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                                                                    EXHIBIT 10.1

                        PACKAGING CORPORATION OF AMERICA

                                  $150,000,000

                            4 3/8% SENIOR NOTES DUE 2008


                                  $400,000,000

                          5 3/4% SENIOR NOTES DUE 2013



                               PURCHASE AGREEMENT

July 15, 2003

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                                                                   July 15, 2003

Morgan Stanley & Co. Incorporated
Citigroup Global Markets Inc.
c/o  Morgan Stanley & Co. Incorporated
     1585 Broadway
     New York, New York 10036

Dear Sirs and Mesdames:

         Packaging Corporation of America, a Delaware corporation (the
"COMPANY"), proposes to issue and sell to the several purchasers named in
Schedule I hereto (the "INITIAL PURCHASERS") $150,000,000 principal amount of
its 4 3/8% Senior Notes due 2008 (the "4 3/8% NOTES") and $400,000,000 principal
amount of its 5 3/4% Senior Notes due 2013 (the "5 3/4% NOTES" and, together
with the 4 3/8% Notes, the "NOTES") to be issued pursuant to the provisions of
an Indenture dated as of July 21, 2003 (the "INDENTURE") between the Company and
U.S. Bank National Association, as Trustee (the "TRUSTEE").

         The Notes will be offered without being registered under the Securities
Act of 1933, as amended (the "SECURITIES ACT"), to qualified institutional
buyers in compliance with the exemption from registration provided by Rule 144A
under the Securities Act, in offshore transactions in reliance on Regulation S
under the Securities Act ("REGULATION S") and to institutional accredited
investors (as defined in Rule 501(a)(1), (2), (3) or (7) under the Securities
Act) that deliver a letter in the form annexed to the Final Memorandum (as
defined below).

         In connection with the sale of the Notes, the Company has prepared a
preliminary offering memorandum (the "PRELIMINARY MEMORANDUM") and will prepare
a final offering memorandum (the "FINAL MEMORANDUM" and, with the Preliminary
Memorandum, each a "MEMORANDUM") including or incorporating by reference a
description of the terms of the Notes, the terms of the offering and a
description of the Company. As used herein, the term "Memorandum" shall include
in each case the documents incorporated by reference therein. The terms
"SUPPLEMENT," "AMENDMENT" and "AMEND" as used herein with respect to a
Memorandum shall include all documents deemed to be incorporated by reference in
the Preliminary Memorandum or Final Memorandum that are filed subsequent to the
date of such Memorandum with the Securities and Exchange Commission (the
"COMMISSION") pursuant to the Securities Exchange Act of 1934, as amended (the
"EXCHANGE ACT").

         The holders of the Notes will be entitled to the benefits of a
Registration Rights Agreement (the "REGISTRATION RIGHTS AGREEMENT"), to be
entered into between the Company and you, as representatives of the Initial
Purchasers, as of the Closing Date (as defined below), pursuant to which the
Company will file a registration statement with the Commission registering the
Notes and Exchange Notes (as defined in the Registration Rights Agreement) under
the Securities Act.

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         1.       REPRESENTATIONS AND WARRANTIES. The Company represents and
warrants to, and agrees with, you that:

                  (a)      (i) Each document, if any, filed or to be filed
         pursuant to the Exchange Act and incorporated by reference in either
         Memorandum complied or will comply when so filed in all material
         respects with the Exchange Act and the applicable rules and regulations
         of the Commission thereunder and (ii) the Preliminary Memorandum does
         not contain and the Final Memorandum, in the form used by the Initial
         Purchasers to confirm sales and on the Closing Date (as defined in
         Section 4), will not contain any untrue statement of a material fact or
         omit to state a material fact necessary to make the statements therein,
         in the light of the circumstances under which they were made, not
         misleading, except that the representations and warranties set forth in
         this paragraph do not apply to statements or omissions in either
         Memorandum based upon information relating to any Initial Purchaser
         furnished to the Company in writing by such Initial Purchaser through
         you expressly for use therein.

                  (b)      The Company has been duly incorporated, is validly
         existing as a corporation in good standing under the laws of the State
         of Delaware, has the corporate power and authority to own its property
         and to conduct its business as described in each Memorandum and is duly
         qualified to transact business and is in good standing in each
         jurisdiction in which the conduct of its business or its ownership or
         leasing of property requires such qualification, except to the extent
         that the failure to be so qualified or be in good standing would not
         have a material adverse effect on the Company and its subsidiaries,
         taken as a whole.

                  (c)      Each subsidiary of the Company has been duly
         incorporated or organized, is validly existing as a corporation or
         limited liability company in good standing under the laws of the
         jurisdiction of its incorporation or organization, has the power and
         authority (corporate or otherwise) to own its property and to conduct
         its business as described in each Memorandum and is duly qualified to
         transact business and is in good standing in each jurisdiction in which
         the conduct of its business or its ownership or leasing of property
         requires such qualification, except to the extent that the failure to
         be so qualified or be in good standing would not have a material
         adverse effect on the Company and its subsidiaries, taken as a whole;
         all of the issued shares of capital stock of each subsidiary of the
         Company have been duly and validly authorized and issued and are fully
         paid and non-assessable and each such share owned directly or
         indirectly by the Company is owned free and clear of all liens,
         encumbrances, equities or claims (other than as the result of stock
         pledged under that certain Credit Agreement dated as of April 12, 1999
         and Amended and Restated as of June 29, 2000, among the Company, Morgan
         Guaranty Trust Company of New York, as Administrative Agent, J.P.
         Morgan Securities Inc. and Deutsche Bank Securities Inc., as Co-Lead
         Arrangers and Joint Book Runners, Deutsche Bank Securities Inc., as
         Syndication Agent, Goldman Sachs Credit Partners L.P., as Documentation
         Agent, and each of the Lenders from time to time a party thereto (the
         "EXISTING CREDIT AGREEMENT")).

