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                                                                     EXHIBIT 4.3

                            THE ALLSTATE CORPORATION

                         FIRST SUPPLEMENTAL INDENTURE TO
                        INDENTURE DATED DECEMBER 16, 1997
                            (SENIOR DEBT SECURITIES)

                                  $250,000,000

                 7 1/8 % Senior Quarterly Interest Bonds due 2097

                  FIRST SUPPLEMENTAL INDENTURE, dated as of December 16, 1997,
between THE ALLSTATE CORPORATION, a Delaware corporation (the "Company"), and
STATE STREET BANK AND TRUST COMPANY, a Massachusetts trust company, as Trustee
(the "Trustee").

                                    RECITALS

                  The Company has heretofore executed and delivered to the
Trustee an Indenture for Senior Debt Securities, dated as of December 16, 1997
(the "Indenture"), providing for the issuance from time to time of series of the
Company's Securities.

                  Section 301 of the Indenture provides for various matters with
respect to any series of Securities issued under the Indenture to be established
in an indenture supplemental to the Indenture.

                  Section 901(7) of the Indenture provides for the Company and
the Trustee to enter into an indenture supplemental to the Indenture to
establish the form or terms of Securities of any series as provided by
Sections 201 and 301 of the Indenture.

                  NOW, THEREFORE, THIS FIRST SUPPLEMENTAL INDENTURE
WITNESSETH:

                  For and in consideration of the premises and the issuance of
the series of Securities provided for herein, it is mutually agreed, for the
equal and proportionate benefit of all Holders of the Securities of such series,
as follows:




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                                    ARTICLE I

                       Relation to Indenture; Definitions

              Section 1.1. Relation to Indenture. This First Supplemental
Indenture constitutes an integral part of the Indenture.

              Section 1.2. Definitions. For all purposes of this First
Supplemental Indenture:

              (a) Capitalized terms used herein without definition shall have
the meanings specified in the Indenture;

              (b) All references herein to Articles and Sections, unless
otherwise specified, refer to the corresponding Articles and Sections of this
First Supplemental Indenture; and

              (c) The terms "herein", "hereof", "hereunder" and other words of
similar import refer to this First Supplemental Indenture.


                                   ARTICLE II

                            The Series of Securities

              Section 2.1. Title of the Securities. There shall be a series of
Securities designated the "71/8 % Senior Quarterly Interest Bonds due 2097" (the
"Bonds").

              Section 2.2. Limitation on Aggregate Principal Amount; Date of
Bonds. The aggregate principal amount of the Bonds which may be authenticated
and delivered under this Supplemental Indenture shall be limited to $250,000,000
(except for Bonds which may be authenticated and delivered upon transfer of, or
in exchange for, or in lieu of Bonds pursuant to the Indenture).

              Section 2.3. Principal Payment Date.

                   (a) The principal amount of the Bonds (together with any
         accrued and unpaid interest) shall be payable in a single installment
         on December 15, 2097, which date shall be the Stated Maturity of the
         principal amount of the Bonds.

                   (b) Notwithstanding the foregoing, upon the occurrence of a
         Tax Event, as defined below, the Company shall have the right to
         shorten the maturity of the Bonds to the extent required, in the
         opinion of a nationally recognized independent tax counsel experienced
         in such matters, so that, after such shortening of the maturity,
         interest paid on


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         the Bonds shall be deductible by the Company for United States federal
         income tax purposes.

                   (c) If the maturity of the Bonds is shortened upon the
         occurrence of a Tax Event, the Company shall mail a notice to each
         Holder of the Bonds by first-class mail not more than 60 days after the
         occurrence of such Tax Event, stating the new maturity date of the
         Bonds, which date thereafter shall be the Stated Maturity of the
         principal amount of the Bonds. Such notice shall be effective
         immediately upon mailing.

