Exhibit 1.1

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                                                               EXECUTION VERSION



                       INTERSTATE POWER AND LIGHT COMPANY


                              (an Iowa corporation)


                        5.875% SENIOR DEBENTURES DUE 2018



                               PURCHASE AGREEMENT




                            Dated: September 10, 2003



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                                TABLE OF CONTENTS



                                                                            Page
                                                                            ----
                                                                         
SECTION 1. Representations and Warranties ................................     2

     (a)   Representations and Warranties by the Company .................     2

           (i)     Compliance with Registration Requirements .............     2

           (ii)    Incorporated Documents ................................     3

           (iii)   Independent Accountants ...............................     4

           (iv)    Financial Statements ..................................     4

           (v)     No Material Adverse Change in Business ................     4

           (vi)    Good Standing of the Company ..........................     5

           (vii)   No Significant Subsidiaries ...........................     5

           (viii)  Capitalization ........................................     5

           (ix)    Authorization of Agreement ............................     5

           (x)     Authorization of the Indenture ........................     5

           (xi)    Authorization of the Securities .......................     6

           (xii)   Description of the Securities and the Indenture .......     6

           (xiii)  Absence of Defaults and Conflicts .....................     6

           (xiv)   Absence of Labor Dispute ..............................     7

           (xv)    Absence of Proceedings ................................     7

           (xvi)   Accuracy of Exhibits ..................................     7

           (xvii)  Absence of Further Requirements .......................     7

           (xviii) Possession of Licenses and Permits ....................     7

           (xix)   Title to Property .....................................     8

           (xx)    Investment Company Act ................................     8

           (xxi)   Environmental Laws ....................................     8


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     (b)   Officer's Certificates ............................................    9

SECTION 2. Sale and Delivery to Underwriters; Closing ........................    9

     (a)   The Securities ....................................................    9

     (b)   Payment ...........................................................    9

     (c)   Denominations; Registration .......................................   10

SECTION 3. Covenants of the Company ..........................................   10

     (a)   Compliance with Securities Regulations and Commission Requests ....   10

     (b)   Filing of Amendments ..............................................   10

     (c)   Delivery of Registration Statements ...............................   11

     (d)   Delivery of Prospectuses ..........................................   11

     (e)   Continued Compliance with Securities Laws .........................   11

     (f)   Blue Sky Qualifications ...........................................   11

     (g)   Rule 158 ..........................................................   12

     (h)   Use of Proceeds ...................................................   12

     (i)   Restriction on Sale of Securities .................................   12

     (j)   Reporting Requirements ............................................   12

     (k)   1935 Act Filings ..................................................   12

     (l)   Rating of Securities ..............................................   12

     (m)   DTC ...............................................................   13

     (n)   Compliance with Regulatory Approvals ..............................   13

SECTION 4. Payment of Expenses ...............................................   13

     (a)   Expenses ..........................................................   13

     (b)   Termination of Agreement ..........................................   13

SECTION 5. Conditions of Underwriters' Obligations ...........................   13

     (a)   Effectiveness of Registration Statement ...........................   14


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     (b)    Opinion of Counsel for Company ...................................  14

     (c)    Opinion of Counsel for Underwriters ..............................  14

     (d)    Officers' Certificate ............................................  14

     (e)    Accountant's Comfort Letter ......................................  15

     (f)    Bring-down Comfort Letter ........................................  15

     (g)    Maintenance of Rating ............................................  15

     (h)    Additional Documents .............................................  15

     (i)    Termination of Agreement .........................................  16

SECTION 6.  Indemnification ..................................................  16

     (a)    Indemnification of Underwriters ..................................  16

     (b)    Indemnification of Company, Directors and Officers ...............  17

     (c)    Actions against Parties; Notification ............................  17

     (d)    Settlement without Consent if Failure to Reimburse ...............  18

SECTION 7.  Contribution .....................................................  18

SECTION 8.  Representations, Warranties and Agreements to Survive Delivery ...  20

SECTION 9.  Termination of Agreement .........................................  20

     (a)    Termination; General .............................................  20

     (b)    Liabilities ......................................................  20

SECTION 10. Default by One or More of the Underwriters .......................  21

SECTION 11. Tax Disclosure ...................................................  21

SECTION 12. Notices ..........................................................  21

SECTION 13. Parties ..........................................................  22

SECTION 14. Governing Law and Time ...........................................  22

SECTION 15. Effect of Headings ...............................................  22

SECTION 16. Counterparts .....................................................  22


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SCHEDULES

     Schedule A - List of Underwriters
     Schedule B - Pricing Information

EXHIBITS

     Exhibit A - Form of Opinion of Company's Counsel
     Exhibit B - Form of Opinion of Company's In-House Counsel

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                       INTERSTATE POWER AND LIGHT COMPANY
                              (an Iowa corporation)

                        5.875% SENIOR DEBENTURES DUE 2018

                               PURCHASE AGREEMENT

                                                              September 10, 2003

Merrill Lynch & Co.
Merrill Lynch, Pierce, Fenner & Smith Incorporated
Barclays Capital Inc.
     as Representatives of the several Underwriters
c/o  Merrill Lynch & Co.
     Merrill Lynch, Pierce, Fenner & Smith Incorporated
4 World Financial Center
New York, New York  10080

Ladies and Gentlemen:

     Interstate Power and Light Company, an Iowa corporation (the "Company"),
confirms its agreement with Merrill Lynch & Co., Merrill Lynch, Pierce, Fenner &
Smith Incorporated ("Merrill Lynch") and each of the other Underwriters named in
Schedule A hereto (collectively, the "Underwriters", which term shall also
include any underwriter substituted as hereinafter provided in Section 10
hereof), for whom Merrill Lynch and Barclays Capital Inc. are acting as
representatives (in such capacity, the "Representatives"), with respect to the
issue and sale by the Company and the purchase by the Underwriters, acting
severally and not jointly, of the respective principal amounts set forth on
Schedule A of $100,000,000 aggregate principal amount of the Company's 5.875%
Senior Debentures due 2018 (the "Securities"). The Securities will be issued
pursuant to an indenture dated as of August 20, 2003 (the "Indenture") between
the Company and Bank One Trust Company, National Association, as trustee (the
"Trustee"). The term "Indenture," as used herein, includes the Officer's
Certificate (as defined in the Indenture) to be executed in connection with the
offering of the Securities establishing the form and terms of the Securities
pursuant to Section 301 of the Indenture. The Securities are to be issued in
book-entry form and will be issued to Cede & Co. as nominee of The Depository
Trust Company ("DTC") pursuant to a letter agreement, to be dated as of the
Closing Time (as defined in Section 2(b)) (the "DTC Agreement"), among the
Company, the Trustee and DTC.

     The Company understands that the Underwriters propose to make a public
offering of the Securities as soon as the Representatives deem advisable after
this Agreement has been executed and delivered.

     The Company has filed with the Securities and Exchange Commission (the
"Commission") a registration statement on Form S-3 (No. 333-108199), including
the related

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preliminary prospectus or prospectuses, covering the registration of the
Securities under the Securities Act of 1933, as amended (the "1933 Act").
Promptly after execution and delivery of this Agreement, the Company will
prepare and file a prospectus in accordance with the provisions of Rule 430A
("Rule 430A") of the rules and regulations of the Commission under the 1933 Act
(the "1933 Act Regulations") and paragraph (b) of Rule 424 ("Rule 424(b)") of
the 1933 Act Regulations. The information included in such prospectus that was
omitted from such registration statement at the time it became effective but
that is deemed to be part of such registration statement at the time it became
effective pursuant to paragraph (b) of Rule 430A is referred to as "Rule 430A
Information." Each prospectus used before such registration statement became
effective, and any prospectus that omitted the Rule 430A Information, that was
used after such effectiveness and prior to the execution and delivery of this
Agreement, is herein called a "preliminary prospectus." Such registration
statement, including the exhibits and any schedules thereto, at the time it
became effective, and including the documents incorporated by reference therein
pursuant to Item 12 of Form S-3 under the 1933 Act at such time and the Rule
430A Information, is herein called the "Registration Statement." Any
registration statement filed pursuant to Rule 462(b) of the 1933 Act Regulations
is herein referred to as the "Rule 462(b) Registration Statement," and after
such filing the term "Registration Statement" shall include the Rule 462(b)
Registration Statement. The final prospectus in the form first furnished to the
Underwriters for use in connection with the offering of the Securities,
including the documents incorporated by reference therein pursuant to Item 12 of
Form S-3 under the 1933 Act filed prior to the time of the execution of this
Agreement, is herein called the "Prospectus." For purposes of this Agreement,
all references to the Registration Statement, any preliminary prospectus, the
Prospectus or any amendment or supplement to any of the foregoing shall be
deemed to include the copy filed with the Commission pursuant to its Electronic
Data Gathering, Analysis and Retrieval system ("EDGAR").

