Exhibit 4.1


                    REGISTRATION RIGHTS AND LOCK-UP AGREEMENT
                    -----------------------------------------


                  THIS   REGISTRATION   RIGHTS  AND  LOCK-UP   AGREEMENT   (this
"Agreement"),  is made and  entered  into as of January 27,  2004,  by and among
Acadia  Realty  Trust,  a Maryland  real estate  investment  trust (the "REIT"),
Acadia  Realty  Limited   Partnership,   a  Delaware  limited  partnership  (the
"Partnership"),  and the  undersigned  Klaff  Realty,  LP,  a  Delaware  limited
Partnership  ("Klaff"),  which,  at the  Closing  (the  "Closing  Date")  of the
transactions  contemplated  by the Agreement of  Contribution by and among Klaff
and Klaff Realty,  Limited,  the REIT, and the  Partnership  (the  "Contribution
Agreement"),  are receiving preferred units of limited partnership  interests in
the Partnership  ("Preferred  Units") which are convertible into common units of
limited partnership interest in the Partnership ("OP Units"), which in turn, are
exchangeable for Conversion Shares (as defined below).


                  NOW,  THEREFORE,  in  consideration  of the  premises  and the
mutual covenants contained herein, and intending to be legally bound hereby, the
REIT, the Partnership and Klaff hereby agree as follows:

                  1.  Certain  Definitions.  As  used  in  this  Agreement,  the
following terms shall have the following respective meanings:

                           (a)  "Commission"  means the  Securities and Exchange
Commission, or any other federal agency at the time administering the Securities
Act.

                           (b)  "Conversion  Shares"  means the Shares  issuable
upon exchange of the OP Units from time to time.

                           (c) "Exchange Act" means the Securities  Exchange Act
of 1934,  as  amended,  or any  successor  federal  statute,  and the  rules and
regulations of the Commission  issued under such Exchange Act, as they each may,
from time to time, be in effect.

                           (d) "Holder(s)" means a holder of Registrable  Shares
entitled to the rights arising hereunder.

                           (e)  "Participating  Holder"  means  a  Holder  whose
Registrable Shares are included in a Registration Statement.


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                           (f)   "Registration   Expenses"  means  the  expenses
described in Section 4 hereof.

                           (g)  "Registration  Statement"  means a  registration
statement  filed by the REIT with the Commission for a public  offering and sale
of equity  securities of the REIT (other than a  registration  statement on Form
S-8 or Form S-4, or their  successors,  or any registration  statement  covering
only  securities  proposed to be issued in exchange for  securities or assets of
another corporation).

                           (h)  "Registrable  Shares"  means (i) the  Conversion
Shares,  (ii) any other Shares issued in respect of Conversion Shares, and (iii)
any other  Shares  issued with  respect to the Shares  issued in clauses (i) and
(ii)   (because   of   share   splits,   share   dividends,   reclassifications,
recapitalizations,  or similar events); provided, however, that Shares which are
Registrable  Shares  shall  cease  to be  Registrable  Shares  (x) upon any sale
pursuant  to a  Registration  Statement,  or any other sale or  transfer  of the
Registrable  Shares in any manner to any person or entity other than a Permitted
Transferee (as defined) or as otherwise expressly provided herein, or (y) in the
event that Registrable Shares may be freely sold and/or transferred  pursuant to
Rule 144(k) under the Securities Act.

                           (i)  "Securities  Act"  means the  Securities  Act of
1933,  as  amended,  or  any  successor  federal  statute,  and  the  rules  and
regulations of the  Commission  issued under such  Securities  Act, as they each
may, from time to time, be in effect.

                           (j)  "Shares"   means  Common  Shares  of  Beneficial
Interest of the REIT, par value $.001 per share.

