<PAGE>

                                                                   EXHIBIT 10.18


                               GUARANTY AGREEMENT


         THIS GUARANTY AGREEMENT (this "Agreement") is made and given as of
October 25, 2002 by FIVE STAR QUALITY CARE, INC., a Maryland corporation (the
"Guarantor"), for the benefit of SENIOR HOUSING PROPERTIES TRUST, a Maryland
real estate investment trust (together with its successors and assigns, "SNH"),
and SNH CHS PROPERTIES TRUST, a Maryland real estate investment trust (together
with its successors and assigns, the "Landlord" and, together with SNH,
collectively, the "Beneficiaries").



                              W I T N E S S E T H :

         WHEREAS, in connection with the execution of a Purchase and Sale
Agreement, dated as of August 26, 2002, by and among Constellation Health
Services, Inc. and certain of its subsidiaries as further identified therein
(collectively, the "Seller"), Constellation Real Estate Group, Inc. ("CREG"),
and SNH, as amended by that certain First Amendment to Purchase and Sale
Agreement, dated as of the date hereof, by and among the Seller, CREG, SNH and
the Guarantor (as so amended, the "Purchase Agreement"), SNH and the Guarantor
agreed, as between themselves, that the Guarantor would indemnify SNH for
losses, claims and expenses relating to certain assets being acquired by the
Guarantor pursuant to the Purchase Agreement;

         WHEREAS, pursuant to a Lease Agreement, dated as of the date hereof
(the "Lease"), the Landlord has agreed to lease to FVE-CHS LLC, an indirect
wholly owned subsidiary of the Guarantor (the "Tenant"), and the Tenant has
agreed to lease from the Landlord, certain real property, together with certain
related improvements and personal property, as more particularly described in
the Lease; and

         WHEREAS, it is a condition precedent to the Landlord's entering into
the Lease that the Guarantor guarantee all of the payment and performance
obligations of the Tenant with respect to the Lease; and

         WHEREAS, the transactions contemplated by the Lease are of direct
material benefit to the Guarantor;

         NOW, THEREFORE, in consideration of the foregoing and for other good
and valuable consideration, the mutual receipt and legal sufficiency of which
are hereby acknowledged, the Guarantor hereby agrees as follows:

<PAGE>


         1. Certain Terms. Capitalized terms used and not otherwise defined in
this Agreement shall have the meanings ascribed to such terms in the Lease. The
Lease and the Incidental Documents are herein collectively referred to as the
"Transaction Documents."

         2. Guaranteed Obligations. For purposes of this Agreement:

         (i) the term "SNH Guaranteed Obligations" shall mean the payment and
performance of the obligation of the Guarantor to indemnify, protect and hold
harmless SNH from and against any and all liabilities, obligations, claims,
damages, penalties, causes of action, costs and reasonable expenses (including,
without limitation, reasonable attorneys' fees), to the maximum extent permitted
by law, imposed upon or incurred by or asserted against SNH and related to those
properties described on Exhibit A attached hereto and made a part hereof
(including, without limitation, any claim raised by any party under the Purchase
Agreement with respect to such properties); and

         (ii) the term "Landlord Guaranteed Obligations" shall mean (i) the
payment and performance of each and every obligation of the Tenant to the
Landlord under the Transaction Documents or relating thereto, whether now
existing or hereafter arising, and including, without limitation, the payment of
the full amount of the Rent payable under the Lease and (ii) the repayment to
the Landlord and its Affiliated Persons of any and all amounts from time to time
advanced or incurred by the Landlord or such Affiliated Persons in connection
with any guaranty or other agreement provided by the Landlord or such Affiliated
Persons to any Governmental Agency to facilitate the licensing of any Facility
located upon the Leased Property; and

         (iii) the term "Guaranteed Obligations" shall mean the SNH Guaranteed
Obligations and the Landlord Guaranteed Obligations, collectively.