     All references in this Agreement to financial statements and schedules and
other information which are "contained," "included" or "stated" (or other
references of like import) in the Registration Statement, Prospectus or
preliminary prospectus shall be deemed to mean and include all such financial
statements and schedules and other information which are incorporated by
reference, as of such applicable date, in the Registration Statement, Prospectus
or preliminary prospectus, as the case may be; and all references in this
Agreement to the Registration Agreement, amendments or supplements to the
Registration Statement, Prospectus or preliminary prospectus shall be deemed to
include the filing of any document under the Securities Exchange Act of 1934, as
amended (the "1934 Act") which is incorporated by reference, as of such
applicable date, in the Registration Statement, Prospectus or preliminary
prospectus, as the case may be.

     SECTION 1. Representations and Warranties.

(a)  Representations and Warranties by the Company. The Company represents and
     warrants to each Underwriter as of the date hereof and as of the Closing
     Time referred to in Section 2(b) hereof, and agrees with each Underwriter,
     as follows:

          (i) Compliance with Registration Requirements. The Company meets the
     requirements for use of Form S-3 under the 1933 Act. Each of the
     Registration Statement

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     and any Rule 462(b) Registration Statement has become effective under the
     1933 Act and no stop order suspending the effectiveness of the Registration
     Statement or any Rule 462(b) Registration Statement has been issued under
     the 1933 Act and no proceedings for that purpose have been instituted or
     are pending or, to the knowledge of the Company, are contemplated by the
     Commission, and any request on the part of the Commission for additional
     information has been complied with.

          At the respective times the Registration Statement, any Rule 462(b)
     Registration Statement and any post-effective amendments thereto became
     effective and at the Closing Time, the Registration Statement, the Rule
     462(b) Registration Statement and any amendments and supplements thereto
     complied or will comply, as the case may be, in all material respects with
     the requirements of the 1933 Act and the 1933 Act Regulations and the Trust
     Indenture Act of 1939, as amended (the "1939 Act") and the rules and
     regulations of the Commission under the 1939 Act (the "1939 Act
     Regulations"), and did not or will not, as the case may be, 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 and the Indenture complied and will comply in all material
     respects with the requirements of the 1939 Act. Neither the Prospectus nor
     any amendments or supplements thereto, at the time the Prospectus or any
     such amendment or supplement was issued and at the Closing Time, included
     or will include an untrue statement of a material fact or omitted or will
     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 representations and warranties in this subsection shall not
     apply to statements in or omissions from the Registration Statement or
     Prospectus made in reliance upon and in conformity with information
     furnished to the Company in writing by any Underwriter through Merrill
     Lynch expressly for use in the Registration Statement (or any amendment
     thereto) or Prospectus (or any amendment thereto).

          Each preliminary prospectus and the prospectus filed as part of the
     Registration Statement as originally filed or as part of any amendment
     thereto, or filed pursuant to Rule 424 under the 1933 Act, complied when so
     filed in all material respects with the 1933 Act Regulations and each
     preliminary prospectus and the Prospectus delivered to the Underwriters for
     use in connection with this offering was identical to the electronically
     transmitted copies thereof filed with the Commission pursuant to EDGAR,
     except to the extent permitted by Regulation S-T.

          (ii) Incorporated Documents.

               (1) The documents incorporated or deemed to be incorporated by
          reference in the Registration Statement and the Prospectus, at the
          time they were or hereafter are filed with the Commission, complied or
          will comply, as the case may be, in all material respects with the
          requirements of the 1934 Act and the rules and regulations of the
          Commission thereunder (the "1934 Act Regulations"), as applicable,
          and, when read together with the other information in the Prospectus,
          at the time the Registration Statement became effective, at the time
          the Prospectus was issued and at the Closing Time, did not or will
          not, as the case may be, contain an

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          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.

                (2) The description of regulatory matters to which the Company
          is subject, as disclosed in the Company's filings with the Commission
          under the 1934 Act and the 1934 Act Regulations and as incorporated by
          reference into the Registration Statement, is true and correct in all
          material respects, except to the extent such description in any
          specific filing has been superseded, updated or supplemented by such
          description in a subsequent filing under the 1934 Act or the 1934 Act
          Regulations made prior to the date hereof or by such description in
          the Prospectus.

          (iii) Independent Accountants. The accountants who certified the
     financial statements and supporting schedules included in the Registration
     Statement are independent public accountants with respect to the Company
     and its subsidiaries within the meaning of Regulation S-X under the 1933
     Act.

          (iv)  Financial Statements. The financial statements included in the
     Registration Statement and the Prospectus, together with the related
     schedules and notes, present fairly in all material respects the financial
     position of the Company and its consolidated subsidiaries at the dates
     indicated and the statement of income, changes in common equity and cash
     flows of the Company and its consolidated subsidiaries for the periods
     specified; said financial statements have been prepared in conformity with
     generally accepted accounting principles ("GAAP") applied on a consistent
     basis throughout the periods involved. The supporting schedules, if any,
     included in the Registration Statement present fairly in all material
     respects in accordance with GAAP the information required to be stated
     therein. The selected financial data and the summary financial information
     included in the Prospectus present fairly in all material respects the
     information shown therein and have been compiled on a basis consistent with
     that of the audited financial statements included in the Registration
     Statement.

          (v)  No Material Adverse Change in Business. Since the respective
     dates as of which information is given in the Registration Statement and
     the Prospectus, except as otherwise stated therein, (A) there has been no
     material adverse change in the condition, financial or otherwise, in the
     earnings or business affairs of the Company and its subsidiaries considered
     as one enterprise, whether or not arising in the ordinary course of
     business nor has there been any developments involving a prospective
     material adverse change of the Company and its subsidiaries considered as
     one enterprise, whether or not arising in the ordinary course of business
     (a "Material Adverse Effect"), (B) there have been no transactions entered
     into by the Company or any of its subsidiaries, other than those in the
     ordinary course of business, which are material with respect to the Company
     and its subsidiaries, and (C) except for regular dividends on the common
     stock, par value $2.50 per share, of the Company and the 8.375% Series B
     Cumulative Preferred Stock, $0.01 par value per share, of the Company in
     amounts per share that are consistent with past practice or the terms of
     the 8.375% Series B Cumulative Preferred Stock, as the case may be, there
     has been no dividend or distribution of any kind declared, paid or made by
     the Company on any class of its capital stock.

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          (vi)   Good Standing of the Company. The Company has been duly
     organized and is validly existing as a corporation under the laws of the
     State of Iowa and has corporate power and authority to own, lease and
     operate its properties and to conduct its business as described in the
     Prospectus and to enter into and perform its obligations under this
     Agreement; and the Company is duly qualified as a foreign corporation to
     transact business and is in good standing in each other 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 so
     to qualify or to be in good standing would not result in a Material Adverse
     Effect.

          (vii)  No Significant Subsidiaries. The Company has no "significant
     subsidiary" as defined in Rule 1-02 of Regulation S-X.

          (viii) Capitalization. The authorized, issued and outstanding capital
     stock of the Company as of the date hereof is set forth in the Prospectus
     in the column entitled "Actual" under the caption "Capitalization" (except
     for subsequent issuances, if any, pursuant to this Agreement, pursuant to
     existing reservations, agreements or employee benefit plans, or pursuant to
     the exercise of convertible securities or options outstanding on the date
     hereof or pursuant to any dividend reinvestment plan). All of the issued
     and outstanding shares of capital stock of the Company have been duly
     authorized and validly issued and are fully paid and non-assessable and
     none of the outstanding shares of capital stock of the Company was issued
     in violation of the preemptive or other similar rights of any
     securityholder of the Company. As of the date hereof, except for 6,000,000
     shares of the Company's 8.375% Series B Cumulative Preferred Stock, all of
     the issued and outstanding shares of the capital stock of the Company are
     owned by Alliant Energy Corporation, a Wisconsin corporation (the
     "Parent"), free and clear of all liens, encumbrances, equities or claims.
     Immediately prior to the Closing Time, except for 6,000,000 shares of the
     capital stock of the Company's 8.375% Series B Cumulative Preferred Stock
     and 1,600,000 shares of the Company's 7.10% Series C Cumulative Preferred
     Stock, all of the issued and outstanding shares of capital stock of the
     Company will be owned directly by Parent, free and clear of all liens,
     encumbrances, equities or claims. The Parent is a "holding company" and the
     Company is a "subsidiary" of a "holding company" as such terms are defined
     under the Public Utility Holding Company Act of 1935, as amended.

          (ix)   Authorization of Agreement. The Company has all requisite
     corporate power and authority to execute and deliver this Agreement and to
     perform its obligations hereunder. This Agreement has been duly authorized,
     executed and delivered by the Company.

