Exhibit 23 CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM We consent to the incorporation by reference in the Registration Statement (Form S-8 No. 333-90333) pertaining to the Pactiv 401(k) Savings and Investment Plan, of our report dated May 20, 2004, with respect to the financial statements and schedule of the Pactiv 401(k) Savings and Investment Plan included in this Annual Report (Form 11-K) for the year ended December 31, 2003. Ernst & Young LLP Chicago, Illinois June 28, 2004