         3. Representations and Covenants. The Guarantor represents, warrants,
covenants, and agrees that:

         3.1 Incorporation of Representations and Warranties. The
representations and warranties of the Tenant and its Affiliated Persons set
forth in the Transaction Documents are true and correct on and as of the date
hereof in all material respects.

         3.2 Performance of Covenants and Agreements. The Guarantor hereby
agrees to take all lawful action in its power





                                      -2-

<PAGE>


to cause the Tenant duly and punctually to perform all of the covenants and
agreements set forth in the Transaction Documents.

         3.3 Validity of Agreement. The Guarantor has duly and validly executed
and delivered this Agreement; this Agreement constitutes the legal, valid and
binding obligation of the Guarantor, enforceable against the Guarantor in
accordance with its terms, except as the enforceability thereof may be subject
to bankruptcy, fraudulent conveyance, insolvency, reorganization, moratorium and
other laws relating to or affecting creditors' rights generally and subject to
general equitable principles, regardless of whether enforceability is considered
in a proceeding at law or in equity; and the execution, delivery and performance
of this Agreement have been duly authorized by all requisite action of the
Guarantor and such execution, delivery and performance by the Guarantor will not
result in any breach of the terms, conditions or provisions of, or conflict with
or constitute a default under, or result in the creation of any lien, charge or
encumbrance upon any of the property or assets of the Guarantor pursuant to the
terms of, any indenture, mortgage, deed of trust, note, other evidence of
indebtedness, agreement or other instrument to which it may be a party or by
which it or any of its property or assets may be bound, or violate any provision
of law, or any applicable order, writ, injunction, judgment or decree of any
court or any order or other public regulation of any governmental commission,
bureau or administrative agency.

         3.4 Payment of Expenses. The Guarantor agrees, as principal obligor and
not as guarantor only, to pay to the Beneficiaries forthwith, upon demand, in
immediately available federal funds, all costs and expenses (including
reasonable attorneys' fees and disbursements) incurred or expended by the
Beneficiaries in connection with the enforcement of this Agreement, together
with interest on amounts recoverable under this Agreement from the time such
amounts become due until payment at the Overdue Rate. The Guarantor's covenants
and agreements set forth in this Section 3.4 shall survive the termination of
this Agreement.

         3.5 Notices. The Guarantor shall promptly give notice to the
Beneficiaries of any event known to it which might reasonably result in a
material adverse change in its financial condition.

         3.6 Reports. The Guarantor shall promptly provide to the Landlord each
of the financial reports, certificates and other documents required of it under
the Transaction Documents.



                                      -3-

<PAGE>


         3.7 Books and Records. The Guarantor shall at all times keep proper
books of record and account in which full, true and correct entries shall be
made of its transactions in accordance with generally accepted accounting
principles and shall set aside on its books from its earnings for each fiscal
year all such proper reserves, including reserves for depreciation, depletion,
obsolescence and amortization of its properties during such fiscal year, as
shall be required in accordance with generally accepted accounting principles,
consistently applied, in connection with its business. The Guarantor shall
permit access by the Beneficiaries and their agents to the books and records
maintained by the Guarantor during normal business hours and upon reasonable
notice. Any proprietary information obtained by Landlord with respect to the
Guarantor pursuant to the provisions of this Agreement shall be treated as
confidential, except that such information may be disclosed or used, subject to
appropriate confidentiality safeguards, pursuant to any court order or in any
litigation between the parties and except further that Landlord may disclose
such information to its prospective lenders, provided that Landlord shall direct
such lenders to maintain such information as confidential.

         3.8 Taxes, Etc. The Guarantor shall pay and discharge promptly as they
become due and payable all taxes, assessments and other governmental charges or
levies imposed upon the Guarantor or the income of the Guarantor or upon any of
the property, real, personal or mixed, of the Guarantor, or upon any part
thereof, as well as all claims of any kind (including claims for labor,
materials and supplies) which, if unpaid, might by law become a lien or charge
upon any property and result in a material adverse change in the financial
condition of the Guarantor; provided, however, that the Guarantor shall not be
required to pay any such tax, assessment, charge, levy or claim if the amount,
applicability or validity thereof shall currently be contested in good faith by
appropriate proceedings or other appropriate actions promptly initiated and
diligently conducted and if the Guarantor shall have set aside on its books such
reserves of the Guarantor, if any, with respect thereto as are required by
generally accepted accounting principles.