                  2. Certain  Shelf  Registration.  Within ninety (90) days from
the  date of this  Agreement,  the  REIT  shall,  at its  expense,  file a shelf
Registration Statement pursuant to Rule 415 under the Securities Act to register
the  Registrable  Shares for resale,  including for issuance upon  conversion or
exchange  of OP  Units.  The  REIT  shall,  at  its  expense,  use  commercially
reasonable  efforts to maintain  the  effectiveness  of such shelf  Registration
Statement  until the  earlier  of (i) such  time as when all of the  Registrable
Shares  have been  disposed  of or (ii)  three  years  after the  conversion  or
exchange  into  Shares  of all of the OP Units  issued  upon  conversion  of the
Preferred Units issued under the Contribution Agreement.


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                  3.  Registration  Procedures.  If and  whenever  the  REIT  is
required by the provisions of this Agreement to effect the  registration  of any
of the  Registrable  Shares under the  Securities  Act,  the REIT shall,  at its
expense:

                           (a)   prepare   and  file  with  the   Commission   a
Registration  Statement  with  respect to such  Registrable  Shares and use best
efforts to cause that Registration Statement to become effective;

                           (b) use commercially  reasonable efforts to cause the
Registration Statement to remain effective;

                           (c) subject to the  provision of Section 2,  promptly
prepare and file with the  Commission  any  amendments  and  supplements  to the
Registration Statement and the prospectus included in the Registration Statement
as may be necessary to keep the Registration  Statement effective for the period
of time required by the Commission;

                           (d)  promptly  furnish to each  Participating  Holder
such  reasonable  numbers of copies of the  prospectus,  including a preliminary
prospectus,  in conformity with the requirements of the Securities Act, and such
other documents as the Participating  Holders may reasonably request in order to
facilitate the public sale or other disposition of the Registrable  Shares owned
by such Participating Holders and included in the Registration Statement; and

                           (e) promptly use commercially  reasonable  efforts to
register or qualify the Registrable Shares covered by the Registration Statement
under the  securities or Blue Sky laws of states within the United States as the
Participating Holders shall reasonably request; provided, however, that the REIT
shall not be required in connection with this subsection 3(e) to: (i) qualify as
a foreign  corporation in any  jurisdiction  where,  but for the requirements of
this subsection 3(e), it would not be obligated to be so qualified; (ii) execute
a general  consent to service of  process  in any  jurisdiction;  (iii)  subject
itself to  taxation  in any such  jurisdiction;  or (iv)  register  in any state
requiring,  as a condition  to  registration,  escrow or  surrender  of any REIT
securities held by any security holder other than the Participating Holders.

                  If the REIT has delivered a preliminary or final prospectus to
a  Participating  Holder and, after having done so,


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the prospectus is amended to comply with the requirements of the Securities Act,
the REIT shall promptly notify such Participating Holder and, if requested, such
Participating Holder shall immediately cease making offers of Registrable Shares
and  return  all  prospectuses  to the REIT.  The REIT  shall  promptly  provide
Participating  Holders with revised  prospectuses and,  following receipt of the
revised  prospectuses,  Participating  Holders  shall be free to  resume  making
offers of the Registrable Shares.

                  Notwithstanding  any other provisions of this Agreement to the
contrary,  upon receipt by a Participating  Holder of a written notice signed by
the Chief Executive  Officer,  General Counsel or Chief Financial Officer of the
REIT,  to the effect set forth below,  the REIT shall not be obligated  during a
reasonable  period of time  thereafter to effect any  registrations  pursuant to
this  Agreement,  and  each  such  Participating  Holder  agrees  that  it  will
immediately suspend sales of Shares under any effective  Registration  Statement
for a reasonable  period of time,  in either case not to exceed 90 days,  at any
time during which, in the REIT's reasonable judgment, (i) there is a development
involving the REIT or any of its affiliates  which is material but which has not
yet been publicly disclosed or (ii) sales pursuant to the Registration Statement
would  materially and adversely  affect an underwritten  public offering for the
account of the REIT or any other material  financing project or where a proposed
or pending  material merger or other material  acquisition or material  business
combination or material  disposition of the REIT's assets,  to which the REIT or
any of its  affiliates  is,  or is  expected  to be,  a  party.  In the  event a
registration  is postponed  or sales by a  Participating  Holder  pursuant to an
effective   Registration   Statement  are  suspended  in  accordance  with  this
paragraph, there shall be added to the period during which the REIT is obligated
to keep a  Registration  Statement  effective  the  number of days for which the
Registration Statement was postponed or sales were suspended.