                   (d) "Tax Event" means that the Company has received an
         opinion of a nationally recognized independent tax counsel experienced
         in such matters to the effect that on or after the date of the issuance
         of the Bonds, as a result of (a) any amendment to, clarification of, or
         change (including any announced prospective change) in laws, or any
         regulations thereunder, of the United States; (b) any judicial
         decision, official administrative pronouncement, ruling, regulatory
         procedure, notice or announcement, including any notice or announcement
         of intent to adopt such procedures or regulations (an "Administrative
         Action"); or (c) any amendment to, clarification of, or change in the
         official position or the interpretation of such Administrative Action
         or judicial decision that differs from the theretofore generally
         accepted position, in each case, on or after the date of the issuance
         of the Bonds, there is more an than insubstantial risk that interest
         paid by the Company on the Bonds is not, or will not be deductible, in
         whole or in part, by the Company for purposes of federal income tax.

                  Section 2.4. Interest and Interest Rates. The rate of interest
on each Bond shall be 71/8 % per annum, accruing from December 19, 1997, or from
the most recent interest payment date (each such date, an "Interest Payment
Date") to which interest has been paid or duly provided for, payable quarterly
in arrears on March 15, June 15, September 15 and December 15 of each year
commencing March 15, 1998 until the principal thereof shall have become due and
payable, and until the principal hereof is paid or duly provided for or made
available for payment. The amount of interest payable on any Interest Payment
Date shall be computed on the basis of a 360-day year of twelve 30-day months.
The amount of interest payable for any partial period shall be computed on the
basis of the actual number of days elapsed in a 360-day year of twelve 30-day
months. In the event that any date on which interest is payable on any Bond is
not a Business Day, then payment of interest payable on such date will be made
on the next succeeding day that is a Business Day (and without any interest or
other payment in respect of any such delay). A "Business Day" shall mean any
day, other than a Saturday or Sunday, on which banks in the City of New York are
not required by law to close. The interest installment so payable in respect of
any Bond, and punctually paid or duly provided for, on any Interest Payment Date
will, as provided in the Indenture, be paid to the person in whose name such
Bond (or one or more Predecessor Securities) is registered at the close of
business on the 15th calendar day prior to such Interest Payment Date (a
"Regular Record Date"). Any such interest installment not punctually paid or
duly provided for in respect of any Bond shall forthwith cease to be payable to
the registered Holder on such Regular Record Date and may either


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be paid to the Person in whose name such Bond (or one or more Predecessor
Securities) is registered at the close of business on a Special Record Date to
be fixed by the Trustee for the payment of such Defaulted Interest, notice
whereof shall be given to the Holders of Bonds not less than 10 days prior to
such Special Record Date, or be paid at any time in any other lawful manner not
inconsistent with the requirements of any securities exchange on which the Bonds
may be listed, and upon such notice as may be required by such exchange, all as
more fully provided in the Indenture.

                  Section 2.5. Place of Payment. The Place of Payment where the
Bonds may be presented or surrendered for payment, where the Bonds may be
surrendered for registration of transfer or exchange and where notices and
demand to or upon the Company in respect of the Bonds and the Indenture may be
served shall be the Corporate Trust Office of the Trustee.

                  Section 2.6. Redemption. On or after December 19, 2002, the
Company may at any time, at its option, subject to the terms and conditions of
Article Eleven of the Indenture, redeem the Bonds in whole or in part, from time
to time, at 100% of the principal amount to be redeemed, plus accrued and unpaid
interest to the Redemption Date.

                  Section 2.7. Denomination. The Bonds shall be issuable in
book-entry form only and in denominations of $25 and integral multiples thereof.

                  Section 2.8. Currency. Principal and interest on the Bonds
shall be payable in such coin or currency of the United States of America that
at the time of payment is legal tender for payment of public and private debts.

                  Section 2.9. Form of Bonds. The Bonds shall be substantially
in the form attached as Exhibit A hereto.

                  Section 2.10. Securities Registrar and Paying Agent. The
Trustee shall serve initially as Securities Registrar and Paying Agent.

                  Section 2.11. Sinking Fund Obligations. The Company has no
obligation to redeem or purchase any Bonds pursuant to any sinking fund or
analogous requirement or upon the happening of a specified event or at the
option of a Holder thereof.

                  Section 2.12 Defeasance and Covenant Defeasance. Pursuant to
Section 1301 of the Indenture, the Company hereby designates the Bonds as
defeasible pursuant to Section 1302 (relating to defeasance and discharge) and
Section 1303 (relating to covenant defeasance) of the Indenture.

