Execution Copy



                          FIRST SUPPLEMENTAL INDENTURE


                          DATED AS OF NOVEMBER 4, 1999





                         ALLIANT ENERGY RESOURCES, INC.,
                                    Company,


                           ALLIANT ENERGY CORPORATION,
                                  As Guarantor

                                       and

                               FIRSTAR BANK, N.A.,
                                   as Trustee




                       First Supplemental Indenture to the
                                    Indenture
                          dated as of November 4, 1999


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          FIRST  SUPPLEMENTAL  INDENTURE,  dated as of  November  4,  1999  (the
"Supplemental  Indenture"),  among ALLIANT ENERGY  RESOURCES,  INC., a Wisconsin
corporation   (the   "Company"),   ALLIANT  ENERGY   CORPORATION,   a  Wisconsin
corporation, as guarantor (the "Guarantor"),  and FIRSTAR BANK, N.A., as Trustee
(the "Trustee").

                    RECITALS OF THE COMPANY AND THE GUARANTOR

          The Company and the Guarantor have  heretofore  executed and delivered
to the Trustee an Indenture,  dated as of November 4, 1999 (as  supplemented and
amended from time to time,  the  "Indenture"),  providing  for the issuance from
time to time of the  Company's  unsecured  unsubordinated  debentures,  notes or
other evidences of indebtedness (the "Securities"),  to be issued in one or more
series as provided in the Indenture.

          It is provided in Section 2.02 of the Indenture that the Company,  the
Guarantor  and the Trustee  may enter into  indentures  supplemental  thereto to
establish the form or terms of Securities of any series.

          The  Company  and the  Guarantor  desire to  supplement  and amend the
Indenture to allow for the issuance of  Securities  to be initially  sold within
the United States to U.S.  Persons that are Qualified  Institutional  Buyers and
Institutional  Accredited  Investors  and  issued  in the  form  of one or  more
Restricted  Global Securities  deposited with the Trustee,  as custodian for the
Depositary,  and  registered  in the name of a nominee  of the  Depositary,  and
Restricted Physical Securities.

          The Company and the  Guarantor  desire to set forth the terms and form
of a new series of  Restricted  Securities  to be known as the  Company's 7 3/8%
Senior Notes Due 2009, in an aggregate principal amount of TWO HUNDRED AND FIFTY
MILLION DOLLARS ($250,000,000) (the "7 3/8% Senior Notes" or the "Senior Notes")
and guaranteed by the Guarantor.

          The 7 3/8% Senior Notes and the  certificate of  authentication  to be
borne by the 7 3/8% Senior Notes are to be  substantially  in the form set forth
in Exhibit A hereto.

          NOW, THEREFORE, THIS SUPPLEMENTAL INDENTURE WITNESSETH:

          For and in  consideration  of the  premises  and the purchase of the 7
3/8% Senior  Notes by the Holders (as defined  herein)  thereof,  it is mutually
covenanted  and

<PAGE>

agreed as follows for the equal and ratable benefit of the Holders of the 7 3/8%
Senior Notes:

                                   ARTICLE 1.

                                   AMENDMENTS

          Section 1.01. Article 1 of the Indenture shall be amended by inserting
in Section 1.01 the following new terms with the  following  definitions  in the
appropriate alphabetic positions:

          "Additional Interest" has the meaning set forth in Section 2.06 of the
Supplemental Indenture.

          "Closing  Time"  means,  with  respect  to  the 7 3/8%  Senior  Notes,
November  9,  1999,  the  date of  initial  issuance  of the  Securities  issued
hereunder.

          "Comparable  Treasury Issue" has the meaning set forth in Section 2.07
of the Supplemental Indenture.

          "Comparable  Treasury Price" has the meaning set forth in Section 2.07
of the Supplemental Indenture.

          "Depositary" means The Depositary Trust Company of New York City.

          "Event  Date"  has  the  meaning  set  forth  in  Section  2.06 of the
Supplemental Indenture.

          "Exchange  Certificate" means a certificate  substantially in the form
of Exhibit C hereto, as such form may be revised or modified with respect to any
series of Securities  by a Board  Resolution  or indenture  supplemental  hereto
creating such series.

          "Exchange  Securities"  means Securities that are issued and exchanged
for any series of Restricted Securities in accordance with an Exchange Offer, as
provided for in a registration  rights agreement related to such series and this
Indenture, containing substantially identical terms as such series of Restricted
Securities,  except that (i) such  Exchange  Securities  shall not contain terms
with  respect  to  transfer  restrictions  and shall be issued in a  transaction
registered under the Securities Act and (ii) certain  provisions  relating to an
increase in the stated rate of interest thereon shall be eliminated.


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<PAGE>

          "Exchange  Offer"  means an offer by the  Company  to  Holders  of any
series of Restricted  Securities to exchange all of such  Restricted  Securities
for  Exchange  Securities,  as  provided  for in a related  registration  rights
agreement.

          "Exchange  Offer  Registration  Statement"  means  an  exchange  offer
registration  statement on Form S-4 (or, if applicable,  on another  appropriate
form), and all amendments and supplements to such  registration  statement,  all
exhibits thereto and all documents incorporated by reference therein.

          "IAI Letter"  means a Letter for  Institutional  Accredited  Investors
which must be signed by each such investor attached hereto as Exhibit D.

          "Independent  Investment  Banker" has the meaning set forth in Section
2.07 of the Supplemental Indenture.

          "Institutional  Accredited Investor" means an institutional accredited
investor  within  the  meaning  of  Rule  501(a)(1),  (2),  (3),  and (7) of the
Regulation D under the Securities Act.

          "Qualified   Institutional   Buyer"  or  "QIB"   means  a   "qualified
institutional buyer" as such term is defined in Rule 144A.

          "Reference  Treasury Dealer" has the meaning set forth in Section 2.07
of the Supplemental Indenture.

          "Reference  Treasury  Dealer  Quotation"  has the meaning set forth in
Section 2.07 of the Supplemental Indenture.

          "Registration  Default"  has the meaning set forth in Section  2.06 of
the Supplemental Indenture.

          "Registration  Rights  Agreement"  means,  with  respect to the 7 3/8%
Senior Notes,  the  Registration  Rights Agreement dated as of November 9, 1999,
among the Company, the Guarantor and Merrill Lynch & Co., Merrill Lynch, Pierce,
Fenner & Smith Incorporated,  Morgan Stanley & Co.  Incorporated,  Salomon Smith
Barney  Inc.,  ABN Amro  Incorporated  and  Barclays  Capital  Inc.,  as initial
purchasers.

          "Restricted  Global Security" means any Restricted  Security that is a
Global Security.

          "Restricted  Physical  Security"  means  any  Restricted  Security  in
permanent certificated form.


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<PAGE>


          "Restricted  Security"  means  any  Security  issued  pursuant  to  an
exemption from the Securities Act and bearing a Restrictive Legend.

          "Restrictive  Legend" has the meaning set forth in Section 2.19 of the
Indenture.

          "Rule 144A" means Rule 144A under the Securities Act.

          "Securities Act" means the Securities Act of 1933, as amended.

          "Shelf  Registration  Statement"  means, with respect to any series of
Restricted  Securities,  the  Shelf  Registration  Statement  specified  in  the
registration rights agreement related to such series.

          "Supplemental  Indenture" means the First Supplemental Indenture dated
as of November 9, 1999 among the Company, the Guarantor and the Trustee.

          "Transfer  Certificate" means a certificate  substantially in the form
of Exhibit B hereto and to be  attached  as Annex A to the Form of 7 3/8% Senior
Notes,  as such form may be varied or  modified  with  respect  to any series of
Securities by a Board Resolution or indenture supplemental hereto.

          "Treasury  Yield" has the  meaning  set forth in  Section  2.07 of the
Supplemental Indenture.

          "7 3/8% Senior Notes" has the meaning set forth in Section 2.01 of the
Supplemental Indenture.

          Section 1.02. Article 2 of the Indenture shall be amended by adding to
the end of Section 2.15 the following:

                    "Securities  offered and sold in reliance on Rule 144A under
          the  Securities Act may be issued in the form of one or more permanent
          Global Securities in substantially the form set forth in Exhibit A and
          containing  the legend set forth in Section 2.19 (each,  a "Restricted
          Global Security"),  deposited with the Depositary or with the Trustee,
          as custodian for the  Depositary or its nominee,  duly executed by the
          Company  and  authenticated  by the  Trustee as herein  provided.  The
          aggregate  principal  amount of a Restricted  Global Security may from
          time to time be  increased or  decreased  by  adjustments  made on the
          records  of the  Depositary  or the  Trustee,  as  custodian  for  the
          Depositary or its nominee, as hereinafter provided.


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<PAGE>


                    Restricted  Securities  issued to  Institutional  Accredited
          Investors  and  pursuant to Sections  2.08 and 2.20 in exchange for or
          upon transfer of beneficial  interests in a Restricted Global Security
          may be in the form of Restricted  Physical  Securities  containing the
          Restrictive  Legend  as set  forth  in  Section  2.19  (a  "Restricted
          Physical  Security")  until such time as the  conditions  set forth in
          Section 2.19 are  satisfied,  in  substantially  the form set forth in
          Exhibit A, as provided in Section 2.20.

                    Exchange  Securities  shall be issued in  substantially  the
          form set forth in Exhibit A, but without any Restrictive Legend."

          Section 1.03. Article 2 of the Indenture shall be amended by adding to
the end of such Article the following:

                    "Section 2.19.  RESTRICTIVE LEGENDS.  Unless and until (i) a
          Restricted   Security  is  sold   pursuant  to  an   effective   Shelf
          Registration  Statement or (ii) a Restricted Security is exchanged for
          an Exchange  Security in an Exchange  Offer  pursuant to an  effective
          Exchange  Offer  Registration  Statement,  in each case pursuant to an
          applicable  registration  rights  agreement,  each  Restricted  Global
          Security and  Restricted  Physical  Security  shall bear the following
          legend set forth below (the "Restrictive Legend") on the face thereof:

                              THE  NOTES  HAVE NOT  BEEN  REGISTERED  UNDER  THE
                    SECURITIES ACT OF 1933, AS AMENDED (THE  "SECURITIES  ACT"),
                    OR ANY STATE OR OTHER SECURITIES LAWS. NEITHER THIS NOTE NOR
                    ANY INTEREST OR PARTICIPATION HEREIN MAY BE REOFFERED, SOLD,
                    ASSIGNED,  TRANSFERRED,  PLEDGED,  ENCUMBERED  OR  OTHERWISE
                    DISPOSED  OF IN THE ABSENCE OF SUCH  REGISTRATION  OR UNLESS
                    THE  TRANSACTION  IS EXEMPT  FROM,  OR NOT  SUBJECT  TO, THE
                    REGISTRATION  REQUIREMENTS  OF THE  SECURITIES  ACT.  BY ITS
                    ACQUISITION HEREOF, THE HOLDER (1) REPRESENTS THAT (A) IT IS
                    A "QUALIFIED  INSTITUTIONAL  BUYER" (AS DEFINED IN RULE 144A
                    ("RULE  144A")  UNDER  THE  SECURITIES  ACT) OR (B) IT IS AN
                    INSTITUTIONAL  "ACCREDITED  INVESTOR"  WITHIN THE MEANING OF
                    SUBPARAGRAPHS (A)(1), (2), (3), OR (7) OF RULE 501 UNDER THE
                    SECURITIES  ACT  THAT IS  ACQUIRING  THIS  NOTE  FOR ITS OWN
                    ACCOUNT OR FOR THE ACCOUNT OF SUCH INSTITUTIONAL  ACCREDITED
                    INVESTOR FOR INVESTMENT  PURPOSES AND NOT WITH A VIEW TO, OR
                    FOR OFFER OR SALE IN CONNECTION  WITH, ANY  DISTRIBUTION  IN