                  (d)      This Agreement has been duly authorized, executed and
         delivered by the Company.

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                  (e)      The Notes have been duly authorized and, when
         executed and authenticated in accordance with the provisions of the
         Indenture and delivered to and paid for by the Initial Purchasers in
         accordance with the terms of this Agreement, will be valid and binding
         obligations of the Company, enforceable in accordance with their terms,
         subject to applicable bankruptcy, insolvency or similar laws affecting
         creditors' rights generally and general principles of equity, and will
         be entitled to the benefits of the Indenture.

                  (f)      The Indenture has been duly authorized, executed and
         delivered by, and is a valid and binding agreement of, the Company,
         enforceable against it in accordance with its terms, subject to
         applicable bankruptcy, insolvency or similar laws affecting creditors'
         rights generally and general principles of equity.

                  (g)      The Registration Rights Agreement has been duly

         authorized by the Company and, on the Closing Date, will have been duly
         executed and delivered by, and will be a valid and binding agreement
         of, the Company, enforceable against it in accordance with its terms,
         subject to applicable bankruptcy, insolvency or similar laws affecting
         creditors' rights generally and general principles of equity.

                  (h)      The Notes, the Indenture and the Registration Rights
         Agreement will conform in all material respects to the respective
         statements relating thereto contained in each Memorandum and will be in
         substantially the respective forms last delivered to the Initial
         Purchasers prior to the date of this Agreement.

                  (i)      The execution and delivery by the Company of, and the
         performance by the Company of its obligations under, this Agreement,
         the Indenture, the Registration Rights Agreement, the Notes and the
         Exchange Notes do not and will not contravene any provision of
         applicable law or the certificate of incorporation or by-laws of the
         Company or any agreement or other instrument binding upon the Company
         or any of its subsidiaries that is material to the Company and its
         subsidiaries, taken as a whole (other than the Existing Credit
         Agreement), or any judgment, order or decree of any governmental body,
         agency or court having jurisdiction over the Company or any subsidiary,
         and no consent, approval, authorization or order of, or qualification
         with, any governmental body or agency is required for the performance
         by the Company of its obligations under this Agreement, the Indenture,
         the Registration Rights Agreement, the Notes or the Exchange Notes,
         except such as may be required by the securities or Blue Sky laws of
         the various states in connection with the offer and sale of the Notes
         and by federal and state securities laws with respect to the Company's
         obligations under the Registration Rights Agreement.

                  (j)      There has not occurred any material adverse change,
         or any development involving a prospective material adverse change, in
         the condition, financial or otherwise, or in the earnings, business or
         operations of the Company and its subsidiaries, taken as a whole, from
         that set forth in the Final Memorandum.

                  (k)      There are no legal or governmental proceedings
         pending or threatened to which the Company or any of its subsidiaries
         is a party or to which any of the properties

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         of the Company or any of its subsidiaries is subject other than
         proceedings described in each Memorandum and proceedings that would not
         have a material adverse effect on the Company and its subsidiaries,
         taken as a whole, or on the power or ability of the Company to perform
         its obligations under this Agreement, the Indenture, the Registration
         Rights Agreement, the Notes or the Exchange Notes, or to consummate the
         transactions contemplated by the Final Memorandum.

                  (l)      The Company and its subsidiaries (i) are in
         compliance with any and all applicable foreign, Federal, state and
         local laws and regulations relating to the protection of human health
         and safety, the environment or hazardous or toxic substances or wastes,
         pollutants or contaminants ("ENVIRONMENTAL LAWS"), (ii) have received
         all permits, licenses or other approvals required of them under
         applicable Environmental Laws to conduct their respective businesses
         and (iii) are in compliance with all terms and conditions of any such
         permit, license or approval, except where such noncompliance with
         Environmental Laws, failure to receive required permits, licenses or
         other approvals or failure to comply with the terms and conditions of
         such permits, licenses or approvals would not, singly or in the
         aggregate, have a material adverse effect on the Company and its
         subsidiaries, taken as a whole.

                  (m)      Except as described in each Memorandum, there are no
         costs or liabilities associated with Environmental Laws (including,
         without limitation, any capital or operating expenditures required for
         clean-up, closure of properties or compliance with Environmental Laws
         or any permit, license or approval, any related constraints on
         operating activities and any potential liabilities to third parties)
         which would, singly or in the aggregate, have a material adverse effect
         on the Company and its subsidiaries, taken as a whole.

                  (n)      No labor dispute with the employees of the Company or
         any of its subsidiaries exists or, to the knowledge of the Company, is
         imminent, and the Company is not aware of any existing or imminent
         labor disturbance by the employees of any of its or any of its
         subsidiaries' principal suppliers, manufacturers, customers or
         contractors, which, in either case, may reasonably be expected to cause
         a material adverse change, or a prospective material adverse change, in
         the condition, financial or otherwise, or in the earnings, business or
         operations of the Company and its subsidiaries, taken as a whole, from
         that set forth in the Final Memorandum.

                  (o)      The Company and its subsidiaries possess all
         certificates, authorizations, approvals, licenses, registrations and
         permits issued by appropriate Federal, state or foreign regulatory
         authorities necessary to conduct their respective businesses, except
         where the failure to possess such certificates, authorizations,
         approvals, licenses, registrations or permits would not have a material
         adverse effect on the Company and its subsidiaries, taken as a whole,
         and neither the Company nor any such subsidiary has received notice of
         any proceedings relating to the revocation or modification of any such
         certificate, authorization, approval, license, registration or permit,
         except where such proceedings would not have a material adverse effect
         on the Company and its subsidiaries, taken as a whole.

