<PAGE>



                                                                     EXHIBIT 4.1




                                     Form of

                          SUPPLEMENTAL INDENTURE NO. 12

                                 by and between

                              HRPT PROPERTIES TRUST

                                       and

                         U.S. BANK NATIONAL ASSOCIATION

                             as of January 30, 2003



             SUPPLEMENTAL TO THE INDENTURE DATED AS OF JULY 9, 1997



                      ------------------------------------



                              HRPT PROPERTIES TRUST

                    6.40% Senior Notes due February 15, 2015


<PAGE>



         This SUPPLEMENTAL INDENTURE NO. 12 (this "Supplemental Indenture") made
and entered into as of January 30, 2003 between HRPT PROPERTIES TRUST, a
Maryland real estate investment trust (the "Company"), and U.S. BANK NATIONAL
ASSOCIATION, a national banking association (and successor to State Street Bank
and Trust Company ("State Street") in its capacity as Trustee), as Trustee (the
"Trustee"),

                                WITNESSETH THAT:

         WHEREAS, the Company and the Trustee have executed and delivered an
Indenture, dated as of July 9, 1997 (the "Indenture"), relating to the Company's
issuance, from time to time, of various series of debt securities; and

         WHEREAS, U.S. Bank National Association has acquired and succeeded to
substantially all of the corporate trust business of State Street, and, being
eligible to serve as trustee under the Indenture, has succeeded to State Street
as Trustee under the Indenture; and

         WHEREAS, the Company has determined to issue debt securities known as
its 6.40% Senior Notes due February 15, 2015; and

         WHEREAS, the Indenture provides that certain terms and conditions for
each series of debt securities issued by the Company thereunder may be set forth
in an indenture supplemental to the Indenture;

         NOW, THEREFORE, THIS SUPPLEMENTAL INDENTURE WITNESSETH:

                                   ARTICLE 1

                                  DEFINED TERMS

         SECTION 1.1 The following definitions supplement, and, to the extent
inconsistent with, replace the definitions in Section 101 of the Indenture:

         "Acquired Debt" means Debt of a Person or entity (i) existing at the
time such Person or entity becomes a Subsidiary or (ii) assumed in connection
with the acquisition of assets from such Person or entity, in each case, other
than Debt incurred in connection with, or in contemplation of, such Person or
entity becoming a Subsidiary or such acquisition. Acquired Debt shall be deemed
to be incurred on the date of the related acquisition of assets from any Person
or entity or the date the acquired Person or entity becomes a Subsidiary.

         "Annual Debt Service" as of any date means the maximum amount which is
expensed in any 12-month period for interest on Debt of the Company and its
Subsidiaries.

         "Business Day" means any day other than a Saturday or Sunday or a day
on which banking institutions in the City of New York or in the city in which
the Corporate Trust Office of the Trustee is located, are required or authorized
to close.

         "Capital Stock" means, with respect to any Person, any capital stock
(including preferred stock), shares, interests, participation or other ownership
interests (however designated) of such


<PAGE>


Person and any rights (other than debt securities convertible into or
exchangeable for capital stock), warrants or options to purchase any thereof.

         "Consolidated Income Available for Debt Service" for any period means
Earnings from Operations of the Company and its Subsidiaries plus amounts which
have been deducted, and minus amounts which have been added, for the following
(without duplication): (i) interest on Debt of the Company and its Subsidiaries,
(ii) provision for taxes of the Company and its Subsidiaries based on income,
(iii) amortization of debt discount and deferred financing costs, (iv)
provisions for gains and losses on properties and property, depreciation and
amortization, (v) the effect of any noncash charge resulting from a change in
accounting principles in determining Earnings from Operations for such period
and (vi) amortization of deferred charges.

