PROPERTY CO-TENANCY
                       OWNERSHIP AGREEMENT
                  Champps Americana Restaurant
                        Livonia, Michigan

THIS CO-TENANCY AGREEMENT,

Made  and entered into as of the 14th day of March, 2002, by  and
between   AEI  Income  &  Growth  Fund  XXI  Limited  Partnership
(hereinafter  called  "Co-Tenancy Manager"),  and  Biscayne  Reef
Properties  LLC  (hereinafter called "Biscayne"). (Biscayne,  Co-
Tenancy Manager (and any other Owner in Fee where the context  so
indicates)  being hereinafter sometimes collectively called  "Co-
Tenants" and referred to in the neuter gender).
WITNESSETH:

WHEREAS,  AEI  Income  &  Growth  Fund  XXI  Limited  Partnership
presently  owns  an undivided 58.4122% interest in  and  to,  and
Biscayne presently owns an undivided 16.2679% interest in and to,
and  Gregory  A.  Roemhild presently owns  an  undivided  3.8828%
interest  in  and to, and David Louis Cruickshank, trustee  under
the trust created by the will dated June 5, 1964 of Louis William
Achenbach, deceased presently owns an undivided 5.5769%  interest
in  and  to,  and  Barbara A. Bou-Sliman, Trustee  of  the  First
Amended  and  Restated Trust Agreement of Barbara  A.  Bou-Sliman
dated  July 8, 1992 presently owns an undivided 3.4211%  interest
in  and to, and Sherrill L. Hossom as Trustee of the Sherrill  L.
Hossom  Family  Trust  dated  May  15,  1992  presently  owns  an
undivided  4.2226%  interest in and to, and Linda  L.  Landes  as
Trustee  of the Linda L. Landes Family Trust dated May  15,  1992
presently  owns  an  undivided 4.6600% interest  in  and  to  and
Elizabeth C. Hsu Living Trust dated 11/13/89, Elizabeth  C.  Hsu,
trustee  presently owns an undivided 3.5565% interest in  and  to
the  land, situated in the City of Livonia, County of Wayne,  and
State  of  Michigan, (legally described upon Exhibit  A  attached
hereto  and  hereby  made  a  part hereof)  and  in  and  to  the
improvements located thereon (hereinafter called "Premises");

WHEREAS,  The  parties hereto wish to provide  for:  the  orderly
monitoring  of performance by the present tenant of the  Premises
under  the  triple  net  lease agreement  for  the  Premises;  if
necessary,  upon  a  vacancy in the Premises, the  operation  and
management of the Premises; the continued leasing of space within
the  Premises; and, the distribution of income from and the  pro-
rata sharing in expenses of the Premises by Co-Tenancy Manager in
connection with Biscayne's interest in the Premises.

NOW THEREFORE, in consideration of the purchase by Biscayne of an
undivided  interest  in and to the Premises,  for  at  least  One
Dollar  ($1.00) and other good and valuable consideration by  the
parties  hereto  to  one another in hand paid,  the  receipt  and
sufficiency of which are hereby acknowledged, and of  the  mutual


Co-Tenant Initial:
Co-Tenancy Agreement for Champp's Americana Restaurant, Livonia Michigan


covenants and agreements herein contained, it is hereby agreed by
and between the parties hereto, as follows:



1.   Biscayne, subject to the limitations and power of revocation
herein  expressed, hereby designates Co-Tenancy  Manager  as  its
sole and exclusive agent and delegates to Co-Tenancy Manager  the
sole right to monitor and enforce on behalf of Biscayne the terms
of  the  present lease of the Premises, including but not limited
to  any  amendments, consents to assignment, sublet, releases  or
modifications  to the lease or guarantees of lease  and  to  deal
with  any  property agent or tenant. Should the  Premises  become
vacant,  the  operation  and  management  of  the  Premises,   is
delegated  by  the  Co-Tenants,  subject  to  revocation  on   an
individual  basis  by an individual Co-Tenant  as  otherwise  set
forth  herein,  to  Co-Tenancy Manager, or its designated  agent,
successors  or assigns. Provided, however, if Co-Tenancy  Manager
shall  sell  all of its interest in the Premises,  (or  shall  no
longer   be  delegated  the  operation  and  management  of   the
Premises),  the  duties  and obligations  of  Co-Tenancy  Manager
respecting  management  of  the Premises  as  set  forth  herein,
including   but  not  limited  to  its  duties  and   obligations
respecting  paragraphs 2, 3, and 4 hereof, shall be exercised  by
the   holder  or  holders  of  a  majority  undivided  co-tenancy
interests  in the Premises. Subject to the approval  of  all  Co-
Tenants  evidenced  by their written consent, Co-Tenancy  Manager
shall  negotiate  and  execute re-leases  of  the  Premises  upon
termination of the present lease of the Premises or negotiate and
execute easements affecting the Premises, may incur ordinary  and
necessary operating expenses in connection with the management of
the  Premises, and propose extraordinary or capital  expenditures
to  the  Premises. Until Biscayne shall revoke such authority  as
provided  herein,  Co-Tenancy  Manager  or  Biscayne  itself  may
obligate  Biscayne  with  respect to any ordinary  and  necessary
operating expense for the Premises.  However, Co-Tenancy  Manager
has no right to obtain a loan for which any other Co-Tenant would
be  liable,  nor may Co-Tenancy Manager finance or refinance  the
Premises  by  secured by any lien or any pledge of the  Premises.
Biscayne agrees to execute and deliver to Co-Tenancy Manager such
written approval of documents approved by Biscayne, such approval
to  take  such  form as may be reasonably required by  Co-Tenancy
Manager  to evidence its authority to sign approved documents  on
behalf of Biscayne.

As  further  set forth in paragraph 2 hereof, Co-Tenancy  Manager
agrees to require any lessee of the Premises to name Biscayne  as
an  insured  or  additional  insured in  all  insurance  policies
provided for, or contemplated by, any lease on the Premises.  Co-
Tenancy Manager shall use its best efforts to obtain endorsements
adding Co-Tenants to said policies from lessee within 30 days  of
commencement of this agreement. In any event, Co-Tenancy  Manager
shall  distribute any insurance proceeds it may receive,  to  the
extent  consistent  with any lease on the Premises,  to  the  Co-
Tenants  in  proportion  to  their respective  ownership  of  the
Premises.

2.    Income and expenses shall be allocated among the Co-Tenants
in  proportion to their respective share(s) of ownership.  Shares
of  net income shall be pro-rated for any partial calendar  years
included  within the term of this Agreement.  Co-Tenancy  Manager
may offset against, pay to itself and deduct from any payment due
to  Biscayne  under  this Agreement, and may pay  to  itself  the



Co-Tenant Initial: /s/ KHN
Co-Tenancy Agreement for Champp's Americana Restaurant, Livonia Michigan



amount  of  Biscayne's share of any reasonable  expenses  of  the
Premises which are not paid by Biscayne to Co-Tenancy Manager  or
its  assigns,  within  ten (10) days after demand  by  Co-Tenancy
Manager.   In  the  event there is insufficient operating  income
from  which  to  deduct  Biscayne's  unpaid  share  of  operating
expenses,  Co-Tenancy  Manager  may  pursue  any  and  all  legal
remedies for collection.

Operating  Expenses  shall include all normal operating  expense,
including  but not limited to: maintenance, utilities,  supplies,
labor, management, advertising and promotional expenses, salaries
and wages of rental and management personnel, leasing commissions
to  third  parties, a monthly accrual to pay insurance  premiums,
real  estate taxes, installments of special assessments  and  for
structural repairs and replacements, management fees, legal  fees
and accounting fees, but excluding all operating expenses paid by
tenant under terms of any lease agreement of the Premises.