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                  (p)      The Company is not, and after giving effect to the
         offering and sale of the Notes and the application of the proceeds
         thereof as described in the Final Memorandum, will not be required to
         register as, an "investment company" as such term is defined in the
         Investment Company Act of 1940, as amended.

                  (q)      Neither the Company nor any affiliate (as defined in
         Rule 501(b) of Regulation D under the Securities Act, an "AFFILIATE")
         of the Company has directly, or through any agent, (i) sold, offered
         for sale, solicited offers to buy or otherwise negotiated in respect
         of, any security (as defined in the Securities Act) which is or will be
         integrated with the sale of the Notes in a manner that would require
         the registration under the Securities Act of the Notes or (ii) engaged
         in any form of general solicitation or general advertising in
         connection with the offering of the Notes (as those terms are used in
         Regulation D under the Securities Act), or in any manner involving a
         public offering within the meaning of Section 4(2) of the Securities
         Act.

                  (r)      None of the Company, its Affiliates or any person
         acting on its or their behalf has engaged or will engage in any
         directed selling efforts (within the meaning of Regulation S) with
         respect to the Notes and the Company and its Affiliates and any person
         acting on its or their behalf have complied and will comply with the
         offering restrictions requirement of Regulation S, except no
         representation, warranty or agreement is made by the Company in this
         paragraph with respect to the Initial Purchasers.

                  (s)      Assuming the accuracy of the representations of the
         Initial Purchasers contained in Section 7 hereof, it is not necessary
         in connection with the offer, sale and delivery of the Notes to the
         Initial Purchasers in the manner contemplated by this Agreement to
         register the Notes under the Securities Act or to qualify the Indenture
         under the Trust Indenture Act of 1939, as amended.

                  (t)      The Notes satisfy the requirements set forth in Rule
         144A(d)(3) under the Securities Act.

         2.       AGREEMENTS TO SELL AND PURCHASE. The Company hereby agrees to
sell to the several Initial Purchasers, and each Initial Purchaser, upon the
basis of the representations and warranties herein contained, but subject to the
conditions hereinafter stated, agrees, severally and not jointly, to purchase
from the Company the respective principal amount, of 4 3/8% Notes and 5 3/4%
Notes set forth in Schedule I hereto opposite its name at a purchase price of
98.944% of the principal amount of 4 3/8% Notes and 98.493% of the principal
amount of 5 3/4% Notes (the "PURCHASE PRICE"), in each case, plus accrued
interest, if any, to the Closing Date.

         The Company hereby agrees that, without the prior written consent of
Morgan Stanley & Co. Incorporated and Citigroup Global Markets Inc. on behalf of
the Initial Purchasers, it will not, during the period beginning on the date
hereof and continuing to and including the Closing Date, offer, sell, contract
to sell or otherwise dispose of any debt securities of the Company or warrants
to purchase debt securities of the Company substantially similar to the Notes
(other than the sale of the Notes under this Agreement).

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         3.       TERMS OF OFFERING. You have advised the Company that the
Initial Purchasers will make an offering of the Notes purchased by the Initial
Purchasers hereunder, on the terms to be set forth in the Final Memorandum, as
soon as practicable after this Agreement is entered into as in your judgment is
advisable.

         4.       PAYMENT AND DELIVERY. Payment for the Notes shall be made to
the Company in Federal or other immediately available funds to an account
specified by the Company against delivery of such Notes for the respective
accounts of the several Initial Purchasers at 10:00 a.m., New York City time, on
July 21, 2003, or at such other time on the same or such other date, not later
than July 28, 2003, as shall be designated in writing by you. The time and date
of such payment are hereinafter referred to as the "CLOSING DATE."

         Certificates for the Notes shall be in definitive form or global form,
as specified by you, and registered in such names and in such denominations as
you shall request in writing not later than one full business day prior to the
Closing Date. The certificates evidencing the Notes shall be delivered to you on
the Closing Date for the respective accounts of the several Initial Purchasers,
with any transfer taxes payable in connection with the transfer of the Notes to
the Initial Purchasers duly paid, against payment of the Purchase Price therefor
plus accrued interest, if any, to the date of payment and delivery.

         5.       CONDITIONS TO THE INITIAL PURCHASERS' OBLIGATIONS. The several
obligations of the Initial Purchasers to purchase and pay for the Notes on the
Closing Date are subject to the following conditions:

                  (a)      Subsequent to the execution and delivery of this
         Agreement and prior to the Closing Date:

                           (i)      there shall not have occurred any
                  downgrading, nor shall any notice have been given of any
                  intended or potential downgrading or of any review for a
                  possible change that does not indicate the direction of the
                  possible change, in the rating accorded the Company or any of
                  the Company's securities by any "NATIONALLY RECOGNIZED
                  STATISTICAL RATING ORGANIZATION," as such term is defined for
                  purposes of Rule 436(g)(2) under the Securities Act; and

                           (ii)     there shall not have occurred any change, or
                  any development involving a prospective change, in the
                  condition, financial or otherwise, or in the earnings,
                  business or operations of the Company and its subsidiaries,
                  taken as a whole, from that set forth in the Final Memorandum
                  (exclusive of any amendments or supplements thereto subsequent
                  to the date of this Agreement) that, in your judgment, is
                  material and adverse and that makes it, in your judgment,
                  impracticable to market the Notes on the terms and in the
                  manner contemplated in the Final Memorandum.

                  (b)      The Initial Purchasers shall have received on the
         Closing Date a certificate, dated the Closing Date and signed by an
         executive officer of the Company, to the effect set forth in Section
         5(a) and to the effect that the representations and warranties of the
         Company contained in this Agreement are true and correct as of the
         Closing Date

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         and that the Company has complied with all of the agreements and
         satisfied all of the conditions on its part to be performed or
         satisfied hereunder on or before the Closing Date (except to the extent
         such compliance has been waived by you in writing). The officer signing
         and delivering such certificate may rely upon the best of his or her
         knowledge as to proceedings threatened.