         3.9 Legal Existence of Guarantor. The Guarantor shall do or cause to be
done all things necessary to preserve and keep in full force and effect its
legal existence.

         3.10 Compliance. The Guarantor shall use reasonable business efforts to
comply in all material respects with all applicable statutes, rules, regulations
and orders of, and all applicable restrictions imposed by, all governmental
authorities



                                      -4-

<PAGE>


in respect of the conduct of its business and the ownership of its property
(including, without limitation, applicable statutes, rules, regulations, orders
and restrictions relating to environmental, safety and other similar standards
or controls).

         3.11 Insurance. The Guarantor shall maintain, with financially sound
and reputable insurers, insurance with respect to its properties and business
against loss or damage of the kinds customarily insured against by owners of
established reputation engaged in the same or similar businesses and similarly
situated, in such amounts and by such methods as shall be customary for such
owners and deemed adequate by the Guarantor.

         3.12 No Change in Control. The Guarantor shall not permit the
occurrence of any direct or indirect Change in Control of the Tenant or the
Guarantor.

         4. Guarantee. The Guarantor hereby unconditionally guarantees that the
Guaranteed Obligations which are monetary obligations shall be paid in full when
due and payable, whether upon demand, at the stated or accelerated maturity
thereof pursuant to any Transaction Document, or otherwise, and that the
Guaranteed Obligations which are performance obligations shall be fully
performed at the times and in the manner such performance is required by the
Transaction Documents. With respect to the Guaranteed Obligations which are
monetary obligations, this guarantee is a guarantee of payment and not of
collectibility and is absolute and in no way conditional or contingent. In case
any part of the Guaranteed Obligations shall not have been paid when due and
payable or performed at the time performance is required, the Guarantor shall,
in the case of monetary obligations, within five (5) Business Days after receipt
of notice from the applicable Beneficiary, pay or cause to be paid to such
Beneficiary the amount thereof as is then due and payable and unpaid (including
interest and other charges, if any, due thereon through the date of payment in
accordance with the applicable provisions of the Transaction Documents) or, in
the case of nonmonetary obligations, perform or cause to be performed such
obligations in accordance with the Transaction Documents.

         5. Set-Off. The Guarantor hereby authorizes the Landlord, at any time
and without notice to set off the whole or any portion or portions of any or all
sums credited by or due from the Landlord to it against amounts payable under
this Agreement. The Landlord shall promptly notify the Guarantor of



                                      -5-

<PAGE>

any such set-off made by the Landlord and the application made by the Landlord
of the proceeds thereof.

         6. Unenforceability of Guaranteed Obligations, Etc. If the Tenant is
for any reason under no legal obligation to discharge any of the Guaranteed
Obligations (other than because the same have been previously discharged in
accordance with the terms of the Transaction Documents), or if any other moneys
included in the Guaranteed Obligations have become unrecoverable from the Tenant
by operation of law or for any other reason, including, without limitation, the
invalidity or irregularity in whole or in part of any Guaranteed Obligation or
of any Transaction Document or any limitation on the liability of the Tenant
thereunder not contemplated by the Transaction Documents or any limitation on
the method or terms of payment thereunder which may now or hereafter be caused
or imposed in any manner whatsoever, the guarantees contained in this Agreement
shall nevertheless remain in full force and effect and shall be binding upon the
Guarantor to the same extent as if the Guarantor at all times had been the
principal debtor on all such Guaranteed Obligations.

         7. Additional Guarantees. This Agreement shall be in addition to any
other guarantee or other security for the Guaranteed Obligations and it shall
not be prejudiced or rendered unenforceable by the invalidity of any such other
guarantee or security or by any waiver, amendment, release or modification
thereof.

