Underwriting Agreement

Exhibit 1.1

EXECUTION COPY

DUKE REALTY CORPORATION

(an Indiana Corporation)

11,000,000 Depositary Shares

Each Representing 1/10 of a 8.375% Series O Cumulative Redeemable

Preferred Share (Par Value $0.01 Per Share)

(Liquidation Preference Equivalent to $25.00 Per Depositary Share)

TERMS AGREEMENT

Dated: As of February 14, 2008

Attention:  Chairman of the Board of Directors

Ladies and Gentlemen:

We understand that Duke Realty Corporation, an Indiana corporation (the “ Company ”), proposes to issue and sell 11,000,000 depositary shares (the “ Depositary Shares ”) each representing 1/10th of a 8.375% Series O Cumulative Redeemable Preferred Share, par value $0.01 (collectively, the “ Series O Preferred Shares ”), of the Company (such Depositary Shares being collectively hereinafter referred to as the “ Underwritten Securities ”).  Subject to the terms and conditions set forth or incorporated by reference herein, the underwriters named below (the “ Underwriters ”) offer to purchase the Initial Securities (as defined in the Underwriting Agreement referred to below) set forth below opposite their respective names, and a proportionate share of Option Securities (as defined in the Underwriting Agreement referred to below) at the purchase price set forth below.  For purposes of this offering, the term “ Registration Statement ” (as defined in the Underwriting Agreement referred to below) means the registration statement on Form S-3 (No. 333- 136173 ).

The Underwritten Securities shall have the following terms:

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Underwriting Agreement :

Except as expressly provided herein, all the provisions contained in the document attached as Annex A hereto entitled “Duke Realty Corporation and Duke Realty Limited Partnership — Common Stock, Preferred Stock, Depositary Shares, Warrants, Stock Purchase Contracts, Duke Units and Debt Securities -  Underwriting Agreement”, dated August 17, 2006, are incorporated by reference in their entirety herein and shall be deemed to be a part of this Terms Agreement to the same extent as if such provisions had been set forth in full herein.  Terms used but not defined shall have the meanings set forth in the Underwriting Agreement.  Notices to the Underwriters shall be directed to Wachovia Capital Markets, LLC, One Wachovia Center, 301 S. College Street, 6 ^th Floor, Charlotte, NC 28202, Attention: Transaction Management Group.

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Please accept this offer no later than 10 o’clock P.M. (New York City time) on February 14, 2008 by signing a copy of this Terms Agreement in the space set forth below and returning the signed copy to us.

Annex A

DUKE REALTY CORPORATION

(an Indiana Corporation)

DUKE REALTY LIMITED PARTNERSHIP

(an Indiana limited partnership)

Common Stock, Preferred Stock, Depositary Shares, Warrants,

Stock Purchase Contracts, Duke Units and Debt Securities

UNDERWRITING AGREEMENT

August 17, 2006

The Representatives Named in the Terms Agreement

Ladies and Gentlemen:

Duke Realty Corporation (the “Company”) may from time to time offer in one or more series (i) shares of Common Stock, $.01 par value (the “Common Stock”), (ii) shares of preferred stock, $.01 par value (the “Preferred Stock”), (iii) shares of Preferred Stock represented by depositary shares (the “Depositary Shares”), (iv) warrants to purchase Common Stock, Preferred Stock and/or Depositary Shares (“Warrants”), (v) stock purchase contracts to purchase Common Stock, Preferred Stock and/or Depositary Shares (“Stock Purchase Contracts”), and (vi) units comprised of one or more of the Securities (as defined below) (“Duke Units”). Duke Realty Limited Partnership (the “Operating Partnership”) may from time to time offer in one or more series unsecured non-convertible investment grade debt securities (the “Debt Securities”).  The Common Stock, Preferred Stock, Depositary Shares, Warrants, Stock Purchase Contracts, Duke Units and Debt Securities (collectively, the “Securities”) may be offered, separately or together, in separate series, in amounts, at prices and on terms to be set forth in one or more Prospectus Supplements as hereinafter defined.  The Debt Securities will be issued under one or more indentures, as amended or supplemented (each, an “Indenture”), between the Operating Partnership and a trustee (a “Trustee”).  Each series of Debt Securities may vary, as applicable, as to aggregate principal amount, maturity date, interest rate or formula and timing of payments thereof, redemption or repayment provisions, and any other variable terms which the Indenture contemplates may be set forth in the Debt Securities as issued from time to time.  As used herein, “the Representatives,” unless the context otherwise requires, shall mean the parties, identified in the applicable Terms Agreement (as hereinafter defined) as the Representatives with respect to Underwritten Securities (as hereinafter defined) purchased pursuant thereto.

Whenever the Company or the Operating Partnership determines to make an offering of Securities through the Representatives or through an underwriting syndicate managed by the Representatives, the Company or the Operating Partnership, as the case may be, will enter into an agreement (the “Terms Agreement”) providing for the sale of such Securities (the “Underwritten Securities”) to, and the purchase and offering thereof by, the Representatives and such other underwriters, if any, selected by the Representatives as have authorized the Representatives to enter into such Terms Agreement on their behalf (the “Underwriters,” which term shall include the Representatives whether acting alone in the sale of the Underwritten Securities or as a member of an underwriting syndicate and any Underwriter