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<PAGE>


                    VIOLATION  OF THE  SECURITIES  ACT, (2) AGREES NOT TO OFFER,
                    SELL OR OTHERWISE  TRANSFER  THIS NOTE PRIOR TO (X) THE DATE
                    WHICH  IS TWO  YEARS  (OR  SUCH  SHORTER  PERIOD  OF TIME AS
                    PERMITTED BY RULE 144(K) UNDER THE SECURITIES ACT) AFTER THE
                    LATER OF THE  ORIGINAL  ISSUE DATE OF THE NOTES AND THE LAST
                    DATE  ON  WHICH  ALLIANT  ENERGY  RESOURCES,   INC.  OR  ANY
                    "AFFILIATE"  (AS  DEFINED  IN RULE 144 UNDER THE  SECURITIES
                    ACT) OF ALLIANT ENERGY RESOURCES, INC. WAS THE OWNER OF THIS
                    NOTE (OR ANY  PREDECESSOR  OF THIS  NOTE) OR (Y) SUCH  LATER
                    DATE,  IF ANY,  AS MAY BE REQUIRED  BY  APPLICABLE  LAW (THE
                    "RESALE RESTRICTION TERMINATION DATE") EXCEPT (A) TO ALLIANT
                    ENERGY  RESOURCES,  INC.,  (B)  PURSUANT  TO A  REGISTRATION
                    STATEMENT  THAT  HAS  BEEN  DECLARED   EFFECTIVE  UNDER  THE
                    SECURITIES  ACT,  (C)  FOR SO  LONG  AS THE  SECURITIES  ARE
                    ELIGIBLE  FOR RESALE  PURSUANT TO RULE 144A,  TO A PERSON IT
                    REASONABLY BELIEVES IS A "QUALIFIED  INSTITUTIONAL BUYER" AS
                    DEFINED IN RULE 144A THAT  PURCHASES  FOR ITS OWN ACCOUNT OR
                    FOR THE ACCOUNT OF A QUALIFIED  INSTITUTIONAL BUYER, IN EACH
                    CASE TO WHOM NOTICE IS GIVEN THAT THE TRANSFER IS BEING MADE
                    IN   RELIANCE  ON  RULE  144A,   (D)  TO  AN   INSTITUTIONAL
                    "ACCREDITED  INVESTOR"  WITHIN THE MEANING OF  SUBPARAGRAPHS
                    (a)(1), (2), (3) OR (7) OF RULE 501 UNDER THE SECURITIES ACT
                    THAT IS  ACQUIRING  THIS NOTE FOR ITS OWN ACCOUNT OR FOR THE
                    ACCOUNT OF SUCH AN  INSTITUTIONAL  ACCREDITED  INVESTOR  FOR
                    INVESTMENT PURPOSES AND NOT WITH A VIEW TO, OR OFFER OR SALE
                    IN CONNECTION  WITH,  ANY  DISTRIBUTION  IN VIOLATION OF THE
                    SECURITIES   ACT  OR  (E)  PURSUANT  TO  ANOTHER   AVAILABLE
                    EXEMPTION  FROM  THE   REGISTRATION   REQUIREMENTS   OF  THE
                    SECURITIES ACT SUBJECT IN EACH OF THE FOREGOING CASES OF ANY
                    REQUIREMENT  OF LAW THAT THE  DISPOSITION OF ITS PROPERTY OR
                    THE PROPERTY OF SUCH INVESTOR  ACCOUNT OR ACCOUNTS BE AT ALL
                    TIMES  WITHIN ITS OR THEIR  CONTROL,  AND (3) AGREES THAT IT
                    WILL GIVE TO EACH PERSON TO WHOM THIS NOTE IS  TRANSFERRED A
                    NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND;  PROVIDED
                    THAT ALLIANT  ENERGY  RESOURCES,  INC. AND THE TRUSTEE SHALL
                    HAVE THE RIGHT PRIOR TO ANY SUCH


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<PAGE>


                    OFFER, SALE OR TRANSFER (I) PURSUANT TO CLAUSE (D) OR (E) TO
                    REQUIRE THE DELIVERY OF AN OPINION OF COUNSEL, CERTIFICATION
                    AND/OR OTHER  INFORMATION  SATISFACTORY TO EACH OF THEM, AND
                    (II) IN EACH OF THE FOREGOING  CASES,  BUT ONLY IF THIS NOTE
                    IS NOT A  GLOBAL  SECURITY  (AS  DEFINED  IN  THE  INDENTURE
                    REFERRED  TO HEREIN),  TO REQUIRE  THAT A  CERTIFICATION  OF
                    TRANSFER  IN THE FORM  APPEARING  ON THE OTHER  SIDE OF THIS
                    NOTE IS COMPLETED AND DELIVERED BY THE TRANSFEROR TO ALLIANT
                    ENERGY RESOURCES,  INC. AND THE TRUSTEE. THIS LEGEND WILL BE
                    REMOVED  UPON THE  REQUEST  OF THE  HOLDER  AFTER THE RESALE
                    RESTRICTION TERMINATION DATE.

          Section 1.04.  Article 2 of the  Indenture  shall be amended by adding
the following to the end of Section 2.08:

                    "Any Physical Security delivered in exchange for an interest
          in the  Global  Security  pursuant  to this  Section  shall  bear  the
          Restrictive  Legend  unless  such  exchange  is made on or after (i) a
          Restricted  Security  is  exchanged  for an  Exchange  Security  in an
          Exchange  Offer  under  an  effective   Exchange  Offer   Registration
          Statement, (ii) a Restricted Security is sold under an effective Shelf
          Registration  Statement  or (iii)  two  years  after  the later of the
          original  issue  date of a  Restricted  Security  and the last date on
          which the  Company or any  affiliate  of the  Company was the owner of
          such Restricted Security (the "Resale  Restriction  Termination Date")
          and except as otherwise provided in Section 2.20."

          Section 1.05.  Article 2 of the  Indenture  shall be amended by adding
the following to the end of such Article:

                    "Section 2.20. TRANSFER  PROVISIONS.  Unless and until (i) a
          Restricted  Security  is  exchanged  for an  Exchange  Security  in an
          Exchange  Offer  under  an  effective   Exchange  Offer   Registration
          Statement  or  (ii) a  Restricted  Security  is  sold  pursuant  to an
          effective Shelf Registration Statement, the following provisions shall
          apply:

                    (a) The  provisions  of this Section 2.20 shall apply to all
          transfers   involving  any  Restricted   Physical   Security  and  any
          beneficial interest in any Restricted Global Security.


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<PAGE>

                    (b) As used in  this  Section  2.20  only,  "delivery"  of a
          certificate  by a transferee or  transferor  means the delivery to the
          Registrar  by  such   transferee  or  transferor  of  the   applicable
          certificate  duly completed;  "holding"  includes both possession of a
          Physical  Security and ownership of a beneficial  interest in a Global
          Security,  as the context  requires;  "transferring" a Global Security
          means  transferring  that  portion  of  the  principal  amount  of the
          transferor's  beneficial  interest  therein  that the  transferor  has
          notified  the   Registrar   that  it  has  agreed  to  transfer;   and
          "transferring" a Physical Security means  transferring that portion of
          the  principal  amount  thereof that the  transferor  has notified the
          Registrar that it has agreed to transfer.

                    As used in this  Indenture,  "Non-Registration  Opinion  and
          Supporting  Evidence"  means a written  Opinion of Counsel  reasonably
          acceptable  to  the  Company  to  the  effect  that,  and  such  other
          certification or information as the Company may reasonably  require to
          confirm  that,  the  proposed  transfer  is being made  pursuant to an
          exemption from, or in a transaction  not subject to, the  registration
          requirements of the Securities Act.

                    (c) An  Exchange  Certificate,  if not  actually  delivered,
          shall  be  deemed  delivered  if (i) (A) the  transferor  advises  the
          Company and the Trustee in writing  that the  relevant  offer and sale
          were  made in  accordance  with the  provisions  of Rule 144A or to an
          Institutional  Accredited  Investor that is acquiring the Security for
          its own account or for the account of such an Institutional Accredited
          Investor for investment  purposes and not with a view to, or for offer
          or sale in  connection  with,  any  distribution  in  violation of the
          Securities Act (or, in the case of a transfer of a Restricted Physical
          Security,  the transferor  checks the box provided on such Security to
          that  effect)  and (B) the  transferee  advises  the  Company  and the
          Trustee in writing  that (x) it and, if  applicable,  each account for
          which it is acting in  connection  with the  relevant  transfer,  is a
          "Qualified  Institutional  Buyer,"  or  an  "Institutional  Accredited
          Investor," (y) it is aware that the transfer of Restricted  Securities
          to it is being made in reliance on the exemption  from the  provisions
          of  Section  5 of  the  Securities  Act  provided  by  Rule  144A  and
          Regulation  D and (z) prior to the  proposed  date of  transfer it has
          been given the  opportunity to obtain from the Company the information
          referred  to  in  Rule  144A(d)(4),   and  has  either  declined  such
          opportunity  or has received  such  information  (or, in the case of a
          transfer of a Restricted  Physical Security,  the transferee signs the
          certification  provided on the such Security to that effect);  or (ii)
          the   transferor   holds  the  Restricted   Global   Security  and  is
          transferring  to a transferee  that shall take delivery in the form of
          the Restricted Global Security.


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<PAGE>


                    (d) If the proposed transferor holds:

                              (1)  a  Restricted   Physical  Security  which  is
                    surrendered to the Registrar, and the proposed transferee or
                    transferor, as applicable:

                                        (A)  delivers  (or  is  deemed  to  have
                              delivered   pursuant   to  clause  (c)  above)  an
                              Exchange  Certificate and the proposed  transferee
                              requests  delivery  in the  form  of a  Restricted
                              Physical  Security,  then the Registrar  shall (x)
                              register   such  transfer  in  the  name  of  such
                              transferee  and  record  the date  thereof  in its
                              books and  records,  (y) cancel  such  surrendered
                              Restricted Physical Security and (z) deliver a new
                              Restricted  Physical  Security to such  transferee
                              duly  registered in the name of such transferee in
                              principal  amount  equal to the  principal  amount
                              being  transferred of such surrendered  Restricted
                              Physical Security; or

                                        (B)  delivers  (or  is  deemed  to  have
                              delivered   pursuant   to  clause  (c)  above)  an
                              Exchange  Certificate and the proposed  transferee
                              is or is  acting  through a  participant  with the
                              Depositary   and   requests   that  the   proposed
                              transferee  receive a  beneficial  interest in the
                              Restricted  Global  Security,  then the  Registrar
                              shall  (x)  cancel  such  surrendered   Restricted
                              Physical  Security,  (y) record an increase in the
                              principal  amount of the Global  Security equal to
                              the  principal  amount being  transferred  of such
                              surrendered  Restricted  Physical Security and (z)
                              notify  the  Depositary  in  accordance  with  the
                              procedures of the Depositary  that it has effected
                              such transfer.

                              In any of the  cases  described  in  this  Section
                    2.20(d)(1),  the Registrar shall deliver to the transferor a
                    new Restricted  Physical  Security in principal amount equal
                    to the  principal  amount  not  being  transferred  of  such
                    surrendered Restricted Physical Security, as applicable.