         8. Consents and Waivers, Etc. The Guarantor hereby acknowledges receipt
of correct and complete copies of each of the Transaction Documents, and
consents to all of the terms and provisions thereof, as the same may be from
time to time hereafter amended or changed in accordance with the terms and
conditions thereof, and, except as otherwise provided herein, to the maximum
extent permitted by applicable law, waives (a) presentment, demand for payment,
and protest of nonpayment, of any principal of or interest on any of the
Guaranteed Obligations, (b) notice of acceptance of this Agreement and of
diligence, presentment, demand and protest, (c) notice of any default hereunder
and any default, breach or nonperformance or Event of Default under any of the
Guaranteed Obligations or the Transaction Documents, (d) notice of the terms,
time and place of any private or public sale of any collateral held as security
for the Guaranteed Obligations, (e) demand for performance or observance of, and
any enforcement of any provision of, or any pursuit or exhaustion of rights or
remedies against the Tenant or any other guarantor of the Guaranteed
Obligations, under or pursuant to the Transaction Documents, or any agreement
directly



                                      -6-

<PAGE>


or indirectly relating thereto and any requirements of diligence or promptness
on the part of the holders of the Guaranteed Obligations in connection
therewith, and (f) to the extent the Guarantor lawfully may do so, any and all
demands and notices of every kind and description with respect to the foregoing
or which may be required to be given by any statute or rule of law and any
defense of any kind which it may now or hereafter have with respect to this
Agreement, or any of the Transaction Documents or the Guaranteed Obligations
(other than that the same have been discharged in accordance with the
Transaction Documents).

         9. No Impairment, Etc. The obligations, covenants, agreements and
duties of the Guarantor under this Agreement shall not be affected or impaired
by any assignment or transfer in whole or in part of any of the Guaranteed
Obligations without notice to the Guarantor, or any waiver by either Beneficiary
or any holder of any of the Guaranteed Obligations or by the holders of all of
the Guaranteed Obligations of the performance or observance by the Tenant or any
other guarantor of any of the agreements, covenants, terms or conditions
contained in the Guaranteed Obligations or the Transaction Documents or any
indulgence in or the extension of the time for payment by the Tenant or any
other guarantor of any amounts payable under or in connection with the
Guaranteed Obligations or the Transaction Documents or any other instrument or
agreement relating to the Guaranteed Obligations or of the time for performance
by the Tenant or any other guarantor of any other obligations under or arising
out of any of the foregoing or the extension or renewal thereof (except that
with respect to any extension of time for payment or performance of any of the
Guaranteed Obligations granted by the Landlord or any other holder of such
Guaranteed Obligations to the Tenant, the Guarantor's obligations to pay or
perform such Guaranteed Obligation shall be subject to the same extension of
time for performance), or the modification or amendment (whether material or
otherwise) of any duty, agreement or obligation of the Tenant or any other
guarantor set forth in any of the foregoing, or the voluntary or involuntary
sale or other disposition of all or substantially all the assets of the Tenant
or any other guarantor or insolvency, bankruptcy, or other similar proceedings
affecting the Tenant or any other guarantor or any assets of the Tenant or any
such other guarantor, or the release or discharge of the Tenant or any such
other guarantor from the performance or observance of any agreement, covenant,
term or condition contained in any of the foregoing without the consent of the
holders of the Guaranteed Obligations by operation of law, or any other cause,
whether similar or dissimilar to the foregoing.