         "Debt" of the Company or any Subsidiary means, without duplication, any
indebtedness of the Company or any Subsidiary, whether or not contingent, in
respect of (i) borrowed money or evidenced by bonds, notes, debentures or
similar instruments, (ii) indebtedness for borrowed money secured by any
Encumbrance existing on property owned by the Company or any Subsidiary, to the
extent of the lesser of (x) the amount of indebtedness so secured and (y) the
fair market value of the property subject to such Encumbrance, (iii) the
reimbursement obligations, contingent or otherwise, in connection with any
letters of credit actually issued (other than letters of credit issued to
provide credit enhancement or support with respect to other indebtedness of the
Company or any Subsidiary otherwise reflected as Debt hereunder) or amounts
representing the balance deferred and unpaid of the purchase price of any
property or services, except any such balance that constitutes an accrued
expense or trade payable, or all conditional sale obligations or obligations
under any title retention agreement, (iv) the principal amount of all
obligations of the Company or any Subsidiary with respect to redemption,
repayment or other repurchase of any Disqualified Stock, or (v) any lease of
property by the Company or any Subsidiary as lessee which is reflected on the
Company's consolidated balance sheet as a capitalized lease in accordance with
GAAP, to the extent, in the case of items of indebtedness under (i) through
(iii) above, that any such items (other than letters of credit) would appear as
a liability on the Company's consolidated balance sheet in accordance with GAAP,
and also includes, to the extent not otherwise included, any obligation by the
Company or any Subsidiary to be liable for, or to pay, as obligor, guarantor or
otherwise (other than for purposes of collection in the ordinary course of
business), Debt of another Person (other than the Company or any Subsidiary) (it
being understood that Debt shall be deemed to be incurred by the Company or any
Subsidiary whenever the Company or such Subsidiary shall create, assume,
guarantee or otherwise become liable in respect thereof).

         "Disqualified Stock" means, with respect to any Person, any Capital
Stock of such Person which by the terms of such Capital Stock (or by the terms
of any security into which it is convertible or for which it is exchangeable or
exercisable), upon the happening of any event or otherwise (i) matures or is
mandatorily redeemable, pursuant to a sinking fund obligation or otherwise
(other than Capital Stock which is redeemable solely in exchange for common
stock or shares), (ii) is convertible into or exchangeable or exercisable for
Debt or Disqualified Stock, or (iii) is redeemable at the option of the holder
thereof, in whole or in part (other than Capital Stock which is redeemable
solely in exchange for common stock or shares), in each case on or prior to the
stated maturity of the Notes.


                                      -2-


<PAGE>


         "Earnings from Operations" for any period means net earnings excluding
gains and losses on sales of investments, extraordinary items, gains and losses
on early extinguishment of debt and property valuation losses, as reflected in
the financial statements of the Company and its Subsidiaries for such period,
determined on a consolidated basis in accordance with GAAP.

         "Encumbrance" means any mortgage, lien, charge, pledge or security
interest of any kind.

         "Make-Whole Amount" means, in connection with any optional redemption
or accelerated payment of any notes prior to August 15, 2014, the excess, if
any, of (i) the aggregate present value as of the date of such redemption or
accelerated payment of each dollar of principal being redeemed or paid and the
amount of interest (exclusive of interest accrued to the date of redemption or
accelerated payment) that would have been payable in respect of such dollar if
such redemption or accelerated payment had been made on August 15, 2014,
determined by discounting, on a semiannual basis, such principal and interest at
the Reinvestment Rate (determined on the third Business Day preceding the date
such notice of redemption is given or declaration of acceleration is made) from
the respective dates on which such principal and interest would have been
payable if such redemption or accelerated payment had been made on August 15,
2014, over (ii) the aggregate principal amount of the Notes being redeemed or
paid. In the case of any redemption or accelerated payment of notes on or after
August 15, 2014, the Make-Whole Amount means zero. For purposes of this
Supplemental Indenture and the Notes, references in the Indenture to the payment
of the principal (and premium, if any) and interest on the Notes shall be deemed
to include the payment of the Make-Whole Amount, if any, due upon redemption
with respect to the Notes. The Make-Whole Amount shall be calculated by the
Company and set forth in an Officer's Certificate delivered to the Trustee, and
the Trustee shall be entitled to rely on said Officer's Certificate.

         "Notes" means the Company's 6.40% Senior Notes due February 15, 2015,
issued under this Supplemental Indenture and the Indenture, as amended or
supplemented from time to time.

         "Reinvestment Rate" means a rate per annum equal to the sum of 0.50%
(fifty one-hundredths of one percent) plus the yield on treasury securities at
constant maturity under the heading "Week Ending" published in the Statistical
Release under the caption "Treasury Constant Maturities" for the maturity
(rounded to the nearest month) corresponding to the remaining life to maturity
(which, in the case of maturities corresponding to the principal and interest
due on the notes at their maturity, shall be deemed to be August 15, 2014), as
of the payment date of the principal being redeemed or paid. If no maturity
exactly corresponds to such maturity, yields for the two published maturities
most closely corresponding to such maturity shall be calculated pursuant to the
immediately preceding sentence and the Reinvestment Rate shall be interpolated
or extrapolated from such yields on a straight-line basis, rounding in each of
such relevant periods to the nearest month. For purposes of calculating the
Reinvestment Rate, the most recent Statistical Release published prior to the
date of determination of the Make-Whole Amount shall be used.

         "Secured Debt" means Debt secured by any mortgage, lien, charge, pledge
or security interest of any kind.