                              (2) a beneficial  interest in a Restricted  Global
                    Security,  and the proposed  transferee  or  transferor,  as
                    applicable:

                                        (A)  delivers  (or  is  deemed  to  have
                              delivered   pursuant   to  clause  (c)  above)  an
                              Exchange  Certificate and the proposed  transferee
                              requests  delivery  in the  form  of a  Restricted
                              Physical  Security,  then the Registrar  shall (w)
                              register   such  transfer  in  the  name  of  such
                              transferee  and  record  the date  thereof  in its


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<PAGE>


                              books and  records,  (x) record a decrease  in the
                              principal amount of the Restricted Global Security
                              in an  amount  equal  to the  beneficial  interest
                              therein  being  transferred,  (y)  deliver  a  new
                              Restricted  Physical  Security to such  transferee
                              duly  registered in the name of such transferee in
                              principal  amount  equal  to the  amount  of  such
                              decrease   and  (z)  notify  the   Depositary   in
                              accordance  with the  procedures of the Depositary
                              that it has effected such transfer; or

                                        (B)  delivers  (or  is  deemed  to  have
                              delivered   pursuant   to  clause  (c)  above)  an
                              Exchange  Certificate and the proposed  transferee
                              is or is  acting  through a  participant  with the
                              Depositary   and   requests   that  the   proposed
                              transferee  receive a  beneficial  interest in the
                              Restricted  Global  Security,  then  the  transfer
                              shall  be   effected   in   accordance   with  the
                              procedures of the Depositary therefor.

                              (e) In any case in which the Registrar is required
                    to deliver a Restricted Physical Security to a transferee or
                    transferor,  the Company shall execute,  the Guarantor shall
                    guarantee  and  the  Trustee  shall  authenticate  and  make
                    available for delivery, such Restricted Physical Security.

                              (f)  Any   transferee   entitled   to   receive  a
                    Restricted  Physical Security may request that the principal
                    amount  thereof  be  evidenced  by  one or  more  Restricted
                    Physical  Securities  in  any  authorized   denomination  or
                    denominations  and the  Registrar  shall  comply  with  such
                    request if all other transfer restrictions are satisfied.

                              (g) The  Registrar  shall effect and record,  upon
                    receipt  of a  written  request  from  the  Company  or  the
                    Guarantor  so to do, a transfer not  otherwise  permitted by
                    Section  2.20(d),  such  recording to be done in  accordance
                    with the otherwise applicable provisions of Section 2.20(d),
                    upon the furnishing by the proposed transferor or transferee
                    of a Non-Registration Opinion and Supporting Evidence.

                              (h) By its acceptance of any Security  bearing the
                    Restrictive   Legend,   each   Holder   of   such   Security
                    acknowledges  the  restrictions on transfer of such Security
                    set forth in this  Indenture and in the  Restrictive  Legend
                    and agrees  that it shall  transfer  such  Security  only as
                    provided in this Indenture. The Registrar shall not register
                    a transfer of any  Security  unless such  transfer  complies
                    with the restrictions with respect thereto set forth in this
                    Indenture.  The Registrar shall not be required to determine
                    (but may rely upon a determination made by the


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<PAGE>


                    Company) the sufficiency of any such  certifications,  legal
                    opinions or other information.

                              (i) Upon the transfer,  exchange or replacement of
                    Securities not bearing the Restrictive Legend, the Registrar
                    shall deliver  Securities  that do not bear the  Restrictive
                    Legend.  Upon  the  transfer,  exchange  or  replacement  of
                    Securities  bearing the  Restrictive  Legend,  the Registrar
                    shall  deliver  only  Securities  that bear the  Restrictive
                    Legend  unless (i) the  requested  transfer  is at least two
                    years  after  the  original  issue  date  of the  Restricted
                    Security (with respect to any Restricted Physical Security),
                    (ii)  there is  delivered  to the  Registrar  an  Opinion of
                    Counsel  reasonably  satisfactory  to the  Company  and  the
                    Trustee  to the  effect  that  neither  such  legend nor the
                    related  restrictions  on transfer  are required in order to
                    maintain  compliance  with the  provisions of the Securities
                    Act or (iii) such  Securities  are  exchanged  for  Exchange
                    Securities pursuant to an Exchange Offer.

                              Section 2.21.  CUSIP NUMBERS.  The Company may use
                    "CUSIP"  numbers (if then  generally  in use) in issuing the
                    Securities and, if so, the Trustee shall use "CUSIP" numbers
                    in notices to Holders as a convenience to Holders;  provided
                    that any such  notice  may state that no  representation  is
                    made as to the correctness of such numbers either as printed
                    on the  Securities  or as  contained  in any notice and that
                    reliance  may be  placed  only on the  other  identification
                    numbers  printed  on  the  Securities.   The  Company  shall
                    promptly  notify  the  Trustee  of any  change  in the CUSIP
                    numbers."

          Section 1.06.  Article 4 of the  Indenture  shall be amended by adding
the following paragraph immediately following the paragraph contained in Section
4.06:

                    "The  Company  will  take all  actions  necessary  to permit
          resales of any Securities  issued pursuant to Rule 144A and Regulation
          D of the Securities Act including, without limitation, furnishing upon
          request of a Holder of such  Security to such Holder and a prospective
          purchaser designated by such Holder financial and other information of
          the Company  required to be  delivered  under Rule  144A(d)(4)  of the
          Securities  Act if at the time of such  request  the  Company is not a
          reporting  company under Section 13 or Section 15(d) of the Securities
          Exchange Act of 1934, as amended."

          Section  1.07 The  Indenture  shall be  amended  by adding an  exhibit
titled  "Exhibit  A."  Exhibit A shall be the form of 7 3/8% Senior Note and the
related guarantee attached as Exhibit A hereto.


                                       11
<PAGE>


          Section  1.08.  The  Indenture  shall be  amended by adding an exhibit
titled "Exhibit B" immediately  following Exhibit A of the Indenture.  Exhibit B
shall be the form of Transfer Certificate attached as Exhibit B hereto.

          Section  1.09.  The  Indenture  shall be  amended by adding an exhibit
titled "Exhibit C" immediately  following Exhibit B of the Indenture.  Exhibit C
shall be the form of Exchange Certificate attached as Exhibit C hereto.

          Section  1.10.  The  Indenture  shall be  amended by adding an exhibit
titled "Exhibit D" immediately  following Exhibit C of the Indenture.  Exhibit D
shall be in the Form of IAI Letter attached as Exhibit D hereto.


                                   ARTICLE 2.

                     PROVISIONS FOR THE 7 3/8% SENIOR NOTES

          Section 2.01.  There shall be a series of Securities  entitled "7 3/8%
Senior Notes Due 2009" (herein  designated the "7 3/8% Senior Notes").  The form
of the 7 3/8% Senior  Notes,  the  Guarantees  issued by the  Guarantor  and the
Trustee's   certificate  of   authentication   to  be  borne  thereby  shall  be
substantially  in the forms set forth in Exhibit A hereto and shall be executed,
authenticated  and delivered in accordance  with the provisions of, and shall in
all respects be subject to, all of the terms,  conditions  and  covenants of the
Indenture and this Supplemental  Indenture,  including,  but not limited to, the
provisions  of  the  Indenture  with  respect  to  the  transfer,  exchange  and
replacement  thereof.  The aggregate principal amount of the 7 3/8% Senior Notes
that may be executed by the Company and  authenticated by the Trustee  hereunder
shall be limited to TWO HUNDRED FIFTY MILLION DOLLARS ($250,000,000);  provided,
however,  any exchanges or replacements of the Senior Notes made pursuant to the
Indenture  and  the  Supplemental  Indenture  following  the  original  issuance
thereof, .shall not be counted against this limit.

          Section  2.02.  In  accordance  with the terms and  conditions  of the
Indenture,  the Company may issue and sell the 7 3/8%  Senior  Notes  inside the
United States without  registration under the Securities Act in reliance on Rule
144A and Regulation D thereunder.

          Section 2.03.  Except as provided below, the 7 3/8% Senior Notes shall
be  represented  initially in the form of a  Restricted  Global  Security.  Each
Restricted  Global  Security shall be registered in the name of a nominee of the
Depositary  and deposited on behalf of the purchasers of the 7 3/8% Senior Notes
represented  thereby  with a  custodian


                                       12
<PAGE>


for the Depositary  for credit to the respective  accounts of the purchasers (or
to such other  accounts as they may  direct).  Except as set forth  below,  each
Restricted  Global  Security  shall  be in the form of the 7 3/8%  Senior  Notes
attached hereto is Exhibit A and may be  transferred,  in whole and not in part,
only to another nominee of the Depositary or to a successor of the Depositary or
its nominee.

          Notwithstanding   the  above,   Senior  Notes  sold  to  Institutional
Accredited Investors who are not Qualified  Institutional Buyers shall be issued
in certificated,  fully registered form (a "Restricted  Physical  Security").  A
Restricted  Physical  Security shall be subject to  restrictions  on transfer in
accordance  with the IAI Letter that such investor  shall be required to sign, a
form of which is attached hereto as Exhibit D.

          Section  2.04.  (a) Each  Restricted  Global  Security,  or any 7 3/8%
Senior  Notes that may be issued in exchange  for an  interest  in a  Restricted
Global  Security,  shall be dated as provided in Section 2.03 of the  Indenture,
shall  mature on November 9, 2009 and shall bear  interest at the rate of 7 3/8%
per annum from November 9, 1999, payable semiannually on May 9 and November 9 in
each year,  commencing with May 9, 2000,  until payment of the principal  amount
shall have been made or duly  provided for. The record dates with respect to the
interest payment dates for the 7 3/8% Senior Notes shall be May 1 and November 1
(whether or not a business  day),  respectively.  The holder of record of 7 3/8%
Senior Notes on any record date for the payment of interest shall be entitled to
receive the interest payable on such interest payment date.

          (b) Both principal of and interest on the 7 3/8% Senior Notes shall be
payable at the office of the Paying Agent in the  Milwaukee,  Wisconsin  and the
Borough  of  Manhattan,  The City of New York,  New York or at any other  office
maintained  by the  Company  or the  Guarantor,  as the  case  may be,  for such
purpose;  provided that interest may be payable, at the option of the Company or
the Guarantor,  as the case may be, by check mailed to the registered address of
the person  entitled  thereto as such address shall appear on the registry books
of the  Company.  On each  interest  payment  date the Trustee  shall pay to the
registered  holder  interest  accrued in respect  of such 7 3/8%  Senior  Notes.
Payment of  principal  on 7 3/8% Senior  Notes  shall be paid to the  registered
holder or upon his order only upon  presentation  and  surrender  for payment of
such 7 3/8%  Senior  Notes on or after the  payment  date at the  offices of the
Company or the  Guarantor,  as the case may be, in Milwaukee,  Wisconsin and the
Borough of Manhattan,  The City of New York,  New York or at any other office of
the Company or the Guarantor, as the case may be, maintained for such purpose.

          (c)  The 7  3/8%  Senior  Notes  shall  not  be  convertible  into  or
exchangeable for equity securities of the Company or the Guarantor.


                                       13
<PAGE>


          (d) The 7 3/8% Senior Notes shall not be subject to any sinking fund.

          (e) The 7 3/8% Senior  Notes shall not be included  for listing on any
national securities exchange.

          (f) The Trustee,  at its Corporate  Trust Office located at 1555 North
RiverCenter Drive, Suite 301, Milwaukee, Wisconsin 53212, shall initially act as
Paying Agent for the Senior Notes.