substituted pursuant to Section 10 hereof).  In addition to specifying the names of the Representatives, the Terms Agreement relating to the offering of Underwritten Securities shall specify the amount of Underwritten Securities to be initially issued (the “Initial Securities”), the names of the Underwriters participating in such offering (subject to substitution as provided in Section 10 hereof), the amount of Initial Securities which each such Underwriter severally agrees to purchase, the price at which the Initial Securities are to be purchased by the Underwriters from the Company or the Operating Partnership, as the case may be, the initial public offering price, if any, of the Initial Securities, the form, time, date and place of delivery and payment, any delayed delivery arrangements and any other variable terms of the Initial Securities (including, but not limited to, current ratings, designations, liquidation preferences, voting and other rights, denominations, interest rates or formulas, interest payment dates, maturity dates and redemption or repayment provisions applicable to the Initial Securities).  In addition, each Terms Agreement shall specify whether the Underwriters will be granted an option to purchase additional Underwritten Securities to cover over-allotments, if any, and the aggregate amount of Underwritten Securities subject to such option (the “Option Securities”).  As used herein, the term “Underwritten Securities” shall include the Initial Securities and all or any portion of the Option Securities agreed to be purchased by the Underwriters as provided herein, if any.  The Terms Agreement, which shall be substantially in the form of Exhibit A hereto, may take the form of an exchange of any standard form of written telecommunication between the Representatives and the Company or the Operating Partnership, as the case may be.  Each offering of Underwritten Securities through the Representatives or through an underwriting syndicate managed by the Representatives will be governed by this Agreement, as supplemented by the applicable Terms Agreement.

The Company and the Operating Partnership have filed with the Securities and Exchange Commission (the “Commission”) an automatic shelf registration statement on Form S-3 (No. 333-136173) for the registration of the Securities under the Securities Act of 1933, as amended (the “1933 Act”), and the offering thereof from time to time in accordance with Rule 430A or Rule 415 of the rules and regulations of the Commission under the 1933 Act (the “1933 Act Regulations”), and the Company and the Operating Partnership have filed such amendments thereto as may have been required prior to the execution of the applicable Terms Agreement.  Such registration statement (as amended, if applicable), pursuant to the 1933 Act and the 1933 Act Regulations, automatically became effective upon the filing thereof with the Commission, and the Indenture included in such registration statement has been qualified under the Trust Indenture Act of 1939, as amended (the “1939 Act”).  Such registration statement, as amended to the date of the applicable Terms Agreement, including the information, if any, deemed to be part thereof pursuant to Rule 430A or Rule 430(B) of the 1933 Act Regulations, and the prospectus constituting a part thereof in the form first used to confirm sales of the Underwritten Securities (or in the form first made available to the Representatives to meet requests of purchasers pursuant to Rule 173 under the 1933 Act) (the “Basic Prospectus”), together with each prospectus supplement specifically relating to the offering of Underwritten Securities in the form first used to confirm sales of the Underwritten Securities (or in the form first made available to the Representatives to meet requests of purchasers pursuant to Rule 173 under the 1933 Act) pursuant to Rule 415 of the 1933 Act Regulations (each, a “Prospectus Supplement”), including all documents incorporated therein by reference, as from time to time amended or supplemented pursuant to the 1933 Act, the Securities Exchange Act of 1934, as amended (the “1934 Act”) or otherwise, are collectively referred to herein as the “Registration Statement” and the “Prospectus,” respectively; and the term “preliminary prospectus” means the Basic Prospectus together with any preliminary form of the Prospectus Supplement.  For purposes of this Agreement, “free writing prospectus” has the meaning set forth in Rule 405 under the 1933 Act and “Time of Sale Prospectus” means the Basic Prospectus and, if any preliminary prospectus is used, the preliminary prospectus together with the free writing prospectuses, if any, each identified in Schedule I to the applicable Terms Agreement.  Any registration statement (including any supplement thereto or information which is deemed part thereof) filed by the Company or the Operating Partnership under Rule 462(b) of the 1933 Act Regulations (a “Rule 462(b) Registration Statement”) shall be deemed to be part

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of the Registration Statement.  Any prospectus (including any amendment or supplement thereto or information which is deemed part thereof) included in the Rule 462(b) Registration Statement shall be deemed to be part of the Prospectus.  The term “Time of Sale Prospectus” shall also include the documents, if any, incorporated by reference therein.  All references in this Agreement to financial statements and schedules and other information which is “contained,” “included” or “stated” in the Registration Statement, the Time of Sale Prospectus, the Prospectus, or the free writing prospectuses (and all other references of like import) shall be deemed to mean and include all such financial statements and schedules and other information which is or is deemed to be incorporated by reference in the Registration Statement, the Time of Sale Prospectus, the Prospectus, or the free writing prospectuses, as the case may be; and all references in this Agreement to amendments or supplements to the Registration Statement, the Time of Sale Prospectus, the Prospectus, or the free writing prospectuses shall be deemed to mean and include the filing of any document under the 1934 Act which is or is deemed to be incorporated by reference in the Registration Statement, the Time of Sale Prospectus, the Prospectus, or the free writing prospectuses, as the case may be.

The term “subsidiary” means a corporation or a partnership a majority of the outstanding voting stock or partnership interests, as the case may be, of which is owned or controlled, directly or indirectly, by the Company or the Operating Partnership, as the case may be, or by one or more other subsidiaries of the Company or the Operating Partnership.

SECTION 1.           Representations and Warranties of the Company and the Operating Partnership .

(b)   The Company and the Operating Partnership represent and warrant, jointly and severally, to the Representatives, as of the date hereof, and to the Representatives and each other Underwriter named in the applicable Terms Agreement, as of the date thereof, as of the Closing Time (as defined below) and, if applicable, as of each Date of Delivery (as defined below) (in each case, a “Representation Date”), as follows:

(i)            Pursuant to the 1933 Act and the 1933 Act Regulations, the Registration Statement automatically became effective upon the filing thereof with the Commission; no stop order suspending the effectiveness of the Registration Statement has been received by the Company, and, to the Company’s knowledge, no proceedings for such purpose are pending before or threatened by the Commission or by the state securities authority of any jurisdiction, and any request on the part of the Commission for additional information has been complied with.  The Registration Statement is an “automatic effective registration statement” as defined under Rule 405 of the 1933 Act that has been filed with the Commission not earlier than three years prior to the date hereof; and no notice of objection of the Commission to the use of such registration statement or any post-effective amendment thereto pursuant to Rule 401(g)(2) under the 1933 Act has been received by the Company or the Operating Partnership.  No stop order preventing or suspending the use of the Time of Sale Prospectus or the Prospectus has been received by the Company, and, to the Company’s knowledge, no proceedings for such purpose are pending before or threatened by the Commission or by the state securities authority of any jurisdiction.  If the Registration Statement is an automatic shelf registration statement as defined in Rule 405 under the 1933 Act, the Company or the Operating Partnership, as applicable, is a well-known seasoned issuer (as defined in Rule 405 under the 1933 Act) eligible to use the Registration Statement as an automatic shelf registration statement and the Company or the Operating Partnership, as applicable has not received notice that the Commission objects to the use of the Registration Statement as an automatic shelf registration statement.