         "Statistical Release" means the statistical release designated
"H.15(519)" or any successor publication which is published weekly by the
Federal Reserve System and which establishes yields


                                      -3-


<PAGE>


on actively traded United States government securities adjusted to constant
maturities or, if such statistical release is not published at the time of any
determination under this Supplemental Indenture, then any publicly available
source of similar market data which shall be designated by the Company.

         "Subsidiary" means any corporation or other entity of which a majority
of (i) the voting power of the voting equity securities or (ii) the outstanding
equity interests of which are owned, directly or indirectly, by the Company or
one or more other Subsidiaries of the Company. For the purposes of this
definition, "voting equity securities" means equity securities having voting
power for the election of directors, whether at all times or only so long as no
senior class of security has such voting power by reason of any contingency.

         "Total Assets" as of any date means the sum of (i) the Undepreciated
Real Estate Assets and (ii) all other assets of the Company and its Subsidiaries
determined in accordance with GAAP (but excluding accounts receivable and
intangibles).

         "Total Unencumbered Assets" means the sum of (i) those Undepreciated
Real Estate Assets not subject to an Encumbrance for borrowed money and (ii) all
other assets of the Company and its Subsidiaries not subject to an Encumbrance
for borrowed money determined in accordance with GAAP (but excluding accounts
receivable and intangibles).

         "Undepreciated Real Estate Assets" as of any date means the cost
(original cost plus capital improvements) of real estate assets of the Company
and its Subsidiaries on such date, before depreciation and amortization,
determined on a consolidated basis in accordance with GAAP.

         "Unsecured Debt" means Debt which is not secured by any of the
properties of the Company or any Subsidiary.

                                   ARTICLE 2

                               TERMS OF THE NOTES

         SECTION 2.1 Pursuant to Section 301 of the Indenture, the Notes shall
have the following terms and conditions:

         (a) TITLE; AGGREGATE PRINCIPAL AMOUNT; FORM OF NOTES. The Notes shall
be Registered Securities under the Indenture and shall be known as the Company's
"6.40% Senior Notes due February 15, 2015." The Notes will be limited to an
aggregate principal amount of $200,000,000, subject to the right of the Company
to reopen such series for issuances of additional securities of such series and
except as provided in this Section and in Section 306 of the Indenture. The
Notes (together with the Trustee's certificate of authentication) shall be
substantially in the form of Exhibit A hereto, which is hereby incorporated in
and made a part of this Supplemental Indenture.

         The Notes will be issued in the form of one or more registered global
securities without coupons ("Global Notes") that will be deposited with, or on
behalf of, The Depository Trust Company ("DTC"), and registered in the name of
DTC's nominee, Cede & Co. Except under the circumstance described below, the
Notes will not be issuable in definitive form. Unless and until it is exchanged
in whole or in part for the individual notes represented thereby, a Global Note
may


                                      -4-


<PAGE>


not be transferred except as a whole by DTC to a nominee of DTC or by a nominee
of DTC to DTC or another nominee of DTC or by DTC or any nominee of DTC to a
successor depositary or any nominee of such successor.

         So long as DTC or its nominee is the registered owner of a Global Note,
DTC or such nominee, as the case may be, will be considered the sole owner or
holder of the Notes represented by such Global Note for all purposes under this
Supplemental Indenture. Except as described below, owners of beneficial interest
in Notes evidenced by a Global Note will not be entitled to have any of the
individual Notes represented by such Global Note registered in their names, will
not receive or be entitled to receive physical delivery of any such Notes in
definitive form and will not be considered the owners or holders thereof under
the Indenture or this Supplemental Indenture.

         If DTC is at any time unwilling, unable or ineligible to continue as
depositary and a successor depositary is not appointed by the Company within 90
days, the Company will issue individual Notes in exchange for the Global Note or
Global Notes representing such Notes. In addition, the Company may at any time
and in its sole discretion, subject to certain limitations set forth in the
Indenture, determine not to have any of such Notes represented by one or more
Global Notes and, in such event, will issue individual Notes in exchange for the
Global Note or Global Notes representing the Notes. Individual Notes so issued
will be issued in denominations of $1,000 and integral multiples thereof.

         (b) INTEREST AND INTEREST RATE. The Notes will bear interest at a rate
of 6.40% per annum, from January 30, 2003 (or, in the case of Notes issued upon
the reopening of this series of Notes, from the date designated by the Company
in connection with such reopening) or from the immediately preceding Interest
Payment Date to which interest has been paid or duly provided for, payable
semiannually on each February 15 and August 15, commencing August 15, 2003 (each
of which shall be an "Interest Payment Date"), to the Persons in whose names the
Notes are registered in the Security Register at the close of business on the
day falling 14 calendar days (whether or not a Business Day) next preceding such
Interest Payment Date (each, a "Regular Record Date").

