EXHIBIT 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Annual Report of Acacia Research Corporation (the “Company”) on Form 10-K for the annual period ended December 31, 2007, as filed with the Securities and Exchange Commission on March 14, 2008 (the “Report”), I, Paul R. Ryan, Chairman of the Board and Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

1.           The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

2.           The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

By: /s/ Paul R. Ryan                                 

Paul R. Ryan

Chairman of the Board and

Chief Executive Officer

March 14, 2008