          Section  2.05.  (a) So  long as a  nominee  of the  Depositary  is the
registered  owner of any  Restricted  Global  Security,  such  nominee  shall be
considered  the sole owner and holder of the 7 3/8% Senior Notes  represented by
such Restricted Global Security under the Indenture, as supplemented and amended
hereby.  Except  as  herein  provided,  owners of  beneficial  interests  in any
Restricted  Global  Security  shall not be entitled to have 7 3/8% Senior  Notes
represented by the such Restricted  Global  Security  registered in their names,
shall not receive or be entitled to receive  physical  delivery of 7 3/8% Senior
Notes in  certificated  form and shall not be  considered  the owners or holders
thereof under the Indenture.

          (b) None of the Company,  the  Guarantor or the Trustee shall have any
responsibility  or  liability  for any  aspect  of the  records  relating  to or
payments made on account of  beneficial  ownership  interests in any  Restricted
Global  Security,  or for  maintaining,  supervising  or  reviewing  any records
relating to such beneficial interests.

          Section  2.06.  In the  event  that  either  (a)  the  Exchange  Offer
Registration Statement is not filed with the Commission on or prior to the 135th
calendar day  following the Closing Time,  (b) the Exchange  Offer  Registration
Statement has not been declared  effective on or prior to the 180th calendar day
following  the Closing Time,  (c) the Exchange  Offer is not  consummated  on or
prior to the 45th  calendar day  following  the  effective  date of the Exchange
Offer  Registration  Statement  or  (d)  if  required,  the  Shelf  Registration
Statement  is not  declared  effective  on or prior to the  210th  calendar  day
following  the Closing Time (each such event  referred to in clauses (a) through
(d) above,  a  "Registration  Default"),  the interest  rate borne by the Senior
Notes shall be increased  ("Additional  Interest") by one-quarter of one percent
(0.25%) per annum upon the occurrence of a Registration Default, which rate will
increase by  one-quarter  of one percent  (0.25%)  each 90-day  period that such
Additional  Interest continues to accrue under any such  circumstance,  provided
that the maximum aggregate increase in the interest rate will in no event exceed
one-half of one percent (0.5%) per annum. Following the cure of all Registration
Defaults the accrual of  Additional  Interest  will cease and the interest  rate
will revert to the original rate.


                                       14
<PAGE>


          If the Shelf Registration Statement is unusable by the Holders for any
reason after the Shelf Registration Statement has been declared effective by the
Commission,  and the aggregate  number of days in any  consecutive  twelve-month
period for which the Shelf Registration Statement shall not be usable exceeds 30
days in the aggregate,  then the interest rate borne by the Senior Notes will be
increased  by  one-quarter  of one percent  (0.25%)  per annum of the  principal
amount of the Senior  Notes for the first  90-day  period (or  portion  thereof)
beginning  on the 31st day  following  the date  that  such  Shelf  Registration
Statement  ceases to be usable,  which rate shall be increased by an  additional
one-quarter  of one  percent  (0.25%) per annum of the  principal  amount of the
Senior Notes at the beginning of the subsequent 90-day period, provided that the
maximum aggregate increase in the interest rate will in no event exceed one-half
of one percent (0.50%) per annum. Any amounts payable under this paragraph shall
also be deemed  "Additional  Interest"  for  purposes of the  Indenture  and the
Registration Rights Agreement.  Upon the Shelf Registration Statement once again
becoming usable,  the interest rate borne by the Senior Notes will be reduced to
the original  interest  rate if the Company and the  Guarantor  are otherwise in
compliance with this the Indenture and the Registration Rights Agreement at such
time.  Additional  Interest shall be computed based on the actual number of days
elapsed  in each  90-day  period in which the Shelf  Registration  Statement  is
unusable.

          The Company and the  Guarantor  shall notify the Trustee  within three
business  days after each and every date on which an event  occurs in respect of
which Additional  Interest is required to be paid (an "Event Date").  Additional
Interest shall be paid by depositing with the Trustee, in trust, for the benefit
of the  Holders of the Senior  Notes,  on or before  the  applicable  semiannual
interest payment date, immediately available funds in sums sufficient to pay the
Additional  Interest then due. The  Additional  Interest due shall be payable on
each interest  payment date to the record Holder of the Senior Notes entitled to
receive  the  interest  payment  to be  paid on such  date as set  forth  in the
Indenture.  Each obligation to pay Additional Interest shall be deemed to accrue
from and including the day following the applicable Event Date.

          Section  2.07.  The Senior Notes will be  redeemable  at the Company's
option in whole or in part at any  time,  on at least 30 days' but not more than
60 days' prior  written  notice mailed to the  registered  holders of the Senior
Notes,  at a price equal to the greater of (i) 100% of the  principal  amount of
the Senior Notes being  redeemed  and (ii) the sum of the present  values of the
principal amount of the Senior Notes to be redeemed and the remaining  scheduled
payments of interest on the Senior Notes from the redemption date to November 9,
2009 discounted from their respective  scheduled payment dates to the redemption
date semi-annually  (assuming a 360-day year consisting of twelve 30-day months)
at a  discount  rate equal to the  Treasury  Yield  plus 20 basis


                                       15
<PAGE>

points, plus accrued interest on the Senior Notes to the redemption date.

          "Treasury  Yield"  means,  with respect to any  redemption  date,  the
annual  rate  equal  to the  semi-annual  equivalent  yield to  maturity  of the
Comparable  Treasury Issue,  assuming a price for the Comparable  Treasury Issue
(expressed  as a percentage of its  principal  amount)  equal to the  Comparable
Treasury Price for such redemption date.

          "Comparable  Treasury Issue" means the United States treasury security
selected by an Independent  Investment Banker as having a maturity comparable to
the remaining term of the Senior Notes to be redeemed that would be utilized, at
the time of selection and in accordance with customary  financial  practice,  in
pricing new issues of corporate  debt  securities of comparable  maturity to the
remaining term of the Senior Notes.

          "Comparable  Treasury  Price"  means,  with  respect  to any  date  of
redemption,  (1) the  average  of the bid and asked  prices  for the  Comparable
Treasury Issue (expressed in each case as a percentage of its principal  amount)
on the third  business day  preceding the  redemption  date, as set forth in the
daily statistical  release (or any successor  release)  published by the Federal
Reserve Bank of New York and designated "Composite 3:30 p.m. Quotations for U.S.
Government Securities" or (ii) if such release (or any successor release) is not
published or does not contain  such prices on the business day in question,  the
Reference Treasury Dealer Quotation for the redemption date.

          "Independent   Investment  Banker"  means  an  independent  investment
banking institution of national standing appointed by the Company and reasonably
acceptable to the Trustee.

          "Reference  Treasury  Dealer  Quotation"  means,  with  respect to the
Reference Treasury Dealer and redemption date, the average, as determined by the
Company,  of the  bid  and  asked  prices  for  the  Comparable  Treasury  Issue
(expressed in each case as a percentage  of its  principal  amount and quoted in
writing to the  Company by the  Reference  Treasury  Dealer at 5:00 p.m.  on the
third business day preceding the redemption date).

          "Reference  Treasury Dealer" means a primary United States  government
securities  dealer in New York City  appointed  by the  Company  and  reasonably
acceptable to the Trustee.


                                       16
<PAGE>

                                   ARTICLE 3.

                                  MISCELLANEOUS

          Section 3.01. Capitalized terms used but not defined herein shall have
the respective meanings set forth in the Indenture.

          Section 3.02. Except as supplemented and amended hereby, the Indenture
is in all respects ratified and confirmed,  and all of the terms, provisions and
conditions  thereof  shall be and  remain  in full  force and  effect,  and this
Supplemental Indenture and all its provisions shall be deemed a part thereof.

          Section  3.03. In case any  provision in this  Supplemental  Indenture
shall  be  invalid,  illegal  or  unenforceable,   the  validity,  legality  and
enforceability  of the remaining  provisions shall not in any way be affected or
impaired thereby.

          Section 3.04. If any provision of this Supplemental  Indenture limits,
qualifies or conflicts with any other provision hereof or of the Indenture which
provision is required to be included in the  Indenture by any of the  provisions
of the Trust Indenture Act, such required provision shall control.

          Section 3.05.  THIS  SUPPLEMENTAL  INDENTURE  SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE  WITH THE LAWS OF THE STATE OF WISCONSIN  WITHOUT REGARD
TO THE CONFLICTS OF LAWS AND RULES OF SAID STATE.

          Section 3.06.  This  Supplemental  Indenture  has been  simultaneously
executed  in  several  counterparts,  each of  which  shall be  deemed  to be an
original,  and all such counterparts  shall together  constitute but one and the
same  instrument.  Delivery by telecopier of an executed  signature  page hereto
shall be effective as delivery of a manually executed counterpart hereof.

          Section 3.07. This Supplemental Indenture shall be deemed to have been
executed on the date of the acknowledgment thereof by the officer of the Trustee
who signed it on behalf of the Trustee.



                                       17
<PAGE>


          IN WITNESS  WHEREOF,  the Company,  the Guarantor and the Trustee have
caused their names to be signed hereto by their  respective  officers  thereunto
duly  authorized and their  respective  corporate  seals,  duly attested,  to be
hereunto affixed, all as of the day and year first above written.

                                        ALLIANT ENERGY RESOURCES, INC.
ATTEST:



By:/s/ Enrique Bacalao                  By:Edward M. Gleason
   ----------------------------------      -----------------------------------
   Name:  Enrique Bacalao                  Name:  Edward M. Gleason
   Title: Assistant Secretary              Title: Vice President - Treasurer
                                                  and Corporate Secretary


                                        ALLIANT ENERGY CORPORATION,
ATTEST:                                 as Guarantor



By: /s/ Enrique Bacalao                 By:Edward M. Gleason
   ----------------------------------      -----------------------------------
   Name:  Enrique Bacalao                  Name:  Edward M. Gleason
   Title: Assistant Secretary              Title: Vice President - Treasurer
                                                  and Corporate Secretary


                                        FIRSTAR BANK, N.A.,
                                        as Trustee



                                        By: /s/ Pamela Warner
                                           -----------------------------------
                                           Name:  Pamela Warner
                                           Title: Assistant Vice President

                                        Attested by  /s/ Yvonne Siira
                                                        Yvonne Siira
                                                        Assistant Secretary

                                       18

<PAGE>
                                                                       EXHIBIT A

                             [Form of Senior Notes]

          Unless this  certificate is presented by an authorized  representative
of The Depository  Trust Company,  a New York  corporation  ("DTC"),  to Alliant
Energy Resources,  Inc., or its agent for registration of transfer,  exchange or
payment,  and any certificate  issued is registered in the name of Cede & Co. or
to such  other  entity or in such other name as is  requested  by an  authorized
representative  of DTC (and any payment  hereon is made to Cede & Co. or to such
other  entity as is  requested  by an  authorized  representative  of DTC),  ANY
TRANSFER,  PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON
IS WRONGFUL  since the  registered  owner  hereof,  Cede & Co.,  has an interest
herein.

          Transfers  of this Global  Security  shall be limited to  transfers in
whole,  but not in part, to nominees of Cede & Co. or to a successor  thereof or
such successor's nominee and transfers of portions of this Global Security shall
be limited to transfers made in accordance  with the  restrictions  set forth in
Section 2.20 of the Indenture referred to in this Global Security.