          (x)    Authorization of the Indenture. The Indenture has been duly
     authorized, executed and delivered by the Company and duly qualified under
     the 1939 Act and constitutes a valid and binding agreement of the Company
     enforceable against the Company in accordance with its terms, except (A)
     the enforcement thereof may be limited by bankruptcy, insolvency (including
     without limitation, all laws relating to fraudulent transfers),
     reorganization, moratorium or similar laws affecting the enforcement of
     creditors' rights generally and (B) as enforcement thereof is subject to
     general principals of equity (regardless if whether enforcement is
     considered in a proceeding in equity or at law).

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          (xi)   Authorization of the Securities. The Securities have been duly
     authorized and, at the Closing Time, will have been duly executed by the
     Company and, when authenticated, issued and delivered in the manner
     provided for in the Indenture and delivered against payment of the purchase
     price therefor provided for in this Agreement, will constitute valid and
     binding obligations of the Company, enforceable against the Company in
     accordance with their terms, except as the enforcement thereof may be
     limited by bankruptcy, insolvency (including, without limitation, all laws
     relating to fraudulent transfers), reorganization, moratorium or similar
     laws affecting enforcement of creditors' rights generally and except as
     enforcement thereof is subject to general principles of equity (regardless
     of whether enforcement is considered in a proceeding in equity or at law),
     and will be in the form contemplated by, and entitled to the benefits of,
     the Indenture.

          (xii)  Description of the Securities and the Indenture. The statements
     relating to the Securities and the Indenture contained in the Prospectus
     conform, respectively, in all material respects to the terms of the
     Securities and the Indenture.

          (xiii) Absence of Defaults and Conflicts. Neither the Company nor any
     of its subsidiaries is in violation of its charter or by-laws or in default
     in the performance or observance of any obligation, agreement, covenant or
     condition contained in any contract, indenture, mortgage, deed of trust,
     loan or credit agreement, note, lease or other agreement or instrument to
     which the Company or any of its subsidiaries is a party or by which it or
     any of them may be bound, or to which any of the property or assets of the
     Company or any of its subsidiaries is subject (collectively, "Agreements
     and Instruments") except for such violations or defaults that would not
     result in a Material Adverse Effect; and the execution, delivery and
     performance of this Agreement, the Indenture and the Securities, the
     consummation of the transactions contemplated herein and in the
     Registration Statement (including the issuance and sale of the Securities
     and the use of the proceeds from the sale of the Securities as described in
     the Prospectus under the caption "Use of Proceeds") and compliance by the
     Company with its obligations hereunder and under the Indenture and the
     Securities have been duly authorized by all necessary corporate action and
     do not and will not, whether with or without the giving of notice or
     passage of time or both, conflict with or constitute a breach of, or
     default or a Repayment Event (as defined below) under, or result in the
     creation or imposition of any lien, charge or encumbrance upon any property
     or assets of the Company or any of its subsidiaries pursuant to, the
     Agreements and Instruments except for such conflicts, breaches or defaults
     or liens, charges or encumbrances that, singly or in the aggregate, would
     not result in a Material Adverse Effect, nor will such action result in any
     violation of the provisions of (x) the charter or by-laws of the Company or
     any of its subsidiaries (except for such conflicts, breaches, defaults,
     events or liens, charges or encumbrances that would not result in a
     Material Adverse Effect) or (y) any applicable law, statute, rule,
     regulation, judgment, order, writ or decree of any government, government
     instrumentality or court, domestic or foreign, having jurisdiction over the
     Company or any of its subsidiaries or any of their assets, properties or
     operations, except for any such violations with respect to this clause (y)
     as would not, individually or in the aggregate, result in a Material
     Adverse Effect. As used herein, a "Repayment Event" means any event or
     condition which gives the holder of any note, debenture or other evidence
     of indebtedness (or any person acting on such holder's behalf) the right to
     require the repurchase, redemption

                                       6



     or repayment of all or a portion of such indebtedness by the Company or any
     of its subsidiaries.

          (xiv)   Absence of Labor Disputes. No labor dispute with the employees
     of the Company or any of its subsidiaries exists or, to the knowledge of
     the Company, is imminent, and the Company is not aware of any existing or
     imminent labor disturbance by the employees of any of its or any of its
     subsidiaries' respective principal suppliers, manufacturers, customers or
     contractors, which, in either case, may reasonably be expected to result in
     a Material Adverse Effect.

          (xv)    Absence of Proceedings. Except as disclosed in the Prospectus,
     there is no action, suit, proceeding, inquiry or investigation before or
     brought by any court or governmental agency or body, domestic or foreign,
     now pending, or, to the knowledge of the Company, threatened, against or
     affecting the Company or any of its subsidiaries which might reasonably be
     expected to result in a Material Adverse Effect, or which might reasonably
     be expected to materially and adversely affect (A) the properties or assets
     of the Company and its subsidiaries or (B) the consummation of the
     transactions contemplated by this Agreement or the performance by the
     Company of its obligations hereunder. The aggregate of all pending legal or
     governmental proceedings to which the Company or any of its subsidiaries is
     a party or of which any of their respective property or assets is the
     subject which are not described in the Registration Statement, including
     ordinary routine litigation incidental to the business, could not
     reasonably be expected to result in a Material Adverse Effect.

          (xvi)   Accuracy of Exhibits. There are no contracts or documents
     which are required to be described in the Registration Statement, the
     Prospectus or the documents incorporated by reference therein or to be
     filed as exhibits thereto which have not been so described and filed as
     required except that this Agreement will be filed as an exhibit to a
     Current Report on Form 8-K which shall be filed with the Commission in
     accordance with the 1934 Act and the 1934 Act Regulations prior to the
     filing of the Prospectus.

          (xvii)  Absence of Further Requirements. No filing with, or
     authorization, approval, consent, license, order, registration,
     qualification or decree of, any court or governmental authority or agency
     is necessary or required for the performance by the Company of its
     obligations hereunder, in connection with the offering, issuance or sale of
     the Securities hereunder, the consummation of the transactions contemplated
     by this Agreement or for the due execution, delivery and performance of the
     Indenture by the Company, except (A) such as have been already obtained,
     (B) such as may be required under the 1933 Act or the 1933 Act Regulations
     or state securities laws, and (C) such as may be required by the Public
     Utility Holding Company Act of 1935, as amended (the "1935 Act"), solely
     with respect to filings required to be made with the Commission subsequent
     to the Closing Time (such 1935 Act filings to be made by the Company).

          (xviii) Possession of Licenses and Permits. The Company and its
     subsidiaries possess such permits, licenses, approvals, consents and other
     authorizations (collectively, "Governmental Licenses") issued by the
     appropriate federal, state, local or foreign regulatory agencies or bodies
     necessary to conduct the business now operated by them

                                       7



     except where the failure to possess any such Governmental Licenses would
     not have a Material Adverse Effect; the Company and its subsidiaries are in
     compliance with the terms and conditions of all such Governmental Licenses,
     except where the failure so to possess or comply would not, singly or in
     the aggregate, have a Material Adverse Effect; all of the Governmental
     Licenses are valid and in full force and effect, except where the
     invalidity of such Governmental Licenses or the failure of such
     Governmental Licenses to be in full force and effect would not have a
     Material Adverse Effect; and neither the Company nor any of its
     subsidiaries has received any notice of proceedings relating to the
     revocation or modification of any such Governmental Licenses which, singly
     or in the aggregate, if the subject of an unfavorable decision, ruling or
     finding, would result in a Material Adverse Effect. Without limiting the
     foregoing, the Company has received final orders of the Illinois Commerce
     Commission, dated September 4, 2003, and the Minnesota Public Utilities
     Commission, dated March 28, 2003 (as amended August 7, 2003), and the
     approval, dated October 24, 2001, of the Commission under the 1935 Act
     authorizing the issuance of the Securities and such issuance is in
     compliance with the terms and conditions of such orders and approval. Such
     orders and approval are in full force and effect and have not been amended
     supplemented or otherwise modified. No proceeding to review, suspend,
     limit, modify, restrict or revoke any such order or approval has been
     instituted.

          (xix)  Title to Property. The Company and its subsidiaries have good
     and marketable title to all real property owned by the Company and its
     subsidiaries and good title to all other properties owned by them, in each
     case, free and clear of all mortgages, pledges, liens, security interests,
     claims, restrictions or encumbrances of any kind except such as (A) are
     described in the Prospectus or (B) do not, singly or in the aggregate,
     materially affect the value of such property and do not interfere with the
     use made and proposed to be made of such property by the Company or any of
     its subsidiaries; and all of the leases and subleases material to the
     business of the Company and its subsidiaries, considered as one enterprise,
     and under which the Company or any of its subsidiaries holds properties
     described in the Prospectus, are in full force and effect, and neither the
     Company nor any of its subsidiaries has any notice of any material claim of
     any sort that has been asserted by anyone adverse to the rights of the
     Company or any of its subsidiaries under any of the leases or subleases
     mentioned above, or affecting or questioning the rights of the Company or
     any of its subsidiaries to the continued possession of the leased or
     subleased premises under any such lease or sublease, except where such
     would not have a Material Adverse Effect.