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(ii)           The Registration Statement at the time the Registration Statement became effective, complied, and as of each Representation Date will comply, in all material respects with the requirements of the 1933 Act, the 1933 Act Regulations and the 1939 Act and the rules and regulations thereunder (the “1939 Act Regulations”).  The Registration Statement, at the time the Registration Statement became effective, did not, and as of each Representation Date, will not, contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading.  The Time of Sale Prospectus, at the time of each sale of the applicable Underwritten Securities (the “Applicable Time”), the Closing Time and the Date of Delivery, if any, as then amended or supplemented by the Company, if applicable, will not include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.  The Prospectus, as of its date and as of the Closing Time and Date of Delivery, if any, will not, include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.  Notwithstanding the foregoing, however, the representations and warranties in this subsection shall not apply to statements in or omissions from the Registration Statement, the Time of Sale Prospectus or the Prospectus made in reliance upon and in conformity with information furnished to the Company or the Operating Partnership in writing by any Underwriter through the Representatives expressly for use in the Registration Statement, the Time of Sale Prospectus or the Prospectus or to that part of the Registration Statement which shall constitute the Statement of Eligibility on Form T-1 under the 1939 Act (the “Statement of Eligibility”) of a Trustee under an Indenture.  If a Rule 462(b) Registration Statement is required in connection with the offering and sale of the Securities, the Company and the Operating Partnership have complied or will comply with the requirements of Rule 111 under the 1933 Act Regulations relating to the payment of filing fees therefor.

(iii)          Each preliminary prospectus, the Time of Sale Prospectus, the Prospectus, and any Prospectus Supplement filed as part of the Registration Statement as originally filed or as part of any amendment thereto, or filed pursuant to Rule 424 or Rule 433 (to the extent prepared by the Company) under the 1933 Act, complied or will comply when so filed in all material respects with the 1933 Act and the 1933 Act Regulations thereunder.

(iv)          The documents incorporated or deemed to be incorporated by reference in the Registration Statement, the Time of Sale Prospectus and the Prospectus pursuant to Item 12 of Form S-3 under the 1933 Act, at the time they were or hereafter are filed with the Commission, complied and will comply in all material respects with the requirements of the 1934 Act and the rules and regulations of the Commission under the 1934 Act (the “1934 Act Regulations”), and, when read together with the other information in the Prospectus, at the time the Registration Statement became effective and as of the applicable Representation Date or during the period specified in Section 3(f), did not and will not include an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading.

(v)           Each of the Company and the Operating Partnership is not an “ineligible issuer” in connection with the offering of the applicable Underwritten Securities pursuant to Rules 164, 405 and 433 under the 1933 Act.  Any free writing prospectus that the Company or the Operating Partnership is required to file pursuant to Rule 433(d) under the 1933 Act has been, or will be, filed with the Commission in accordance with the requirements of the 1933 Act and the applicable rules and regulations of the Commission thereunder.  Each free writing prospectus that the Company and the Operating Partnership has filed, or is required to file, pursuant to

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Rule 433(d) under the 1933 Act or that was prepared by or on behalf of or used or referred to by the Company and the Operating Partnership complies or will comply in all material respects with the requirements of the 1933 Act and the applicable rules and regulations of the Commission thereunder.  Except for the free writing prospectuses, if any, identified in Schedule I to the applicable Terms Agreement, and electronic road shows each furnished to you before first use, if any, the Company has not prepared, used or referred to, and will not, without your prior consent, prepare, use or refer to, any free writing prospectus.

(vi)          KPMG LLP, the accounting firm that audited the financial statements and supporting schedules included in, or incorporated by reference into, the Registration Statement, Time of Sale Prospectus and the Prospectus, are independent public accountants as required by the 1933 Act and the 1933 Act Regulations.

(vii)         The financial statements included in, or incorporated by reference into, the Registration Statement, Time of Sale Prospectus and the Prospectus, together with the related schedules and notes, present fairly the financial position of the respective entity or entities presented therein at the respective dates indicated and the results of their operations for the respective periods specified.  Except as otherwise stated in the Registration Statement, Time of Sale Prospectus and the Prospectus, said financial statements have been prepared in conformity with generally accepted accounting principles applied on a consistent basis throughout the periods involved.  The supporting schedules included or incorporated by reference in the Registration Statement, Time of Sale Prospectus and the Prospectus present fairly the information required to be stated therein.  The Company’s ratios of earnings to fixed charges (actual and, if any, pro forma) included in the Prospectus under the caption “Ratios of Earnings to Fixed Charges” and in Exhibit 12 to the Registration Statement have been calculated in compliance with Item 503(d) of Regulation S-K of the Commission.  The financial information and data included in the Registration Statement, Time of Sale Prospectus and the Prospectus present fairly the information included therein and have been prepared on a basis consistent with that of the financial statements included or incorporated by reference in the Registration Statement, Time of Sale Prospectus and the Prospectus and the books and records of the respective entities presented therein.  Pro forma financial information included in or incorporated by reference in the Registration Statement, the Time of Sale Prospectus and  the Prospectus has been prepared in accordance with the applicable requirements of the 1933 Act and the 1933 Act Regulations and includes all adjustments necessary to present fairly the pro forma financial position of the Operating Partnership and the Company, as applicable, at the respective dates indicated and the results of operations for the respective periods specified.