          THE NOTES HAVE NOT BEEN  REGISTERED  UNDER THE SECURITIES ACT OF 1933,
AS  AMENDED  (THE  "SECURITIES  ACT"),  OR ANY STATE OR OTHER  SECURITIES  LAWS.
NEITHER THIS NOTE NOR ANY  INTEREST OR  PARTICIPATION  HEREIN MAY BE  REOFFERED,
SOLD, ASSIGNED, TRANSFERRED, PLEDGED, ENCUMBERED OR OTHERWISE DISPOSED OF IN THE
ABSENCE OF SUCH  REGISTRATION  OR UNLESS THE  TRANSACTION IS EXEMPT FROM, OR NOT
SUBJECT  TO,  THE  REGISTRATION  REQUIREMENTS  OF  THE  SECURITIES  ACT.  BY ITS
ACQUISITION  HEREOF,  THE  HOLDER  (1)  REPRESENTS  THAT (A) IT IS A  "QUALIFIED
INSTITUTIONAL  BUYER"  ("QIB") (AS DEFINED IN RULE 144A ("RULE  144A") UNDER THE
SECURITIES ACT) OR (B) IT IS AN INSTITUTIONAL  "ACCREDITED  INVESTOR" WITHIN THE
MEANING  OF  SUBPARAGRAPHS  (a)(1),  (2),  (3) OR  (7) OF  RULE  501  UNDER  THE
SECURITIES  ACT  THAT IS  ACQUIRING  THIS  NOTE FOR ITS OWN  ACCOUNT  OR FOR THE
ACCOUNT OF SUCH INSTITUTIONAL  ACCREDITED  INVESTOR FOR INVESTMENT  PURPOSES AND
NOT WITH A VIEW TO OR FOR OFFER OR SALE IN CONNECTION  WITH, ANY DISTRIBUTION IN
VIOLATION  OF THE  SECURITIES  ACT (2)  AGREES NOT TO OFFER,  SELL OR  OTHERWISE
TRANSFER  THIS NOTE  PRIOR TO (X) THE DATE  WHICH IS TWO YEARS (OR SUCH  SHORTER
PERIOD OF TIME AS PERMITTED BY RULE 144(K) UNDER THE  SECURITIES  ACT) AFTER THE
LATER OF THE ORIGINAL ISSUE DATE OF THE NOTES AND THE LAST DATE ON WHICH ALLIANT
ENERGY  RESOURCES,  INC.  OR ANY  "AFFILIATE"  (AS DEFINED IN RULE 144 UNDER THE
SECURITIES ACT) OF ALLIANT ENERGY RESOURCES,

<PAGE>

INC.  WAS THE OWNER OF THIS NOTE (OR ANY  PREDECESSOR  OF THIS NOTE) OR (Y) SUCH
LATER  DATE,  IF  ANY,  AS  MAY BE  REQUIRED  BY  APPLICABLE  LAW  (THE  "RESALE
RESTRICTION TERMINATION DATE") EXCEPT (A) TO ALLIANT ENERGY RESOURCES, INC., (B)
PURSUANT TO A REGISTRATION  STATEMENT THAT HAS BEEN DECLARED EFFECTIVE UNDER THE
SECURITIES  ACT,  (C) FOR SO LONG AS THE  SECURITIES  ARE  ELIGIBLE  FOR  RESALE
PURSUANT  TO RULE  144A,  TO A PERSON IT  REASONABLY  BELIEVES  IS A  "QUALIFIED
INSTITUTIONAL  BUYER" AS DEFINED IN RULE 144A THAT PURCHASES FOR ITS OWN ACCOUNT
OR FOR THE  ACCOUNT OF A  QUALIFIED  INSTITUTIONAL  BUYER,  IN EACH CASE TO WHOM
NOTICE IS GIVEN THAT THE TRANSFER IS BEING MADE IN RELIANCE ON RULE 144A, (D) TO
AN  INSTITUTIONAL  "ACCREDITED  INVESTOR"  WITHIN THE  MEANING OF  SUBPARAGRAPHS
(a)(1),  (2), (3) or (7) OF RULE 501 UNDER THE  SECURITIES ACT THAT IS ACQUIRING
THIS  NOTE  FOR ITS OWN  ACCOUNT  OR FOR THE  ACCOUNT  OF SUCH AN  INSTITUTIONAL
ACCREDITED INVESTOR FOR INVESTMENT PURPOSES AND NOT WITH A VIEW TO, OR FOR OFFER
OR SALE IN CONNECTION  WITH, ANY DISTRIBUTION IN VIOLATION OF THE SECURITIES ACT
OR  (E)  PURSUANT  TO  ANOTHER   AVAILABLE   EXEMPTION  FROM  THE   REGISTRATION
REQUIREMENTS OF THE SECURITIES ACT SUBJECT IN EACH OF THE FOREGOING CASES OF ANY
REQUIREMENT OF LAW THAT THE  DISPOSITION OF ITS PROPERTY OR THE PROPERTY OF SUCH
INVESTOR  ACCOUNT OR ACCOUNTS BE AT ALL TIMES WITHIN ITS OR THEIR  CONTROL,  AND
(3) AGREES THAT IT WILL GIVE TO EACH PERSON TO WHOM THIS NOTE IS  TRANSFERRED  A
NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND;  PROVIDED THAT ALLIANT ENERGY
RESOURCES,  INC.  AND THE TRUSTEE  SHALL HAVE THE RIGHT PRIOR TO ANY SUCH OFFER,
SALE OR TRANSFER (I) PURSUANT TO CLAUSE (D) OR (E) TO REQUIRE THE DELIVERY OF AN
OPINION OF COUNSEL,  CERTIFICATION AND/OR OTHER INFORMATION SATISFACTORY TO EACH
OF THEM, AND (II) IN EACH OF THE FOREGOING CASES, BUT ONLY IF THIS NOTE IS NOT A
GLOBAL  SECURITY (AS DEFINED IN THE  INDENTURE  REFERRED TO HEREIN),  TO REQUIRE
THAT A CERTIFICATION OF TRANSFER IN THE FORM APPEARING ON THE OTHER SIDE OF THIS
NOTE IS COMPLETED AND DELIVERED BY THE TRANSFEROR TO ALLIANT  ENERGY  RESOURCES,
INC. AND THE TRUSTEE. THIS LEGEND WILL BE REMOVED UPON THE REQUEST OF THE HOLDER
AFTER THE RESALE RESTRICTION TERMINATION DATE.


                                       2
<PAGE>

                         ALLIANT ENERGY RESOURCES, INC.
                          7 3/8% SENIOR NOTES DUE 2009

CUSIP No. 018803AA4
$250,000,000

Global Note

          Alliant  Energy  Resources,  Inc., a  corporation  duly  organized and
existing  under the laws of the State of Wisconsin  (the  "Company,"  which term
includes any successor person under the Indenture  hereinafter referred to), for
value received,  hereby promises to pay to Cede & Co. or registered assigns, the
principal sum of TWO HUNDRED FIFTY MILLION  DOLLARS ($  250,000,000) on November
9, 2009, at the office or agency of the Company  referred to below, in such coin
or currency  of the United  States of America as at the time of payment is legal
tender for the payment of public and private debts,  and to pay interest thereon
in like coin or currency from November 9, 1999, or from the most recent interest
payment date on which interest has been paid or duly provided for, semi-annually
in arrears on May 9 and November 9 in each year,  commencing May 9, 2000, at the
rate of 7 3/8% per annum,  until the principal  hereof is paid or made available
for  payment,  and (to the extent  lawful) to pay  interest at the same rate per
annum on any overdue  principal  and premium and on any overdue  installment  of
interest until paid.

          Interest so payable,  and punctually paid or duly provided for, on any
Interest payment date, as provided in the Indenture, shall be paid to the person
in whose name this  Senior  Note (or one or more  predecessor  Senior  Notes) is
registered at the close of business on the record date for such interest,  which
shall be May 1 or  November 1 (whether or not a business  day),  as the case may
be,  next  preceding  such  Interest  payment  date.  Any such  interest  not so
punctually  paid or duly provided for will forthwith  cease to be payable to the
person in whose name this Senior Note is  registered on such record date and may
either be paid to the person in whose name this Senior Note is registered at the
close of business on a record date for the payment of such defaulted interest to
be fixed by the Trustee,  notice  whereof  shall be given to the person in whose
name this Senior Note is registered  not less than ten days prior to such record
date,  or be paid at any time in any  other  lawful  manner,  all as more  fully
provided in the Indenture.

          This Senior Note is a "book-entry" security and is being registered in
the name of Cede & Co. as nominee of The  Depository  Trust Company  ("DTC"),  a
clearing agency. Subject to the terms of the Indenture,  dated as of November 4,
1999 (as supplemented by the First  Supplemental  Indenture dated as of November
4, 1999 and as  supplemented  and amended from time to time,  the  "Indenture"),
among the Company,


                                       3
<PAGE>

Alliant Energy Corporation (the "Guarantor"), and Firstar Bank, N.A., as trustee
(the "Trustee"),  and except as provided therein,  this Senior Note will be held
by a clearing  agency or its nominee,  and beneficial  interests will be held by
beneficial  owners through the book-entry  facilities of such clearing agency or
its  nominee in minimum  denominations  of $1,000  and  increments  of $1,000 in
excess thereof.

          The  statements  set  forth in the  restrictive  legend  above  are an
integral  part of the terms of this  Senior Note and by  acceptance  hereof each
holder of this  Senior  Note  agrees to be subject to and bound by the terms and
provisions set forth in such legend.

          The Trustee will make payments of principal of and interest on (except
as otherwise  provided  below) this Senior Note by wire transfer of  immediately
available  funds.  Notwithstanding  the above,  the final payment on this Senior
Note  will be made  after due  notice by the  Trustee  of the  pendency  of such
payment  and only upon  presentation  and  surrender  of this Senior Note at its
principal  corporate trust office or such other offices or agencies appointed by
the Trustee for that purpose and such other locations provided in the Indenture.

          Payments of  principal of (and  premium,  if any) and interest on this
Senior  Note  will  be made at the  offices  or  agency  of the  Company  or the
Guarantor,  as the  case  may be,  maintained  for that  purpose  in  Milwaukee,
Wisconsin and the Borough of Manhattan,  The City of New York,  New York in such
coin or  currency  of the United  States of America as at the time of payment is
legal tender for payments of public and private debts;  provided,  however, that
at the option of the Company or the  Guarantor,  as the case may be,  payment of
interest  may be made by check  mailed to the  address  of the  person  entitled
thereto as such address shall appear in the register of the Company.

          This Senior Note is one of a duly  authorized  issue of  Securities of
the Company,  designated 7 3/8% Senior Notes due 2009 (the "7 3/8% Senior Notes"
or the  "Senior  Notes"),  limited  in  aggregate  principal  amount at any time
outstanding  to TWO HUNDRED FIFTY MILLION  DOLLARS  ($250,000,000)  which may be
issued under the First Supplemental  Indenture.  Reference is hereby made to the
Indenture,  the First  Supplemental  Indenture and all  indentures  supplemental
thereto for a statement of the respective rights, limitations of rights, duties,
obligations and immunities thereunder of the Company, the Guarantor, the Trustee
and the Holders of the Senior  Notes,  and the terms upon which the Senior Notes
are, and are to be,  authenticated and delivered.  All terms used in this Senior
Note that are defined in the Indenture shall have the meanings  assigned to them
in the Indenture.

