UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                  SCHEDULE 13G

                    Under the Securities Exchange Act of 1934
                                (Amendment No.)*


                          Senior Housing Properties Trust
                           ------------------------------
                                (Name of Issuer)

                                    COMMON
                               --------------------
                         (Title of Class of Securities)

                                 81721M109
                               --------------------
                                 (CUSIP Number)


             Date of Event which Requires Filing of this Statement

                                December 31, 2007
                               --------------------

Check the appropriate box to designate the rule pursuant to which the Schedule
is filed:

[x]     Rule 13d-1(b)
[ ]     Rule 13d-1(c)
[ ]     Rule 13d-1(d)

* The remainder of this cover page shall be filled out for a reporting  person's
initial filing on this form with respect to the subject class of securities, and
for any  subsequent  amendment  containing  information  which  would  alter the
disclosures provided in prior coverage.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of the Securities  Exchange Act of 1934 ("Act") or
otherwise  subject to the  liabilities  of that  section of the Act but shall be
subject to all other provisions of the Act (however, see the Notes).

SEC 1745 (12-02)




Schedule 13G (continued)

CUSIP No. 81721M109
--------------------------------------------------------------------------------
   1   NAME OF REPORTING PERSON
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

       Cohen & Steers, Inc. 14-1904657
--------------------------------------------------------------------------------
   2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                             (a)  [ ]
                                                             (b)  [x]
--------------------------------------------------------------------------------
   3   SEC USE ONLY


--------------------------------------------------------------------------------
   4   CITIZENSHIP OR PLACE OF ORGANIZATION

       Delaware
--------------------------------------------------------------------------------
   NUMBER OF      5    SOLE VOTING POWER
     SHARES            6,251,135
  BENEFICIALLY    -------------------------------------------------------------
    OWNED BY      6    SHARED VOTING POWER
      EACH             0
   REPORTING      -------------------------------------------------------------
     PERSON       7    SOLE DISPOSITIVE POWER
      WITH             6,389,435
                  -------------------------------------------------------------
                  8    SHARED DISPOSITIVE POWER
                       0
--------------------------------------------------------------------------------
   9   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

       6,389,435
--------------------------------------------------------------------------------
  10   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

       [ ]
--------------------------------------------------------------------------------
  11   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

       7.20%
--------------------------------------------------------------------------------
  12   TYPE OF REPORTING PERSON*

       HC, CO
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT



Schedule 13G (continued)

CUSIP No. 81721M109
--------------------------------------------------------------------------------
   1   NAME OF REPORTING PERSON
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

       Cohen & Steers Capital Management, Inc.     13-3353336
--------------------------------------------------------------------------------
   2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                             (a)  [ ]
                                                             (b)  [x]
--------------------------------------------------------------------------------
   3   SEC USE ONLY


--------------------------------------------------------------------------------
   4   CITIZENSHIP OR PLACE OF ORGANIZATION

       New York
--------------------------------------------------------------------------------
   NUMBER OF      5    SOLE VOTING POWER
     SHARES            6,251,135
  BENEFICIALLY    -------------------------------------------------------------
    OWNED BY      6    SHARED VOTING POWER
      EACH             0
   REPORTING      -------------------------------------------------------------
     PERSON       7    SOLE DISPOSITIVE POWER
      WITH             6,389,435
                  -------------------------------------------------------------
                  8    SHARED DISPOSITIVE POWER
                       0
--------------------------------------------------------------------------------
   9   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

       6,389,435
--------------------------------------------------------------------------------
  10   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

       [ ]
--------------------------------------------------------------------------------
  11   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

       7.20%
--------------------------------------------------------------------------------
  12   TYPE OF REPORTING PERSON*

       IA, CO
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT



Schedule 13G (continued)


Item 1.

        (a)  Name of Issuer:
             Senior Housing Properties Trust

        (b)  Address of Issuer's Principal Executive Offices:
             400 Center Street
             Newton, MA 02458
Item 2.