Biscayne  has no requirement to, but has, nonetheless elected  to
retain, and agrees to annually compensate, Co-Tenancy Manager  in
the  amount  of  $2,623  for the expenses, direct  and  indirect,
incurred  by  Co-Tenancy  Manager  in  providing  Biscayne   with
monthly  accounting and distributions of Biscayne's share of  net
income  and for tracking, reporting and assessing the calculation
of  Biscayne's  share  of operating expenses  incurred  from  the
Premises.  This  invoice amount shall be  pro-rated  for  partial
years  and Biscayne authorizes Co-Tenancy Manager to deduct  such
amount  from  Biscayne's  share of  revenue  from  the  Premises.
Biscayne   may   terminate  this  agreement  in  this   paragraph
respecting  accounting and distributions at any time and  attempt
to  collect its share of rental income directly from the  tenant;
Co-Tenancy  Manager  may  terminate  its  obligation  under  this
paragraph  upon 30 days written notice to Biscayne prior  to  the
end  of each anniversary hereof, unless agreed in writing to  the
contrary.

3.    Full, accurate and complete books of account shall be  kept
in accordance with generally accepted accounting principles at Co-
Tenancy  Manager  's principal office, and each  Co-Tenant  shall
have  access  to  such books and may inspect and  copy  any  part
thereof  during  normal business hours. Within ninety  (90)  days
after  the end of each calendar year during the term hereof,  Co-
Tenancy  Manager shall prepare an accurate income  statement  for
the  ownership of the Premises for said calendar year  and  shall
furnish copies of the same to all Co-Tenants. Quarterly,  as  its
share,  Biscayne  shall be entitled to receive  16.2679%  of  all
items  of  income  and expense generated by the  Premises.   Upon
receipt of said accounting, if the payments received by each  Co-
Tenant  pursuant  to  this Paragraph  3  do  not  equal,  in  the
aggregate,  the  amounts  which  each  are  entitled  to  receive
proportional  to  its  share of ownership with  respect  to  said
calendar  year  pursuant  to Paragraph 2 hereof,  an  appropriate
adjustment  shall  be  made so that each Co-Tenant  receives  the
amount to which it is entitled.

4.    If  Net Income from the Premises is less than $0.00  (i.e.,
the  Premises  operates  at a loss), or if capital  improvements,
repairs, and/or replacements, for which adequate reserves do  not
exist,  need  to  be made to the Premises, the  Co-Tenants,  upon
receipt  of  a written request therefore from Co-Tenancy  Manager
shall, within fifteen (15) business days after receipt of notice,
make  payment  to Co-Tenancy Manager sufficient to pay  said  net
operating  losses and to provide necessary operating capital  for



Co-Tenant Initial: /s/ KHN
Co-Tenancy Agreement for Champp's Americana Restaurant, Livonia Michigan



the  premises  and to pay for said capital improvements,  repairs
and/or   replacements,  all  in  proportion  to  their  undivided
interests in and to the Premises. All Co-Tenants shall  have  the
right to review all contracts that will have a material effect on
the  Premises.   All Co-Tenants shall have the right  to  approve
budgets  and  major capital expenditures affecting the  Premises.
While  Co-Tenancy Manager shall own an interest in the  Premises,
Co-Tenants  agree to delegate the determination of  such  budgets
and  need for capital expenditures to Co-Tenancy Manager  subject
to  the  power  of  any Co-Tenant to revoke  such  delegation  in
accordance with the provisions hereof.

5.    Co-Tenants  may, at any time, sell, finance,  or  otherwise
create  a lien upon their interest in the Premises but only  upon
their  interest  and not upon any part of the interest  held,  or
owned, by any other Co-Tenant, and shall not create any lien upon
their  individual interest if by operation of law such lien shall
by  law  extend to the interest of any other Co-Tenant.  All  Co-
Tenants reserve the right to escrow proceeds from a sale of their
interests in the Premises to obtain tax deferral by the  purchase
of replacement property.

6.    If any Co-Tenant shall be in default with respect to any of
its  obligations hereunder, and if said default is not  corrected
within  thirty  (30)  days after receipt by said  defaulting  Co-
Tenant  of written notice of said default, or within a reasonable
period  if  said default does not consist solely of a failure  to
pay money, the remaining Co-Tenant(s) may resort to any available
remedy to cure said default at law, in equity, or by statute.