         (c) PRINCIPAL REPAYMENT; CURRENCY. The stated maturity of the Notes is
February 15, 2015, provided, however, the Notes may be earlier redeemed at the
option of the Company as provided in paragraph (d) below. The principal of each
Note payable on its maturity date shall be paid against presentation and
surrender thereof at the Corporate Trust Office of the Trustee, located
initially at Two Avenue de Lafayette, Boston, Massachusetts 02111, in such coin
or currency of the United States of America as at the time of payment is legal
tender for the payment of public or private debts. The Company will not pay
Additional Amounts (as defined in the Indenture) on the Notes.

         (d) REDEMPTION AT THE OPTION OF THE COMPANY; ACCELERATION. The Notes
will be subject to redemption at any time at the option of the Company, in whole
or in part, upon not less than 30 nor more than 60 days' notice to each Holder
of Notes to be redeemed at its address appearing in the Security Register, at a
price equal to the sum of (i) the principal amount of the Notes being redeemed,
plus accrued and unpaid interest to but excluding the applicable Redemption
Date, plus (ii) the Make-Whole Amount, if any. If the notes are redeemed on or
after August 15, 2014, the redemption price will not include the Make-Whole
Amount. Upon the acceleration of the Notes in


                                      -5-


<PAGE>


accordance with Section 502 of the Indenture, if such acceleration occurs prior
to August 15, 2014, the principal amount of the Notes, plus accrued and unpaid
interest thereon and the Make-Whole Amount shall become due and payable
immediately.

         (e) NOTICES. All notices and other communications hereunder shall be in
writing and shall be deemed to have been duly given if mailed or transmitted by
any standard form of telecommunication. Notices to the Company shall be directed
to it at 400 Centre Street, Newton, Massachusetts 02458, Attention: President;
notices to the Trustee shall be directed to it at Two Avenue de Lafayette,
Boston, Massachusetts 02111, Attention: Corporate Trust Department, Re: HRPT
Properties Trust 6.40% Senior Notes due February 15, 2015; or as to either
party, at such other address as shall be designated by such party in a written
notice to the other party.

         (f) GLOBAL NOTE LEGEND. Each Global Note shall bear the following
legend on the face thereof:

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
         THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE
         ISSUER OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT,
         AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR
         IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF
         DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS
         IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER,
         PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON
         IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
         INTEREST HEREIN.

         (g) APPLICABILITY OF DISCHARGE, DEFEASANCE AND COVENANT DEFEASANCE
PROVISIONS. The Discharge, Defeasance and Covenant Defeasance provisions in
Article Fourteen of the Indenture will apply to the Notes.

                                   ARTICLE 3

                              ADDITIONAL COVENANTS

         SECTION 3.1 In addition to the covenants of the Company set forth in
Article Ten of the Indenture, for the benefit of the holders of the Notes:

         (a) LIMITATIONS ON INCURRENCE OF DEBT.

               (i) The Company will not, and will not permit any Subsidiary to,
          incur any Debt if, immediately after giving effect to the incurrence
          of such additional Debt and the application of the proceeds thereof,
          the aggregate principal amount of all outstanding Debt of the Company
          and its Subsidiaries on a consolidated basis determined in accordance
          with GAAP is greater than 60% of the sum ("Adjusted Total Assets") of
          (without duplication) (A) the Total Assets of the Company and its
          Subsidiaries as of the end of the calendar


                                      -6-


<PAGE>


          quarter covered in the Company's Annual Report on Form 10-K, or the
          Quarterly Report on Form 10-Q, as the case may be, most recently filed
          with the Securities and Exchange Commission (or, if such filing is not
          permitted under the Securities Exchange Act of 1934, as amended, with
          the Trustee) prior to the incurrence of such additional Debt and (B)
          the purchase price of any real estate assets or mortgages receivable
          acquired, and the amount of any securities offering proceeds received
          (to the extent that such proceeds were not used to acquire real estate
          assets or mortgages receivable or used to reduce Debt), by the Company
          or any Subsidiary since the end of such calendar quarter, including
          those proceeds obtained in connection with the incurrence of such
          additional Debt.

               (ii) In addition to the foregoing limitations on the incurrence
          of Debt, the Company will not, and will not permit any Subsidiary to,
          incur any Secured Debt if, immediately after giving effect to the
          incurrence of such additional Secured Debt and the application of the
          proceeds thereof, the aggregate principal amount of all outstanding
          Secured Debt of the Company and its Subsidiaries on a consolidated
          basis is greater than 40% of Adjusted Total Assets.

