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                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                 FORM 10-K/A(2)

<Table>
<S>    <C>
(MARK ONE)
[X]           ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d)
                  OF THE SECURITIES EXCHANGE ACT OF 1934

FOR THE FISCAL YEAR ENDED DECEMBER 31, 2003

[ ]         TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d)
                  OF THE SECURITIES EXCHANGE ACT OF 1934

COMMISSION FILE NUMBER: 1-15157
</Table>

                               PACTIV CORPORATION
             (Exact name of Registrant as Specified in its Charter)

<Table>
<S>                                              <C>
                   DELAWARE                                        36-2552989
        (State or other jurisdiction of                         (I.R.S. Employer
        incorporation or organization)                         Identification No.)
             1900 WEST FIELD COURT                                    60045
             LAKE FOREST, ILLINOIS                                 (Zip Code)
   (Address of principal executive offices)
</Table>

Registrant's telephone number, including area code: (847) 482-2000

SECURITIES REGISTERED PURSUANT TO SECTION 12 (b) OF THE ACT:

<Table>
<S>                                                       <C>
                                                                           NAME OF EACH EXCHANGE
                                                                            ON WHICH REGISTERED
                  TITLE OF EACH CLASS                     --------------------------------------------------------
--------------------------------------------------------
 Common Stock ($.01 par value) and associated Preferred                   New York Stock Exchange
                 Stock Purchase Rights
</Table>

    Securities registered pursuant to Section 12(g) of the Act: None

    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 by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K.  [ ]

    Indicate by check mark whether the registrant is an accelerated filer (as
defined in Rule 12b-2 of the Act).

                                Yes  X   No  __

    State the aggregate market value of the voting stock held by non-affiliates
of the registrant. The aggregate market value is computed by reference to the
price at which the stock was sold, or the average bid and asked prices of such
stock, as of the last business day of the registrant's most recently completed
second fiscal quarter.

<Table>
<S>                                                       <C>
       CLASS OF VOTING STOCK AND NUMBER OF SHARES                   MARKET VALUE OF COMMON STOCK HELD BY
        HELD BY NON-AFFILIATES AT JUNE 28, 2003                                NON-AFFILIATES
--------------------------------------------------------  --------------------------------------------------------
            COMMON STOCK 156,337,490 SHARES                                    $3,081,411,928
</Table>

    INDICATE THE NUMBER OF SHARES OUTSTANDING OF EACH OF THE REGISTRANT'S
CLASSES OF COMMON STOCK, AS OF THE LATEST PRACTICABLE DATE. Common Stock ($.01
par value). 153,809,913 shares outstanding as of February 29, 2004. (See Note 12
to the Financial Statements.)

                      DOCUMENTS INCORPORATED BY REFERENCE:

<Table>
<S>                                                       <C>
                                                                           PART OF THE FORM 10-K
                        DOCUMENT                                          INTO WHICH INCORPORATED
--------------------------------------------------------  --------------------------------------------------------
  Pactiv Corporation's Definitive Proxy Statement For                             Part III
 the Annual Meeting of Shareholders to be held May 14,
                          2004
</Table>

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                                EXPLANATORY NOTE

     This amendment to Pactiv Corporation's Annual Report on Form 10-K for the
fiscal year ended December 31, 2003, is being filed to amend Item 9A. Controls
and Procedures, to conform the wording more closely to that required by Items
307 and 308(c) of Regulation S-K. No revisions have been made to the Pactiv
Corporation financial statements or any other disclosures contained in the
Annual Report.

ITEM 9A.  CONTROLS AND PROCEDURES.

     The company's disclosure controls and procedures are designed to ensure
that information required to be disclosed by the company in the reports it files
or submits under the Securities Exchange Act is recorded, processed, summarized,
and reported within the appropriate time periods. The company, under the
supervision and with the participation of its management, including the
company's principal executive officer and principal financial officer, has
evaluated the effectiveness of its disclosure controls and procedures (as
defined in Exchange Act Rules 13a-15(e) and 15d-15(e)), and the company and such
officers have concluded that such controls and procedures were adequate and
effective as of December 31, 2003. The company completed its evaluation of such
controls and procedures in connection with the preparation of this annual report
on Form 10-K on February 12, 2004.

     There have been no significant changes in the company's internal controls
or in other factors that could significantly affect these controls subsequent to
the date of their evaluation, including any corrective actions with regard to
significant deficiencies and material weaknesses therein. There have been no
changes in internal controls over financial reporting during the quarter ended
December 31, 2003 that have materially affected, or are reasonably likely to
affect, internal controls over financial reporting.
<PAGE>

                                   SIGNATURES

     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the registrant has duly caused the report to be signed on
its behalf by the undersigned, thereunto duly authorized.

                                          PACTIV CORPORATION

                                          By: /s/ RICHARD L. WAMBOLD
                                            ------------------------------------
                                                  Richard L. Wambold
                                                  Chairman, President and
                                                  Chief Executive Officer

Date: January 31, 2005

     Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed below by the following on behalf of the registrant and in
the capacities and on the dates indicated.

<Table>
<Caption>
                    SIGNATURE                                     TITLE                      DATE
                    ---------                                     -----                      ----
<C>     <S>                                          <C>                               <C>

/s/ RICHARD L. WAMBOLD                               Chairman, President, Chief        January 31, 2005
------------------------------------------------       Executive Officer and
     Richard L. Wambold                                Director (principal executive
                                                       officer)


/s/ ANDREW A. CAMPBELL                               Senior Vice President and Chief   January 31, 2005
------------------------------------------------       Financial Officer (principal
     Andrew A. Campbell                                financial and accounting
                                                       officer)


/s/ LARRY D. BRADY*                                  Director                          January 31, 2005
------------------------------------------------
     Larry D. Brady


/s/ K. DANE BROOKSHER*                               Director                          January 31, 2005
------------------------------------------------
     K. Dane Brooksher


/s/ ROBERT J. DARNALL*                               Director                          January 31, 2005
------------------------------------------------
     Robert J. Darnall


/s/ MARY R. (NINA) HENDERSON*                        Director                          January 31, 2005
------------------------------------------------
     Mary R. (Nina) Henderson


/s/ ROGER B. PORTER*                                 Director                          January 31, 2005
------------------------------------------------
     Roger B. Porter


/s/ PAUL T. STECKO*                                  Director                          January 31, 2005
------------------------------------------------
     Paul T. Stecko
</Table>
<PAGE>

<Table>
<Caption>
                    SIGNATURE                                     TITLE                      DATE
                    ---------                                     -----                      ----
<C>     <S>                                          <C>                               <C>

/s/ NORMAN H. WESLEY*                                Director                          January 31, 2005
------------------------------------------------
     Norman H. Wesley


 *By:   /s/ JAMES V. FAULKNER, JR.                                                     January 31, 2005
         -----------------------------------------
              James V. Faulkner, Jr.
              Attorney-in-fact
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