                  4.   Expenses   of   Registration.   The  REIT  will  pay  all
Registration Expenses of all registrations under this Agreement. For purposes of
this  Agreement,  the term  "Registration  Expenses"  shall  mean  all  expenses
incurred  by the  REIT in  complying  with  this  Agreement,  including  without
limitation,  all registration and filing fees,  exchange listing fees,  printing
expenses,  the fees and disbursements of counsel for the REIT and the reasonable
fees and disbursements of one counsel selected by the Participating Holders, the
fees  and  disbursements  of the  REIT's  accountants,  state  Blue Sky fees and
expenses, and the expense


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of any special  audits  incident to or  required by any such  registration,  but
excluding underwriting discounts and selling commissions.

                  5.       Indemnification.

                           (a) Indemnification of Participating  Holders. In the
event of any registration of any of the Registrable  Shares under the Securities
Act pursuant to this  Agreement,  the REIT will indemnify and hold harmless each
Participating  Holder, each of its directors and officers and each other person,
if any,  who  controls  such  Participating  Holder  within  the  meaning of the
Securities  Act or the  Exchange  Act,  against any losses,  claims,  damages or
liabilities to which such Participating  Holder or controlling person may become
subject under the Securities  Act, the Exchange Act, Blue Sky laws or otherwise,
insofar as such losses,  claims,  damages or liabilities  (or actions in respect
thereof)  arise out of or are based upon any untrue  statement or alleged untrue
statement of any material fact  contained in any  Registration  Statement  under
which such  Registrable  Shares were  registered  under the Securities  Act, any
preliminary  prospectus  or  final  prospectus  contained  in  the  Registration
Statement,  or any amendment or supplement to such  Registration  Statement,  or
arise out of or are based  upon the  omission  or  alleged  omission  to state a
material fact required to be stated  therein or necessary to make the statements
therein,  in light of the circumstances in which they were made, not misleading;
and the REIT will reimburse such Participating  Holder and each such controlling
person  for  any  legal  or any  other  expenses  reasonably  incurred  by  such
Participating  Holder or controlling  person in connection with investigating or
defending any such loss, claim, damage, liability or action; provided,  however,
that the REIT will not be liable  in any such case to the  extent  that any such
loss,  claim,  damage or  liability  arises  out of or is based  upon any untrue
statement  or  omission  made  in  such  Registration   Statement,   preliminary
prospectus or prospectus,  or any such amendment or supplement, in reliance upon
and in conformity with information  furnished to the REIT, in writing,  by or on
behalf of any Participating Holder or controlling person specifically for use in
the preparation thereof; and provided further, however, that any indemnification
contained in this paragraph with respect to any preliminary prospectus shall not
inure to the benefit of any person who otherwise is entitled to  indemnification
hereunder on account of any loss, liability,  claim, damage or expense if a copy
of an amended or supplemental  preliminary prospectus,  or the final prospectus,
shall have been delivered or sent to such


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person within the time required by the Securities Act, and the untrue  statement
or omission of a material  fact was  corrected in such  amended or  supplemental
preliminary prospectus or final prospectus and provided that such person did not
deliver such amended or supplemental  preliminary prospectus or final prospectus
on a timely basis.