(viii)        Since the respective dates as of which information is given in the Registration Statement, the Time of Sale Prospectus and the Prospectus (in the case of the Registration Statement and the Prospectus, as updated by information incorporated by reference therein), except as otherwise stated therein, (A) there has been no material adverse change in the condition, financial or otherwise, or in the earnings, assets or business prospects of the Company, the Operating Partnership and any of their respective subsidiaries, whether or not arising in the ordinary course of business; (B) there has been no adverse change, material to the Duke Group (as hereinafter defined) as a whole, in the condition, financial or otherwise, or in the earnings, assets or business prospects of any of the real properties owned, directly or indirectly, by the Company, the Operating Partnership or any subsidiary (the “Properties”) or any entity wholly or partially owned by the Company, the Operating Partnership or any subsidiary which owns any Property (a “Property Partnership”) (the Company, the Operating Partnership, the subsidiaries and the Property Partnerships are hereinafter jointly referred to as the “Duke Group”), whether or not

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arising in the ordinary course of business; (C) no casualty loss, condemnation or other adverse event with respect to any Property has occurred, which is material to the Duke Group taken as a whole; (D) there have been no transactions or acquisitions entered into by the Duke Group, other than those arising in the ordinary course of business, which are material with respect to the Duke Group as a whole; (E) neither the Company, the Operating Partnership nor any of their respective subsidiaries has incurred any obligation or liability, direct, contingent or otherwise which is material to the Duke Group as a whole; (F) there has been no material change in the short-term debt or long-term debt of the Duke Group as a whole; (G) except for quarterly dividends on the Common Stock and dividends on the Preferred Stock, there has been no dividend or distribution of any kind declared, paid or made by the Company on any class of its capital stock; and (H) with the exception of transactions in connection with stock option and dividend reinvestment plans, the issuance of shares of Common Stock upon the exchange of partnership interests in the Operating Partnership (“Units”) and the issuance of Units in connection with the acquisition of real or personal property, there has been no change in the capital stock or in the partnership interests, as the case may be, of the Company, the Operating Partnership or any subsidiary.

(ix)           Each of the Company and the Operating Partnership has been duly formed, and is validly existing and in good standing as a corporation or partnership under the laws of its jurisdiction of organization, with corporate or partnership power and authority to conduct the business in which it is engaged or proposes to engage and to own, lease and operate its properties as described in the Time of Sale Prospectus and to enter into and perform its obligations under this Agreement, the Terms Agreement and the Indenture.

(x)            Each of the Company’s and the Operating Partnership’s subsidiaries has been duly formed, and is validly existing and in good standing as a corporation or partnership under the laws of its jurisdiction of organization, with corporate or partnership power and authority to conduct the business in which it is engaged or proposes to engage and to own, lease and operate its properties as described in the Time of Sale Prospectus.

(xi)           Each of the Company, the Operating Partnership, their respective subsidiaries and the Property Partnerships is duly qualified or registered as a foreign partnership or corporation in good standing and authorized to do business in each jurisdiction in which such qualification is required whether by reason of the ownership or leasing of property or the conduct of business, except where the failure to so qualify would not have a material adverse effect on the condition, financial or otherwise, or the earnings, assets or business prospects of the Duke Group considered as a single enterprise (a “Material Adverse Effect”).

(xii)          If the applicable Underwritten Securities are issued by the Company, and if the Time of Sale Prospectus contains the caption “Capitalization,” the authorized, issued and outstanding shares of capital stock of the Company as of the date specified therein is as set forth in the column entitled “Historical” under such caption.  All the issued and outstanding shares of capital stock of the Company have been duly authorized and are validly issued, fully paid and non-assessable and have been offered and sold in compliance with all applicable laws (including, without limitation, federal, state or foreign securities laws) and none of such shares of capital stock was issued in violation of preemptive or other similar rights of any securityholder of the Company.

(xiii)         If the applicable Underwritten Securities are issued by the Operating Partnership, and if the Time of Sale Prospectus contains the caption “Capitalization,” the partner’s equity of the Operating Partnership is as set forth in the column entitled “Historical” under such caption.  All the issued and outstanding Units have been duly authorized and are validly issued,

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fully paid and non-assessable, except as provided under Indiana Code § 23-16-7-8, and have been offered and sold or exchanged in compliance with all applicable laws (including, without limitation, federal, state or foreign securities laws).

(xiv)        All of the issued and outstanding shares of capital stock and partnership interests, as the case may be, of each subsidiary have been validly issued and fully paid and, other than the Property Partnerships, Duke Realty Services Limited Partnership (the “Services Partnership”) and Duke Construction Limited Partnership (the “Construction Partnership”), are owned by the Company, the Operating Partnership or a subsidiary, in each case free and clear of any security interest, mortgage, pledge, lien, encumbrance, claim or equity.  Neither the Company nor the Operating Partnership owns any direct or indirect equity interest in any entity other than the subsidiaries and the Property Partnerships, except for such interests as, in the aggregate, are not material to the condition, financial or otherwise, or the earnings, assets, business affairs or business prospects of the Duke Group considered as a single enterprise.  The Company is the sole general partner and a 1% owner of the Services Partnership, and the Operating Partnership and Duke Management, Inc. are the sole limited partners and 9% and 90% owners, respectively, of the Services Partnership.  Duke Business Centers Corporation, a wholly-owned subsidiary of Duke Realty Construction, Inc. is the sole general partner and a 1% owner of the Construction Partnership.  The 99% limited partnership interest of the Construction Partnership is owned by Duke Realty Construction, Inc., an Indiana corporation which is wholly owned by the Operating Partnership.