               (iii) In addition to the foregoing limitations on the incurrence
          of Debt, the Company will not, and will not permit any Subsidiary to,
          incur any Debt if the ratio of Consolidated Income Available for Debt
          Service to the Annual Debt Service for the four consecutive fiscal
          quarters most recently ended prior to the date on which such
          additional Debt is to be incurred shall have been less than 1.5 to
          1.0, on a pro forma basis after giving effect thereto and to the
          application of the proceeds therefrom, and calculated on the
          assumption that (A) such Debt and any other Debt incurred by the
          Company and its Subsidiaries since the first day of such four-quarter
          period and the application of the proceeds therefrom, including to
          refinance other Debt, had occurred at the beginning of such period;
          (B) the repayment or retirement of any other Debt by the Company and
          its Subsidiaries since the first date of such four-quarter period had
          been repaid or retired at the beginning of such period (except that,
          in making such computation, the amount of Debt under any revolving
          credit facility shall be computed based upon the average daily balance
          of such Debt during such period); (C) in the case of Acquired Debt or
          Debt incurred in connection with any acquisition since the first day
          of such four-quarter period, the related acquisition had occurred as
          of the first day of such period with appropriate adjustments with
          respect to such acquisition being included in such pro forma
          calculation; and (D) in the case of any acquisition or disposition by
          the Company or its Subsidiaries of any asset or group of assets since
          the first day of such four-quarter period, whether by merger, stock
          purchase or sale, or asset purchase or sale, such acquisition or
          disposition or any related repayment of Debt had occurred as of the
          first day of such period with the appropriate adjustments with respect
          to such acquisition or disposition being included in such pro forma
          calculation. If the Debt giving rise to the need to make the foregoing
          calculation or any other Debt incurred after the first day of the
          relevant four-quarter period bears interest at a floating rate then,
          for purposes of calculating the Annual Debt Service, the interest rate
          on such Debt shall be computed on a pro forma basis as if the average
          interest rate which would have been in effect during the entire such
          four-quarter period had been the applicable rate for the entire such
          period.


                                      -7-


<PAGE>


         (b) MAINTENANCE OF TOTAL UNENCUMBERED ASSETS. The Company and its
Subsidiaries will maintain at all times Total Unencumbered Assets of not less
than 200% of the aggregate outstanding principal amount of the Unsecured Debt of
the Company and its Subsidiaries on a consolidated basis.

                                   ARTICLE 4

                          ADDITIONAL EVENTS OF DEFAULT

         SECTION 4.1 For purposes of this Supplemental Indenture and the Notes,
in addition to the Events of Default set forth in Section 501 of the Indenture,
it shall also constitute an "Event of Default" if a default under any bond,
debenture, note or other evidence of indebtedness of the Company (including a
default with respect to any other series of securities), or under any mortgage,
indenture or other instrument of the Company under which there may be issued or
by which there may be secured or evidenced any indebtedness for money borrowed
by the Company (or by any Subsidiary, the repayment of which the Company has
guaranteed or for which the Company is directly responsible or liable as obligor
or guarantor) having an aggregate principal amount outstanding of at least
$20,000,000, whether such indebtedness now exists or shall hereafter be incurred
or created, which default shall have resulted in such indebtedness becoming or
being declared due and payable prior to the date on which it would otherwise
have become due and payable, without such indebtedness having been discharged,
or such acceleration having been rescinded or annulled, within a period of ten
days after there shall have been given, by registered or certified mail, to the
Company by the Trustee or to the Company and the Trustee by the Holders of at
least 25% in principal amount of the outstanding Notes, a written notice
specifying such default and requiring the Company to cause such indebtedness to
be discharged or cause such acceleration to be rescinded or annulled and stating
that such notice is a "Notice of Default" hereunder.

         SECTION 4.2 Notwithstanding any provisions to the contrary in the
Indenture, upon any acceleration of the Notes under Section 502 of the
Indenture, the amount immediately due and payable in respect of the Notes shall
equal the Outstanding principal amount thereof, plus accrued interest, plus, if
such acceleration occurs prior to August 15, 2014, the Make-Whole Amount.

                                   ARTICLE 5

                                  EFFECTIVENESS

         This Supplemental Indenture shall be effective for all purposes as of
the date and time this Supplemental Indenture has been executed and delivered by
the Company and the Trustee in accordance with Article Nine of the Indenture. As
supplemented hereby, the Indenture is hereby confirmed as being in full force
and effect.