                  (c)      The Initial Purchasers shall have received on the
         Closing Date an opinion of Kirkland & Ellis LLP, outside counsel for
         the Company, dated the Closing Date, to the effect set forth in Exhibit
         A. Such opinion shall be rendered to the Initial Purchasers at the
         request of the Company and shall so state therein.

                  (d)      The Initial Purchasers shall have received on the
         Closing Date an opinion of Sidley Austin Brown & Wood LLP, counsel for
         the Initial Purchasers, dated the Closing Date, to the effect set forth
         in Exhibit B.

                  (e)      The Initial Purchasers shall have received on each of
         the date hereof and the Closing Date a letter, dated the date hereof or
         the Closing Date, as the case may be, in form and substance
         satisfactory to the Initial Purchasers, from Ernst & Young LLP,
         independent public accountants, containing statements and information
         of the type ordinarily included in accountants' "comfort letters" to
         underwriters with respect to the financial statements and certain
         financial information contained in or incorporated by reference into
         the Final Memorandum; provided that the letter delivered on the Closing
         Date shall use a "cut-off date" not earlier than the date hereof.

                  (f)      At the Closing Date, the Registration Rights
         Agreement shall have been duly executed and delivered by the Company.

                  (g)      At the Closing Date, the Notes shall be rated at
         least Ba1 by Moody's Investors Service Inc. ("MOODY'S") and BBB- by
         Standard & Poor's Ratings Services, a division of McGraw Hill, Inc.
         ("S&P"), and the Company shall have delivered to the Initial Purchasers
         written evidence satisfactory to the Initial Purchasers confirming that
         the Notes have such ratings (such as letters from such rating agencies
         or copies of any press releases or other public announcements).

                  (h)      At or prior to the Closing Date, the Existing Credit
         Agreement shall be extinguished and evidence thereof reasonably
         satisfactory to the Initial Purchasers shall have been delivered to the
         Initial Purchasers.

                  (i)      At or prior to the Closing Date, the Company shall
         have furnished to the Initial Purchasers such documents and opinions,
         in addition to the foregoing, as the Initial Purchasers may reasonably
         request in connection with the purchase of the Notes as herein
         contemplated and related transactions contemplated hereunder.

         6.       COVENANTS OF THE COMPANY. In further consideration of the
agreements of the Initial Purchasers contained in this Agreement, the Company
covenants with each Initial Purchaser as follows:

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                  (a)      To furnish to you in New York City, without charge,
         prior to 10:00 a.m., New York City time, on the business day next
         succeeding the date of this Agreement and during the period mentioned
         in Section 6(c), as many copies of the Final Memorandum, any documents
         incorporated by reference therein and any supplements and amendments
         thereto as you may reasonably request.

                  (b)      Before amending or supplementing either Memorandum,
         to furnish to you a copy of each such proposed amendment or supplement
         and not to use any such proposed amendment or supplement to which you
         reasonably object.

                  (c)      If, during such period after the date hereof and
         prior to the date on which all of the Notes shall have been sold by the
         Initial Purchasers, any event shall occur or condition exist as a
         result of which it is necessary to amend or supplement the Final
         Memorandum in order to make the statements therein, in the light of the
         circumstances when the Final Memorandum is delivered to a purchaser,
         not misleading, or if, in the opinion of counsel for the Initial
         Purchasers, it is necessary to amend or supplement the Final Memorandum
         to comply with applicable law, forthwith to prepare and furnish, at its
         own expense, to the Initial Purchasers, either amendments or
         supplements to the Final Memorandum so that the statements in the Final
         Memorandum as so amended or supplemented will not, in the light of the
         circumstances when the Final Memorandum is delivered to a purchaser, be
         misleading or so that the Final Memorandum, as amended or supplemented,
         will comply with applicable law.

                  (d)      To endeavor to qualify the Notes for offer and sale
         under the securities or Blue Sky laws of such jurisdictions as you
         shall reasonably request.

                  (e)      To take all reasonable action necessary to enable S&P
         and Moody's to provide their respective credit ratings of the Notes.

                  (f)      Whether or not the transactions contemplated in this
         Agreement are consummated or this Agreement is terminated, to pay or
         cause to be paid all expenses incident to the performance of its
         obligations under this Agreement, including: (i) the fees,
         disbursements and expenses of the Company's counsel and the Company's
         accountants in connection with the issuance and sale of the Notes and
         all other fees or expenses in connection with the preparation of each
         Memorandum and all amendments and supplements thereto, including all
         printing costs associated therewith, and the delivering of copies
         thereof to the Initial Purchasers, in the quantities herein above
         specified, (ii) all costs and expenses related to the transfer and
         delivery of the Notes to the Initial Purchasers, including any transfer
         or other taxes payable thereon, (iii) the cost of printing or producing
         any Blue Sky or legal investment memorandum in connection with the
         offer and sale of the Notes under state securities laws and all
         expenses in connection with the qualification of the Notes for offer
         and sale under state securities laws as provided in Section 6(d)
         hereof, including filing fees and the reasonable fees and disbursements
         of counsel for the Initial Purchasers in connection with such
         qualification and in connection with the Blue Sky or legal investment
         memorandum, (iv) any fees charged by rating agencies for the rating of
         the Notes, (v) the costs and charges of the Trustee and any transfer
         agent, registrar or depositary, (vi) the cost of the preparation,

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         issuance and delivery of the Notes, (vii) the costs and expenses of the
         Company relating to investor presentations on any "road show"
         undertaken in connection with the marketing of the offering of the
         Notes, including, without limitation, expenses associated with the
         production of road show slides and graphics, fees and expenses of any
         consultants engaged in connection with the road show presentations with
         the prior approval of the Company, travel and lodging expenses of the
         representatives and officers of the Company and any such consultants,
         and the cost of any aircraft chartered in connection with the road
         show, and (viii) all other cost and expenses incident to the
         performance of the obligations of the Company hereunder for which
         provision is not otherwise made in this Section. It is understood,
         however, that except as provided in this Section, Section 8, and the
         last paragraph of Section 10, the Initial Purchasers will pay all of
         their costs and expenses, including fees and disbursements of their
         counsel, transfer taxes payable on resale of any of the Notes by them
         and any advertising expenses connected with any offers they may make.