          (xx)   Investment Company Act. The Company is not, and upon the
     issuance and sale of the Securities as herein contemplated and the
     application of the net proceeds therefrom as described in the Prospectus
     will not be, an "investment company" or an entity "controlled" by an
     "investment company" as such terms are defined in the Investment Company
     Act of 1940, as amended (the "1940 Act").

          (xxi)  Environmental Laws. Except as described in the Registration
     Statement and except as would not, singly or in the aggregate, result in a
     Material Adverse Effect, (A) neither the Company nor any of its
     subsidiaries is in violation of any federal, state, local or foreign
     statute, law, rule, regulation, ordinance, code, policy or rule of common
     law or any judicial or administrative interpretation thereof, including any
     judicial or administrative

                                       8



         order, consent, decree or judgment, relating to pollution or protection
         of human health, the environment (including, without limitation,
         ambient air, surface water, groundwater, land surface or subsurface
         strata) or wildlife, including, without limitation, laws and
         regulations relating to the release or threatened release of chemicals,
         pollutants, contaminants, wastes, toxic substances, hazardous
         substances, petroleum or petroleum products (collectively, "Hazardous
         Materials") or to the manufacture, processing, distribution, use,
         treatment, storage, disposal, transport or handling of Hazardous
         Materials (collectively, "Environmental Laws"), (B) the Company and its
         subsidiaries have all permits, authorizations and approvals required
         under any applicable Environmental Laws and are each in compliance with
         their requirements, (C) there are no pending or, to the knowledge of
         the Company, threatened administrative, regulatory or judicial actions,
         suits, demands, demand letters, claims, liens, notices of noncompliance
         or violation, investigation or proceedings relating to any
         Environmental Law against the Company or any of its subsidiaries and
         (D) there are no events or circumstances that might reasonably be
         expected to form the basis of an order for clean-up or remediation, or
         an action, suit or proceeding by any private party or governmental body
         or agency, against or affecting the Company or any of its subsidiaries
         relating to Hazardous Materials or any Environmental Laws.

(b)      Officer's Certificates. Any certificate signed by any officer of the
         Company or any of its subsidiaries delivered to the Representatives or
         to counsel for the Underwriters shall be deemed a representation and
         warranty by the Company to each Underwriter as to the matters covered
         thereby.

         SECTION 2.  Sale and Delivery to Underwriters; Closing.

(a)      The Securities. On the basis of the representations, warranties and
         agreements herein contained and subject to the terms and conditions
         herein set forth, the Company agrees to sell to each Underwriter,
         severally and not jointly, and each Underwriter, severally and not
         jointly, agrees to purchase from the Company, at the price set forth in
         Schedule B, the aggregate principal amount of Securities set forth in
         Schedule A opposite the name of such Underwriter, plus any additional
         principal amount of Securities which such Underwriter may become
         obligated to purchase pursuant to the provisions of Section 10 hereof.

(b)      Payment. Payment of the purchase price for, and delivery of
         certificates for, the Securities shall be made at the offices of the
         Company at 4902 North Biltmore Lane, Madison, Wisconsin, 53718, or at
         such other place as shall be agreed upon by the Representatives and the
         Company, at 10:00 A.M. (Eastern time) on the fifth business day after
         the date hereof (unless postponed in accordance with the provisions of
         Section 10), or such other time not later than ten business days after
         such date as shall be agreed upon by the Representatives and the
         Company (such time and date of payment and delivery being herein called
         the "Closing Time").

         Payment shall be made to the Company by wire transfer of immediately
available funds to a bank account designated by the Company, against delivery to
the Representatives for the respective accounts of the Underwriters of
certificates for the Securities to be purchased by them. It is understood that
each Underwriter has authorized the Representatives, for its account, to

                                       9



accept delivery of, receipt for, and make payment of the purchase price for, the
Securities which it has agreed to purchase. Merrill Lynch, individually and not
as representative of the Underwriters, may (but shall not be obligated to) make
payment of the purchase price for the Securities to be purchased by any
Underwriter whose funds have not been received by the Closing Time, but such
payment shall not relieve such Underwriter from its obligations hereunder.

(c)      Denominations; Registration. Certificates for the Securities shall be
         in such denominations (in integral multiples of $1,000) as the
         Representatives may request in writing at least two full business days
         before the Closing Time and registered in the name of Cede & Co., as
         nominee of DTC. The certificates for the Securities will be made
         available for examination and packaging by the Representatives in New
         York, New York not later than noon (Eastern time) on the last business
         day prior to the Closing Time.

         SECTION 3. Covenants of the Company. The Company covenants with each
Underwriter as follows:

(a)      Compliance with Securities Regulations and Commission Requests. The
         Company, subject to Section 3(b), will notify the Representatives
         immediately and confirm the notice in writing, (i) when any
         post-effective amendment to the Registration Statement shall become
         effective, or any supplement to the Prospectus or any amended
         Prospectus shall have been filed, (ii) of the receipt of any comments
         from the Commission with respect to the Registration Statement, (iii)
         of any request by the Commission for any amendment to the Registration
         Statement or any amendment or supplement to the Prospectus or for
         additional information, and (iv) of the issuance by the Commission of
         any stop order suspending the effectiveness of the Registration
         Statement or of any order preventing or suspending the use of any
         preliminary prospectus, or of the suspension of the qualification of
         the Securities for offering or sale in any jurisdiction, or of the
         initiation or threatening of any proceedings for any of such purposes.
         The Company will promptly effect the filings necessary pursuant to Rule
         424(b) and will take such steps as it deems necessary to ascertain
         promptly whether the form of prospectus transmitted for filing under
         Rule 424(b) was received for filing by the Commission and, in the event
         that it was not, it will promptly file such prospectus. The Company
         will make every reasonable effort to prevent the issuance of any stop
         order and, if any stop order is issued, to obtain the lifting thereof
         at the earliest possible moment.

(b)      Filing of Amendments. The Company will give the Representatives notice
         of its intention to file or prepare any amendment to the Registration
         Statement (including any filing under Rule 462(b)), any amendment,
         supplement or revision to either the prospectus included in the
         Registration Statement at the time it became effective or to the
         Prospectus, whether pursuant to the 1933 Act, the 1934 Act or
         otherwise, will furnish the Representatives with copies of any such
         documents a reasonable amount of time prior to such proposed filing or
         use, as the case may be, and will not file or use any such document to
         which the Representatives or counsel for the Underwriters shall
         reasonably object.

                                       10



(c)      Delivery of Registration Statements. The Company has furnished or will
         deliver to the Representatives and counsel for the Underwriters,
         without charge, copies (one of which shall be manually signed) of the
         Registration Statement as originally filed and of each amendment
         thereto (including exhibits filed therewith or incorporated by
         reference therein and documents incorporated or deemed to be
         incorporated by reference therein) and copies (one of which shall be
         manually signed) of all consents and certificates of experts, and will
         also deliver to the Representatives, without charge, a conformed copy
         of the Registration Statement as originally filed and of each amendment
         thereto (without exhibits) for each of the Underwriters. The copies of
         the Registration Statement and each amendment thereto furnished to the
         Underwriters will be identical to the electronically transmitted copies
         thereof filed with the Commission pursuant to EDGAR, except to the
         extent permitted by Regulation S-T.

(d)      Delivery of Prospectuses. The Company has delivered or will deliver to
         each Underwriter, without charge, as many copies of each preliminary
         prospectus and final prospectus as such Underwriter reasonably
         requested, and the Company hereby consents to the use of such copies
         for purposes permitted by the 1933 Act. The Company will furnish to
         each Underwriter, without charge, during the period when the Prospectus
         is required to be delivered under the 1933 Act or the 1934 Act, such
         number of copies of the Prospectus (as amended or supplemented) as such
         Underwriter may reasonably request. The Prospectus and any amendments
         or supplements thereto furnished to the Underwriters will be identical
         to the electronically transmitted copies thereof filed with the
         Commission pursuant to EDGAR, except to the extent permitted by
         Regulation S-T.