                  Section 2.13 Immediately Available Funds. All payments of
principal and interest on the Bonds shall be made in immediately available
funds.



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                                   ARTICLE III

                                    Expenses

                  Section 3.1. Payment of Expenses. In connection with the
offering, sale and issuance of the Bonds, the Company, in its capacity as
borrower with respect to the Bonds, shall pay all costs and expenses relating to
the offering, sale and issuance of the Bonds, including commissions to the
underwriters payable pursuant to the Underwriting Agreement and compensation and
expenses of the Trustee under the Indenture in accordance with the provisions of
Section 607 of the Indenture.

                  Section 3.2. Payment Upon Resignation or Removal. Upon
termination of this First Supplemental Indenture or the Indenture or the removal
or resignation of the Trustee, unless otherwise stated, the Company shall pay to
the Trustee all amounts accrued to the date of such termination, removal or
resignation.



                                   ARTICLE IV

                            Miscellaneous Provisions

                  Section 4.1. 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.

                  Section 4.2. Adoption, Ratification and Confirmation. The
Indenture, as supplemented and amended by this First Supplemental Indenture, is
in all respects hereby adopted, ratified and confirmed.

                  Section 4.3. Counterparts. This First Supplemental Indenture
may be executed in any number of counterparts, each of which shall be an
original, but such counterparts shall together constitute but one and the same
instrument.

                  Section 4.4. GOVERNING LAW. THIS FIRST SUPPLEMENTAL INDENTURE
AND EACH BOND SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE INTERNAL
LAWS OF THE STATE OF NEW YORK.




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                  IN WITNESS WHEREOF, the parties hereto have caused this First
Supplemental Indenture to be duly executed, and their respective corporate seals
to be hereunto affixed and attested, on the date or dates indicated in the
acknowledgments and as of the day and year first above written.


                                            THE ALLSTATE CORPORATION

                                                     
                                            By:  /s/  James P. Zils
                                                 -----------------------------
                                            Name:   James P. Zils
                                            Title:  Treasurer


ATTEST:

         
By:  /s/ Robert W. Pike  
    -------------------------
Name:  Robert W. Pike
Title: Vice President, Secretary
           and General Counsel


                                            STATE STREET BANK AND TRUST 
                                            COMPANY, as Trustee


                                                     
                                            By:  /s/ James Mogavero
                                                -------------------------------
                                            Name:   James Mogavero
                                            Title:  Vice President




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                                                                       EXHIBIT A
                           (FORM OF FACE OF SECURITY)

                  This Security is a Global Security within the meaning of the
Indenture hereinafter referred to and is registered in the name of a Depositary
or a nominee of a Depositary. This Security is exchangeable for Securities
registered in the name of a person other than the Depositary or its nominee only
in the limited circumstances described in the Indenture, and no transfer of this
Security (other than a transfer of this Security as a whole by the Depositary to
a nominee of the Depositary or by a nominee of the Depositary to the Depositary
or another nominee of the Depositary) may be registered except in limited
circumstances.

                  Unless this Security is presented by an authorized
representative of The Depository Trust Company (55 Water Street, New York, New
York) to the issuer or its agent for registration of transfer, exchange or
payment, and any Security issued is registered in the name of Cede & Co. or such
other name as requested by an authorized representative of The Depository Trust
Company and any payment hereon is made to Cede & Co., ANY TRANSFER, PLEDGE OR
OTHER USE HEREOF FOR VALUE OR OTHERWISE BY A PERSON IS WRONGFUL since the
registered owner hereof, Cede & Co., has an interest herein.