                                      -8-


<PAGE>


                                   ARTICLE 6

                                  MISCELLANEOUS

         SECTION 6.1 In the event any provision of this Supplemental Indenture
shall be held invalid or unenforceable by any court of competent jurisdiction,
such holding shall not invalidate or render unenforceable any other provision
hereof or any provision of the Indenture.

         SECTION 6.2 To the extent that any terms of this Supplemental Indenture
or the Notes are inconsistent with the terms of the Indenture, the terms of this
Supplemental Indenture or the Notes shall govern and supersede such inconsistent
terms.

         SECTION 6.3 This Supplemental Indenture shall be governed by and
construed in accordance with the laws of The Commonwealth of Massachusetts.

         SECTION 6.4 This Supplemental Indenture may be executed in several
counterparts, each of which shall be an original and all of which shall
constitute but one and the same instrument.



                  [Remainder of page intentionally left blank.]

















                                      -9-


<PAGE>




         IN WITNESS WHEREOF, the Company and the Trustee have caused this
Supplemental Indenture to be executed as an instrument under seal in their
respective corporate names as of the date first above written.

                             HRPT PROPERTIES TRUST

                             By:
                                ------------------------------------------------
                                  Name:  John C. Popeo
                                  Title: Treasurer and Chief Financial Officer


                             U.S. BANK NATIONAL ASSOCIATION,
                             as Trustee

                             By:
                                ------------------------------------------------
                                  Name:
                                  Title:













                                      -10-


<PAGE>



                                                                       EXHIBIT A

                                  FORM OF NOTE

                                 [FACE OF NOTE]

                     6.40% Senior Note due February 15, 2015

No. ______                                                           $__________

                              HRPT PROPERTIES TRUST

promises to pay to _______ or registered assigns, the principal sum of
__________ ($_______) on January 15, 2013, subject to the terms set forth on the
reverse of this Note and the terms of the Indenture referred to therein.

         Interest Payment Dates: each February 15 and August 15, commencing
August 15, 2003.

         Record Dates: the day falling 14 calendar days prior to any Interest
Payment Date.

CUSIP No.:
           ------------------------

                                                      HRPT PROPERTIES TRUST

                                                      By:
                                                         -----------------------
                                                         Name:
                                                         Title:

Attest:
       ----------------------------
[SEAL]

CERTIFICATE OF AUTHENTICATION

Dated: January 30, 2003

This is one of the Notes referred to in the within-mentioned Indenture:

U.S. BANK NATIONAL ASSOCIATION, as Trustee

By:_______________________________
     Authorized Officer



<PAGE>


             [THE FOLLOWING CONSTITUTES THE REVERSE OF THE SECURITY]

                              HRPT PROPERTIES TRUST

                     6.40% Senior Note due February 15, 2015

         Capitalized terms used herein have the meanings assigned to them in the
Indenture (as defined below) unless otherwise indicated.

         1. INTEREST. HRPT Properties Trust, a Maryland real estate investment
trust (the "Company"), promises to pay interest on the principal amount of this
Note at the rate and in the manner specified below.

         The Company shall pay in cash interest on the principal amount of this
Note at the rate per annum of 6.40%. The Company will pay interest semi-annually
in arrears on each February 15 and August 15, commencing on August 15, 2003, or,
if any such day is not a Business Day (as defined in the Indenture), on the next
succeeding Business Day (each an "Interest Payment Date"), to Holders of record
on the day falling 14 calendar days immediately preceding such Interest Payment
Date (whether or not a Business Day).

         Interest will be computed on the basis of a 360-day year consisting of
twelve 30-day months. Interest shall accrue from the most recent date to which
interest has been paid or, if no interest has been paid, from January 30, 2003.

         2. METHOD OF PAYMENT. The Company will pay interest on the Notes
(except defaulted interest) to the Persons who are registered Holders of Notes
at the close of business on the record date next preceding the Interest Payment
Date, even if such Notes are canceled after such record date and on or before
such Interest Payment Date. The Company will pay principal and interest in money
of the United States that at the time of payment is legal tender for payment of
public and private debts. The Company, however, may pay principal, premium, if
any, and interest by check payable in such money. It may mail an interest check
to a Holder's registered address.

         3. INDENTURE. The Company issued the Notes under an Indenture, dated as
of July 9, 1997, and a Supplemental Indenture No. 12 thereto, dated as of
January 30, 2003 (collectively, the "Indenture"), between the Company and the
Trustee. The terms of the Notes include those stated in the Indenture and those
made part of the Indenture by reference to the Trust Indenture Act of 1939 as in
effect on the date of the Indenture. The Notes are subject to all such terms,
and Holders of the Notes are referred to the Indenture and such Act for a
statement of such terms. The terms of the Indenture shall govern any
inconsistencies between the Indenture and the Notes. The Notes are unsecured
general obligations of the Company limited to $200,000,000 in aggregate
principal amount, except as otherwise provided in the Indenture.