(e)      Continued Compliance with Securities Laws. The Company will comply with
         the 1933 Act and the 1933 Act Regulations and the 1934 Act and the 1934
         Act Regulations and the 1939 Act and the 1939 Act Regulations so as to
         permit the completion of the distribution of the Securities as
         contemplated in this Agreement and in the Prospectus. If at any time
         when a prospectus is required by the 1933 Act to be delivered in
         connection with sales of the Securities, any event shall occur or
         condition shall exist as a result of which it is necessary, in the
         reasonable opinion of counsel for the Underwriters or for the Company,
         to amend the Registration Statement or amend or supplement the
         Prospectus in order that the Prospectus will not include any untrue
         statements of a material fact or omit to state a material fact
         necessary in order to make the statements therein not misleading in the
         light of the circumstances existing at the time it is delivered to a
         purchaser, or if it shall be necessary, in the reasonable opinion of
         such counsel, at any such time to amend the Registration Statement or
         amend or supplement the Prospectus in order to comply with the
         requirements of the 1933 Act or the 1933 Act Regulations, the Company
         will promptly prepare and file with the Commission, subject to Section
         3(b), such amendment or supplement as may be necessary to correct such
         statement or omission or to make the Registration Statement or the
         Prospectus comply with such requirements, and the Company will furnish
         to the Underwriters such number of copies of such amendment or
         supplement as the Underwriters may reasonably request.

(f)      Blue Sky Qualifications. The Company will use its best efforts, in
         cooperation with the Underwriters, to qualify the Securities for
         offering and sale under the applicable securities laws of such states
         and other jurisdictions as the Representatives may designate

                                       11



         and to maintain such qualifications in effect so long as required for
         the sale of the Securities; provided, however, that the Company shall
         not be obligated to file any general consent to service of process or
         to qualify as a foreign corporation or as a dealer in securities in any
         jurisdiction in which it is not so qualified or to subject itself to
         taxation in respect of doing business in any jurisdiction in which it
         is not otherwise so subject. In each jurisdiction in which the
         Securities have been so qualified, the Company will file such
         statements and reports as may be required by the laws of such
         jurisdiction to continue such qualification in effect for such period.

(g)      Rule 158. The Company will timely file such reports pursuant to the
         1934 Act as are necessary in order to make generally available to its
         securityholders as soon as practicable an earnings statement for the
         purposes of, and to provide the benefits contemplated by, the last
         paragraph of Section 11(a) of the 1933 Act.

(h)      Use of Proceeds. The Company will use the net proceeds received by it
         from the sale of the Securities in the manner specified in the
         Prospectus under "Use of Proceeds."

(i)      Restriction on Sale of Securities. During a period of 15 days from the
         date of the Prospectus, the Company will not, without the prior written
         consent of Merrill Lynch, (i) directly or indirectly, offer, pledge,
         sell, contract to sell, sell any option or contract to purchase,
         purchase any option or contract to sell, grant any option, right or
         warrant to purchase or otherwise transfer or dispose of any debt
         securities of the Company or any securities convertible into or
         exercisable or exchangeable for debt securities of the Company or file
         any registration statement under the 1933 Act with respect to any of
         the foregoing or (ii) enter into any swap or any other agreement or any
         transaction that transfers, in whole or in part, directly or
         indirectly, the economic consequence of ownership of debt securities of
         the Company, whether any such swap or transaction described in clause
         (i) or (ii) above is to be settled by delivery of debt securities of
         the Company or such other securities, in cash or otherwise. The
         foregoing sentence shall not apply to the Securities to be sold
         hereunder.

(j)      Reporting Requirements. The Company, during the period when the
         Prospectus is required to be delivered under the 1933 Act or the 1934
         Act, will file all documents required to be filed with the Commission
         pursuant to the 1934 Act within the time periods required by the 1934
         Act and the 1934 Act Regulations.

(k)      1935 Act Filings. The Company shall timely file all notifications,
         forms and reports that may be required under the 1935 Act so as to
         permit the completion of the distribution and sale of the Securities as
         contemplated in this Agreement and in the Prospectus

(l)      Rating of Securities. The Company shall take all reasonable action
         necessary to enable Standard & Poor's Ratings Services, a division of
         McGraw Hill, Inc. ("S&P"), and Moody's Investors Service Inc.
         ("Moody's") to provide their respective credit ratings of the
         Securities.

                                       12



(m)      DTC. The Company will cooperate with the Representatives and use its
         best efforts to permit the Securities to be eligible for clearance and
         settlement through the facilities of DTC.

(n)      Compliance with Regulatory Approvals. The Company will comply with the
         terms and conditions of the final orders of the Illinois Commerce
         Commission and the Minnesota Public Utilities Commission and the
         approval of the Commission under the 1935 Act issued on September 4,
         2003, March 28, 2003 (as amended August 7, 2003) and October 24, 2001,
         respectively, as such orders are amended from time to time until
         superseded, and shall timely file all notifications, forms and reports
         that may be required in connection therewith so as to permit the
         completion of the distribution and sale of the Securities as
         contemplated in this Agreement and in the Prospectus.

         SECTION 4. Payment of Expenses.

(a)      Expenses. The Company will pay all expenses incident to the performance
         of its obligations under this Agreement, including (i) the preparation,
         printing and filing of the Registration Statement (including financial
         statements and any schedules or exhibits and any document incorporated
         therein by reference) and of each amendment or supplement thereto, (ii)
         the reproduction and delivery to the Underwriters of this Agreement,
         the Indenture, any Agreement among Underwriters and such other
         documents as may be required in connection with the offering, purchase,
         sale, issuance or delivery of the Securities, (iii) the preparation,
         issuance and delivery of the certificates for the Securities to the
         Underwriters, including any transfer taxes and any stamp or other
         duties payable upon the sale, issuance or delivery of the Securities to
         the Underwriters and any charges of DTC in connection therewith, (iv)
         the fees and disbursements of the Company's counsel, accountants and
         other advisors, (v) the qualification of the Securities under
         securities laws in accordance with the provisions of Section 3(f)
         hereof, including filing fees and the reasonable fees and disbursements
         of counsel for the Underwriters in connection therewith and in
         connection with the preparation of the Blue Sky Survey and any
         supplement thereto (provided that counsel fees in connection therewith
         do not exceed $5,000), (vi) the printing and delivery to the
         Underwriters of copies of each preliminary prospectus and of the
         Prospectus and any amendments or supplements thereto, (vii) the fees
         and expenses of the Trustee, including the fees and disbursements of
         counsel for the Trustee in connection with the Indenture and the
         Securities and (viii) any fees payable in connection with the rating of
         the Securities.


(b)      Termination of Agreement. If this Agreement is terminated by the
         Representatives in accordance with the provisions of Section 5 or
         Section 9(a)(i) hereof, the Company shall reimburse the Underwriters
         for all of their out-of-pocket expenses, including the reasonable fees
         and disbursements of counsel for the Underwriters (provided that such
         out-of-pocket expenses, fees and disbursements do not exceed $200,000).

         SECTION 5. Conditions of Underwriters' Obligations. The obligations of
the several Underwriters hereunder are subject to the accuracy in all material
respects of the representations and warranties of the Company contained in
Section 1 hereof or in certificates of any officer of the Company or any
subsidiary of the Company delivered pursuant to the provisions hereof, to

                                       13



the performance in all material respects by the Company of its covenants and
other obligations hereunder, and to the following further conditions:

(a)      Effectiveness of Registration Statement. The Registration Statement,
         including any Rule 462(b) Registration Statement, has become effective
         and at the Closing Time no stop order suspending the effectiveness of
         the Registration Statement shall have been issued under the 1933 Act or
         proceedings therefor initiated or threatened by the Commission, and any
         request on the part of the Commission for additional information shall
         have been complied with to the reasonable satisfaction of counsel to
         the Underwriters. A prospectus containing the information to be
         included upon pricing in a form of prospectus filed with the Commission
         pursuant to Rule 424(b) of the 1933 Act Regulations shall have been
         filed with the Commission in accordance with Rule 424(b).

(b)      Opinion of Counsel for Company. At the Closing Time, the
         Representatives shall have received the favorable opinion, dated as of
         the Closing Time, of Foley & Lardner, counsel for the Company, in form
         and substance reasonably satisfactory to counsel for the Underwriters,
         together with signed or reproduced copies of such letter for each of
         the other Underwriters, to the effect set forth in Exhibit A hereto. At
         the Closing Time, the Representatives shall have received the favorable
         opinion regarding certain state and local regulatory matters, dated as
         of the Closing Time, of Barbara J. Swan, Executive Vice President and
         General Counsel of the Company, in form and substance reasonably
         satisfactory to counsel for the Underwriters, together with signed or
         reproduced copies of such letter for each of the other Underwriters, to
         the effect set forth in Exhibit B hereto. In rendering such opinions,
         such counsel may rely as to matters of fact (but not as to legal
         conclusions), to the extent they deem proper, on certificates of
         responsible officers of the Company and its subsidiaries and of public
         officials.