          The Holder of this  Senior  Note is  entitled  to the  benefits of the
Registration  Rights Agreement,  dated as of November 9, 1999 (the "Registration
Rights


                                       4
<PAGE>

Agreement"),  among the Company,  the Guarantor and the initial purchasers named
therein (the  "Initial  Purchasers").  In the event that (i) the Company and the
Guarantor fails to file an Exchange Offer Registration Statement with respect to
the Senior Notes with the Securities and Exchange  Commission (the "Commission")
on or prior to the 135th  calendar  day  following  the Closing  Time,  (ii) the
Commission does not declare such Exchange Offer Registration Statement effective
on or prior to the 180th  calendar day  following  the Closing  Time,  (iii) the
Exchange Offer is not consummated on or prior to the 45th calendar day following
the  effective  date of the  Exchange  Offer  Registration  Statement or (iv) if
required, a Shelf Registration Statement with respect to the Senior Notes is not
declared  effective  by the  Commission  on or prior to the 210th  calendar  day
following  the Closing  Time (each,  a  "Registration  Default"),  the per annum
interest rate borne by the Senior Notes shall be increased by one-quarter of one
percent (0.25%) per annum for the first 90-day period following the Registration
Default.  The  interest  rate borne by the Senior  Notes will be increased by an
additional  one-quarter  of one  percent  (0.25%)  per annum for the  subsequent
90-day period (or portion  thereof) during which any such  Registration  Default
continues  up to a maximum  aggregate  increase in the annual  interest  rate of
one-half  of  one  percent  (0.50%)  per  annum.   Following  the  cure  of  all
Registration  Defaults,  the  interest  rate borne by the Senior  Notes shall be
reduced to the original  interest rate borne by the Senior  Notes.  If the Shelf
Registration Statement is unusable by the Holders for any reason after the Shelf
Registration  Statement has been declared  effective by the Commission,  and the
aggregate  number of days in any consecutive  twelve-month  period for which the
Shelf  Registration  is  unusable  exceeds  30 days in the  aggregate,  then the
interest rate borne by the Senior Notes will be increased by  one-quarter of one
percent  (0.25%) per annum of the  principal  amount of the Senior Notes for the
first 90-day period (or a portion thereof)  beginning the 31st day following the
date that such Shelf  Registration  Statement  ceases to be  usable,  which rate
shall be increased by an additional one-quarter of one percent (0.25%) per annum
of the  principal  amount of Senior  Notes at the  beginning  of the  subsequent
90-day period, provided that the maximum aggregate increase in the interest rate
will in no event exceed one-half of one percent  (0.50%) per annum.  All accrued
additional  interest  shall be paid to Holders by the Company in the same manner
and at the same time as interest is paid  pursuant to the  Indenture.  All terms
used in this Senior Note that are defined in the  Registration  Rights Agreement
shall have the meanings assigned to them in the Registration Rights Agreement.

          Each purchaser of Senior Notes,  by its acquisition  thereof,  will be
deemed  to  have  acknowledged,  represented  to and  agreed  with  the  Initial
Purchasers, the Company and the Guarantor as follows:


                                       5
<PAGE>

                    (1) Such purchaser  understands  and  acknowledges  that the
          Senior Notes have not been registered  under the Securities Act or any
          other  applicable  securities  laws,  are being  offered for resale in
          transactions  not requiring  registration  under the Securities Act or
          any other  securities laws including sales pursuant to Rule 144A under
          the  Securities  Act,  and  may  not be  offered,  sold  or  otherwise
          transferred except in compliance with the registration requirements of
          the Securities Act or any other applicable securities law, or pursuant
          to an exemption therefrom or in a transaction not subject thereto, and
          in each case in compliance  with the conditions for transfer set forth
          in paragraph (4) below.

                    (2) Such purchaser is not an "affiliate" (as defined in Rule
          144 under the Securities Act) of the Company and it is either:

                              (a) a QIB and is aware  that  any  sale of  Senior
                    Notes to it will be made in  reliance  on Rule 144A and such
                    acquisition  will be for its own  account or for the account
                    of  another  QIB with  respect  to which it  exercises  sole
                    investment  discretion  and to whom it has given notice that
                    the Senior Notes are being sold in reliance on Rule 144A; or

                              (b) an Institutional  Accredited  Investor and, if
                    the  Senior  Notes  are to be  purchased  for  one  or  more
                    accounts  ("investor  accounts")  for  which it is acting as
                    fiduciary  or  agent,  each  such  investor  account  is  an
                    Institutional  Accredited  Investor on a like basis;  in the
                    normal  course of its  business,  it invests in or purchases
                    securities  similar to the Senior  Notes and such  purchaser
                    has such  knowledge and experience in financial and business
                    matters  that it is  capable  of  evaluating  the merits and
                    risks of purchasing  any of the Senior Notes and it is aware
                    that it (or any such  investor  account)  may be required to
                    bear the economic  risk of an investment in the Senior Notes
                    for an  indefinite  period of time and it (or such  investor
                    account) is able to bear such risk for an indefinite  period
                    and  such   purchaser   has   agreed  to  deliver  a  letter
                    substantially  in  the  form  of  Exhibit  D  to  the  First
                    Supplemental Indenture to the Company.

                    (3) Such  purchaser  acknowledges  that none of the Company,
          the Guarantor or the Initial  Purchasers,  or any person  representing
          the Company,  the  Guarantor or the Initial  Purchasers,  has made any
          representation to it with respect to the Company, the Guarantor or the
          offering  or sale of any  Senior  Notes  other  than  the  information
          contained in the Offering  Memorandum,  which has been delivered to it
          and upon which  such  purchaser  is  relying in making its  investment
          decision with respect to the Senior Notes. Accordingly, such purchaser
          acknowledges that no representation or warranty is made by the Initial
          Purchasers


                                       6
<PAGE>


          as to the accuracy or completeness  of such materials.  Such purchaser
          has had access to such financial and other information  concerning the
          Company, the Guarantor and the Senior Notes (and the Guarantees) as it
          has deemed  necessary in connection  with its decision to purchase any
          of the Senior Notes,  including an opportunity to ask questions of and
          request information from the Initial  Purchasers,  the Company and the
          Guarantor.

                    (4) Such  purchaser is  purchasing  the Senior Notes for its
          own  account,  or for one or more  investor  accounts  for which it is
          acting as a fiduciary or agent, in each case for  investment,  and not
          with a  view  to,  or for  offer  or  sale  in  connection  with,  any
          distribution  thereof in violation of the Securities  Act,  subject to
          any  requirement  of law that the  disposition  of its property or the
          property of such  investor  account or accounts be at all times within
          its or their  control  and  subject to its or their  ability to resell
          such  Senior  Notes  pursuant  to  Rule  144A  or any  exemption  from
          registration  available  under the  Securities  Act or  pursuant  to a
          registration  statement  which has been declared  effective  under the
          Securities Act. Such purchaser  agrees on its own behalf and on behalf
          of any investor  account for which it is purchasing  the Senior Notes,
          and each  subsequent  holder  of the  Senior  Notes by its  acceptance
          thereof will be deemed to agree, to offer, sell or otherwise  transfer
          the  Senior  Notes  prior to (x) the date  which is two years (or such
          shorter  period  of  time  as  permitted  by  Rule  144(k)  under  the
          Securities  Act) after the later of the date of original  issue of the
          Senior  Notes  and the last date on which  the  Company  or any of its
          "affiliates" (as defined in Rule 144 under the Securities Act) was the
          owner of the Senior  Notes (or any  predecessor  thereto)  or (y) such
          later date, if any, as may be required by applicable  law (the "Resale
          Restriction  Termination Date"), only (a) to the Company, (b) pursuant
          to a registration  statement  which has been declared  effective under
          the  Securities  Act, (c) for so long as the Senior Notes are eligible
          for resale pursuant to Rule 144A to a person it reasonably believes is
          a QIB that  purchases for its own account or for the account of a QIB,
          in each case to whom  notice is given that the  transfer is being made
          in reliance on Rule 144A, (d) to an Institutional  Accredited Investor
          that is  acquiring  the  Senior  Notes for its own  account or for the
          account of such an  Institutional  Accredited  Investor for investment
          purposes  and not with a view to, or for  offer or sale in  connection
          with,  any  distribution  in  violation of the  Securities  Act or (e)
          pursuant  to any  other  available  exemption  from  the  registration
          requirements of the Securities  Act,  subject in each of the foregoing
          cases to any  requirement of law that the  disposition of its property
          or the property of such  investor  account or accounts be at all times
          within its or their  control  and to  compliance  with any  applicable
          state or other  securities  laws.  If any  resale or  transfer  of the
          Senior Notes is proposed to be made pursuant to clause (d) above


                                       7
<PAGE>

          prior to the Resale Restriction Termination Date, the transferor shall
          deliver  a letter  from the  transferee  substantially  in the form of
          Exhibit D to the First  Supplemental  Indenture to the Company and the
          Trustee.   The  foregoing   restrictions  on  resale  will  not  apply
          subsequent to the Resale Restriction  Termination Date. Each purchaser
          of Senior Notes  acknowledges that the Company,  the Guarantor and the
          Trustee  reserve the right prior to any offer,  sale or other transfer
          of Senior  Notes  prior to the  Resale  Restriction  Termination  Date
          pursuant to clauses (d) or (e),  above,  to require the delivery of an
          opinion  of   counsel,   certifications   and/or   other   information
          satisfactory  to them and the Trustee.  Each purchaser of Senior Notes
          acknowledges that each Senior Note will contain a legend substantially
          in the form on the face of this Senior Note unless otherwise agreed by
          the Company, the Guarantor and the Trustee.

                    (5)  Such  purchaser  acknowledges  that  the  Company,  the
          Guarantor,  the Initial  Purchasers,  the Trustee and others will rely
          upon  the  truth  and  accuracy  of  the  foregoing   acknowledgments,
          representations   and  agreements  and  agree  that,  if  any  of  the
          acknowledgments,  representations, warranties and agreements deemed to
          have been made by its purchase of the notes are no longer accurate, it
          shall  promptly  notify the Initial  Purchasers.  If such purchaser is
          acquiring  any notes as a fiduciary or agent for one or more  investor
          accounts,  it represents that it has sole  investment  discretion with
          respect  to each  such  account  and it has  full  power  to make  the
          foregoing acknowledgments, representations and agreements on behalf of
          each such account and that each such  investor  account is eligible to
          purchase the notes.

                    (6)  Such  purchaser  acknowledges  that  the  Trustee,  the
          transfer  agent and the  registrar  will not be required to accept for
          registration  of  transfer  any  notes  acquired  by it,  except  upon
          presentation  of evidence  satisfactory to the Company and the Trustee
          that the restrictions set forth above have been complied with.

                    (7)  Such   purchaser   acknowledges   that  the   foregoing
          restrictions  apply to holders of  beneficial  interests in the Senior
          Notes, as well as the holders of the Senior Notes.

          The  Senior  Notes  do  not  have  the  benefit  of any  sinking  fund
obligations  and shall not be  repayable  at the option of the  Holder  prior to
maturity.

          The Senior Notes may be redeemed at the Company's  option, in whole or
in part,  at any time on at least 30 days',  but not more  than 60 days',  prior
written notice mailed to the registered  holders of the Senior Notes, at a price
equal to the  greater of (a) 100% of the  principal  amount of the Senior  Notes
being redeemed and (b) the sum of the


                                       8
<PAGE>


present  values of the  principal  amount of the Senior Notes to be redeemed and
the  remaining  scheduled  payments  of  interest  on the Senior  Notes from the
redemption date to November 9, 2009 discounted from their  respective  scheduled
payment  dates to the  redemption  date  semi-annually  (assuming a 360-day year
consisting of twelve 30-day  months) at a discount rate equal to the  equivalent
yield to maturity of a comparable  treasury security plus 20 basis points,  plus
accrued interest on the Senior Notes to the redemption date.

          If an Event of Default shall occur and be continuing, the principal of
all the Senior  Notes may be declared due and payable in the manner and with the
effect provided in the Indenture.

