EXHIBIT
      4.2




**Execution
      Copy**










**MIDAMERICAN
      ENERGY COMPANY**




and




**THE
      BANK OF NEW YORK TRUST COMPANY, NA,**




as
      Trustee




________________




5.800 %
      Notes
      due 2036




________________




First
      Supplemental Indenture




________________




Dated
      as
      of October 6, 2006

















FIRST
      SUPPLEMENTAL INDENTURE, dated as of October 6, 2006 (herein called the
“ First
      Supplemental Indenture ”),
      between MIDAMERICAN ENERGY COMPANY, a corporation duly organized and existing
      under the laws of the State of Iowa (herein called the “ Company ”),
      and
      THE BANK OF NEW YORK TRUST COMPANY, NA, a New York banking association duly
      organized and existing under the laws of the United States of America, as
      Trustee (herein called the “ Trustee ”),
      under
      the Original Indenture referred to below.




W
      I T N E
      S S E T H :




WHEREAS,
      the Company has heretofore executed and delivered to the Trustee an indenture
      dated as of October 1, 2006 (herein called the “ Original
      Indenture ”),
      to
      provide for the issuance from time to time of its unsubordinated debentures,
      notes or other evidences of indebtedness, the form and terms of which are to
      be
      established as set forth in Sections 2.01 and 3.01 of the Original
      Indenture;




WHEREAS,
      Section 9.01 of the Original Indenture provides, among other things, that the
      Company and the Trustee may enter into indentures supplemental to the Original
      Indenture for, among other things, (i) the purpose of establishing the form
      and
      terms of the Securities (as defined in the Original Indenture) of any series
      as
      permitted by Sections 2.01 and 3.01 of the Original Indenture, and (ii) to
      add
      to the covenants of the Company for the benefit of the Holders of all or any
      series of Securities (as defined in the Original Indenture);




WHEREAS,
      the Company desires to create one series of securities to be designated the
      “ 5.800 %
      Notes
      due 2036” and all action on the part of the Company necessary to authorize the
      issuance of up to three hundred fifty million dollars ($350,000,000) aggregate
      principal amount of such securities (the “ Securities ”)
      under
      the Original Indenture and this First Supplemental Indenture has been duly
      taken;




WHEREAS,
      the Company and the Trustee desire to make certain amendments to the Original
      Indenture in conformance with the requirements described above; and




WHEREAS,
      all acts and things necessary to make the Securities, when executed by the
      Company and authenticated and delivered by the Trustee as provided in the
      Original Indenture, the valid and binding obligations of the Company and to
      constitute these presents a valid and binding supplemental indenture and
      agreement according to its terms, have been done and performed.




NOW,
      THEREFORE, THIS FIRST SUPPLEMENTAL INDENTURE WITNESSETH:






1






That
      in
      consideration of the premises and of the acceptance and purchase of the
      Securities by the holders thereof and of the acceptance of this trust by the
      Trustee, the Company covenants and agrees with the Trustee, for the equal
      benefit of holders of the Securities, as follows:




ARTICLE
      I


DEFINITIONS




Unless
      otherwise defined herein, the use of the terms and expressions herein is in
      accordance with the definitions, uses and constructions contained in the
      Original Indenture and the form of Security attached hereto as Exhibit
      A .




ARTICLE
      II


TERMS
      AND
      ISSUANCE OF THE SECURITIES




Section
      2.01. *Issue
      of Securities* .
      One
      series of notes, which shall be designated the “ 5.800 %
      Notes
      due 2036”, shall be executed, authenticated and delivered in accordance with the
      provisions of, and shall in all respects be subject to, the terms, conditions
      and covenants of the Original Indenture and this First Supplemental Indenture
      (including the form of Security set forth in Exhibit
      A ).




Section
      2.02. *Optional
      Redemption* .
      The
      Securities may be redeemed, in whole or in part, at the option of the Company
      pursuant to the terms set forth in Annex
      1 to the
      Securities to be redeemed. The provisions of Article XI of the Original
      Indenture shall also apply to any optional redemption of Securities by the
      Company.




Section
      2.03. *Defeasance
      and Discharge* .
      The
      provisions of Section 14.02 of the Original Indenture shall be applicable to
      the
      Securities.




Section
      2.04. *Covenant
      Defeasance* .
      The
      provisions of Section 14.03 of the Original Indenture shall be applicable to
      the
      Securities.