                  (g)      Neither the Company nor any Affiliate will sell,
         offer for sale or solicit offers to buy or otherwise negotiate in
         respect of any security (as defined in the Securities Act) which could
         be integrated with the sale of the Notes in a manner which would
         require the registration under the Securities Act of the Notes.

                  (h)      Neither the Company nor any Affiliate will solicit
         any offer to buy or offer or sell the Notes by means of any form of
         general solicitation or general advertising (as those terms are used in
         Regulation D under the Securities Act) or in any manner involving a
         public offering within the meaning of Section 4(2) of the Securities
         Act, except for the exchange offer to be made by the Company in
         accordance with the terms of the Registration Rights Agreement.

                  (i)      While any of the Notes remain "RESTRICTED SECURITIES"
         within the meaning of the Securities Act, to make available, upon
         request, to any seller of such Notes the information specified in Rule
         144A(d)(4) under the Securities Act, unless the Company is then subject
         to Section 13 or 15(d) of the Exchange Act.

                  (j)      None of the Company, its Affiliates or any person
         acting on its or their behalf (other than the Initial Purchasers, as to
         which the Company makes no covenant) will engage in any directed
         selling efforts (as that term is defined in Regulation S) with respect
         to the Notes, and the Company and its Affiliates and each person acting
         on its or their behalf (other than the Initial Purchasers) will comply
         with the offering restrictions requirement of Regulation S.

                  (k)      During the period of two years after the Closing
         Date, the Company will not, and will not permit any of its affiliates
         (as defined in Rule 144A under the Securities Act) to resell any of the
         Notes which constitute "RESTRICTED SECURITIES" under Rule 144A that
         have been reacquired by any of them.

         7.       OFFERING OF NOTES; RESTRICTIONS ON TRANSFER. (a) Each Initial
Purchaser, severally and not jointly, represents and warrants that such Initial
Purchaser is a "qualified institutional buyer" as defined in Rule 144A under the
Securities Act (a "QIB"). Each Initial Purchaser,

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severally and not jointly, agrees with the Company that (i) it will not solicit
offers for, or offer or sell, such Notes by any form of general solicitation or
general advertising (as those terms are used in Regulation D under the
Securities Act) or in any manner involving a public offering within the meaning
of Section 4(2) of the Securities Act and (ii) it will solicit offers for such
Notes only from, and will offer such Notes only to, persons that it reasonably
believes to be (A) in the case of offers inside the United States, (1) other
QIBs or (2) institutional "accredited investors" (as defined in Rule 501(a)(1),
(2), (3) or (7) under the Securities Act ("INSTITUTIONAL ACCREDITED INVESTORS")
that, prior to their purchase of the Notes, deliver to such Initial Purchaser a
letter containing the representations and agreements set forth in Appendix A to
the Memorandum and (B) in the case of offers outside the United States, to
persons other than U.S. persons ("FOREIGN PURCHASERS," which term shall include
dealers or other professional fiduciaries organized, incorporated or (if an
individual) resident in the United States acting on a discretionary basis for
non-U.S. persons (other than an estate or trust)) in reliance upon Regulation S
under the Securities Act that, in each case, in purchasing such Notes are deemed
to have represented and agreed as provided in the Final Memorandum under the
caption "Transfer Restrictions."

                  (b)      Each Initial Purchaser, severally and not jointly,
         represents, warrants, and agrees with respect to offers and sales
         outside the United States that:

                           (i)      such Initial Purchaser understands that no
                  action has been or will be taken in any jurisdiction by the
                  Company that would permit a public offering of the Notes, or
                  possession or distribution of either Memorandum or any other
                  offering or publicity material relating to the Notes, in any
                  country or jurisdiction where action for that purpose is
                  required;

                           (ii)     such Initial Purchaser will comply with all
                  applicable laws and regulations in each jurisdiction in which
                  it acquires, offers, sells or delivers Notes or has in its
                  possession or distributes either Memorandum or any such other
                  material, in all cases at its own expense;

                           (iii)    such Initial Purchaser agrees that the Notes
                  offered or sold, or to be offered or sold, by such Initial
                  Purchaser pursuant hereto in reliance on Regulation S have
                  been and will be offered and sold only in offshore
                  transactions;

                           (iv)     such Initial Purchaser understands that the
                  Notes have not been registered under the Securities Act and
                  agrees that the Notes may not be offered or sold within the
                  United States or to, or for the account or benefit of, U.S.
                  persons except in accordance with Rule 144A or Regulation S
                  under the Securities Act or pursuant to another exemption from
                  the registration requirements of the Securities Act;

                           (v)      such Initial Purchaser has offered the Notes
                  and will offer and sell the Notes (A) as part of their
                  distribution at any time and (B) otherwise until 40 days after
                  the later of the commencement of the offering and the Closing
                  Date, only in accordance with Rule 903 of Regulation S or as
                  otherwise permitted in Section 7(a); accordingly, neither such
                  Initial Purchaser, its Affiliates nor any