                           (b)  Indemnification of the REIT. In the event of any
registration of any of the Registrable  Shares under the Securities Act pursuant
to this Agreement,  each  Participating  Holder will indemnify and hold harmless
the REIT,  each of its  directors  and  officers  and each  person,  if any, who
controls the REIT within the meaning of the  Securities Act or the Exchange Act,
against any losses, claims,  damages or liabilities,  joint or several, to which
the REIT, such directors and officers or controlling  persons may become subject
under the Securities Act,  Exchange Act, Blue Sky laws or otherwise,  insofar as
such losses,  claims,  damages or  liabilities  (or actions in respect  thereof)
arise out of or are based upon any untrue  statement or alleged untrue statement
of a material  fact  contained in any  Registration  Statement  under which such
Registrable  Shares were  registered  under the Securities  Act, any preliminary
prospectus or final prospectus contained in the Registration  Statement,  or any
amendment or supplement to the  Registration  Statement,  or arise out of or are
based upon any omission or alleged omission to state a material fact required to
be stated therein or necessary to make the statements  therein,  in light of the
circumstances in which they were made, not misleading, in each case only if such
statement  or  omission  was  made  in  reliance  upon  and in  conformity  with
information  furnished  in  writing  to  the  REIT  by  or  on  behalf  of  such
Participating  Holder or controlling person,  specifically for use in connection
with the preparation of such Registration  Statement,  prospectus,  amendment or
supplement.  No  Participating  Holder shall be liable  pursuant to this Section
5(b) for any amount in excess of the proceeds of the  offering  received by such
Participating Holder.

                           (c)  Notice  of  Claim.   Each  party   entitled   to
indemnification under this Section 5 (the "Indemnified Party") shall give notice
to the party  required to provide  indemnification  (the  "Indemnifying  Party")
promptly after such  Indemnified  Party has actual  knowledge of any claim as to
which indemnity may be sought, and shall permit the Indemnifying Party to assume
the defense of any such claim or any litigation  resulting  therefrom;  provided
that counsel for the  Indemnifying  Party, who shall conduct the defense of such
claim or


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litigation, shall be approved by the Indemnified Party (whose approval shall not
be  unreasonably  withheld);  and,  provided,  further,  that the failure of any
Indemnified  Party to give  notice as  provided  herein  shall not  relieve  the
Indemnifying Party of its obligations under this Section 5 unless the failure to
provide such notice materially  prejudices the defense by the Indemnifying Party
against such claim.  The  Indemnified  Party may  participate in such defense at
such party's expense (provided that the counsel of the Indemnifying  Party shall
control the defense of such claim or proceeding);  provided,  however,  that the
Indemnifying  Party shall pay such expense if representation of such Indemnified
Party by the counsel retained by the Indemnifying Party would, in the opinion of
counsel of the Indemnified  Party, be  inappropriate  due to actual or potential
differing   interests   between  the  Indemnified  Party  and  any  other  party
represented by such counsel in such proceeding,  it being  understood,  however,
that in such event,  the  Indemnifying  Party shall be liable for the reasonable
fees  and  expenses  of  only  one  counsel  for  the  Indemnified  Parties.  No
Indemnifying  Party, in the defense of any such claim or litigation  shall as to
an Indemnified Party, except with the consent of such Indemnified Party, consent
to entry of any judgment or enter into any settlement  which does not include as
an  unconditional  term  thereof the giving by the claimant or plaintiff to such
Indemnified  Party of a release  from all  liability in respect of such claim or
litigation,  and no Indemnified  Party shall consent to entry of any judgment or
settle  such  claim or  litigation  without  the prior  written  consent  of the
Indemnifying Party.

                  6. Rule 144. The REIT  covenants that it will file the reports
required to be filed by it under the Securities Act and the Exchange Act and the
rules and regulations  adopted by the Commission  thereunder (or, if the REIT is
not required to file such reports,  it will,  upon the request of the holders of
the  Registrable  Securities,   make  publicly  available  such  information  as
necessary to permit sales pursuant to Rule 144 under the Securities  Act) and it
will do all such other acts and things from time to time as reasonably requested
by the holders of the Registrable Securities to the extent required from time to
time to enable the holders of the Registrable  Shares to sell Registrable Shares
without  registration  under the  Securities  Act within the  limitation  of the
exemptions  provided by Rule 144 under the  Securities  Act, as such Rule may be
amended from time to time, or any similar rule or regulation  hereunder  adopted
by the Commission.


