Exhibit 32.1

Certification Pursuant to 18 U.S.C. Sec. 1350

(Section 906 of the Sarbanes – Oxley Act of 2002)

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In connection with the filing by Senior Housing Properties Trust (the “Company”) of the Amendment No. 2 to the Annual Report on Form 10-K for the period ending December 31, 2004 (the “Report”), each of the undersigned hereby certifies, to the best of his knowledge:

	1.	The 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 Report fairly presents, in all material respects, the financial condition and results of operations of the Company.
/s/ Barry M. Portnoy			/s/ David J. Hegarty
Barry M. Portnoy			David J. Hegarty
Managing Trustee			President and Chief Operating Officer
/s/ Gerard M. Martin			/s/ John R. Hoadley
Gerard M. Martin			John R. Hoadley
Managing Trustee			Treasurer and Chief Financial Officer