                                      -7-

<PAGE>


         10. Reimbursement, Subrogation, Etc. The Guarantor hereby covenants and
agrees that it will not enforce or otherwise exercise any rights of
reimbursement, subrogation, contribution or other similar rights against the
Tenant (or any other person against whom the Landlord may proceed) with respect
to the Guaranteed Obligations prior to the payment in full of all amounts owing
with respect to the Lease, and until all indebtedness of the Tenant to the
Landlord shall have been paid in full, the Guarantor shall not have any right of
subrogation, and the Guarantor waives any defense it may have based upon any
election of remedies by the Landlord which destroys its subrogation rights or
its rights to proceed against the Tenant for reimbursement, including, without
limitation, any loss of rights the Guarantor may suffer by reason of any rights,
powers or remedies of the Tenant in connection with any anti-deficiency laws or
any other laws limiting, qualifying or discharging the indebtedness to the
Landlord. Until all obligations of the Tenant pursuant to the Transaction
Documents shall have been paid and satisfied in full, the Guarantor further
waives any right to enforce any remedy which the Landlord now has or may in the
future have against the Tenant, any other guarantor or any other person and any
benefit of, or any right to participate in, any security whatsoever now or in
the future held by the Landlord.

         11. Defeasance. This Agreement shall terminate at such time as the
Guaranteed Obligations have been paid and performed in full and all other
obligations of the Guarantor to the Beneficiaries under this Agreement have been
satisfied in full; provided, however, if at any time, all or any part of any
payment applied on account of the Guaranteed Obligations is or must be rescinded
or returned for any reason whatsoever (including, without limitation, the
insolvency, bankruptcy or reorganization of the Tenant), this Agreement, to the
extent such payment is or must be rescinded or returned, shall be deemed to have
continued in existence notwithstanding any such termination.

         12. Notices. (a) Any and all notices, demands, consents, approvals,
offers, elections and other communications required or permitted under this
Agreement shall be deemed adequately given if in writing and the same shall be
delivered either in hand, by telecopier with written acknowledgment of receipt,
or by mail or Federal Express or similar expedited commercial carrier, addressed
to the recipient of the notice, postpaid and registered or certified with return
receipt requested (if by mail), or with all freight charges prepaid (if by
Federal Express or similar carrier).



                                      -8-

<PAGE>


         (b) All notices required or permitted to be sent hereunder shall be
deemed to have been given for all purposes of this Agreement upon the date of
acknowledged receipt, in the case of a notice by telecopier, and, in all other
cases, upon the date of receipt or refusal, except that whenever under this
Agreement a notice is either received on a day which is not a Business Day or is
required to be delivered on or before a specific day which is not a Business
Day, the day of receipt or required delivery shall automatically be extended to
the next Business Day.



         (c) All such notices shall be addressed,


         if to either Beneficiary:


                  Senior Housing Properties Trust
                  400 Centre Street
                  Newton, Massachusetts  02458
                  Attn:  Mr. David J. Hegarty
                  [Telecopier No. (617) 796-8349]



         if to the Guarantor to:


                  Five Star Quality Care, Inc.
                  400 Centre Street
                  Newton, Massachusetts  02458
                  Attn:  Mr. Evrett W. Benton
                  [Telecopier No. (617) 796-8385]



         (d) By notice given as herein provided, the parties hereto and their
respective successors and assigns shall have the right from time to time and at
any time during the term of this Agreement to change their respective addresses
effective upon receipt by the other parties of such notice and each shall have
the right to specify as its address any other address within the United States
of America.

         13. Successors and Assigns. Whenever in this Agreement any of the
parties hereto is referred to, such reference shall be deemed to include the
successors and assigns of such party, including without limitation the holders,
from time to time, of the Guaranteed Obligations; and all representations,
warranties, covenants and agreements by or on behalf of the Guarantor which are
contained in this Agreement shall inure to the benefit of the Landlord's
uccessors and assigns, including without limitation said holders, whether so
expressed or not.

         14. Applicable Law. Except as to matters regarding the internal affairs
of the Beneficiaries and issues of or limitations on any personal liability of
the shareholders and



                                      -9-

<PAGE>


trustees of the Beneficiaries for obligations of the Beneficiaries, as to which
the laws of the State of Maryland shall govern, this Agreement, the Transaction
Documents and any other instruments executed and delivered to evidence, complete
or perfect the transactions contemplated hereby and thereby shall be
interpreted, construed, applied and enforced in accordance with the laws of The
Commonwealth of Massachusetts applicable to contracts between residents of
Massachusetts which are to be performed entirely within Massachusetts,
regardless of (i) where any such instrument is executed or delivered; or (ii)
where any payment or other performance required by any such instrument is made
or required to be made; or (iii) where any breach of any provision of any such
instrument occurs, or any cause of action otherwise accrues; or (iv) where any
action or other proceeding is instituted or pending; or (v) the nationality,
citizenship, domicile, principal place of business, or jurisdiction of
organization or domestication of any party; or (vi) whether the laws of the
forum jurisdiction otherwise would apply the laws of a jurisdiction other than
The Commonwealth of Massachusetts; or (vii) any combination of the foregoing.