         4. OPTIONAL REDEMPTION. The Notes will be subject to redemption at any
time at the option of the Company, in whole or in part, upon not less than 30
nor more than 60 days' notice, at a redemption price equal to the sum of (i) the
principal amount of the Notes being redeemed, plus accrued and unpaid interest
to but excluding the applicable Redemption Date and (ii) the Make-Whole Amount,
if any. If the Notes are redeemed on or after August 15, 2014, the redemption
price will not include the Make-Whole Amount.


                                      A-2


<PAGE>


         As used herein the term "Make-Whole Amount" means, in connection with
any optional redemption or accelerated payment of any notes prior to August 15,
2014, the excess, if any, of (i) the aggregate present value as of the date of
such redemption or accelerated payment of each dollar of principal being
redeemed or paid and the amount of interest (exclusive of interest accrued to
the date of redemption or accelerated payment) that would have been payable in
respect of such dollar if such redemption or accelerated payment had been made
on August 15, 2014, determined by discounting, on a semiannual basis, such
principal and interest at the Reinvestment Rate (determined on the third
Business Day preceding the date such notice of redemption is given or
declaration of acceleration is made) from the respective dates on which such
principal and interest would have been payable if such redemption or accelerated
payment had been made on August 15, 2014, over (ii) the aggregate principal
amount of the Notes being redeemed or paid. In the case of any redemption or
accelerated payment of notes on or after August 15, 2014, the Make-Whole Amount
means zero. For purposes of the Indenture and the Notes, references in the
Indenture to the payment of the principal (and premium, if any) and interest on
the Notes shall be deemed to include the payment of the Make-Whole Amount, if
any, due upon redemption with respect to the Notes. The Make-Whole Amount shall
be calculated by the Company and set forth in an Officer's Certificate delivered
to the Trustee, and the Trustee shall be entitled to rely on said Officer's
Certificate.

         As used herein the term "Reinvestment Rate" means a rate per annum
equal to the sum of 0.50% (fifty one-hundredths of one percent) plus the yield
on treasury securities at constant maturity under the heading "Week Ending"
published in the Statistical Release (as defined herein) under the caption
"Treasury Constant Maturities" for the maturity (rounded to the nearest month)
corresponding to the remaining life to maturity (which, in the case of
maturities corresponding to the principal and interest due on the notes at their
maturity, shall be deemed to be August 15, 2014), as of the payment date of the
principal being redeemed or paid. If no maturity exactly corresponds to such
maturity, yields for the two published maturities most closely corresponding to
such maturity shall be calculated pursuant to the immediately preceding sentence
and the Reinvestment Rate shall be interpolated or extrapolated from such yields
on a straight-line basis, rounding in each of such relevant periods to the
nearest month. For purposes of calculating the Reinvestment Rate, the most
recent Statistical Release published prior to the date of determination of the
Make-Whole Amount shall be used.

         As used herein the term "Statistical Release" means the statistical
release designated "H.15(519)" or any successor publication which is published
weekly by the Federal Reserve System and which establishes yields on actively
traded United States government securities adjusted to constant maturities or,
if such statistical release is not published at the time of any determination
under the Supplemental Indenture, then any publicly available source of similar
market data which shall be designated by the Company.

         5. MANDATORY REDEMPTION. The Company shall not be required to make
sinking fund or redemption payments with respect to the Notes.

         6. NOTICE OF REDEMPTION. Notice of redemption shall be mailed at least
30 days but not more than 60 days before the Redemption Date to each Holder of
Notes to be redeemed at its registered address. Notes may be redeemed in part
but only in whole multiples of $1,000, unless


                                      A-3


<PAGE>


all of the Notes held by a Holder are to be redeemed. On and after the
redemption date, interest ceases to accrue on Notes or portions of them called
for redemption.

         7. DENOMINATIONS, TRANSFER, EXCHANGE. The Notes are in registered form
without coupons in denominations of $1,000 and integral multiples of $1,000 in
excess thereof. The transfer of Notes may be registered and Notes may be
exchanged as provided in the Indenture. The Security Registrar and the Trustee
may require a Holder, among other things, to furnish appropriate endorsements
and transfer documents and to pay any taxes and fees required by law or
permitted by the Indenture. The Security Registrar need not exchange or register
the transfer of any Note or portion of a Note selected for redemption. Also, it
need not exchange or register the transfer of any Notes for a period of 15 days
before the mailing of a notice of redemption of Notes, or during the period
between a record date and the corresponding Interest Payment Date.