(xv)         Except for transactions described in the Time of Sale Prospectus and transactions in connection with dividend reinvestment plans, stock option and other employee benefit plans, the Company’s Series D Preferred Shares and as otherwise set forth below, there are no outstanding rights, warrants or options to acquire, or instruments convertible into or exchangeable for, or agreements or understandings with respect to the sale or issuance of, any shares of capital stock of or partnership or other equity interest in the Company, the Operating Partnership or any subsidiary except for the shares of Common Stock which may be issued in exchange for Units.  The Company is required to purchase Duke Management, Inc.’s interest in the Services Partnership for 833,334 Units upon a change in control of the Company or a dissolution of the Operating Partnership.

(xvi)        Each of the Property Partnerships has been duly formed as a partnership or a limited liability company, as the case may be, and is validly existing and in good standing as a partnership or limited liability company under the laws of its jurisdiction of organization and, if formed under the laws of a jurisdiction other than the State of Indiana, in good standing under the laws of such jurisdiction; each of the Property Partnerships has the requisite power and authority to own, lease and operate its properties, to conduct the business in which it is engaged and to enter into and perform its respective obligations under the agreements, to which it is a party.  Each of the partnership or operating agreements, as the case may be, of the Property Partnerships is in full force and effect.

(xvii)       The applicable Underwritten Securities, if such Underwritten Securities are either Common Stock, Preferred Stock or Depositary Shares, have been duly authorized by the Company for issuance and sale to the Underwriters pursuant to this Agreement, and, when issued and delivered by the Company pursuant to this Agreement and the applicable Terms Agreement against payment of the consideration set forth in the Terms Agreement or any Delayed Delivery Contract (as defined in Section 2 hereof), will be validly issued, fully paid and non-assessable.  Upon payment of the purchase price and delivery of such Underwritten Securities in accordance herewith, each of the Underwriters will receive good, valid and marketable title to such

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Underwritten Securities, free and clear of all security interests, mortgages, pledges, liens, encumbrances, claims and equities.  The terms of such applicable Underwritten Securities conform to all statements and descriptions related thereto contained in the Time of Sale Prospectus.  The form of stock or depositary certificate to be used to evidence the applicable Underwritten Securities will be in due and proper form and will comply with all applicable legal requirements.  The issuance of such applicable Underwritten Securities is not subject to any preemptive or other similar rights.

(xviii)      The applicable Underwritten Securities, if such Underwritten Securities are Debt Securities, are in the form contemplated by the Indenture, have been duly authorized by the Operating Partnership for issuance and sale to the Underwriters pursuant to this Agreement and, when executed, authenticated, issued and delivered in the manner provided for in this Agreement, any Terms Agreement and the applicable Indenture, against payment of the consideration therefor specified in the applicable Terms Agreement or any Delayed Delivery Contract (as defined in Section 2 hereof), such Debt Securities will constitute valid and legally binding obligations of the Operating Partnership, entitled to the benefits of the Indenture and such Debt Securities will be enforceable against the Operating Partnership in accordance with their terms.  Upon payment of the purchase price and delivery of such Underwritten Securities in accordance herewith, each of the Underwriters will receive good, valid and marketable title to such Underwritten Securities, free and clear of all security interests, mortgages, pledges, liens, encumbrances, claims and equities.  The terms of such applicable Underwritten Securities conform to all statements and descriptions related thereto in the Time of Sale Prospectus.  Such Underwritten Securities rank and will rank on a parity with all unsecured indebtedness (other than subordinated indebtedness) of the Operating Partnership that is outstanding on the Representation Date or that may be incurred thereafter, and senior to all subordinated indebtedness of the Operating Partnership that is outstanding on the Representation Date or that may be incurred thereafter, except that such Underwritten Securities will be effectively subordinated to the prior claims of each secured mortgage lender to any specific Property which secures such lender’s mortgage.

(xix)         If applicable, the Common Stock issuable upon conversion of any of the Preferred Stock (including Preferred Stock represented by Depositary Shares) will have been duly and validly authorized and reserved for issuance upon such conversion or exercise by all necessary action and such stock, when issued upon such conversion or exercise, will be duly and validly issued, fully paid and non-assessable, and the issuance of such stock upon such conversion or exercise will not be subject to preemptive or other similar rights; the Common Stock so issuable conforms in all material respects to all statements relating thereto contained in the Time of Sale Prospectus.

(xx)          The Underwritten Securities being sold pursuant to the applicable Terms Agreement will conform in all material respects to the statements relating thereto contained in the Time of Sale Prospectus and will be in substantially the form filed or incorporated by reference, as the case may be, as an exhibit to the Registration Statement.

(xxi)         There are no contracts or documents which are required to be described in the Registration Statement, the Time of Sale Prospectus or the documents incorporated by reference therein or to be filed as exhibits thereto which have not been so described and/or filed as required and the descriptions thereof or references thereto are correct in all material respects and no material defaults exist in the due performance or observance of any material obligation, agreement, covenant or condition contained in any such contract or document.

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(xxii)        None of the entities comprising the Duke Group is in violation of its charter, by-laws, certificate of limited partnership or partnership agreement, as the case may be, or in default in the performance or observance of any obligation, agreement, covenant or condition contained in any contract, indenture, mortgage, loan agreement, note, lease or other instrument to which such entity is a party or by which such entity may be bound, or to which any of its property or assets is subject, which default separately or in the aggregate would have a Material Adverse Effect.

(xxiii)       (A)  This Agreement has been duly and validly authorized, executed and delivered by the Company and the Operating Partnership, and, assuming due authorization, execution and delivery by the Representatives, constitutes a valid and binding obligation of the Company and the Operating Partnership, enforceable in accordance with its terms, and (B) at the Representation Date, the Terms Agreement and the Delayed Delivery Contracts (as defined in Section 2 hereof), if any, will have been duly and validly authorized, executed and delivered by the Company and the Operating Partnership, as the case may be, and, assuming due authorization, execution and delivery by the Representatives will be valid and binding agreements, enforceable in accordance with its or their terms.

