occur with billing, payroll, or
        financial closings at month, quarter or year-end. The Company believes
        that any such problems are likely to be minor and correctable. In
        addition, the Company could still be negatively affected if the Year
        2000 or similar issues adversely affect its customers or suppliers. The
        Company currently is not aware of any significant Year 2000 or similar
        problems that have arisen for its customers and suppliers.

        The Company expended less then $150,000 on Year 2000 readiness efforts
        from 1998 to 1999. These efforts included replacing some outdated,
        noncompliant hardware and noncompliant software as well as identifying
        and remediating potential Year 2000 problems.

ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK.

FOREIGN CURRENCY

        The Company has a subsidiary operating in Mexico. Accordingly, the
        Company is exposed to transaction gains and losses that could result
        from changes in foreign currency exchange rates. The Company does not
        believe that this foreign currency market risk is material.



                                       11
<PAGE>   12

                           PART II - OTHER INFORMATION

Item 6.         Exhibits and Reports on Form 8-K

                (a)     Exhibits

<TABLE>
<CAPTION>
    Exhibit No.                               Exhibit
    -----------                               -------
    <S>         <C>
         3.1    Restated Articles of Incorporation of the Company (2)

         3.2    Certificate of Amendment to Restated Articles of Incorporation
                dated June 14, 1991 (3)

         3.3    Certificate of Amendment to Restated Articles of Incorporation
                dated May 12, 1992 (4)

         3.4    Certificate of Determination covering Company's Series B
                Preferred Stock filed with the Secretary of State on October 5,
                1992 (4)

         3.5    Restated Bylaws as of July 22, 1991 of the Company (3)

         4.1    Specimen Common Stock Certificate (4)

         4.2    Warrant Agreement between the Company and American Stock
                Transfer & Trust Company, as Warrant Agent, dated February 13,
                1990 (1)

         4.3    Form of Warrant dated July 22, 1996, issued in conjunction with
                The acquisition of Block Medical, Inc. (5)

        10.1    Employment Agreement with Donald M. Earhart dated May 16, 1990
                (2)(6)

        10.2    1987-1988 Incentive Stock Option Plan and Non-Statutory Stock
                Option Plan Restated as of March 23, 1992 (5)(6)

        10.3    1992 Non-Employee Director Stock Option Plan (4)(6)

        10.4    License and Transfer Agreement with SoloPak Pharmaceuticals
                Inc., dated March 6, 1996 (7)

        10.5    1996 Stock Incentive Plan (6)(9)

        10.6    Agreement for Purchase and Sale of Assets dated as of July 3,
                1996 by and among I-Flow Corporation, Block Medical, Inc. and
                Hillenbrand Industries, Inc. (8)

        10.7    Employment Agreement with James J. Dal Porto dated September 6,
                1996 (10)(6)

        10.8    Lease Agreement between Industrial Developments International,
                Inc. as Landlord and I-Flow Corporation as Tenant dated April
                14, 1997 (11)

        10.9    Agreement and Plan of Merger by and among I-Flow Corporation,
                I-Flow Subsidiary, Inc., Venture Medical, Inc., and InfuSystems
                II, Inc. and the Shareholders of Venture Medical, Inc. and
                InfuSystems II, Inc. (12)

        10.10   Loan and Security Agreement between Silicon Valley Bank and
                I-Flow Corporation dated September 28, 1995 (13)

        10.11   Amendment to Loan Agreement between Silicon Valley Bank and
                I-Flow Corporation dated March 2, 1999 (13)

        10.12   Agreement and Plan of Merger by and Among I-Flow Corporation,
                Spinal Acquisition Corp., Spinal Specialties, Inc. and the
                Shareholders of Spinal Specialties, Inc. dated January 13, 2000
                (14)

        27      Financial Data Schedule
</TABLE>


        (1)     Incorporated by reference to exhibit with this title filed with
                the Company's Registration Statement (#33-32263-LA) declared
                effective February 1, 1990.



                                       12
<PAGE>   13

        (2)     Incorporated by reference to exhibit with this title filed with
                the Company's Form 10-K for its fiscal year ended September 30,
                1990.

        (3)     Incorporated by reference to exhibit with this title filed with
                the Company's Registration Statement (#33-41207-LA) declared
                effective August 8, 1991.

        (4)     Incorporated by reference to exhibit with this title filed with
                the Company's Form 10-K for its fiscal year ended December 31,
                1991.

        (5)     Incorporated by reference to exhibit with this title filed with
                the Company's Post Effective Amendment to its Registration
                Statement (#33-41207-LA) declared effective November 6, 1992.

        (6)     Management contract or compensatory plan or arrangement required
                to be filed as an exhibit pursuant to applicable rules of the
                Securities and Exchange Commission.

        (7)     Incorporated by reference to exhibit with this title filed with
                the Company's Form 10-K for its fiscal year ended December 31,
                1995.

        (8)     Incorporated by reference to exhibit with this title filed with
                the Company's Report on Form 8-K dated July 22, 1996.

        (9)     Incorporated by reference to exhibit with this title filed with
                the Company's Registration Statement (#333-16547) declared
                effective November 20, 1996.

        (10)    Incorporated by reference to exhibit with this title filed with
                the Company's Form 10-K for its fiscal year ended December 31,
                1996.

        (11)    Incorporated by reference to exhibit with this title filed with
                the Company's Report on Form 8-K dated April 14, 1997.

        (12)    Incorporated by reference to exhibit with this title filed with
                the Company's Report on Form 8-K dated February 9, 1999.

        (13)    Incorporated by reference to exhibit with this title filed with
                the Company's Form 10-K for its fiscal year ended December 31,
                1997.