         8. DEFAULTS AND REMEDIES. In case an Event of Default (as defined in
the Indenture) with respect to the Notes shall have occurred and be continuing,
the principal hereof may be declared, and upon such declaration shall become,
due and payable, in the manner, with the effect and subject to the provisions
provided in the Indenture.

         9. ACTIONS OF HOLDERS. The Indenture contains provisions permitting the
holders of not less than a majority of the aggregate principal amount of the
outstanding Notes, subject to certain exceptions as provided in the Indenture,
on behalf of the holders of all such Notes at a meeting duly called and held as
provided in the Indenture, to make, give or take any request, demand,
authorization, direction, notice, consent, waiver or other action provided in
the Indenture to be made, given or taken by the holders of the Notes, including
without limitation, waiving (a) compliance by the Company with certain
provisions of the Indenture, and (b) certain past defaults under the Indenture
and their consequences. Any resolution passed or decision taken at any meeting
of the holders of the Notes in accordance with the provisions of the Indenture
shall be conclusive and binding upon such holders and upon all future holders of
this Note and other Notes issued upon the registration of transfer hereof or in
exchange heretofore or in lieu hereof.

         10. PERSONS DEEMED OWNERS. The Company, the Trustee, and any agent of
the Company or the Trustee may deem and treat the Person in whose name this Note
is registered on the Security Register as its absolute owner for all purposes.

         11. AUTHENTICATION. This Note shall not be valid until authenticated by
the manual signature of the Trustee or an authenticating agent.

         12. GOVERNING LAW. THE INTERNAL LAW OF THE COMMONWEALTH OF
MASSACHUSETTS SHALL GOVERN AND BE USED TO CONSTRUE THE INDENTURE AND THE NOTES.

         13. NO PERSONAL LIABILITY. THE AMENDED AND RESTATED DECLARATION OF
TRUST OF THE COMPANY, DATED JULY 1, 1994, A COPY OF WHICH, TOGETHER WITH ALL
AMENDMENTS THERETO (THE "DECLARATION"), IS DULY FILED IN THE OFFICE OF THE
DEPARTMENT OF ASSESSMENTS AND TAXATION OF THE STATE OF MARYLAND, PROVIDES THAT
THE NAME "HRPT PROPERTIES TRUST" REFERS TO THE TRUSTEES UNDER THE DECLARATION
COLLECTIVELY AS TRUSTEES, BUT NOT


                                      A-4


<PAGE>


INDIVIDUALLY OR PERSONALLY, AND THAT NO TRUSTEE, OFFICER, SHAREHOLDER, EMPLOYEE
OR AGENT OF THE COMPANY SHALL BE HELD TO ANY PERSONAL LIABILITY, JOINTLY OR
SEVERALLY, FOR ANY OBLIGATION OF, OR CLAIM AGAINST, THE COMPANY. ALL PERSONS
DEALING WITH THE COMPANY, IN ANY WAY, SHALL LOOK ONLY TO THE ASSETS OF THE
COMPANY FOR THE PAYMENT OF ANY SUM OR THE PERFORMANCE OF ANY OBLIGATION.

         The Company will furnish to any Holder upon written request and without
charge a copy of the Indenture. Request may be made to:

         HRPT Properties Trust
         400 Centre Street
         Newton, MA 02458
         Telecopier No.:  (617) 332-2261
         Attention: President

or such other address as the Company may specify pursuant to the Indenture.













                                      A-5


<PAGE>


                                 ASSIGNMENT FORM

                                   To assign this Note, fill in the form below:

[I] [We] assign and transfer this Note to ______________________________________

__________________________________ [PRINT OR TYPE ASSIGNEE'S NAME, ADDRESS AND
                                   ZIP CODE]

__________________________________ [INSERT ASSIGNEE'S SOC. SEC. OR TAX I.D. NO.]

and irrevocably appoint_________________________________________________________

to transfer this Note on the books of the Company. The agent may substitute

another to act for him.

Date:
      ----------------
                                   Your Signature:
                                                  ------------------------------
                                   [SIGN EXACTLY AS YOUR NAME APPEARS ON THE
                                   FACE OF THIS NOTE]

Signature Guarantee:

--------------------------
[THE SIGNATURE MUST BE GUARANTEED BY
AN OFFICER OF A PARTICIPANT IN A RECOGNIZED
SIGNATURE GUARANTEE PROGRAM. NOTARIZED
OR WITNESSED SIGNATURES ARE NOT ACCEPTABLE.]












                                      A-6