        (a)  Name of Persons Filing:
               Cohen & Steers, Inc.
               Cohen & Steers Capital Management, Inc.
        (b)  Address of Principal Business Office for Cohen & Steers, Inc.
             and Cohen & Steers Capital Management, Inc. is:
               280 Park Avenue
               10th Floor
               New York, NY 10017
        (c)  Citizenship:
               Cohen & Steers, Inc: Delaware corporation
               Cohen & Steers Capital Management, Inc: New York corporation
        (d)  Title of Class Securities:
               Commmon
        (e)  CUSIP Number:
              81721M109


Item 3.     If this statement is filed pursuant to Rule 13d-l(b), or
            13d-2(b), check whether the person filing is a

            (a)  [ ]  Broker or Dealer registered under Section 15 of the Act

            (b)  [ ]  Bank as defined in Section 3(a)(6) of the Act

            (c)  [ ]  Insurance Company as defined in section 3(a)(19) of
                      the Act

            (d)  [ ]  Investment Company registered under Section 8 of the
                      Investment Company Act

            (e)  [x]  An investment advisor in accordance with Section
                      240.13d-1(b)(1)(ii)(E)

            (f)  [ ]  An employee benefit plan or endowment fund in accordance
                      with 240.13d-1(b)(1)(ii)(F)

            (g)  [x]  A parent holding company or control person in accordance
                      with Section 240.13d-l(b)(1)(ii)(G)

            (h)  [ ]  A savings association as defined in Section 3(b) of the
                      Federal Deposit Insurance Act (12 U.S.C. 1813)

            (i)  [ ]  A church plan that is excluded from the definition of an
                      investment company under section 3(c)(14) of the
                      Investment Company Act of 1940 (15U.S.C. 80a-3)

            (j)  [ ]  Group, in accordance with Section 240.13d-1(b)(l)(ii)(J)



Item 4.    OWNERSHIP:

         (a) Amount Beneficially Owned as of December 31, 2007:

               See row 9 on cover sheet

         (b) Percent of Class:

               See row 11 on cover sheet


          (c) Number of shares as to which such person has:
                (i)   sole power to vote or direct the vote:
                         See row 5 on cover sheet

                (ii)  shared power to vote or direct the vote:
                         See row 6 on cover sheet

                (iii) sole power to dispose or to direct
                      the disposition of:
                          See row 7 on cover sheet

                (iv)  shared power to dispose or direct
                      the disposition of:
                          See row 8 on cover sheet


Item 5.  OWNERSHIP  OF 5% OR LESS OF A CLASS
         N/A

Item 6.  OWNERSHIP OF MORE THAN 5% ON BEHALF OF ANOTHER PERSON
         N/A

Item 7.  IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH
         ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT
         HOLDING COMPANY

         Cohen & Steers, Inc holds a 100% interest in Cohen & Steers Capital
         Management, Inc., an investment advisor registerd under Section 203
         of the Investment Advisers Act.

Item 8.  IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP

         Cohen & Steers, Inc holds a 100% interest in Cohen & Steers Capital
         Management, Inc., an investment advisor registerd under Section 203
         of the Investment Advisers Act.

Item 9   NOTICE OF DISSOLUTION OF GROUP:
         Not Applicable



Item 10      Certification

     By signing  below I certify  that,  to the best of my knowledge and
belief,the  securities  referred to above were  acquired  and are held in the
ordinary course of business  and were not acquired and are not held for the
purpose of or with the effect of  changing  or  influencing  the  control of
the issuer of the securities  and were not acquired and are not held in
connection  with or as a participant in any transaction having that purpose
or effect.


Signature


     After  reasonable  inquiry and to the best of my  knowledge  and belief,
I certify that the information  set forth in this statement is true,
complete and correct.

Date: February 14, 2008


/s/Lisa Phelan
---------------------------------------------------
Signature


Lisa Phelan, Senior Vice President, Chief Compliance Officer
Cohen & Steers, Inc.
Cohen & Steers Capital Management, Inc.
---------------------------------------------------
Name and Title



                             JOINT FILING AGREEMENT

     In accordance with Rule 13d-1(k)  promulgated under the Securities Exchange
Act of 1934, as amended,  the undersigned  hereby agree to the joint filing with
all  other  Reporting  Persons  (as such term is  defined  in the  Schedule  13G
referred  to below) on behalf of each of them of a  Statement  on  Schedule  13G
including  amendments  thereto) with respect to the common shares of Senior
Housing Properties Trust,and that this Agreement may be included as an
Exhibit to such joint filing.  This  Agreement may be executed in any number of
counterparts,  all of which together shall constitute one and the same
instrument.

     IN WITNESS  WHEREOF,  the  undersigned  hereby execute this Agreement as of
February 14, 2008.

                              COHEN & STEERS, INC.

                                        /s/Lisa Phelan
                                   By:-----------------------------------------
                                            Name: Lisa Phelan
                                            Title: Senior Vice President
 						   Chief Compliance Officer



                              COHEN & STEERS CAPITAL MANAGEMENT, INC.

                                        /s/Lisa Phelan
                                    By:----------------------------------------
                                             Name: Lisa Phelan
                                             Title: Senior Vice President
						    Chief Compliance Officer