7.    This Co-Tenancy agreement shall continue in full force  and
effect  and shall bind and inure to the benefit of the  Co-Tenant
and  their respective heirs, executors, administrators,  personal
representatives, successors and permitted assigns until  May  31,
2018  or upon the sale of the entire Premises in accordance  with
the terms hereof and proper disbursement of the proceeds thereof,
whichever shall first occur.  Unless specifically identified as a
personal  contract  right or obligation  herein,  this  agreement
shall  run  with any interest in the Property and with the  title
thereto. Once any person, party or entity has ceased to  have  an
interest  in fee in any portion of the Entire Property, it  shall
not be bound by, subject to or benefit from the terms hereof; but
its  heirs,  executors, administrators, personal representatives,
successors  or assigns, as the case may be, shall be  substituted
for it hereunder.   Any Co-Tenant may, at any time effective upon
written notice to Co-Tenancy Manager revoke the designation of Co-
Tenancy Manager as such Co-Tenant's agent for the purposes as set
forth  herein.   Any Co-Tenant revoking such designation  of  Co-
Tenancy  Manager's  agency  shall notify  Co-Tenancy  Manager  in
writing  in  accordance with the terms hereof and such revocation
shall  be  effective upon Co-Tenancy Manager's  receipt  of  such
written revocation.

8.    Any notice or election required or permitted to be given or
served by any party hereto to, or upon any other, shall be  given
to  all known Co-Tenants and deemed given or served in accordance
with  the  provisions  of  this  Agreement,  if  said  notice  or
elections addressed as follows;



Co-Tenant Initial: /s/ KHN
Co-Tenancy Agreement for Champp's Americana Restaurant, Livonia Michigan



If to AEI Income & Growth Fund XXI Limited Partnership:


     AEI Income & Growth Fund XXI Limited Partnership
     30 East Seventh Street
     Suite 1300
     St. Paul, MN 55101

If to Biscayne:

     Biscayne Reef Properties LLC
     13823 Darnel Court
     Rosemount, MN 55068

If to Roemhild:

     Gregory A. Roemhild
     814 - 10 1/2 Avenue
     Box 103
     Almena, WI 54805

If to Cruickshank:

     David Louis Cruickshank, trustee under the trust created
     by the will dated June 5, 1964 of Louis William Achenbach,
     deceased
     8050 Poplar Lane
     Carmel, CA 93923

If to Bou-Sliman:

     Barbara A. Bou-Sliman, Trustee of the
     First Amended and Restated Trust Agreement of
     Barbara A. Bou-Sliman, dated July 8, 1992
     267 Colonade Circle
     Naples, FL 34103

If to Hossom:

     Sherrill L. Hossom as trustee of the
     Sherrill L. Hossom Family Trust,
     dated May 15, 1992
     16428 Lookout Lane
     Bow, WA 98232



Co-Tenant Initial: /s/ KHN
Co-Tenancy Agreement for Champp's Americana Restaurant, Livonia Michigan



If to Landes:

     Linda L. Landes as trustee of the
     Linda L. Landes Family Trust,
     dated May 15, 1992
     5621 Corso Di Napoli
     Long Beach, CA 90802

If to Hsu:

     Elizabeth C. Hsu Living Trust,
     dated 11/13/89
     7224 Old Mill Road
     Bloomfield Township, MI 48301


Each mailed notice or election shall be deemed to have been given
to,  or served upon, the party to which addressed on the date the
same  is  deposited in the United States certified  mail,  return
receipt  requested,  postage prepaid, or given  to  a  nationally
recognized  courier  service guaranteeing overnight  delivery  as
properly addressed in the manner above provided. Any party hereto
may  change  its address for the service of notice  hereunder  by
delivering  written notice of said change to  the  other  parties
hereunder, in the manner above specified, at least ten (10)  days
prior  to  the  effective  date of said  change.   Any  Co-Tenant
selling or transferring all or a portion of its interest  in  the
Premises  shall  provide,  within a  reasonable  time  after  the
completion of such sale or transfer, written notice to all  other
Co-Tenants of the name and address of such new Co-Tenant and  the
interest held by such new Co-Tenant.