(xxiv)       If applicable, the Indenture (A) has been duly qualified under the 1939 Act, has been duly and validly authorized, executed and delivered by the Operating Partnership, and when executed and delivered by the Trustee, will constitute a valid and binding obligation of the Operating Partnership, enforceable in accordance with its terms, and (B) conforms in all material respects to the description thereof in the Time of Sale Prospectus.

(xxv)        Each of the partnership agreements to which any of the Company, the Operating Partnership or their respective subsidiaries is a party has been duly authorized, executed and delivered by such party and constitutes a valid and binding obligation thereof, enforceable in accordance with its terms.

(xxvi)       The execution and delivery of this Agreement, the applicable Terms Agreement, any Indenture and any deposit agreement and the issuance of the Underwritten Securities, the performance of the obligations set forth herein or therein, and the consummation of the transactions contemplated hereby and thereby or in the Prospectus by the Company and the Operating Partnership, will not conflict with or constitute a breach or violation by the Company or the Operating Partnership of, or default under, or result in the creation or imposition of any lien, charge or encumbrance upon any Property or assets of the Duke Group pursuant to any contract, indenture, mortgage, loan agreement, note, lease, joint venture or partnership agreement or other instrument or agreement to which the Company, the Operating Partnership or any subsidiary is a party or by which they, either of them, any of their respective properties or other assets or any Property may be bound or subject which event is material to the Duke Group as a whole; nor will such action conflict with or constitute a breach or violation by the Company or the Operating Partnership of, or default under, (A) the charter, by-laws, certificate of limited partnership or partnership agreement, as the case may be, of the Company, the Operating Partnership or any subsidiary or (B) to the extent material, any applicable law, rule, order, administrative regulation or administrative or court decree.

(xxvii)      No labor dispute with the employees of the Duke Group exists or, to the knowledge of the Company or the Operating Partnership, is imminent; and neither the Company nor the Operating Partnership is aware of any existing or imminent labor disturbance by the employees of any of its principal suppliers, manufacturers or contractors which might be expected to have a Material Adverse Effect.

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(xxviii)     There is no action, suit or proceeding before or by any court or governmental agency or body, domestic or foreign, now pending, or, to the knowledge of the Company or the Operating Partnership, threatened against or affecting any entity belonging to the Duke Group, any Properties or any officer or director of the Company, which is material to the Duke Group as a whole and is required to be disclosed in the Registration Statement or Prospectus (other than as disclosed therein), or that, if determined adversely to any entity belonging to the Duke Group or any Property, or any such officer or director, will or could reasonably be expected to result in any Material Adverse Effect, or which might materially and adversely affect the Properties or assets of the Duke Group or which might materially and adversely affect the consummation of this Agreement, the applicable Terms Agreement, the Indenture, if any, or the transactions contemplated herein and therein.  Other than as disclosed in the Registration Statement or the Time of Sale Prospectus, there are no pending legal or governmental proceedings to which any entity belonging to the Duke Group is a party or of which they or any of their respective properties or assets or any Property or Property Partnership is the subject, including ordinary routine litigation incidental to the business, that are, considered in the aggregate, material to the condition, financial or otherwise, or the earnings, assets, business affairs or business prospects of the Duke Group as a whole.  There are no contracts or documents of the entities comprising the Duke Group which are required to be filed as exhibits to the Registration Statement by the 1933 Act or by the 1933 Act Regulations which have not been so filed.  The Time of Sale Prospectus contains in all material respects the same description of the foregoing matters contained in the Prospectus.

(xxix)       No authorization, approval, consent or order of any court or governmental authority or agency is required that has not been obtained in connection with the consummation by the Company, the Operating Partnership or both, as the case may be, of the transactions contemplated by this Agreement, the applicable Terms Agreement, or the applicable Indenture, if any, except such as may be required under the 1933 Act or the 1933 Act Regulations or the 1939 Act or the 1939 Act Regulations or state or foreign securities laws or real estate syndication laws or such as have been received prior to the date of this Agreement.

(xxx)        At all times since February 13, 1986, the Company has been, and upon the sale of the applicable Underwritten Securities, the Company will continue to be, organized and operated in conformity with the requirements for qualification as a real estate investment trust under the Internal Revenue Code of 1986, as amended (the “Code”), and its proposed method of operation will enable it to continue to meet the requirements for taxation as a real estate investment trust under the Code.

(xxxi)       None of the entities comprising the Duke Group is required to be registered under the Investment Company Act of 1940, as amended (the “1940 Act”), or is or will become a “holding company” or a “subsidiary company” of a “registered holding company” as defined in the Public Utility Holding Company Act of 1935, as amended.

(xxxii)      None of the entities comprising the Duke Group is required to own or possess any trademarks, service marks, trade names or copyrights not now lawfully owned, possessed or licensed in order to conduct the business now operated by such entity, the absence of which would have a Material Adverse Effect.

(xxxiii)     Each entity belonging to the Duke Group possesses such certificates, authorizations or permits issued by the appropriate state, federal or foreign regulatory agencies or bodies necessary to conduct the business now operated by it, or proposed to be conducted by it, the absence of which would have a Material Adverse Effect; and none of the entities comprising

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the Duke Group has received any notice of proceedings relating to the revocation or modification of any such certificate, authority or permit which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would have a Material Adverse Effect.

(xxxiv)     Except as disclosed in the Time of Sale Prospectus and except for persons who received Units in connection with transactions with the Operating Partnership, there are no persons with registration or other similar rights to have any securities registered pursuant to the Registration Statement or otherwise registered by the Company or the Operating Partnership under the 1933 Act.