                                      10
<Page>

                  persons acting on its or their behalf have engaged or will
                  engage in any directed selling efforts (within the meaning of
                  Regulation S) with respect to the Notes, and any such Initial
                  Purchaser, its Affiliates and any such persons have complied
                  and will comply with the offering restrictions requirement of
                  Regulation S;

                           (vi)     such Initial Purchaser has (A) not offered
                  or sold and, prior to the date six months after the Closing
                  Date, will not offer or sell any Notes to persons in the
                  United Kingdom except to persons whose ordinary activities
                  involve them in acquiring, holding, managing or disposing of
                  investments (as principal or agent) for the purposes of their
                  businesses or otherwise in circumstances which have not
                  resulted and will not result in an offer to the public in the
                  United Kingdom within the meaning of the Public Offers of
                  Securities Regulations 1995 (as amended), (B) only
                  communicated or caused to be communicated and will only
                  communicate or cause to be communicated any invitation or
                  inducement to engage in investment activity (within the
                  meaning of Section 21 of the Financial Services and Markets
                  Act 2000 (the "FSMA")) received by it in connection with the
                  issue or sale of any Notes in circumstances in which Section
                  21(1) of the FSMA does not apply to the Company and (C)
                  complied and will comply with all applicable provisions of the
                  FSMA with respect to anything done by it in relation to the
                  Notes in, from or otherwise involving the United Kingdom;

                           (vii)    such Initial Purchaser understands that the
                  Notes have not been and will not be registered under the
                  Securities and Exchange Law of Japan, and represents that it
                  has not offered or sold, and agrees not to offer or sell,
                  directly or indirectly, any Notes in Japan or for the account
                  of any resident thereof except pursuant to any exemption from
                  the registration requirements of the Securities and Exchange
                  Law of Japan and otherwise in compliance with applicable
                  provisions of Japanese law; and

                           (viii)   such Initial Purchaser agrees that, at or
                  prior to confirmation of sales of the Notes, it will have sent
                  to each distributor, "DEALER" (as defined in Section 2(a)(12)
                  of the Securities Act) or person receiving a selling
                  concession, fee or other remuneration that purchases Notes
                  from it during the "DISTRIBUTION COMPLIANCE PERIOD" (as
                  defined in Regulation S) a confirmation or notice to
                  substantially the following effect:

                           "The Notes covered hereby have not been registered
                           under the U.S. Securities Act of 1933 (the
                           "Securities Act") and may not be offered and sold
                           within the United States or to, or for the account or
                           benefit of, U.S. persons (i) as part of their
                           distribution at any time or (ii) otherwise until 40
                           days after the later of the commencement of the
                           offering and the closing date, except in either case
                           in accordance with Regulation S (or Rule 144A if
                           available) under the Securities Act. Terms used above
                           have the meaning given to them by Regulation S."

                                      11
<Page>

         Terms used in this Section 7(b) have the meanings given to them by
Regulation S.

         8.       INDEMNITY AND CONTRIBUTION. (a) The Company agrees to
indemnify and hold harmless each Initial Purchaser and each person, if any, who
controls any Initial Purchaser within the meaning of either Section 15 of the
Securities Act or Section 20 of the Exchange Act, and each affiliate of each
Initial Purchaser within the meaning of Rule 405 under the Securities Act from
and against any and all losses, claims, damages and liabilities (including,
without limitation, any legal or other expenses reasonably incurred in
connection with defending or investigating any such action or claim) caused by
any untrue statement or alleged untrue statement of a material fact contained in
either Memorandum (as amended or supplemented if the Company shall have
furnished any amendments or supplements thereto), or caused by any omission or
alleged omission to state therein a material fact necessary to make the
statements therein in the light of the circumstances under which they were made
not misleading, except insofar as such losses, claims, damages or liabilities
are caused by any such untrue statement or omission or alleged untrue statement
or omission based upon information relating to any Initial Purchaser furnished
to the Company in writing by such Initial Purchaser through you expressly for
use therein; provided, however, that the foregoing indemnity agreement with
respect to any Preliminary Memorandum shall not inure to the benefit of any
Initial Purchaser from whom the person asserting any such losses, claims,
damages or liabilities purchased Notes, or any person controlling such Initial
Purchaser, if a copy of the Final Memorandum (as then amended or supplemented if
the Company shall have furnished any amendments or supplements thereto) was not
sent or given by or on behalf of such Initial Purchaser to such person, if
required by law so to have been delivered, at or prior to the written
confirmation of the sale of the Notes to such person, and if the Final
Memorandum (as so amended or supplemented) would have cured the defect giving
rise to such losses, claims, damages or liabilities, unless such failure is the
result of noncompliance by the Company with Section 6(a) hereof or unless such
defect shall have been cured by a document which is incorporated or deemed to be
incorporated by reference in the Final Memorandum.

                  (b)      Each Initial Purchaser agrees, severally and not
         jointly, to indemnify and hold harmless the Company, its directors, its
         officers and each person, if any, who controls the Company within the
         meaning of either Section 15 of the Securities Act or Section 20 of the
         Exchange Act to the same extent as the foregoing indemnity from the
         Company to such Initial Purchaser, but only with reference to
         information relating to such Initial Purchaser furnished to the Company
         in writing by such Initial Purchaser through you expressly for use in
         either Memorandum or any amendments or supplements thereto.