9.    This  Agreement shall not create any partnership  or  joint
venture  among or between the Co-Tenants or any of them;  no  Co-
Tenant shall file any partnership tax returns nor otherwise  take
any action respecting nor represent the relationship among the Co-
Tenants  as other than co-tenants of undivided interests in  real
property.  The only relationship among and between the Co-Tenants
hereunder  shall be that of owners of the Premises as tenants  in
common subject to the terms hereof.

10.    The  unenforceability or invalidity of  any  provision  or
provisions  of  this Agreement as to any person or  circumstances
shall  not render that provision, nor any other provision hereof,
unenforceable or invalid as to any other person or circumstances,
and  all  provisions hereof, in all other respects, shall  remain
valid and enforceable.

11.   In  the  event  any litigation arises between  the  parties
hereto  relating  to  this Agreement, or any  of  the  provisions
hereof, the party prevailing in such action shall be entitled  to
receive  from the losing party, in addition to all other  relief,
remedies  and  damages  to  which it is otherwise  entitled,  all
reasonable  costs  and expenses, including reasonable  attorneys'
fees,  incurred by the prevailing party in connection  with  said
litigation.


Co-Tenant Initial: /s/ KHN
Co-Tenancy Agreement for Champp's Americana Restaurant, Livonia Michigan



12.   To  the extent that this agreement binds all Co-Tenants  of
the  Premises, such covenants are deemed to run with the land and
shall be evidenced in a Co-Tenancy Agreement entered into by  any
Co-Tenant  with  any  purchaser of all  or  any  portion  of  its
interest  in  the  Premises.  Except  as  otherwise  provided  or
modified herein, Co-Tenants retain all rights otherwise available
under law to any Co-Tenant of an interest in Real Property.

13.   Every  Co-Tenant, shall have a right of  first  refusal  to
purchase  the  interest of any other Co-Tenant in  the  Premises,
upon  the  following limited terms and conditions.  If  and  only
when  a  Co-Tenant shall give written notice to another Co-Tenant
(and only as to such Co-Tenant receiving such notice) of a desire
to  be  notified  of  any  proposed sale  "Notice  of  Desire  to
Purchase"), Co-Tenants desiring notice of proposed sales  of  Co-
Tenancy interests shall receive notice of proposed sales  of  the
interest of the Co-Tenant who has received a Notice of Desire  to
Purchase.  Any  Co-Tenant offering its interest  or  any  portion
thereof for sale ("Selling Co-Tenant") shall first notify all Co-
Tenants  who  have provided a Notice of Desire to Purchase.  Such
notice  ("Selling  Co-Tenant's Notice") shall  give  Selling  Co-
Tenant's name and address and state a price at which Selling  Co-
Tenant  intends to sell and will sell a specified portion or  all
of its interest in the fee simple to the Leased Premises.

If  a Co-Tenant shall fail to exercise its Right of First Refusal
as  set forth herein, those Co-Tenant's exercising their Right of
First  Refusal  shall  buy all, but not less  than  all,  of  the
interest  in  the  Premises offered for sale by the  Selling  Co-
Tenant, purchasing prorata in proportion that the purchasing  Co-
Tenant's  interests in the Premises shall bear  to  one  another.
For  ten (10) business days (the "Right of First Refusal Period")
following the giving of such notice, a Co-Tenant shall  have  the
option  to  purchase  such portion of the  fee  interest  of  the
Selling  Co-Tenant as set forth in Selling Co-Tenant's Notice  at
the  price  in cash stated in the Selling Co-Tenant's Notice.   A
written notice addressed to Selling Co-Tenant and signed  by  the
purchasing  Co-Tenant  shall be given,  in  accordance  with  the
provisions  hereof  respecting the giving of notice,  within  the
period set forth above for exercising the Right of First Refusal.
If  no  Co-Tenant  shall  exercise its Right  of  First  Refusal,
Selling  Co-Tenant shall be free to market its  interest  in  the
Premises  after  expiration of the Right of First Refusal  Period
and  shall be free to sell all or any portion of its interest  in
the  Premises at a price prorata greater than, or equal to,  that
which is set forth in the Selling Co-Tenant's Notice.

The above provisions shall not apply to the sale or transfer of a
Co-Tenant's  interest in the Premises if such  sale  or  transfer
shall be to an affiliate of the selling or transferring Co-Tenant
or  to  a trust established by such Co-Tenant for estate planning
purposes.