         15. Arbitration. Either Beneficiary or the Guarantor may elect to
submit to arbitration any dispute hereunder that has an amount in controversy in
excess of $250,000. Any such arbitration shall be conducted in Boston,
Massachusetts in accordance with the Commercial Arbitration Rules of the
American Arbitration Association then pertaining and the decision of the
arbitrators with respect to such dispute shall be binding, final and conclusive
on the parties.

         In the event that any such dispute is submitted to arbitration
hereunder, the applicable Beneficiary and the Guarantor shall each appoint and
pay all fees of a fit and impartial person as arbitrator with at least ten (10)
years' recent professional experience in the general subject matter of the
dispute. Notice of such appointment shall be sent in writing by each party to
the other, and the arbitrators so appointed, in the event of their failure to
agree within thirty (30) days after the appointment of the second arbitrator
upon the matter so submitted, shall appoint a third arbitrator. If either the
Landlord or the Guarantor shall fail to appoint an arbitrator as aforesaid for a
period of twenty (20) days after written notice from the other party to make
such appointment, then the arbitrator appointed by the party having made such
appointment shall appoint a second arbitrator and the two (2) so appointed
shall, in the event of their failure to agree upon any decision within thirty
(30) days thereafter, appoint a third



                                      -10-

<PAGE>


arbitrator. If such arbitrators fail to agree upon a third arbitrator within
forty five (45) days after the appointment of the second arbitrator, then such
third arbitrator shall be appointed by the American Arbitration Association from
its qualified panel of arbitrators, and shall be a person having at least ten
(10) years' recent professional experience as to the subject matter in question.
The fees of the third arbitrator and the expenses incident to the proceedings
shall be borne equally between the applicable Beneficiary and the Guarantor,
unless the arbitrators decide otherwise. The fees of respective counsel engaged
by the parties, and the fees of expert witnesses and other witnesses called for
the parties, shall be paid by the respective party engaging such counsel or
calling or engaging such witnesses.

         The decision of the arbitrators shall be rendered within thirty (30)
days after appointment of the third arbitrator. Such decision shall be in
writing and in duplicate, one counterpart thereof to be delivered to the
applicable Beneficiary and one to the Guarantor. A judgment of a court of
competent jurisdiction may be entered upon the award of the arbitrators in
accordance with the rules and statutes applicable thereto then obtaining.

         The Landlord and the Guarantor acknowledge and agree that, to the
extent any such dispute shall involve any Manager and be subject to arbitration
pursuant to such Manager's Management Agreement, the Landlord and the Guarantor
shall cooperate to consolidate any such arbitration hereunder and under such
Management Agreement into a single proceeding.

         16. Modification of Agreement. No modification or waiver of any
provision of this Agreement, nor any consent to any departure by the Guarantor
therefrom, shall in any event be effective unless the same shall be in writing
and signed by the Beneficiaries, and such modification, waiver or consent shall
be effective only in the specific instances and for the purpose for which given.
No notice to or demand on the Guarantor in any case shall entitle the Guarantor
to any other or further notice or demand in the same, similar or other
circumstances. This Agreement may not be amended except by an instrument in
writing executed by or on behalf of the party against whom enforcement of such
amendment is sought.

         17. Waiver of Rights by the Beneficiaries. Neither any failure nor any
delay on the Beneficiaries' part in exercising any right, power or privilege
under this Agreement shall operate as a waiver thereof, nor shall a single or
partial exercise



                                      -11-

<PAGE>


thereof preclude any other or further exercise or the exercise of any other
right, power or privilege.