(xxxv)      The Common Stock will be listed on the New York Stock Exchange on the applicable Representation Date and at the applicable Closing Time.  Unless otherwise agreed upon with reference to Preferred Stock, as of the applicable Representation Date the Preferred Stock will have been approved for listing on the New York Stock Exchange upon notice of issuance.

(xxxvi)     The Debt Securities will have an investment grade rating from one or more nationally recognized statistical rating organizations at the Representation Date and at the applicable Closing Time.

(xxxvii)    (A)  The Company, the Operating Partnership and the Property Partnerships have good and marketable title to all material items of real property (and improvements thereon), leasehold interests and general and limited partnership interests owned by them, in each case free and clear of all liens, encumbrances, claims, security interests and defects, except such as are (i) described in the Time of Sale Prospectus or the Company’s Annual Report on Form 10-K for the most recently ended fiscal year, (ii) referred to in the title policies of such Properties, (iii) serving as security for loans described in the Time of Sale Prospectus, or (iv) nonmaterial to the Duke Group taken as a whole; (B) all material contracts of the Operating Partnership and any subsidiary to provide leasing, property management and construction management services, general contractor services for third parties, and real estate development, construction and miscellaneous tenant services businesses (the “Related Businesses”), are enforceable by and in the name of the Operating Partnership and the applicable subsidiary, as the case may be; (C) all liens, charges, encumbrances, claims, or restrictions on or affecting any of the Properties or Related Businesses and the assets of the entities comprising the Duke Group which are required to be disclosed in the Time of Sale Prospectus are disclosed therein; (D) neither the Operating Partnership, any Property Partnership nor, to the knowledge of the Company or the Operating Partnership, any tenant of any of the Properties is in default under any of the ground leases (as lessee) or space leases (as lessor) relating to, or any of the mortgages or other security documents or other agreements encumbering or otherwise recorded against, the Properties, and none of the entities comprising the Duke Group knows of any event, which, but for the passage of time or the giving of notice, or both, would constitute a default under any of such documents or agreements, other than such defaults that would not have a Material Adverse Effect; (E) no tenant under any of the leases, pursuant to which the Operating Partnership or any Property Partnership, as lessor, leases its Property, has an option or right of first refusal to purchase the premises demised under such lease, the exercise of which would have a Material Adverse Effect; (F) each of the Properties complies with all applicable codes, laws and regulations (including, without limitation, building and zoning codes, laws and regulations and laws relating to access to the Properties), except for such failures to comply that would not individually or in the aggregate have a Material Adverse Effect; and (G) neither the Company nor the Operating Partnership has knowledge of any pending or threatened condemnation proceedings, zoning change, or other proceeding or action that will in any manner affect the size

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of, use of, improvements on, construction on or access to the Properties, except such proceedings or actions that would not have a Material Adverse Effect.

(xxxviii)  Each of the Company, the Operating Partnership and their respective subsidiaries is insured by insurers of recognized financial responsibility against such losses and risks and in such amounts as are customary in the businesses in which they are engaged; and none of the Company, the Operating Partnership and their respective subsidiaries has any reason to believe that it or any of its subsidiaries will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be necessary to continue its businesses at a cost that would not have a Material Adverse Effect, except as described in or contemplated by the Registration Statement and the Time of Sale Prospectus.

(xxxix)      The Company and the Operating Partnership have not taken and will not take, directly or indirectly, any action prohibited by Regulation M under the 1934 Act.

(xl)           The assets of the Company do not constitute “plan assets” under the Employee Retirement Income Security Act of 1974, as amended.

(xli)          Except as disclosed in the Time of Sale Prospectus, and, with respect to clauses (A), (B) and (C) below, except for activities, conditions, circumstances or matters that would not have a Material Adverse Effect, (A) each Property, including, without limitation, the Environment (as defined below) associated with such Property, is free of any Hazardous Substance (as defined below); (B) neither the Company nor the Operating Partnership nor any Property Partnership has caused or suffered to occur any Release (as defined below) of any Hazardous Substance into the Environment on, in, under or from any Property, and no condition exists on, in, under or from any Property, to the knowledge of the Company or the Operating Partnership, that could result in the incurrence of material liabilities or any material violations of any Environmental Law (as defined below), give rise to the imposition of any Lien (as defined below) under any Environmental Law, or cause or constitute a health, safety or environmental hazard to any property, person or entity; (C) neither the Company, the Operating Partnership nor any Property Partnership is engaged in or intends to engage in any manufacturing or any other operations at the Properties that (1) require the use, handling, transportation, storage, treatment or disposal of any Hazardous Substance or (2) require permits or are otherwise regulated pursuant to any Environmental Law, other than permits which have been obtained; (D) neither the Company nor the Operating Partnership nor any Property Partnership has received any notice of a claim material to the Duke Group as a whole under or pursuant to any Environmental Law or under common law pertaining to Hazardous Substances on or originating from any Property; (E) neither the Company nor the Operating Partnership nor any Property Partnership has received any notice from any Governmental Authority (as defined below) claiming any material violation of any Environmental Law; and (F) no Property is included or, to the knowledge of the Company or the Operating Partnership, proposed for inclusion on the National Priorities List issued pursuant to CERCLA (as defined below) by the United States Environmental Protection Agency (the “EPA”) or, with the exception of one Property, in respect to which the EPA has advised the Company that no further remedial action is planned, on the Comprehensive Environmental Response, Compensation, and Liability Information System database maintained by the EPA, and has not otherwise been identified by the EPA as a potential CERCLA removal, remedial or response site or included or, to the knowledge of the Company or the Operating Partnership, proposed for inclusion on, any similar list of potentially contaminated sites pursuant to any other Environmental Law.

