EXHIBIT 32.1 CERTIFICATIONS OF CHIEF EXECUTIVE OFFICER 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 GTJ REIT, Inc. (the "Company") on Form 10-K for the year ended December 31, 2007 as filed with the Securities and Exchange Commission on the date hereof (the "Periodic Report"), I, Jerome Cooper, 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 Periodic Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and 2. the information contained in the Periodic Report fairly presents, in all material respects, the financial condition and results of operations of the Company. Date: April 30, 2008 /s/ Jerome Cooper -------------------------------- Jerome Cooper Chief Executive Officer