(c)      Opinion of Counsel for Underwriters. At the Closing Time, the
         Representatives shall have received the favorable opinion, dated as of
         the Closing Time, of Gibson, Dunn & Crutcher LLP, counsel for the
         Underwriters, together with signed or reproduced copies of such letter
         for each of the other Underwriters. In giving such opinion such counsel
         may rely, as to all matters governed by the laws of jurisdictions other
         than the law of the State of New York, the federal law of the United
         States and the General Corporation Law of the State of Delaware, upon
         the opinions of counsel satisfactory to the Representatives. In
         rendering such opinion, such counsel may rely as to matters of fact
         (but not as to legal conclusions), to the extent they deem proper, on
         certificates of responsible officers of the Company and its
         subsidiaries and of public officials.

(d)      Officers' Certificate. At the Closing Time, there shall not have been,
         since the date hereof or since the respective dates as of which
         information is given in the Prospectus, any material adverse change in
         the condition, financial or otherwise, in the earnings or business
         affairs of the Company and its subsidiaries considered as one
         enterprise, whether or not arising in the ordinary course of business,
         nor has there been any developments involving a prospective material
         adverse change of the Company and its subsidiaries considered as one
         enterprise, whether or not arising in the ordinary course of business,
         and the Representatives shall have received a certificate of the
         President or a Vice President of the Company and of the chief financial
         or chief accounting officer of

                                       14




         the Company, dated as of the Closing Time, together with signed or
         reproduced copies of such letter for each of the other Underwriters, to
         the effect that (i) there has been no such material adverse change or
         any developments involving a prospective material adverse change, (ii)
         the representations and warranties in Section 1(a) hereof are true and
         correct with the same force and effect as though expressly made at and
         as of the Closing Time, (iii) the Company has complied in all material
         respects with all agreements and satisfied all conditions on its part
         to be performed or satisfied at or prior to the Closing Time, (iv) the
         Company is not in default in the performance of any of the covenants to
         be performed by it under the Indenture, and (v) no stop order
         suspending the effectiveness of the Registration Statement has been
         issued and no proceedings for that purpose have been instituted or are
         pending or, to the knowledge of the Company, are contemplated by the
         Commission.

(e)      Accountant's Comfort Letter. At the time of the execution of this
         Agreement, the Representatives shall have received from Deloitte &
         Touche LLP a letter dated such date, in form and substance satisfactory
         to the Representatives, together with signed or reproduced copies of
         such letter for each of the other Underwriters, containing statements
         and information of the type ordinarily included in accountants'
         "comfort letters" to underwriters with respect to the financial
         statements and certain financial information contained in the
         Registration Statement and the Prospectus.

(f)      Bring-down Comfort Letter. At the Closing Time, the Representatives
         shall have received from Deloitte & Touche LLP a letter, dated as of
         the Closing Time, together with signed or reproduced copies of such
         letter for each of the other Underwriters, to the effect that they
         reaffirm the statements made in the letter furnished pursuant to
         subsection (e) of this Section, except that the specified date referred
         to shall be a date not more than three business days prior to the
         Closing Time.

(g)      Maintenance of Rating. At the Closing Time, the Securities shall be
         rated at least "Baa1" by Moody's and "BBB" by S&P, and the Company
         shall have delivered to the Representatives a letter dated the Closing
         Time, from each such rating agency, or other evidence satisfactory to
         the Representatives, confirming that the Securities have such ratings;
         and since the date of this Agreement, there shall not have occurred a
         downgrading in the rating assigned to the Securities or any of the
         Company's other securities by any "nationally recognized statistical
         rating agency," as that term is defined by the Commission for purposes
         of Rule 436(g)(2) under the 1933 Act, and no such securities rating
         agency shall have publicly announced that it has under surveillance or
         review, with possible negative implications, its rating of the
         Securities or any of the Company's other securities.

(h)      Additional Documents. At the Closing Time, counsel for the Underwriters
         shall have been furnished with such documents and opinions (including
         but not limited to those referenced above) as they may reasonably
         require for the purpose of enabling them to pass upon the issuance and
         sale of the Securities as herein contemplated, or in order to evidence
         the accuracy of any of the representations or warranties, or the
         fulfillment of any of the conditions, herein contained; and all
         proceedings taken by the Company in connection with the issuance and
         sale of the Securities as herein contemplated shall be

                                       15



         reasonably satisfactory in form and substance to the Representatives
         and counsel for the Underwriters.

(i)      Termination of Agreement. If any condition specified in this Section
         shall not have been fulfilled when and as required to be fulfilled,
         this Agreement may be terminated by the Representatives by notice to
         the Company at any time at or prior to the Closing Time, and such
         termination shall be without liability of any party to any other party
         except as provided in Section 4 and except that Sections 1, 6, 7 and 8
         shall survive any such termination and remain in full force and effect.

         SECTION 6. Indemnification.

(a)      Indemnification of Underwriters. The Company agrees to indemnify and
         hold harmless each Underwriter and each person, if any, who controls
         any Underwriter within the meaning of Section 15 of the 1933 Act or
         Section 20 of the 1934 Act as follows:

                  (i)   against any and all loss, liability, claim, damage and
         expense whatsoever, as incurred, arising out of any untrue statement or
         alleged untrue statement of a material fact contained in the
         Registration Statement (or any amendment thereto), or the omission or
         alleged omission therefrom of a material fact required to be stated
         therein or necessary to make the statements therein not misleading or
         arising out of any untrue statement or alleged untrue statement of a
         material fact included in any preliminary prospectus or the Prospectus
         (or any amendment or supplement thereto), or the omission or alleged
         omission therefrom of a material fact necessary in order to make the
         statements therein, in the light of the circumstances under which they
         were made, not misleading;

                  (ii)  against any and all loss, liability, claim, damage and
         expense whatsoever, as incurred, to the extent of the aggregate amount
         paid in settlement of any litigation, or any investigation or
         proceeding by any governmental agency or body, commenced or threatened,
         or of any claim whatsoever based upon any such untrue statement or
         omission, or any such alleged untrue statement or omission; provided
         that (subject to Section 6(d) below) any such settlement is effected
         with the written consent of the Company; and

                  (iii) against any and all expense whatsoever, as incurred
         (including the fees and disbursements of counsel chosen by Merrill
         Lynch), reasonably incurred in investigating, preparing or defending
         against any litigation, or any investigation or proceeding by any
         governmental agency or body, commenced or threatened, or any claim
         whatsoever based upon any such untrue statement or omission, or any
         such alleged untrue statement or omission, to the extent that any such
         expense is not paid under (i) or (ii) above;

provided, however, that this indemnity agreement shall not apply to any loss,
liability, claim, damage or expense to the extent arising out of any untrue
statement or omission or alleged untrue statement or omission made in reliance
upon and in conformity with written information furnished to the Company by any
Underwriter through Merrill Lynch expressly for use in the Registration
Statement (or any amendment thereto) or any preliminary prospectus or the
Prospectus (or any amendment or supplement thereto); and provided, further that
this indemnity agreement shall not inure to the benefit of any Underwriter or
any person who controls such

                                       16



Underwriter on account of any such loss, liability, claim, damage or expense
arising out of any such defect or alleged defect in any preliminary prospectus
if a copy of the Prospectus (exclusive of the documents incorporated by
reference therein) shall not have been given or sent by such Underwriter with or
prior to the written confirmation of the sale involved to the extent that (i)
the Prospectus would have cured such defect or alleged defect and (ii)
sufficient quantities of the Prospectus were timely made available to such
Underwriter.

(b)      Indemnification of Company, Directors and Officers. Each Underwriter
         severally agrees to indemnify and hold harmless the Company, its
         directors, each of its officers who signed the Registration Statement,
         and each person, if any, who controls the Company within the meaning of
         Section 15 of the 1933 Act or Section 20 of the 1934 Act against any
         and all loss, liability, claim, damage and expense described in the
         indemnity contained in subsection (a) of this Section, as incurred, but
         only with respect to untrue statements or omissions, or alleged untrue
         statements or omissions, made in the Registration Statement (or any
         amendment thereto) or any preliminary prospectus or the Prospectus (or
         any amendment or supplement thereto) in reliance upon and in conformity
         with written information furnished to the Company by such Underwriter
         through Merrill Lynch expressly for use in the Registration Statement
         (or any amendment thereto) or such preliminary prospectus or the
         Prospectus (or any amendment or supplement thereto).