       THE REMAINDER OF THIS PAGE INTENTIONALLY LEFT BLANK





Co-Tenant Initial: /s/ KHN
Co-Tenancy Agreement for Champp's Americana Restaurant, Livonia Michigan




IN WITNESS WHEREOF, The parties hereto have caused this Agreement
to  be executed and delivered, as of the day and year first above
written.


          Biscayne Reef Properties LLC


          By:  /s/ Katherine H Nelson
                   Katherine H. Nelson, President
          Address: 13823 Darnel Court
                   Rosemount, MN 55068


STATE OF MINNESOTA)
                        ) ss
COUNTY OF DAKOTA)

I,  a Notary Public in and for the state and county of aforesaid,
hereby  certify there appeared before me this 12th day of  March,
2002,  Katherine H. Nelson, President of Biscayne Reef Properties
LLC, who executed the foregoing instrument in said capacity.

                              /s/ Tarell A Friedley
                                    Notary Public

[notary seal]


WITNESS 1:                       WITNESS 2:

By:/s/ Jeffery D Nelson          By: /s/ Tarell A Friedley

(Print Name & Address below)     (Print Name & Address below)

     Jeffrey D Nelson                 Tarell A Friedley
     13823 Darnel Court               6391 129th  St
     Rosemount MN  55068              Apple Valley, MN  55164




Co-Tenant Initial: /s/ KHN
Co-Tenancy Agreement for Champp's Americana Restaurant, Livonia Michigan




           AEI Income & Growth Fund XXI Limited Partnership
           By: AEI Fund Management XXI, Inc., its corporate general
               partner

           By: /s/ Robert P Johnson
                   Robert P. Johnson, its President



State of Minnesota )
                                    ) ss.
County of Ramsey )

I,  a Notary Public in and for the state and county of aforesaid,
hereby  certify there appeared before me this 14th day of  March,
2002,  Robert  P. Johnson, President of AEI Fund Management  XXI,
Inc.,  the corporate general partner of AEI Income & Growth  Fund
XXI  Limited Partnership,  who executed the foregoing  instrument
in said capacity and on behalf of the corporation.

                                   /s/ Debra A Jochum

                                       Notary Public

[notary seal]

WITNESS 1:                       WITNESS 2:

By:/s/ Linda A Bisdorf           By: /s/ Jeanne C Herda

(Print Name & Address below)     (Print Name & Address below)

     Linda A Bisdorf                  Jeanne C Herda
     30 E 7th Street                  30 E 7th Street
     St. Paul, MN 55101              St. Paul, MN 55101




       The name of the party who drafted this document is:
   AEI Fund Management, Inc., 1300 World Trade Center, 30 East
               Seventh Street, St. Paul, MN 55101
                          651-227-7333




Co-Tenant Initial: /s/ KHN
Co-Tenancy Agreement for Champp's Americana Restaurant, Livonia Michigan


                           EXHIBIT "A"

              Champps Restaurant-Livonia, Michigan

Land in the City of Livonia, Wayne County, Michigan described as:


Unit 3, Pentagon Centre Condominium, according to the Master Deed
recorded  in  Liber  29370,  Pages  706  through  766  1/2,  both
inclusive,  as  amended by First Amendment  to  the  Master  Deed
recorded in Liber 29631, Pages 1995 through 2003, both inclusive,
as  amended  by Second Amendment to the Master Deed  recorded  in
Liber 29696, Pages 571 through 577, both inclusive, as amended by
Third  Amendment to the Mater Deed recorded in Liber 29805, Pages
766  through  767,  both  inclusive, and  as  amended  by  Fourth
Amendment  to  the Master Deed recorded in Liber 31338,  Pages  1
through  4,  both inclusive, Wayne County Records, and designated
as  Wayne  County Condominium Subdivision Plan No. 437,  together
with  rights  in  general  common  elements  and  limited  common
elements,  as set forth in the above Master Deed and as described
in  Act 229 of the Public of the Public Acts of 1963, and Act  59
of the Public Acts of 1978, as amended.


19470 Haggerty