          The Indenture  contains  provisions  for defeasance at any time of (a)
the entire  indebtedness  of the Company (and the  Guarantor)  under this Senior
Note and (b) certain  restrictive  covenants and the related defaults and Events
of Default  applicable  to the Company  and the  Guarantor,  in each case,  upon
compliance by the Company and the Guarantor with certain conditions set forth in
the Indenture, which provisions apply to this Senior Note.

          The Indenture  permits,  with certain  exceptions as therein provided,
the amendment  thereof and the modification of the rights and obligations of the
Company  and the  Guarantor  and the rights of the  Holders of the Senior  Notes
under the  Indenture at any time by the Company,  the  Guarantor and the Trustee
with the consent of the Holders of a majority in aggregate  principal  amount of
the Senior Notes at the time outstanding. The Indenture also contains provisions
permitting the Holders of specified percentages in aggregate principal amount of
the Senior Notes at the time outstanding, on behalf of the Holders of all Senior
Notes,  to waive  compliance  by the  Company  and the  Guarantor  with  certain
provisions of the  Indenture  and certain past Defaults  under the Indenture and
their consequences. Any such consent or waiver by the Holder of this Senior Note
shall be conclusive  and binding upon such Holder and upon all future Holders of
this Senior Note and of any Senior Note issued upon the registration of transfer
thereof or in exchange  herefor or in lieu  hereof,  whether or not  notation of
such consent or waiver is made upon this Senior Note.

          No reference herein to the Indenture and provision of this Senior Note
or of the Indenture  shall alter or impair the obligation of the Company and the
Guarantor,  which is absolute and  unconditional,  to pay the  principal of (and
premium,  if any) and interest on this Senior Note at the times, place and rate,
and in the coin or currency, herein prescribed.


                                       9
<PAGE>


          As provided in the  Indenture  and subject to certain  limitations  on
transfer of this Senior Note by DTC or its nominee,  the transfer of this Senior
Note is  registrable  by the  Registrar,  upon surrender of this Senior Note for
registration  of  transfer  at  the  office  or  agency  of the  Company  or the
Guarantor,  as the case may be,  in  Milwaukee,  Wisconsin  and the  Borough  of
Manhattan,  The City of New York, New York,  duly endorsed by, or accompanied by
the written  instrument of transfer  attached hereto duly executed by the Holder
hereof or his attorney duly authorized in writing, and thereupon one or more new
Senior Notes, of authorized  denominations and for the same aggregate  principal
amount, shall be issued to the designated transferee or transferees.

          The Senior Notes are issuable  only in fully  registered  form without
coupons  in  denominations  of $1,000  and any  integral  multiple  thereof.  As
provided in the Indenture and subject to certain  limitations therein set forth,
the Senior  Notes are  exchangeable  for a like  aggregate  principal  amount of
Senior Notes of different  authorized  denomination,  as requested by the Holder
surrendering the same.

          No service charge shall be made for any such  registration of transfer
or exchange of Senior  Notes,  but the  Company  and the  Guarantor  may require
payment  of a sum  sufficient  to  cover  any tax or other  governmental  charge
payable in connection therewith.

          Prior to due  presentment  of this  Senior  Note for  registration  of
transfer, the Company, the Guarantor,  the Trustee and any agent of the Company,
the Guarantor or the Trustee may treat the person in whose name this Senior Note
is registered  as the owner hereof for all purposes,  whether or not this Senior
Note be overdue, and none of the Company, the Guarantor, the Trustee or any such
agent shall be affected by notice to the contrary.

          Interest  on this  Senior  Note  shall be  computed  on the basis of a
360-day year of twelve 30-day months.

          The  Company  shall  furnish to any Holder of record of Senior  Notes,
upon written request and without charge, a copy of the Indenture.

          The  Indenture  and this  Senior  Note each shall be  governed  by and
construed in accordance  with the laws of the State of Wisconsin  without regard
to principles of conflicts of law.

          Unless the certificate of  authentication  hereon has been executed by
the Trustee by manual  signature,  this Senior Note shall not be entitled to any
benefit under the Indenture or be valid or obligatory for any purpose.


                                       10
<PAGE>


          In Witness  Whereof,  Alliant Energy  Resources,  Inc. has caused this
Senior Note to be signed in its corporate name by the facsimile signature of two
of its  officers  thereonto  duly  authorized  and has caused a facsimile of its
corporate seal to be affixed hereto or imprinted or otherwise reproduced hereon.

                                        ALLIANT ENERGY RESOURCES, INC.
ATTEST:


By:_________________________________    By:___________________________________
    Name:                                   Name:
    Title:                                  Title:



                                       11
<PAGE>

          FOR VALUE RECEIVED, the Guarantor,  hereby unconditionally  guarantees
to the Holder of the Security upon which this  Guarantee is endorsed the due and
punctual  payment of the  principal,  of  premium,  if any,  or interest on said
Security,  when and as the same  shall be become  due and  payable,  whether  at
maturity,  upon  redemption or otherwise,  according to the terms thereof and of
the Indenture referred to therein.

          The Guarantor agrees to determine,  at least one business day prior to
the date upon which a payment of principal,  of premium,  if any, or interest on
said Security is due and payable, whether the Company has available the funds to
make such  payment as the same  shall  become  due and  payable.  In case of the
failure of the Company punctually to pay any such principal, premium, if any, or
interest,  the  Guarantor  hereby  agrees to cause any such  payment  to be made
punctually  when  and as the same  shall  become  due and  payable,  whether  at
maturity, upon redemption or otherwise,  and as if such payment were made by the
Company.

          The Guarantor  hereby agrees that its  obligations  hereunder shall be
unconditional,   irrevocable   and  absolute,   irrespective  of  the  validity,
regularity or enforceability of said Security or said Indenture,  the absence of
any  action to  enforce  the same,  any  waiver or consent by the Holder of said
Security with respect to any  provisions  thereof,  the recovery of any judgment
against the Company or any action to enforce the same or any other  circumstance
which might otherwise  constitute a legal or equitable discharge or defense of a
guarantor.  The  Guarantor  hereby  waives  diligence,  presentment,  demand  of
payment,  filing of claims with a court in the event of merger or  bankruptcy of
the  Company,  any right to require a  proceeding  first  against  the  Company,
protest  or notice  with  respect to said  Security  or  indebtedness  evidenced
thereby,  and all demands  whatsoever and covenants that this Guarantee will not
be discharged  except by complete  performance of the  obligations  contained in
said Security and in this Guarantee.

          The Guarantor  shall be subrogated to all rights of the Holder of said
Security  against the Company in respect to any  amounts  paid by the  Guarantor
pursuant  to the  provisions  of this  Guarantee;  provided,  however,  that the
Guarantor shall not, without the consent of the Holders of all of the Securities
then outstanding,  be entitled to enforce or to receive any payments arising out
of or based upon such right of  subrogation  until the principal of and premium,
if any, and interest on all  Securities  shall have been paid in full or payment
thereof shall have been provided for in accordance with said Indenture.

          Notwithstanding   anything  to  the  contrary   contained  herein,  if
following any payment of principal or interest by the Company on the  Securities
to the Holders of


                                       12
<PAGE>


the  Securities  it is  determined  by a final  decision of a court of competent
jurisdiction  that such  payment  shall be avoided  by a trustee  in  bankruptcy
(including any debtor-in-possession) as a preference under 11 U.S.C. Section 547
and such payment is paid by such Holder to such trustee in bankruptcy,  then and
to the extent of such repayment the obligations of the Guarantor hereunder shall
remain in full force and effect.

          This Guarantee shall not be valid or become obligatory for any purpose
with  respect  to a  Security  until a  certificate  of  authentication  on such
Security shall have been signed by the Trustee (or the authenticating agent).

          This  Guarantee  shall  be  governed  by  the  laws  of the  State  of
Wisconsin.

          IN  WITNESS  WHEREOF,  ALLIANT  ENERGY  CORPORATION  has  caused  this
Guarantee  to be signed in its  corporate  name by the  signature  of two of its
officers  thereunto  duly  authorized  and has caused its  corporate  seal to be
affixed hereto or imprinted or otherwise reproduced hereon.


                                        ALLIANT ENERGY CORPORATION,
                                        as Guarantor
ATTEST:


By:_________________________________    By:__________________________________
    Name:                                   Name:
    Title:                                  Title:


                                       13
<PAGE>

                      TRUSTEE CERTIFICATE OF AUTHENTICATION

          This  is  one of  the  Senior  Notes  described  in  the  within-named
Indenture.

                                          FIRSTAR BANK, N.A.,
                                          as Trustee



                                          By:________________________________
                                              Name:
                                              Title:


                                       14
<PAGE>

                                                                       EXHIBIT B
                                     Annex A

                         [FORM OF TRANSFER CERTIFICATE]



Alliant Energy Resources, Inc. (the "Company")
Alliant Energy Corporation, as Guarantor (the "Guarantor")
Firstar Bank, N.A., as Trustee (the "Trustee")

Re: 7 3/8% Senior Notes Due 2009


          Reference  is hereby  made to the  Indenture,  dated as of November 4,
1999 (as supplemented by the First  Supplemental  Indenture dated as of November
4, 1999, and as  supplemented  and amended from time to time, the  "Indenture"),
between the Company,  the Guarantor and the Trustee.  Capitalized terms used but
not defined herein shall have the meanings given to them in the Indenture. Other
terms shall have the meanings given to them in Rule 144A ("Rule 144A") under the
Securities Act of 1933, as amended (the "Securities Act").

          FOR VALUE RECEIVED the undersigned  registered  holder hereby sell(s),
assign(s) and transfer(s) unto

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

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

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

          (Print or type name and address of transferee, including ZIP code)

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

          (Taxpayer Identification Number of transferee)

          the within Senior Note and all rights  thereunder,  hereby irrevocably
constituting and appointing  ____________________  attorney-in-fact  to transfer
said Senior Note on the books of the Company with full power of  substitution in
the premises.

          In connection with any transfer of this Senior Note occurring prior to
the date that is the  earlier  of the date of an  effective  Shelf  Registration
Statement or the

<PAGE>

Resale  Restriction  Termination  Date,  the  undersigned  confirms that without
utilizing any general solicitation or general advertising:

          [Check One]

          ____      Such Senior Note is being transferred in accordance with (i)
                    the transfer restrictions set forth in the Indenture and the
                    Senior  Notes (and such  transfer is subject to the right of
                    the   Company   and  the   Trustee  to  require   additional
                    information   from  the  undersigned,   including,   without
                    limitation,  an opinion of counsel) and (ii) Rule 144A under
                    the  Securities  Act to a  transferee  that  the  transferor
                    reasonably  believes is purchasing  the Senior Notes for its
                    own  account  or  an  account  with  respect  to  which  the
                    transferee  exercises sole  investment  discretion,  and the
                    transferee   and   any   such   account   is  a   "Qualified
                    Institutional  Buyer"  within the meaning of Rule 144A or an
                    Institutional Accredited Investor within the meaning of Rule
                    501(a)(1),  (2), (3) or (7) under the Securities Act that is
                    acquiring  the  Senior  Note for its own  account or for the
                    account of such an investor for investment  purposes and not
                    with a view to, or for offer or sale in connection with, any
                    distribution  in violation of the  Securities  Act, and such
                    transferee  is aware  that  the sale to it is being  made in
                    reliance upon Rule 144A or Regulation D, as the case may be,
                    in each case in a transaction  meeting the  requirements  of
                    Rule  144A or  Regulation  D,  as the  case  may be,  and in
                    accordance with any applicable  securities laws of any state
                    of the United States or any other jurisdiction.

          or

          ____      Such  Senior  Note  is  being  transferred  pursuant  to  an
                    exemption  from   registration   under  the  Securities  Act
                    provided by Rule 144 thereunder upon provision of an opinion
                    of counsel and such other evidence acceptable to the Company
                    that such offer,  sale,  pledge or transfer is in compliance
                    with the Securities Act and other  applicable  laws, in each
                    case in a form satisfactory to the Company.

          or

          ____      Such Senior Note is being transferred in a transaction other
                    than in accordance  with the above upon provision of a legal
                    opinion and


                                       2
<PAGE>

                    other  evidence   requested  by  the  Company  in  form  and
                    substance  satisfactory  to the Company,  to the effect that
                    the proposed transfer is being made pursuant to an exemption
                    from, or in a transaction  not subject to, the  registration
                    requirements of the Securities Act.