Certificate No.                                                   $_____________
                                                            CUSIP No.  _________



                            THE ALLSTATE CORPORATION

                 7 1/8 % Senior Quarterly Interest Bonds due 2097

                  THE ALLSTATE CORPORATION, a Delaware corporation (the
"Company," which term includes any successor corporation under the Indenture
hereinafter referred to), for value received, hereby promises to pay to CEDE &
CO. or registered assigns, the principal sum of ____________ ($__________) on
December 15, 2097. The Company further promises to pay interest on said
principal sum outstanding from December 19, 1997, or from the most recent
interest payment date (each such date, an "Interest Payment Date") to which
interest has been paid or duly provided for, quarterly in arrears on March 15,
June 15, September 15 and December 15 of each year commencing March 15, 1998, at
the rate of 71/8 % per annum, until the principal hereof shall have become due
and payable and, until the principal hereof is paid or duly provided for or made
available for payment. If, however, a Tax Event (as defined below) occurs, the
Company shall have the right to shorten the maturity of this Security as
provided below. The amount of interest payable on any Interest Payment Date
shall be computed on the basis of a 360-day year of twelve 30-day months. The
amount of interest payable for any partial period shall be computed on the basis
of the number of actual days elapsed in a 360-day year of twelve 30-day months.
In the event that any date on which interest is payable on this Security is not
a Business Day, then payment of interest payable on such date will be made on
the next succeeding day that is a Business Day (and without any


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interest or other payment in respect of any such delay). A "Business Day" shall
mean any day, other than a Saturday or Sunday, on which the banks in the City of
New York are not required by law to close. The interest installment so payable,
and punctually paid or duly provided for, on any Interest Payment Date will, as
provided in the Indenture, be paid to the Person in whose name this Security (or
one or more Predecessor Securities) is registered at the close of business on
the 15th calendar day prior to such Interest Payment Date (a "Regular Record
Date"). Any such interest installment not punctually paid or duly provided for
shall forthwith cease to be payable to the registered Holder on such Regular
Record Date and may either be paid to the Person in whose name this Security (or
one or more Predecessor Securities) is registered at the close of business on a
Special Record Date to be fixed by the Trustee for the payment of such Defaulted
Interest, notice whereof shall be given to the Holder of this Security not less
than 10 days prior to such Special Record Date, or be paid at any time in any
other lawful manner not inconsistent with the requirements of any securities
exchange on which this Security may be listed, and upon such notice as may be
required by such exchange, all as more fully provided in the Indenture.

                  The principal of (and premium, if any) and the interest on
this Security shall be payable at the office or agency of the Company maintained
for that purpose in the United States in such coin or currency of the United
States of America that at the time of payment is legal tender for payment of
public and private debts; provided, however, that payment of interest may be
made at the option of the Company by check mailed to the registered Holder at
such address as shall appear in the Security Register. Notwithstanding the
foregoing, so long as the Holder of this Security is The Depository Trust
Company (or its nominee, including, without limitation, Cede & Co.), the payment
of the principal of (and premium, if any) and interest on this Security will be
made at such place and to such account as may be designated by The Depository
Trust Company (or its nominee, including, without limitation, Cede & Co.). All
payments of principal and interest hereunder shall be made in immediately
available funds.

                  Reference is hereby made to the further provisions of this
Security set forth below, which further provisions shall for all purposes have
the same effect as if set forth at this place.

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


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                  IN WITNESS WHEREOF, the Company has caused this instrument to
be executed.

                                             THE ALLSTATE CORPORATION



                                             By:
                                                -------------------------------
                                             Name:
                                             Title:



Attest:



By:
   -----------------------------
   Name:
   Title:


                          CERTIFICATE OF AUTHENTICATION

                  This is one of the Securities of the series designated herein
referred to in the within-mentioned Indenture.

Dated:

STATE STREET BANK AND TRUST COMPANY,
as Trustee



By:
   -----------------------------------------
           Authorized Signatory



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                          (FORM OF REVERSE OF SECURITY)

         This Security is one of a duly authorized issue of a series of
Securities of the Company, designated as its 7 1/8 % Senior Quarterly Interest
Bonds due 2097, issued under and pursuant to an Indenture, dated as of December
16, 1997 between the Company and State Street Bank and Trust Company, as Trustee
(herein called the "Trustee," which term includes any successor trustee under
the Indenture), as supplemented by the First Supplemental Indenture, dated as of
December 16, 1997, between the Company and the Trustee (the Indenture as so
supplemented, the "Indenture"), to which Indenture and all indentures
supplemental thereto reference is hereby made for a description of the rights,
limitations of rights, obligations, duties and immunities thereunder of the
Trustee, the Company and the Holders of this Security and the other Securities
of this series, and of the terms upon which this Security and the other
Securities of this series are, and are to be, authenticated and delivered.