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Excluding such customary amounts as may be lawfully generated, stored, used, treated, disposed of, or otherwise handled or located at any Property, as used herein “Hazardous Substance” shall include, without limitation, any hazardous substance, hazardous waste, toxic or dangerous substance, pollutant, toxic waste or similarly designated materials, including, without limitation, oil, petroleum or any petroleum-derived substance or waste, asbestos or asbestos-containing materials, PCBs, pesticides, explosives, radioactive materials, dioxins, urea formaldehyde insulation or any hazardous constituent of any such substance, pollutant or waste, including any such substance, pollutant or waste identified or regulated under any Environmental Law (including, without limitation, materials listed in the United States Department of Transportation Optional Hazardous Material Table, 49 C.F.R. § 172.101, as the same may now or hereafter be amended, or in the EPA’s List of Hazardous Substances and Reportable Quantities, 40 C.F.R. Part 3202, as the same may now or hereafter be amended); “Environment” shall mean any surface water, drinking water, ground water, land surface, subsurface strata, river sediment, buildings, structures, and ambient, workplace and indoor and outdoor air; “Environmental Law” shall mean the Comprehensive Environmental Response, Compensation and Liability Act of 1980, as amended (42 C. § 9601 et seq.) (“CERCLA”), the Resource Conservation and Recovery Act of 1976, as amended (42 C. § 6901, et seq.), the Clean Air Act, as amended (42 C. § 7401, et seq.), the Clean Water Act, as amended (33 C. § 1251, et seq.), the Toxic Substances Control Act, as amended (15 C. § 2601, et seq.), the Occupational Safety and Health Act of 1970, as amended (29 C. § 651, et seq.), the Hazardous Materials Transportation Act, as amended (49 C. § 1801, et seq.), and all other federal, state and local laws, ordinances, regulations, rules, orders, decisions and permits relating to the protection of the environments or of human health from environmental effects; “Governmental Authority” shall mean any federal, state or local governmental office, agency or authority having the duty or authority to promulgate, implement or enforce any Environmental Law; “Lien” shall mean, with respect to any Property, any mortgage, deed of trust, pledge, security interest, lien, encumbrance, penalty, fine, charge, assessment, judgment or other liability in, on or affecting such Property; and “Release” shall mean any spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, emanating or disposing of any Hazardous Substance into the Environment, including, without limitation, the abandonment or discard of barrels, containers, tanks (including, without limitation, underground storage tanks) or other receptacles containing or previously containing any Hazardous Substance or any release, emission, discharge or similar term, as those terms are defined or used in any Environmental Law.

(xlii)         Each of the Company, the Operating Partnership and their subsidiaries has obtained title insurance on all of the properties owned by each of them in an amount at least equal to (A) the cost to acquire land and improvements in the case of an acquisition of improved property or (B) the cost to acquire land in the case of an acquisition of unimproved property and in each case such title insurance is in full force and effect.

(xliii)        Each of the Company and the Operating Partnership has filed all federal, state, local and foreign income tax returns which have been required to be filed (except in any case in which the failure to so file would not have a material adverse effect on the condition, financial or otherwise, or the earnings, assets, business affairs or business prospects of such entity) and has paid all taxes required to be paid and any other assessment, fine or penalty levied against it, to the extent that any of the foregoing is due and payable, except, in all cases, for any such tax, assessment, fine or penalty that is being contested in good faith and except in any case in which failure to do so would not result in a Material Adverse Effect.

(c)   Any certificate signed by any officer of the Company, the Operating Partnership or of any of their respective subsidiaries and delivered to the Representatives or to counsel for the Underwriters shall be deemed a representation and warranty by such entity to each Underwriter as to the matters covered thereby.

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SECTION 2.           Sale and Delivery to Underwriters; Closing .

(b)   The several commitments of the Underwriters to purchase the Underwritten Securities pursuant to the applicable Terms Agreement shall be deemed to have been made on the basis of the representations and warranties herein contained and shall be subject to the terms and conditions set forth herein or in the applicable Terms Agreement.

(c)   In addition, on the basis of the representations and warranties herein contained and subject to the terms and conditions herein set forth, the Company or the Operating Partnership, as the case may be, may grant, if so provided in the applicable Terms Agreement relating to the Initial Underwritten Securities, an option to the Underwriters named in such Terms Agreement, severally and not jointly, to purchase up to the number of Option Securities set forth therein at the same price per Option Security as is applicable to the Initial Underwritten Securities, less an amount equal to any dividends or distributions declared by the Company and paid or payable on the Initial Underwritten Securities but not payable on the Option Securities.  Such option, if granted, will expire 30 days (or such lesser number of days as may be specified in the applicable Terms Agreement) after the Representation Date relating to the Initial Underwritten Securities, and may be exercised in whole or in part from time to time only for the purpose of covering over-allotments which may be made in connection with the offering and distribution of the Initial Underwritten Securities upon notice by the Representatives to the Company or the Operating Partnership, as the case may be, setting forth the number of Option Securities as to which the several Underwriters are then exercising the option and the time, date and place of payment and delivery for such Option Securities.  Any such time, date and place of delivery (a “Date of Delivery”) shall be determined by the Representatives, but shall not be later than seven full business days nor earlier than two full business days after the exercise of said option, nor in any event prior to the Closing Time, unless otherwise agreed upon by the Representatives and the Company or the Operating Partnership, as the case may be.  If the option is exercised as to all or any portion of the Option Securities, each of the Underwriters, acting severally and not jointly, will purchase that proportion of the total number of Option Securities then being purchased which the number of Initial Underwritten Securities each such Underwriter has severally agreed to purchase as set forth in the applicable Terms Agreement bears to the total number of Initial Underwritten Securities (except as otherwise provided in the applicable Terms Agreement), subject to such adjustments as the Representatives in their discretion shall make to eliminate any sales or purchases of fractional Underwritten Securities.

(d)   Payment of the purchase price for, and delivery of certificates for, the Initial Underwritten Securities to be purcha