        (14)    Incorporated by reference to exhibit with this title filed with
                the Company's quarterly report on form 10-Q for the quarter
                ended March 31, 2000.

                (b)     Reports on Form 8-K. The Company did not file any
                        Reports on Form 8-K during the quarter ended September
                        30, 2000.



                                       13
<PAGE>   14

                                   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.



        Date    November 14, 2000      /s/ Donald M. Earhart
             --------------------      -----------------------------------------
                                       Donald M. Earhart,
                                       Chairman, President and CEO
                                       (As Duly Authorized Officer)


        Date    November 14, 2000      /s/ James R. Talevich
             --------------------      -----------------------------------------
                                       James R. Talevich
                                       Chief Financial Officer
                                       (As Principal Financial Officer)



                                       14
<PAGE>   15

                                INDEX TO EXHIBITS

    Set forth below is a list of the exhibits included or incorporated by
reference as part of this report:

<TABLE>
<CAPTION>
    Exhibit No.                               Exhibit
    -----------                               -------
    <S>         <C>
         3.1    Restated Articles of Incorporation of the Company (2)

         3.2    Certificate of Amendment to Restated Articles of Incorporation
                dated June 14, 1991 (3)

         3.3    Certificate of Amendment to Restated Articles of Incorporation
                dated May 12, 1992 (4)

         3.4    Certificate of Determination covering Company's Series B
                Preferred Stock filed with the Secretary of State on October 5,
                1992 (4)

         3.5    Restated Bylaws as of July 22, 1991 of the Company (3)

         4.1    Specimen Common Stock Certificate (5)

         4.2    Warrant Agreement between the Company and American Stock
                Transfer & Trust Company, as Warrant Agent, dated February 13,
                1990 (1)

         4.3    Form of Warrant dated July 22, 1996, issued in conjunction with
                the acquisition of Block Medical, Inc. (8)

        10.1    Employment Agreement with Donald M. Earhart dated May 16, 1990
                (2)(6)

        10.2    1987-1988 Incentive Stock Option Plan and Non-Statutory Stock
                Option Plan Restated as of March 23, 1992 (5)(6)

        10.3    1992 Non-Employee Director Stock Option Plan (4)(6)

        10.4    License and Transfer Agreement with SoloPak Pharmaceuticals
                Inc., dated March 6, 1996 (7)

        10.5    1996 Stock Incentive Plan (6)(9)

        10.6    Agreement for Purchase and Sale of Assets dated as of July 3,
                1996 by and among I-Flow Corporation, Block Medical, Inc. and
                Hillenbrand Industries, Inc. (8)

        10.7    Employment Agreement with James J. Dal Porto dated September 6,
                1996 (10)(6)

        10.8    Lease Agreement Between Industrial Developments International,
                Inc. as Landlord and I-Flow Corporation as Tenant dated April
                14, 1997 (11)

        10.9    Agreement and Plan of Merger by and among I-Flow Corporation,
                I-Flow Subsidiary, Inc., Venture Medical, Inc., and InfuSystems
                II, Inc. and the Shareholders of Venture Medical, Inc. and
                InfuSystems II, Inc. (12)

        10.10   Loan and Security Agreement between Silicon Valley Bank and
                I-Flow Corporation dated September 28, 1995 (13)

        10.11   Amendment to Loan Agreement between Silicon Valley Bank and
                I-Flow Corporation dated March 2, 1999 (13)

        10.12   Agreement and Plan of Merger by and among I-Flow Corporation,
                Spinal Acquisition Corp. and Spinal Specialties, Inc. dated
                January 13, 2000 (14)

        27      Financial Data Schedule
</TABLE>

        (1)     Incorporated by reference to exhibit with this title filed with
                the Company's Registration Statement (#33-32263-LA) declared
                effective February 1, 1990.

        (2)     Incorporated by reference to exhibit with this title filed with
                the Company's Form 10-K for its fiscal year ended September 30,
                1990.

        (3)     Incorporated by reference to exhibit with this title filed with
                the Company's Registration Statement (#33-41207-LA) declared
                effective August 8, 1991.



                                       15
<PAGE>   16

        (4)     Incorporated by reference to exhibit with this title filed with
                the Company's Form 10-K for its fiscal year ended December 31,
                1991.

        (5)     Incorporated by reference to exhibit with this title filed with
                the Company's Post Effective Amendment to its Registration
                Statement (#33-41207-LA) declared effective November 6, 1992.

        (6)     Management contract or compensatory plan or arrangement required
                to be filed as an exhibit pursuant to applicable rules of the
                Securities and Exchange Commission.

        (7)     Incorporated by reference to exhibit with this title filed with
                the Company's Form 10-K for its fiscal year ended December 31,
                1995.

        (8)     Incorporated by reference to exhibit with this title filed with
                the Company's Report on Form 8-K dated July 22, 1996.

        (9)     Incorporated by reference to exhibit with this title filed with
                the Company's Registration Statement (#333-16547) declared
                effective November 20, 1996.

        (10)    Incorporated by reference to exhibit with this title filed with
                the Company's Form 10-K for its fiscal year ended December 31,
                1996.

        (11)    Incorporated by reference to exhibit with this title filed with
                the Company's Report on Form 8-K dated April 14, 1997.

        (12)    Incorporated by reference to exhibit with this title filed with
                the Company's Report on Form 8-K dated February 9, 1999.

        (13)    Incorporated by reference to exhibit with this title filed with
                the Company's Form 10-K for its fiscal year ended December 31,
                1997.

        (14)    Incorporated by reference to exhibit with this title filed with
                the Company's quarterly report on Form 10-Q for the quarter
                ended March 31, 2000.



                                       16