<Page>
Exhibit 10.188
NOTICE OF FINAL AGREEMENT
LOAN NOS. 753971 AND 753972
THIS NOTICE OF FINAL AGREEMENT is made this 22nd day of June, 2004, and is
incorporated by and into and shall be deemed to amend and supplement any and all
documents constituting "Loan Agreements" as defined by Section 26.02 of the
Texas Business & Commerce Code, executed by and among INLAND WESTERN SAN ANTONIO
HUEBNER OAKS LIMITED PARTNERSHIP, an Illinois limited partnership ("BORROWER"),
INLAND WESTERN RETAIL REAL ESTATE TRUST, INC., a Maryland corporation
("Guarantor"), and PRINCIPAL LIFE INSURANCE COMPANY, an Iowa corporation
("LENDER"), pertaining to the property located at 11745 IH-10, San Antonio,
Texas, and the loan in the stated aggregate principal amount of $48,000,000.00
evidenced by (i) Borrower's Secured Promissory Note 1 (Loan No. 753971) in the
principal amount of $31,723,000.00 and (ii) Borrower's Secured Promissory Note 2
(Loan No. 753972) in the principal amount of $16,277,000.00, each of even date
herewith executed by Borrower to Lender, and such term shall also include said
Secured Promissory Notes, as well as that Deed of Trust, Security Agreement and
Assignment of Rents, that Assignment of Lease and Rents, that Assignment of
Management Agreement and Subordination of Management Fees Agreement, that
Guaranty, and that Environmental Indemnity Agreement, each of even date herewith
from Borrower and/or Guarantor to Lender, but shall exclude the Commitment
issued by Lender.
In addition to the covenants made in the Loan Agreements, Borrower and
Lender further covenant and agree as follows:
1. The rights and obligations of Borrower and Lender shall be determined
solely from the written Loan Agreements and any prior oral agreements between
Lender and Borrower are superseded by and merged into the Loan Agreements.
2. The Loan Agreements may not be varied by any oral agreements or
discussions that occur before, contemporaneously with, or subsequent to the
execution of the Loan Agreements.
3. The following Notice is provided pursuant to Section 26.02 of the
Texas Business & Commerce Code:
THE WRITTEN LOAN AGREEMENTS REPRESENT THE FINAL AGREEMENTS BETWEEN THE
PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS, OR
SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.
THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.
SIGNATURE PAGES FOLLOW
<Page>
SIGNATURE PAGE OF BORROWER TO
NOTICE OF FINAL AGREEMENT
INLAND WESTERN SAN ANTONIO HUEBNER OAKS
LIMITED PARTNERSHIP, an Illinois limited partnership
By: INLAND WESTERN SAN ANTONIO HUEBNER
OAKS GP, L.L.C., a Delaware limited liability
company, its General Partner
By: INLAND WESTERN RETAIL REAL
ESTATE TRUST, INC., a Maryland
corporation, its Sole Member
By: /s/ Valerie Medina
----------------------------------
Name: Valerie Medina
---------------------------
Title: asst. Secretary
---------------------------
2
<Page>
SIGNATURE PAGE OF GUARANTOR TO
NOTICE OF FINAL AGREEMENT
INLAND WESTERN RETAIL REAL ESTATE
TRUST, INC., a Maryland corporation
By: /s/ Valerie Medina
----------------------------------
Name: Valerie Medina
----------------------------
Title: asst. Secretary
---------------------------
3
<Page>
SIGNATURE PAGE OF LENDER TO
NOTICE OF FINAL AGREEMENT
PRINCIPAL LIFE INSURANCE COMPANY, an
Iowa corporation
By: PRINCIPAL REAL ESTATE
INVESTORS, LLC, a Delaware limited
liability company, its authorized
signatory
By:
----------------------------------
Name:
----------------------------
Title:
---------------------------
By:
----------------------------------
Name:
----------------------------
Title:
---------------------------
4