Section
      2.05. *Place
      of Payment* .
      The
      Place of Payment in respect of the Securities will be initially at the Corporate
      Trust Office of The Bank of New York Trust Company, NA (which as of the date
      hereof is located at 2 N. LaSalle Street, Suite 1020, Chicago, Illinois 60602,
      Attention: Corporate Trust Administration).






2




Section
      2.06. *Form
      of Securities; Incorporation of Terms* .
      The
      form of the Securities shall be substantially in the form of Exhibit
      A ,
      the
      terms of which are herein incorporated by reference and which are part of this
      First Supplemental Indenture. The Securities shall be issued as one or more
      Global Securities in fully registered form, as determined in accordance with
      Section 2.01 of the Original Indenture. The Global Securities shall be delivered
      by the Trustee to the Depositary, as the Holder thereof, or a nominee or
      custodian therefore, to be held by the Depositary in accordance with the
      Original Indenture.




Section
      2.07. *Exchange
      of the Global Securities* .
      Each of
      the Global Securities shall be exchangeable for definitive Securities only
      as
      provided in Section 3.05 of the Original Indenture.




Section
      2.08. *Regular
      Record Date for the Securities* .
      The
      Regular Record Date for the Securities shall be the February 1  or
      August
      1  immediately
      prior to each Interest Payment Date.




Section
      2.09. *Authorized
      Denominations.* Beneficial
      interests in Global Securities, as well as definitive Securities, may be held
      only in denominations of $1,000 and integral multiples of $1,000 in excess
      thereof.




Section
      2.10. *Additional
      Securities.* The
      Company may from time to time, without the consent of the Holders of the
      Securities, create and issue further securities having the same terms and
      conditions as the Securities in all respects, except for the original issue
      date
      and offering price. Additional Securities issued in this manner will be
      consolidated with, and form a single series with, the Securities and shall
      thereafter be deemed Securities for all purposes.




ARTICLE
      III


DEPOSITARY




Section
      3.01. *Depositary* .
      The
      Depositary Trust Company, its nominees and their respective successors are
      hereby appointed Depositary with respect to the Global Securities.




ARTICLE
      IV


MISCELLANEOUS




Section
      4.01. *Execution
      as Supplemental Indenture* .
      This
      First Supplemental Indenture is executed and shall be construed as an indenture
      supplemental to the Original Indenture and, as provided in the Original
      Indenture, this First Supplemental Indenture forms a part thereof.




Section
      4.02. *Effect
      of Headings* .
      The
      Article and Section headings herein are for convenience only and shall not
      affect the construction hereof.




3




Section
      4.03. *Successors
      and Assigns* .
      All
      covenants and agreements contained in this First Supplemental Indenture made
      by
      the Company shall bind its successors and assigns, whether so expressed or
      not.




Section
      4.04. *Separability
      Clause* .
      In case
      any provision in this First Supplemental Indenture or in the Securities 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
      4.05. *Benefits
      of First Supplemental Indenture* .
      Nothing
      in this First Supplemental Indenture or in the Securities, express or implied,
      shall give to any person, other than the parties hereto and their successors
      hereunder and the Holders of the Securities, any benefit or any legal or
      equitable right, remedy or claim under this First Supplemental
      Indenture.




Section
      4.06. *Execution
      and Counterparts* .
      This
      First Supplemental Indenture may be executed in any number of counterparts,
      each
      of which shall be deemed to be an original, but all such counterparts shall
      together constitute but one and the same instrument.




Section
      4.07. *Trustee
      Not Responsible for Recitals* .
      The
      recitals herein contained are made by the Company and not by the Trustee, and
      the Trustee assumes no responsibility for the correctness thereof. The Trustee
      makes no representation as to the validity or sufficiency of this First
      Supplemental Indenture or of the Securities. The Trustee shall not be
      accountable for the use or application by the Company of the Securities or
      the
      proceeds thereof.




**[** SIGNATURE
      PAGE FOLLOWS **]**






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IN
      WITNESS WHEREOF, the parties hereof have caused this First Supplemental
      Indenture to be duly executed by their respective officers or directors duly
      authorized thereto, all as of the day and year first above written.




MIDAMERICAN
              ENERGY
              COMPANYBy:
            /s/ Brian
              K. HankelName: Brian K. HankelTitle:
              Vice President and Treasurer




THE
                BANK OF NEW YORK TRUST COMPANY, NA,as
              TrusteeBy:
            /s/ Roxane
              EllwangerName: Roxane EllwangerTitle:
              Assistant Vice President




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