                  All terms used in this Security that are defined in the
Indenture shall have the meanings assigned to them in the Indenture.

                  On or after December 19, 2002, the Company may at any time, at
its option, subject to the terms and conditions of Article Eleven of the
Indenture, redeem this Security in whole or in part at any time or in part from
time to time, at 100% of the principal amount to be redeemed, plus accrued and
unpaid interest to the Redemption Date.

                  In the event of redemption of this Security in part only, a
new Security or Securities of this series for the unredeemed portion hereof will
be issued in the name of the Holder hereof upon the cancellation hereof.

                  If an Event of Default with respect to Securities of this
series shall occur and be continuing, the principal of the Securities of this
series may be declared due and payable in the manner, with the effect and
subject to the conditions provided in the Indenture.

                   Upon the occurrence of a Tax Event, as defined below, the
Company shall have the right to shorten the maturity of this Security to the
extent required, in the opinion of a nationally recognized independent tax
counsel experienced in such matters, so that, after such shortening of the
maturity, interest paid on this Security shall be deductible by the Company for
United States federal income tax purposes.

                  If the maturity of this Security is shortened upon the
occurrence of a Tax Event, the Company shall mail a notice to each Holder of
this Security by first-class mail not more than 60 days after the occurrence of
such Tax Event, stating the new maturity date of this Security, which date
thereafter shall be the Stated Maturity of the principal amount hereof. Such
notice shall be effective immediately upon mailing.



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                  "Tax Event" shall mean that the Company has received an
opinion of a nationally recognized independent tax counsel experienced in such
matters to the effect that on or after the date of the issuance of this
Security, as a result of (a) any amendment to, clarification of, or change
(including any announced prospective change) in laws, or any regulations
thereunder, of the United States; (b) any judicial decision, official
administrative pronouncement, ruling, regulatory procedure, notice or
announcement, including any notice or announcement of intent to adopt such
procedures or regulations (an "Administrative Action"); or (c) any amendment to,
clarification of, or change in the official position or the interpretation of
such Administrative Action or judicial decision that differs from the
theretofore generally accepted position, in each case, on or after the date of
the issuance of this Security, there is more than an insubstantial risk that
interest paid by the Company on this Security is not, or will not be deductible,
in whole or in part, by the Company for purposes of federal income tax.

                  The Indenture contains provisions for satisfaction, discharge
and defeasance at any time of the entire indebtedness of this Security upon
compliance by the Company with certain conditions set forth in the Indenture.
Pursuant to Section 1301 of the Indenture, the Company has designated this
Security as being defeasible pursuant to Section 1302 and Section 1303 of the
Indenture.

                  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 rights of the Holders of the Securities of
each series to be affected under the Indenture at any time by the Company and
the Trustee with the consent of the Holders of a majority in principal amount of
the Securities of each series at the time Outstanding of each series to be
affected. The Indenture also contains provisions permitting Holders of specified
percentages in principal amount of the Securities of each series at the time
Outstanding, on behalf of the Holders of all Securities of such series, to waive
compliance by the Company 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 Security shall be conclusive and binding upon such
Holder and upon all future Holders of this Security and of any Security issued
upon the registration of transfer hereof or in exchange therefor or in lieu
hereof, whether or not notation of such consent or waiver is made upon this
Security.

                  No reference herein to the Indenture and no provision of this
Security or of the Indenture (other than Section 1302 and Section 1303 of the
Indenture) shall alter or impair the obligation of the Company to pay the
principal and interest on this Security at the times, place and rate, and in the
coin or currency, herein prescribed.

                  As provided in the Indenture and subject to certain
limitations therein set forth, the transfer of this Security is registrable in
the Securities Register, upon surrender of this Security for registration of
transfer at the office or agency of the Company maintained under Section 1002 of
the Indenture duly endorsed by, or accompanied by a written instrument of
transfer, in form satisfactory to the Company and the Securities Registrar, duly
executed by the Holder hereof or his or her


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