          If none of the  foregoing  boxes  is  checked,  the  Trustee  or other
Registrar shall not be obligated to register this Senior Note in the name of any
person other than the Holder hereof unless and until the  conditions to any such
transfer of  registration  set forth herein and in Section 2.20 of the Indenture
shall have been satisfied.

          This certificate and the statements contained herein are made for your
benefit  and  the  benefit  of the  Initial  Purchaser  named  in  the  Offering
Memorandum  distributed by the Company and the Guarantor in connection  with the
initial sale of the Senior Notes.

          You are  entitled  to  rely  upon  this  letter  and  are  irrevocably
authorized  to produce this letter or a copy hereof to any  interested  party in
any  administrative  or legal proceeding or official inquiry with respect to the
matters covered hereby.

                                      [Insert Name of Transferor]

                                      By:______________________________________
                                             Name:
                                             Title:

                                      Dated: ____________________



(N.B.: The signature to this assignment must correspond with the name as written
upon the face of the  within-mentioned  instrument in every particular,  without
alteration or any change whatsoever)


       TO BE COMPLETED BY PURCHASER IF THE FIRST OPTION ABOVE IS CHECKED.

          Signatures must be guaranteed by an "eligible  guarantor  institution"
meeting the requirements of the Registrar, which requirements include membership
or participation in the Security  Transfer Agent Medallion  Program ("STAMP") or
such


                                      3
<PAGE>


other  "signature  guarantee  program" as may be  determined by the Registrar in
addition  to,  or in  substitution  for,  STAMP,  all  in  accordance  with  the
Securities Exchange Act of 1934, as amended.

          The  undersigned  represents  and warrants that it is purchasing  this
Senior Note for its own account or an account with respect to which it exercises
sole  investment  discretion  and that it and any such  account is a  "qualified
institutional buyer" within the meaning of Rule 144A under the Securities Act or
an "institutional  accredited investor" within the meaning of Rule 501 under the
Securities Act and to the extent the  undersigned is a "qualified  institutional
buyer," the  undersigned  acknowledges  that it has  received  such  information
regarding  the  Company  and the  Guarantor  as the  undersigned  has  requested
pursuant to Rule 144A or has determined not to request such information and that
it is aware that the  transferor  is relying  upon the  undersigned's  foregoing
representations  in order to claim the exemption from  registration  provided by
Rule 144A.

                                      Date:___________________________

                  (NOTICE:  To be executed by an executive officer)





                              PAYMENT INSTRUCTIONS

          The assignee should include the following for purposes of payment:

          Payment shall be made, by wire transfer or otherwise,  in  immediately
available    funds,    to    _____________________,    for   the    account   of
___________________,  account  number  ___________,  or, if mailed,  by check to
_____________________.  Applicable  reports and  statements  should be mailed to
_____________________.  This  information is provided by  _____________________,
the assignee named above, or _____________________, as its agent.


                                       4
<PAGE>

                                                                       EXHIBIT C

                          FORM OF EXCHANGE CERTIFICATE



Alliant Energy Resources, Inc. (the "Company")
Alliant Energy Corporation, as guarantor (the "Guarantor")
Firstar Bank, N.A., as Trustee (the "Trustee")

RE:  Alliant  Energy  Resources,  Inc. 7 3/8% Senior Notes Due 2009 (the "Senior
     Notes")



Ladies and Gentlemen:

     Reference is hereby made to the Indenture, dated as of November 4, 1999 (as
supplemented  by the First  Supplemental  Indenture dated as of November 4, 1999
and as further  supplemented  and amended from time to time,  the  "Indenture"),
among the Company,  the Guarantor,  and the Trustee.  Capitalized terms used but
not defined herein shall have the meanings given to them in the Indenture. Other
terms shall have the meanings given to them in Rule 144A ("Rule 144A") under the
Securities Act of 1933, as amended (the "Securities Act").

     In  connection  with our proposed sale of  $_________  aggregate  principal
amount of Senior Notes, we confirm that such sale has been effected  pursuant to
and in  accordance  with Rule 144A. We are aware that the transfer of the Senior
Notes to us is being made in reliance on the  exemption  from the  provisions of
Section 5 of the Securities Act provided by Rule 144A. Prior to the date of this
Certificate,  we have been given the  opportunity to obtain from the Company and
the Guarantor the information  referred to in Rule  144A(d)(4),  and have either
declined such opportunity or have received such information.

<PAGE>



     Each of you is entitled to rely upon this  Certificate  and is  irrevocably
authorized to produce this  Certificate or a copy hereof to any interested party
in any  administrative  or legal  proceeding or official inquiry with respect to
the matters covered hereby.



                                               Very truly yours,



                                      [Name of Purchaser]



                                      By:_________________________________
                                            Name:
                                            Title:



                                      Dated:  _________________________


                                       2
<PAGE>

                                   IAI Letter

                           FORM OF PURCHASE LETTER FOR
                       INSTITUTIONAL ACCREDITED INVESTORS


Alliant Energy Resources, Inc.
222 West Washington Avenue
Madison, Wisconsin  53703


Merrill Lynch & Co.


c/o Merrill Lynch & Co.
World Financial Center
North Tower
New York, NY  10281-1237


Dear Ladies and Gentlemen:


          The  undersigned  is  delivering  this  letter in  connection  with an
offering of 7 3/8% Senior Notes due 2009 (the "Senior  Notes") of Alliant Energy
Resources, Inc. (the "Company") all as described in the Offering Memorandum (the
"Offering Memorandum") relating to the offering.

          The undersigned hereby confirms, represents and warrants that:

          (i)  The undersigned is an "institutional  accredited investor" within
               the meaning of Rule  501(a)(1),  (2) or (3) under the  Securities
               Act of 1933 (the  "Securities  Act") or an entity in which all of
               the equity owners are accredited  investors within the meaning of
               Rule  501(a)(1),   (2)  or  (3)  under  the  Securities  Act  (an
               "Institutional Accredited Investor");

          (ii) (A) any purchase of the Senior Notes by the  undersigned  will be
               for the  undersigned's  own  account or for the account of one or
               more other Institutional Accredited Investors or as fiduciary for
               the  account  of  one  or  more  trusts,  each  of  which  is  an
               "institutional  accredited  investor"  within the meaning of Rule
               501(a)(7)  under  the  Securities  Act and for each of which  the
               undersigned exercises

<PAGE>

               sole  investment  discretion or (B) the  undersigned is a "bank,"
               within the meaning of Section 3(a)(2) of the Securities Act, or a
               "savings and loan association" or other institution  described in
               Section  3(a)(5)(A) of the  Securities  Act that is acquiring the
               Senior  Notes  as  fiduciary  for  the  account  of one  or  more
               institutions for which the undersigned  exercises sole investment
               discretion;

          (iii)In the event that the undersigned purchases any Senior Notes, the
               undersigned  will  acquire  the  Senior  Notes  having a  minimum
               principal amount of not less than $100,000 for its own account or
               for any separate account for which the undersigned is acting;

          (iv) The  undersigned  has such  knowledge and experience in financial
               and  business   matters  that  the   undersigned  is  capable  of
               evaluating the merits and risks of purchasing the Senior Notes;

          (v)  The  undersigned is not acquiring the Senior Notes with a view to
               distribution thereof or with any present intention of offering or
               selling the Senior  Notes,  except as permitted  below;  provided
               that the disposition of the  undersigned's  property and property
               of any accounts for which the  undersigned is acting as fiduciary
               shall remain at all times within the undersigned's control; and

          (vi) The  undersigned  has received a copy of the Offering  Memorandum
               and  acknowledges   that  the  undersigned  has  access  to  such
               financial  and  other  information,  and has  been  afforded  the
               opportunity  to ask  such  questions  of  representatives  of the
               Company and receive answers  thereto,  as the  undersigned  deems
               necessary in connection  with its decision to purchase the Senior
               Notes.

          The undersigned understands that the Senior Notes are being offered in
a transaction  not involving any public offering within the United States within
the  meaning  of the  Securities  Act and that the  Senior  Notes  have not been
registered under the Securities Act or any applicable state securities laws, and
the  undersigned  agrees,  on its own behalf and on behalf of each  account  for
which the  undersigned  acquires  any  Senior  Notes,  that if in the future the
undersigned  decides to resell or otherwise  transfer  such Senior  Notes,  such
Senior Notes may be resold or otherwise  transferred  only (a) to the Company or
any  subsidiary  thereof,  (b)  inside  the  United  States to a person who is a
"qualified  institutional  buyer" (as defined in Rule 144A under the  Securities
Act) in a  transaction  meeting the  requirements  of Rule 144A,  (c) inside the
United  States  to an


                                       2
<PAGE>


Institutional Accredited Investor that, prior to such transfer, furnishes to the
trustee (or transfer  agent,  as the case may be) for such Senior Notes a signed
letter  containing  certain  representations  and  agreements  relating  to  the
restrictions  on transfer of such Senior  Notes (the form of which letter can be
obtained from such  Trustee),  (d) pursuant to the exemption  from  registration
provided by Rule 144 under the Securities Act (if applicable) or (e) pursuant to
a registration  statement which has been declared effective under the Securities
Act. The  undersigned  agrees that any such transfer of Senior Notes referred to
in this paragraph shall be in accordance with applicable  securities laws of any
state  of  the  United  States  or  any  other  applicable  jurisdiction  and in
accordance  with the  legends  set forth on the  Senior  Notes,  and that it has
provided the Company with a written  opinion of legal  counsel who is acceptable
to the Company to the effect that, and such other  certification  or information
as the Company may reasonably  require to confirm that, the proposed transfer is
being made pursuant to an exemption  from,  or in a transaction  not subject to,
the  registration  requirements of the Securities  Act. The undersigned  further
agrees to  provide  any  person  purchasing  any of the  Senior  Notes  from the
undersigned a notice  advising such  purchaser that resales of such Senior Notes
are  restricted  as  stated  herein  (unless  the  sale of  securities  has been
registered  under the Securities  Act).  The  undersigned  understands  that the
registrar and transfer agent for the Senior Notes will not be required to accept
for  registration  of transfer any Senior  Notes,  except upon  presentation  of
evidence satisfactory to the Company that the foregoing restrictions on transfer
have been complied with. The  undersigned  further  understands  that any Senior
Notes  will be in the form of  definitive  physical  certificates  and that such
certificates  will bear a legend  (unless the sale of the Senior  Notes has been
registered under the Securities Act) reflecting the substance of this paragraph.

          The undersigned  acknowledges that the Company, the Guarantor,  others
and you will  rely upon the  undersigned's  confirmations,  acknowledgments  and
agreements set forth herein,  and the undersigned  agrees to notify you promptly
in writing  if any of its  representations  or  warranties  herein  ceases to be
accurate and complete.

          THE LETTER SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE
INTERNAL LAWS OF THE STATE OF WISCONSIN.



------------------------------------------
(Name of Purchaser)


By:_______________________________________


Name:____________________________________



                                       3