                                     - 7 -



                  7.  Cooperation.  The Holders  shall  furnish to the REIT such
information regarding the Holders and the distribution proposed by Participating
Holders as the REIT may from time to time  reasonably  request in  writing,  and
shall do such  reasonable  acts  and  things  as the REIT may from  time to time
request, with respect to any registration,  qualification or compliance referred
to in this  Agreement  and in  order  to  permit  the  REIT to  comply  with the
requirements of law. Any failure by a Holder to make available such  information
or to do such acts and things  shall  constitute  a waiver by such Holder of its
rights to include such Holder's Registrable Shares in any such registration.

                  8. Restriction on Resale. Unless otherwise agreed by the REIT,
until the date on which there are no Registrable Shares, each Holder agrees that
it will not  resell  such  Registrable  Shares  without  registration  under the
Securities Act,  compliance with Rule 144 under the Securities Act or an opinion
of counsel for such Holder reasonably  acceptable to the REIT,  addressed to the
REIT, to the effect that no such registration is required. All reasonable costs,
fees and expenses of counsel in  connection  with such opinion shall be borne by
the REIT.

                  9. Lock-Up Agreement. In consideration of the REIT's agreement
to  provide  the  Holders  with the  registration  rights  as set  forth in this
Agreement, Klaff agrees with the REIT and the Partnership that it will not for a
period of three years  commencing  on the Closing Date or such lesser  period if
permitted  pursuant to the  Certificate of Designation of Series B Units of even
date herewith (the "Lock-Up Period") (i) sell, assign, or otherwise transfer the
Preferred  Units to be  issued at the  Closing  (or the OP Units  issuable  upon
conversion of the Preferred  Units) or (ii) convert any OP Units into Conversion
Shares.  Notwithstanding the foregoing, the aforementioned prohibition shall not
apply to (x)  conversion  to OP Units;  (y) a transfer of OP Units  (which shall
nonetheless  comply  with any  requirements  or  conditions  to  transfer in the
Partnership Agreement of the Partnership) to a Permitted Transferee; or (z) bona
fide pledge of OP Units  (provided  that the  pledgee  agrees to be bound by the
terms of this Agreement as if an original  signatory  thereto).  For purposes of
this Section 10, the term "Permitted Transferees" means (i) any partner or other
equity owner of the  Partnership or Klaff;  (ii) any equity owner of any partner
or  other  equity  owner of the  Partnership  or  Klaff;  (iii)  members  of the
Immediate  Family (as defined below) of any person described in (i) or (ii); and
(iv) trusts for the benefit  of, or


                                     - 8 -



entities  controlled  by, one or more of the persons  described in (i),  (ii) or
(iii);   and/or  (v)  any  public  charity,   public  foundation  or  charitable
institution  as defined in Section  501(c)(3)  of the  Internal  Revenue Code of
1986, as amended.  For purposes of this Section 10, the term "Immediate  Family"
means,  with  respect to any  natural  person,  such  natural  person's  spouse,
parents,  parents-in-law,   descendants,  nephews,  nieces,  brothers,  sisters,
brothers-in-law, sisters-in-law and children-in-law (including adopted persons).
A transfer to any Permitted  Transferee shall not be deemed  effective,  and the
REIT may issue stop transfer instructions to its transfer agent of the Shares in
connection with a purported transfer, unless and until the transferor shall give
the REIT written notice stating the name and address of the Permitted Transferee
and  identifying the securities  which are being  transferred and the REIT shall
have received the written  agreement of the Permitted  Transferee to be bound by
the terms of this Agreement as if an original signatory hereto.

                  10. Miscellaneous.

                           (a) Controlling Law. This Agreement shall be governed
by and construed in accordance with the laws of the State of New York.