                  (c)      In case any proceeding (including any governmental
         investigation) shall be instituted involving any person in respect of
         which indemnity may be sought pursuant to Section 8(a) or 8(b), such
         person (the "INDEMNIFIED PARTY") shall promptly notify the person
         against whom such indemnity may be sought (the "INDEMNIFYING PARTY") in
         writing and the indemnifying party, upon request of the indemnified
         party, shall retain counsel reasonably satisfactory to the indemnified
         party to represent the indemnified party and any others the
         indemnifying party may designate in such proceeding and shall pay the
         fees and disbursements of such counsel related to such proceeding. In
         any such proceeding, any indemnified party shall have the right to
         retain its own counsel, but the

                                  12
<Page>

         fees and expenses of such counsel shall be at the expense of such
         indemnified party unless (i) the indemnifying party and the indemnified
         party shall have mutually agreed to the retention of such counsel or
         (ii) the named parties to any such proceeding (including any impleaded
         parties) include both the indemnifying party and the indemnified party
         and representation of both parties by the same counsel would be
         inappropriate due to actual or potential differing interests between
         them. It is understood that the indemnifying party shall not, in
         respect of the legal expenses of any indemnified party in connection
         with any proceeding or related proceedings in the same jurisdiction, be
         liable for the fees and expenses of more than one separate firm (in
         addition to any local counsel) for all such indemnified parties and
         that all such fees and expenses shall be reimbursed as they are
         incurred. Such firm shall be designated in writing by Morgan Stanley &
         Co. Incorporated, in the case of parties indemnified pursuant to
         Section 8(a), and by the Company, in the case of parties indemnified
         pursuant to Section 8(b). The indemnifying party shall not be liable
         for any settlement of any proceeding effected without its written
         consent, but if settled with such consent or if there be a final
         judgment for the plaintiff, the indemnifying party agrees to indemnify
         the indemnified party from and against any loss or liability by reason
         of such settlement or judgment. Notwithstanding the foregoing sentence,
         if at any time an indemnified party shall have requested an
         indemnifying party to reimburse the indemnified party for fees and
         expenses of counsel as contemplated by the second and third sentences
         of this paragraph, the indemnifying party agrees that it shall be
         liable for any settlement of any proceeding effected without its
         written consent if (i) such settlement is entered into more than 30
         days after receipt by such indemnifying party of the aforesaid request
         and (ii) such indemnifying party shall not have reimbursed the
         indemnified party in accordance with such request prior to the date of
         such settlement. No indemnifying party shall, without the prior written
         consent of the indemnified party, effect any settlement of any pending
         or threatened proceeding in respect of which any indemnified party is
         or could have been a party and indemnity could have been sought
         hereunder by such indemnified party, unless such settlement includes an
         unconditional release of such indemnified party from all liability on
         claims that are the subject matter of such proceeding.

                  (d)      To the extent the indemnification provided for in
         Section 8(a) or 8(b) is unavailable to an indemnified party or
         insufficient in respect of any losses, claims, damages or liabilities
         referred to therein, then each indemnifying party under such paragraph,
         in lieu of indemnifying such indemnified party thereunder, shall
         contribute to the amount paid or payable by such indemnified party as a
         result of such losses, claims, damages or liabilities (i) in such
         proportion as is appropriate to reflect the relative benefits received
         by the Company on the one hand and the Initial Purchasers on the other
         hand from the offering of the Notes or (ii) if the allocation provided
         by clause 8(d)(i) above is not permitted by applicable law, in such
         proportion as is appropriate to reflect not only the relative benefits
         referred to in clause 8(d)(i) above but also the relative fault of the
         Company on the one hand and of the Initial Purchasers on the other hand
         in connection with the statements or omissions that resulted in such
         losses, claims, damages or liabilities, as well as any other relevant
         equitable considerations. The relative benefits received by the Company
         on the one hand and the Initial Purchasers on the other hand in
         connection with the offering of the Notes shall be deemed to be in the
         same respective proportions as the net proceeds from the offering of
         the Notes (before deducting

                                      13
<Page>

         expenses) received by the Company and the total discounts and
         commissions received by the Initial Purchasers bear to the aggregate
         offering price of the Notes. The relative fault of the Company on the
         one hand and of the Initial Purchasers on the other hand shall be
         determined by reference to, among other things, whether the untrue or
         alleged untrue statement of a material fact or the omission or alleged
         omission to state a material fact relates to information supplied by
         the Company or by the Initial Purchasers and the parties' relative
         intent, knowledge, access to information and opportunity to correct or
         prevent such statement or omission. The Initial Purchasers' respective
         obligations to contribute pursuant to this Section 8 are several in
         proportion to the respective principal amount of Notes they have
         purchased hereunder, and not joint.

                  (e)      The Company and the Initial Purchasers agree that it
         would not be just or equitable if contribution pursuant to this Section
         8 were determined by pro rata allocation (even if the Initial
         Purchasers were treated as one entity for such purpose) or by any other
         method of allocation that does not take account of the equitable
         considerations referred to in Section 8(d). The amount paid or payable
         by an indemnified party as a result of the losses, claims, damages and
         liabilities referred to in Section 8(d) shall be deemed to include,
         subject to the limitations set forth above, any legal or other expenses
         reasonably incurred by such indemnified party in connection with
         investigating or defending any such action or claim. Notwithstanding
         the provisions of this Section 8, no Initial Purchaser shall be
         required to contribute any amount in excess of the amount by which the
         total price at which the Notes resold by it in the initial placement of
         such Notes were offered to investors exceeds the amount of any damages
         that such Initial Purchaser has otherwise been required to pay by
         reason of such untrue or alleged untrue statement or omission or
         alleged omission. No person guilty of fraudulent misrepresentation
         (within the meaning of Section 11(f) of the Securities Act) shall be
         entitled to contribution from any person who was not guilty of such
         fraudulent misrepresentation. The remedies provided for in this Section
         8 are not exclusive and shall not limit any rights or remedies which
         may otherwise be available to any indemnified party at law or in
         equity.

                  (f)      The indemnity and contribution provisions contained
         in this Section 8 and the representations, warranties and other
         statements of the Company contained in this Agreement shall remain
         operative and in full force and effect regardless of (i) any
         termination of this Agreement, (ii) any investigation made by or on
         behalf of any Initial Purchaser or any person controlling any Initial
         Purchaser or by or on behalf of the Company, its officers or directors
         or any person controlling the Company and (iii) acceptance of and
         payment for any of the Notes.