(c)      Actions against Parties; Notification. Each indemnified party shall
         give notice as promptly as reasonably practicable to each indemnifying
         party of any action commenced against it in respect of which indemnity
         may be sought hereunder, but failure to so notify an indemnifying party
         shall not relieve such indemnifying party from any liability hereunder
         to the extent it is not materially prejudiced as a result thereof and
         in any event shall not relieve it from any liability which it may have
         otherwise than on account of this indemnity agreement. In the case of
         parties indemnified pursuant to Section 6(a) above, counsel to the
         indemnified parties shall be selected by Merrill Lynch, and, in the
         case of parties indemnified pursuant to Section 6(b) above, counsel to
         the indemnified parties shall be selected by the Company. An
         indemnifying party may participate at its own expense in the defense of
         any such action; provided, however, that counsel to the indemnifying
         party shall not (except with the consent of the indemnified party) also
         be counsel to the indemnified party. In no event shall the indemnifying
         parties be liable for fees and expenses of more than one counsel (in
         addition to any local counsel) separate from their own counsel for all
         indemnified parties in connection with any one action or separate but
         similar or related actions in the same jurisdiction arising out of the
         same general allegations or circumstances. In addition, the
         indemnifying party shall be entitled to, to the extent that it wishes,
         jointly with any other similarly notified indemnifying party, to assume
         the defense of any claim or action brought against an indemnified party
         with counsel reasonably satisfactory to the indemnified party. After
         notice from the indemnifying party to the indemnified party of its
         election to assume the defense of such claim or action, the
         indemnifying party shall not be liable to the indemnified party under
         this Section 6 for any legal or other expenses subsequently incurred by
         the indemnified party in connection with the defense thereof other than
         reasonable costs of investigation; provided, however, that the
         Representatives shall have the right to employ one counsel (in addition
         to local counsel) to represent them and those other Underwriters and
         their respective officers, employees and controlling persons who may be
         subject to liability

                                       17



         arising out of any claim in respect of which indemnity may be sought by
         the Underwriters against the Company under this Section 6 if, in the
         reasonable judgment of the Representatives, either (i) there is an
         actual or potential conflict between the position of the Company on the
         one hand and the Underwriters on the other hand or (ii) there may be
         defenses available to it or them that are different from or additional
         to those available to the Company (in any of which events the Company
         shall not have the right to direct the defense of such action on behalf
         of the Representatives with respect to such different defenses), in any
         of which events such reasonable fees and expenses shall be borne by the
         Company. No indemnifying party shall, without the prior written consent
         of the indemnified parties, settle or compromise or consent to the
         entry of any judgment with respect to any litigation, or any
         investigation or proceeding by any governmental agency or body,
         commenced or threatened, or any claim whatsoever in respect of which
         indemnification or contribution could be sought under this Section 6 or
         Section 7 hereof (whether or not the indemnified parties are actual or
         potential parties thereto), unless such settlement, compromise or
         consent (i) includes an unconditional release of each indemnified party
         from all liability arising out of such litigation, investigation,
         proceeding or claim and (ii) does not include a statement as to or an
         admission of fault, culpability or a failure to act by or on behalf of
         any indemnified party.

(d)      Settlement without Consent if Failure to Reimburse. If at any time an
         indemnified party shall have requested an indemnifying party to
         reimburse the indemnified party for fees and expenses of counsel, such
         indemnifying party agrees that it shall be liable for any settlement of
         the nature contemplated by Section 6(a)(ii) effected without its
         written consent if (i) such settlement is entered into more than 45
         days after receipt by such indemnifying party of the aforesaid request,
         (ii) such indemnifying party shall have received notice of the terms of
         such settlement at least 30 days prior to such settlement being entered
         into and (iii) such indemnifying party shall not have reimbursed such
         indemnified party in accordance with such request prior to the date of
         such settlement.

         SECTION 7. Contribution. If the indemnification provided for in Section
6 hereof is for any reason unavailable to or insufficient to hold harmless an
indemnified party in respect of any losses, liabilities, claims, damages or
expenses referred to therein; then each indemnifying party shall contribute to
the aggregate amount of such losses, liabilities, claims, damages and expenses
incurred by such indemnified party, as incurred, (i) in such proportion as is
appropriate to reflect the relative benefits received by the Company on the one
hand and the Underwriters on the other hand from the offering of the Securities
pursuant to this Agreement or (ii) if the allocation provided by clause (i) is
not permitted by applicable law, in such proportion as is appropriate to reflect
not only the relative benefits referred to in clause (i) above but also the
relative fault of the Company on the one hand and of the Underwriters on the
other hand in connection with the statements or omissions, which resulted in
such losses, liabilities, claims, damages or expenses, as well as any other
relevant equitable considerations.

         The relative benefits received by the Company on the one hand and the
Underwriters on the other hand in connection with the offering of the Securities
pursuant to this Agreement shall be deemed to be in the same respective
proportions as the total net proceeds from the offering of the Securities
pursuant to this Agreement (before deducting expenses) received by the Company
and the total underwriting discount received by the Underwriters, in each case
as set forth on the

                                       18



cover of the Prospectus, bear to the aggregate initial public offering price of
the Securities as set forth on such cover.

         The relative fault of the Company on the one hand and the Underwriters
on the other hand shall be determined by reference to, among other things,
whether any such untrue or alleged untrue statement of a material fact or
omission or alleged omission to state a material fact relates to information
supplied by the Company or by the Underwriters and the parties' relative intent,
knowledge, access to information and opportunity to correct or prevent such
statement or omission.

         The Company and the Underwriters agree that it would not be just and
equitable if contribution pursuant to this Section 7 were determined by pro rata
allocation (even if the Underwriters were treated as one entity for such
purpose) or by any other method of allocation which does not take account of the
equitable considerations referred to above in this Section 7. The aggregate
amount of losses, liabilities, claims, damages and expenses incurred by an
indemnified party and referred to above in this Section 7 shall be deemed to
include any legal or other expenses reasonably incurred by such indemnified
party in investigating, preparing or defending against any litigation, or any
investigation or proceeding by any governmental agency or body, commenced or
threatened, or any claim whatsoever based upon any such untrue or alleged untrue
statement or omission or alleged omission.

         Notwithstanding the provisions of this Section 7, no Underwriter shall
be required to contribute any amount in excess of the amount by which the total
price at which the Securities underwritten by it and distributed to the public
were offered to the public exceeds the amount of any damages which such
Underwriter has otherwise been required to pay by reason of any such untrue or
alleged untrue statement or omission or alleged omission.

         No person guilty of fraudulent misrepresentation (within the meaning of
Section 11(f) of the 1933 Act) shall be entitled to contribution from any person
who was not guilty of such fraudulent misrepresentation.

         For purposes of this Section 7, each person, if any, who controls an
Underwriter within the meaning of Section 15 of the 1933 Act or Section 20 of
the 1934 Act shall have the same rights to contribution as such Underwriter, and
each director of the Company, each officer of the Company who signed the
Registration Statement, and each person, if any, who controls the Company within
the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act shall
have the same rights to contribution as the Company. The Underwriters'
respective obligations to contribute pursuant to this Section 7 are several in
proportion to the principal amount of Securities set forth opposite their
respective names in Schedule A hereto and not joint.

                                       19



         SECTION 8. Representations, Warranties and Agreements to Survive
Delivery. All representations, warranties and agreements contained in this
Agreement or in certificates of officers of the Company or any of its
subsidiaries submitted pursuant hereto, shall remain operative and in full force
and effect, regardless of any investigation made by or on behalf of any
Underwriter or controlling person, or by or on behalf of the Company, and shall
survive delivery of and payment for the Securities to the Underwriters.

         SECTION 9. Termination of Agreement.

(a)      Termination; General. The Representatives may terminate this Agreement,
         by notice to the Company, at any time at or prior to the Closing Time
         (i) if there has been, since the time of execution of this Agreement or
         since the respective dates as of which information is given in the
         Prospectus (exclusive of any supplement thereto), any material adverse
         change in the condition, financial or otherwise, in the earnings or
         business affairs of the Company and its subsidiaries considered as one
         enterprise, whether or not arising in the ordinary course of business,
         or any developments involving a prospective material adverse change of
         the Company and its subsidiaries considered as one enterprise, whether
         or not arising in the ordinary course of business, or (ii) if there has
         occurred after the date hereof and prior to the Closing Time any
         material adverse change in the financial markets in the United States
         or the international financial markets, any outbreak of hostilities or
         escalation thereof or other calamity or crisis or any change or
         development involving a prospective change in national or international
         political, financial or economic conditions, in each case the effect of
         which is such as to make it, in the reasonable judgment of the
         Representatives, impracticable to market the Securities or to enforce
         contracts for the sale of the Securities, or (iii) if trading in any
         securities of the Company or the Parent has been suspended or
         materially limited by the Commission or the New York Stock Exchange, or
         if trading generally on the American Stock Exchange or the New York
         Stock Exchange or the Nasdaq National Market has been suspended or
         materially limited, or minimum or maximum prices for trading have been
         fixed, or maximum ranges for prices have been required, by any of said
         exchanges or by such system or by order of the Commission, the National
         Association of Securities Dealers, Inc. or any other governmental
         authority, or (iv) if a banking moratorium has been declared by either
         Federal or New York authorities.

