Exhibit 32.1

CERTIFICATION OF CHIEF EXECUTIVE OFFICER AND CHIEF FINANCIAL OFFICER

PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

I, Robert F. Kirk, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that the Quarterly Report of Avistar Communications Corporation on Form 10-Q for the fiscal quarter ended March 31, 2012 fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and that information contained in such Quarterly Report on Form 10-Q fairly presents in all material respects the financial condition and results of operations of Avistar Communications Corporation.

	By:	/s/ Robert F. Kirk
		Robert F. Kirk
		Chief Executive Officer
Date: May 4, 2012		(Principal Executive Officer)

I, Elias A. MurrayMetzger, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that the Quarterly Report of Avistar Communications Corporation on Form 10-Q for the fiscal quarter ended March 31, 2012 fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and that information contained in such Quarterly Report on Form 10-Q fairly presents in all material respects the financial condition and results of operations of Avistar Communications Corporation.

	By:	/s/ Elias A. MurrayMetzger
		Elias A. MurrayMetzger
		Chief Financial Officer, Chief Administrative Officer and Corporate Secretary
Date: May 4, 2012		(Principal Financial and Accounting Officer)

AVISTAR COMMUNICATIONS CORP 10-Q