                           (b)  Notices.  All notices  and other  communications
hereunder  shall be in  writing  and shall be sent by  certified  mail,  postage
prepaid,  return receipt requested; by an overnight express courier service that
provides  written  confirmation  of  delivery;  or  by  facsimile  with  written
confirmation by the sending  machine or with telephone  confirmation of receipt,
addressed as follows:

                                    (i) If to REIT or Partnership:

                                        Acadia Realty Trust
                                        1311 Mamaroneck Avenue, Suite 260
                                        White Plains, NY  10605
                                        Attention:  Robert Masters, Esq.
                                        Telephone:  914-288-8139
                                        Facsimile:  914-428-3646
                                        Email:      rmasters@acadiarealty.com


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                                    (ii) If to Klaff:

                                        Klaff Realty, LP
                                        122 South Michigan Avenue
                                        Chicago, IL  60603
                                        Attention:  Hersch M. Klaff
                                        Telephone:  312-360-3102
                                        Facsimile:  312-360-0606
                                        Email: hklaff@klaff.com

                                        With a copy to:

                                        Allan J. Reich, Esq.
                                        Seyfarth Shaw LLP
                                        55 E. Monroe Street, Suite 4200
                                        Chicago, IL  60603
                                        Telephone:  312-781-8650
                                        Facsimile:  312-269-8869
                                        Email:  areich@seyfarth.com

                  Any party may alter the  address  to which  communications  or
copies are to be sent by giving  notice of such change of address in  conformity
with the  provisions of this  paragraph for the giving of notice.  Notices given
hereunder  shall be deemed  received upon actual receipt thereof or, in the case
of notice by mail,  upon two days from the date notice is first deposited in the
mail in the manner provided above

                           (a) Binding Nature of Agreement. This Agreement shall
be binding upon and inure to the benefit of (i) the REIT and its  successors and
assigns and (ii) each Holder and its heirs, successors and assigns.

                           (b) Transfer or  Assignment of  Registration  Rights.
Subject to Section 10 hereof,  the rights with respect to any Registrable Shares
to cause the REIT to register  such  securities  granted to a Holder by the REIT
under this Agreement may be transferred or assigned by a Holder,  in whole or in
part,  to a transferee  or assignee of any  Registrable  Shares (or any OP Units
which are convertible,  exercisable or redeemable,  directly or indirectly,  for
Registrable  Shares);  provided  that,  in such  case,  the REIT  shall be given
written notice  stating the name and address of said  transferee or assignee and
identifying  the securities with respect to which such  registration  rights are
being  transferred  or  assigned  and the REIT shall have  received  the written
agreement  of such  transferee  or  assignee  to be bound  by the  terms of this
Agreement.


                                     - 10 -



                           (c) Execution in Counterparts.  This Agreement may be
executed in any number of  counterparts,  each of which shall be deemed to be an
original as against any party whose signature appears thereon,  and all of which
shall together  constitute  one and the same  instrument.  This Agreement  shall
become  binding  when  one  or  more  counterparts  hereof,  individually  taken
together,  shall bear the signatures of all of the parties  reflected  hereon as
the signatories.

                           (d)  Provisions  Separable.  The  provisions  of this
Agreement are  independent  of and separable  from each other,  and no provision
shall be  affected or rendered  invalid or  unenforceable  by virtue of the fact
that for any reason any other or others of them may be invalid or  unenforceable
in whole or in part.

                           (e) Entire  Agreement.  This  Agreement  contains the
entire understanding among the parties hereto with respect to the subject matter
hereof,   and   supersedes   all  prior  and   contemporaneous   agreements  and
understandings,  inducements or conditions, express or implied, oral or written,
except as herein contained.  This Agreement may not be modified or amended other
than by an agreement in writing.

                           (f) Paragraph  Headings.  The  paragraph  headings in
this Agreement are for convenience only; they form no part of this Agreement and
shall not affect its interpretation.


                                     - 11 -



                  IN WITNESS  WHEREOF,  the parties  executed and delivered this
Agreement on the date first above written.


                                        ACADIA REALTY TRUST

                                        By:
                                           -------------------------------------
                                        Name: Kenneth F. Bernstein
                                        Title:  President


                                        ACADIA REALTY LIMITED PARTNERSHIP

                                        By: Acadia Realty Trust,
                                            its General Partner


                                            By:
                                               ---------------------------------
                                            Name:   Kenneth F. Bernstein
                                            Title:  President


                                        KLAFF REALTY, LP

                                        By: Klaff Realty, Limited


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

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


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