(b)      Liabilities. If this Agreement is terminated pursuant to this Section,
         such termination shall be without liability of any party to any other
         party except as provided in Section 4 hereof, and provided further that
         Sections 1, 6, 7 and 8 shall survive such termination and remain in
         full force and effect.

                                       20



         SECTION 10. Default by One or More of the Underwriters. If one or more
of the Underwriters shall fail at the Closing Time to purchase the Securities
which it or they are obligated to purchase under this Agreement (the "Defaulted
Securities"), the Representatives shall have the right, within 24 hours
thereafter, to make arrangements for one or more of the non-defaulting
Underwriters, or any other underwriters, to purchase all, but not less than all,
of the Defaulted Securities in such amounts as may be agreed upon and upon the
terms herein set forth; if, however, the Representatives shall not have
completed such arrangements within such 24-hour period, then:

(a)      if the aggregate principal amount of Defaulted Securities does not
         exceed 10% of the aggregate principal amount of Securities to be
         purchased on such date, each of the non-defaulting Underwriters shall
         be obligated, severally and not jointly, to purchase the full amount
         thereof in the proportions that their respective underwriting
         obligations hereunder bear to the underwriting obligations of all
         non-defaulting Underwriters, or

(b)      if the aggregate principal amount of Defaulted Securities exceeds 10%
         of the aggregate principal amount of Securities to be purchased on such
         date, this Agreement shall terminate without liability on the part of
         any non-defaulting Underwriter.

         No action taken pursuant to this Section shall relieve any defaulting
Underwriter from liability in respect of its default.

         In the event of any such default which does not result in a termination
of this Agreement, either the Representatives or the Company shall have the
right to postpone the Closing Time for a period not exceeding seven days in
order to effect any required changes in the Registration Statement or Prospectus
or in any other documents or arrangements. As used herein, the term
"Underwriter" includes any person substituted for an Underwriter under this
Section 10.

         SECTION 11 Tax Disclosure. Notwithstanding any other provision of this
Agreement, immediately upon commencement of discussions with respect to the
transactions contemplated hereby, the Company (and each employee, representative
or other agent of the Company) may disclose to any and all persons, without
limitation of any kind, the tax treatment and tax structure of the transactions
contemplated by this Agreement and all materials of any kind (including opinions
or other tax analyses) that are provided to the Company relating to such tax
treatment and tax structure. For purposes of the foregoing, the term "tax
treatment" is the purported or claimed federal income tax treatment of the
transactions contemplated hereby, and the term "tax structure" includes any fact
that may be relevant to understanding the purported or claimed federal income
tax treatment of the transactions contemplated hereby.

         SECTION 12 Notices. All notices and other communications hereunder
shall be in writing and shall be deemed to have been duly given if mailed or
transmitted by any standard form of telecommunication. Notices to the
Underwriters shall be directed to the Representatives at 4 World Financial
Center, New York, New York 10080, attention of Karl Fritz Schlopy; and notices
to the Company shall be directed to it at 4902 North Biltmore Lane, Madison,
Wisconsin, 53718, attention of Thomas L. Hanson.

                                       21



         SECTION 13. Parties. This Agreement shall each inure to the benefit of
and be binding upon the Underwriters and the Company and their respective
successors. Nothing expressed or mentioned in this Agreement is intended or
shall be construed to give any person, firm or corporation, other than the
Underwriters and the Company and their respective successors and the controlling
persons and officers and directors referred to in Sections 6 and 7 and their
heirs and legal representatives, any legal or equitable right, remedy or claim
under or in respect of this Agreement or any provision herein contained. This
Agreement and all conditions and provisions hereof are intended to be for the
sole and exclusive benefit of the Underwriters and the Company and their
respective successors, and said controlling persons and officers and directors
and their heirs and legal representatives, and for the benefit of no other
person, firm or corporation. No purchaser of Securities from any Underwriter
shall be deemed to be a successor by reason merely of such purchase.

         SECTION 14. GOVERNING LAW AND TIME. THIS AGREEMENT AND ALL DISPUTES,
CONTROVERSIES OR CLAIMS ARISING OUT OF OR RELATING TO THIS AGREEMENT OR A BREACH
HEREOF SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE
STATE OF NEW YORK. EXCEPT AS OTHERWISE SET FORTH HEREIN, SPECIFIED TIMES OF DAY
REFER TO NEW YORK CITY TIME.

         SECTION 15. Effect of Headings. The Article and Section headings herein
and the Table of Contents are for convenience only and shall not affect the
construction hereof.

         SECTION 16. Counterparts. This Agreement may be executed in one or more
counterparts and, if executed in more than one counterpart, the executed
counterparts shall constitute a single instrument.

                                       22



         If the foregoing is in accordance with your understanding of our
agreement, please sign and return to the Company a counterpart hereof, whereupon
this instrument, along with all counterparts, will become a binding agreement
between the Underwriters and the Company in accordance with its terms.

                                           Very truly yours,

                                           INTERSTATE POWER AND LIGHT COMPANY

                                           By:  /s/ Thomas L. Hanson
                                                --------------------------------
                                                Thomas L. Hanson
                                                Vice President and Treasurer

CONFIRMED AND ACCEPTED,
   as of the date first above written:

MERRILL LYNCH & CO.
MERRILL LYNCH, PIERCE, FENNER & SMITH INCORPORATED
By: MERRILL LYNCH, PIERCE, FENNER & SMITH
           INCORPORATED

By:  /s/ Karl F. Schlopy, Director
     -------------------------------
           Authorized Signatory

BARCLAYS CAPITAL INC.


By:  /s/ Pamela Kendall
     -------------------------------
           Authorized Signatory

For themselves and as Representatives of the other Underwriters named in
Schedule A hereto.

                                       23



                                   SCHEDULE A

         Name of Underwriter                                       Principal
         -------------------                                       amount of
                                                                   Securities
                                                                   ----------

Merrill Lynch, Pierce, Fenner & Smith Incorporated .............  $ 45,000,000
Barclays Capital Inc. ..........................................  $ 30,000,000
Banc One Capital Markets, Inc. .................................  $ 11,000,000
Wachovia Capital Markets, LLC ..................................  $ 11,000,000
Utendahl Capital Partners, L.P .................................  $  3,000,000

                                                                  ------------
Total ..........................................................  $100,000,000
                                                                  ============



                                   SCHEDULE B

                       INTERSTATE POWER AND LIGHT COMPANY
                              (an Iowa corporation)

                        5.875% SENIOR DEBENTURES DUE 2018

         1. The initial public offering price of the Securities shall be 99.440%
of the principal amount thereof, plus accrued interest, if any, from the date of
issuance.

         2. The purchase price to be paid by the Underwriters for the Securities
shall be 98.690% of the principal amount thereof.

         3. The interest rate on the Securities shall be 5.875% per annum.

         4. The Company may redeem the Securities at any time at its option, in
whole or in part, at a redemption price equal to the sum of the principal amount
of the Securities to be redeemed, accrued interest on that principal amount to
the redemption date and the make-whole amount, if any, with respect to the
Securities to be redeemed. This sum is referred to as the redemption price.

         "Make-whole amount" means, in connection with the optional redemption,
the excess, if any, of:

         .   the aggregate present value as of the date of any optional
             redemption of each dollar of principal being redeemed and the
             amount of interest, exclusive of interest accrued to the date of
             redemption, that would have been payable in respect of such dollar
             of principal if such redemption had not been made, determined by
             discounting, on a semi-annual basis, such principal and interest at
             the reinvestment rate, as determined on the third business day
             preceding the date that notice of the redemption is given, from the
             respective dates on which such principal and interest would have
             been payable if such redemption had not been made, over

         .   the aggregate principal amount of the Securities being redeemed.

         "Reinvestment rate" means 0.30% plus the arithmetic mean of the yields
under the headings "Week Ending" published in the most recent statistical
release under the caption "Treasury Constant Maturities" for the maturity,
rounded to the nearest month, corresponding to the remaining life to maturity,
as of the payment date of the principal being redeemed. If no maturity exactly
corresponds to such maturity, yields for the two published maturities most
closely corresponding to such maturity will be calculated pursuant to the
immediately preceding sentence and the reinvestment rate will be interpolated or
extrapolated from such yields on a straight-line basis, rounding in each of the
relevant periods to the nearest month. For purposes of calculating the
reinvestment rate, the most recent statistical release published prior to the
date of determination of the make-whole amount will be used.



         "Statistical release" means the statistical release designated
"H.15(519)" or any successor publication which is published weekly by the
Federal Reserve System and which establishes yields on actively traded United
States government securities adjusted to constant maturities or, if such
statistical release is not published at the time of any determination, then such
other reasonably comparable index which shall be designated by the Company.