         18. Severability. In case any one or more of the provisions contained
in this Agreement should be invalid, illegal or unenforceable in any respect,
the validity, legality and enforceability of the remaining provisions contained
herein shall not in any way be affected or impaired thereby, but this Agreement
shall be reformed and construed and enforced to the maximum extent permitted by
applicable law.

         19. Entire Contract. This Agreement constitutes the entire agreement
between the parties hereto with respect to the subject matter hereof and shall
supersede and take the place of any other instruments purporting to be an
agreement of the parties hereto relating to the subject matter hereof.

         20. Headings; Counterparts. Headings in this Agreement are for purposes
of reference only and shall not limit or otherwise affect the meaning hereof.
This Agreement may be executed in any number of counterparts, each of which
shall be an original, but all of which together shall constitute one instrument,
and in pleading or proving any provision of this Agreement, it shall not be
necessary to produce more than one of such counterparts.

         21. Remedies Cumulative. No remedy herein conferred upon the
Beneficiaries is intended to be exclusive of any other remedy, and each and
every remedy shall be cumulative and shall be in addition to every other remedy
given hereunder or now or hereafter existing at law or in equity or by statute
or otherwise.

         22. NON-LIABILITY OF TRUSTEES. THE DECLARATION OF TRUST ESTABLISHING
THE BENEFICIARIES, COPIES OF WHICH, TOGETHER WITH ALL AMENDMENTS THERETO (THE
"DECLARATION"), ARE DULY FILED WITH THE DEPARTMENT OF ASSESSMENTS AND TAXATION
OF THE STATE OF MARYLAND, PROVIDE THAT THE NAMES "SNH PROPERTIES TRUST" AND "SNH
CHS PROPERTIES TRUST" REFER TO THE TRUSTEES UNDER THE DECLARATIONS COLLECTIVELY
AS TRUSTEES, BUT NOT INDIVIDUALLY OR PERSONALLY, AND THAT NO TRUSTEE, OFFICER,
SHAREHOLDER, EMPLOYEE OR AGENT OF EITHER BENEFICIARY SHALL BE HELD TO ANY
PERSONAL LIABILITY, JOINTLY OR SEVERALLY, FOR ANY OBLIGATION OF OR CLAIM
AGAINST, SUCH BENEFICIARY. ALL PERSONS DEALING WITH THE BENEFICIARIES, IN ANY
WAY, SHALL LOOK ONLY TO THE ASSETS OF THE BENEFICIARIES FOR THE PAYMENT OF ANY
SUM OR THE PERFORMANCE OF ANY OBLIGATION.



                  [Remainder of page intentionally left blank.]



                                      -12-

<PAGE>


         WITNESS the execution hereof under seal as of the date above first
written.



                                     FIVE STAR QUALITY CARE, INC.,
                                     a Maryland corporation



                                     By:  /s/ Bruce J. Mackey Jr.
                                          --------------------------------
                                          Bruce J. Mackey Jr.
                                     Its: Treasurer and Chief Financial Officer







                                      -13-

<PAGE>











                                    EXHIBIT A



                PROPERTIES RELATED TO SNH GUARANTEED OBLIGATIONS


Ellicott City I and II
3004 North Ridge Road
Ellicott City, Maryland 21403


HeartHaven at Seabury
100 Seabury Drive
Bloomfield, Connecticut 06002


HeartHomes at Bay Ridge
3023 Arundale on the Bay Road
Annapolis, Maryland 21403


HeartHomes at Linthicum
804 and 806 Camp Meade Road
Linthicum, Maryland 21090


Hearthomes at Lutherville
1414 and 1420 Front Avenue
Lutherville, Maryland 21093


HeartHomes at Piney Orchard
8735 Piney Orchard Parkway
Odenton, Maryland 21113


HeartHomes at Pasadena
8016 Ritchie Highway
Pasadena, Maryland 21122