         9.       TERMINATION. You may terminate this Agreement by notice given
to the Company, if after the execution and delivery of this Agreement and prior
to the Closing Date (i) trading generally shall have been suspended or
materially limited on, or by, as the case may be, any of the New York Stock
Exchange, the American Stock Exchange, the Nasdaq National Market, the Chicago
Board of Options Exchange, the Chicago Mercantile Exchange or the Chicago Board
of Trade, (ii) trading of any securities of the Company shall have been
suspended on any exchange or in any over-the-counter market, (iii) a material
disruption in securities settlement, payment or clearance services in the United
States shall have occurred, (iv) any moratorium on commercial banking activities
shall have been declared by Federal or New York

                                      14
<Page>

State authorities or (v) there shall have occurred any outbreak or escalation of
hostilities, or any change in financial markets or any calamity or crisis that,
in your judgment, is material and adverse and which, singly or together with any
other event specified in this clause (v), makes it, in your judgment,
impracticable or inadvisable to proceed with the offer, sale or delivery of the
Notes on the terms and in the manner contemplated in the Final Memorandum.

         10.      EFFECTIVENESS; DEFAULTING INITIAL PURCHASERS. This Agreement
shall become effective upon the execution and delivery hereof by the parties
hereto.

         If, on the Closing Date, any one or more of the Initial Purchasers
shall fail or refuse to purchase 4 3/8% Notes or 5 3/4% Notes, as the case may
be, that it or they have agreed to purchase hereunder on such date, and the
aggregate principal amount of such Notes which such defaulting Initial Purchaser
or Initial Purchasers agreed but failed or refused to purchase is not more than
one-tenth of the aggregate principal amount of such series of Notes to be
purchased on such date, the other Initial Purchasers shall be obligated
severally in the proportions that the principal amount of such Notes set forth
opposite their respective names in Schedule I bears to the aggregate principal
amount of such series of Notes set forth opposite the names of all such
non-defaulting Initial Purchasers, or in such other proportions as you may
specify, to purchase such Notes which such defaulting Initial Purchaser or
Initial Purchasers agreed but failed or refused to purchase on such date;
provided that in no event shall the principal amount of such series of Notes
that any Initial Purchaser has agreed to purchase pursuant to this Agreement be
increased pursuant to this Section 10 by an amount in excess of one-ninth of
such principal amount of such series of Notes without the written consent of
such Initial Purchaser. If, on the Closing Date any Initial Purchaser or Initial
Purchasers shall fail or refuse to purchase 4 3/8% Notes or 5 3/4% Notes, as the
case may be, which it or they have agreed to purchase hereunder on such date and
the aggregate principal amount of such Notes with respect to which such default
occurs is more than one-tenth of the aggregate principal amount of such series
of Notes to be purchased on such date, and arrangements satisfactory to you and
the Company for the purchase of such Notes are not made within 36 hours after
such default, this Agreement shall terminate without liability on the part of
any non-defaulting Initial Purchaser or of the Company. In any such case either
you or the Company shall have the right to postpone the Closing Date, but in no
event for longer than seven days, in order that the required changes, if any, in
the Final Memorandum or in any other documents or arrangements may be effected.
Any action taken under this paragraph shall not relieve any defaulting Initial
Purchaser from liability in respect of any default of such Initial Purchaser
under this Agreement.

         If this Agreement shall be terminated by the Initial Purchasers, or any
of them, because of any failure or refusal on the part of the Company to comply
with the terms or to fulfill any of the conditions of this Agreement, or if for
any reason the Company shall be unable to perform its obligations under this
Agreement, the Company will reimburse the Initial Purchasers or such Initial
Purchasers as have so terminated this Agreement with respect to themselves,
severally, for all out-of-pocket expenses (including the fees and disbursements
of their counsel) reasonably incurred by such Initial Purchasers in connection
with this Agreement or the offering contemplated hereunder.

                                      15
<Page>

         11.      COUNTERPARTS. This Agreement may be signed in any number of
counterparts, each of which shall be an original, with the same effect as if the
signatures thereto and hereto were upon the same instrument.

         12.      APPLICABLE LAW; SUBMISSION TO JURISDICTION. THIS AGREEMENT
SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE INTERNAL LAWS OF THE
STATE OF NEW YORK. THE COMPANY HEREBY (A) SUBMITS TO THE JURISDICTION OF ANY NEW
YORK STATE OR FEDERAL COURT SITTING IN NEW YORK CITY WITH RESPECT TO ANY ACTIONS
AND PROCEEDINGS ARISING OUT OF OR RELATING TO THIS AGREEMENT, (B) AGREES THAT
ALL CLAIMS WITH RESPECT TO SUCH ACTIONS OR PROCEEDINGS MAY BE HEARD AND
DETERMINED IN SUCH NEW YORK STATE OR FEDERAL COURT, (C) WAIVES THE DEFENSE OF AN
INCONVENIENT FORUM AND (D) AGREES THAT A FINAL JUDGMENT IN ANY SUCH ACTION OR
PROCEEDING SHALL BE CONCLUSIVE AND MAY BE ENFORCED IN OTHER JURISDICTIONS BY
SUIT ON THE JUDGMENT OR IN ANY OTHER MANNER PROVIDED BY LAW.

         13.      NOTICES. All notices, requests, demands, waivers and other
communications required or permitted to be given under this Agreement shall be
in writing and shall be deemed to have been duly given if (a) delivered
personally, (b) mailed by certified or registered mail with postage prepaid, (c)
sent by next-day or overnight mail or delivery or (d) sent by telecopy or
telegram, as follows:

         If to you:

                  Morgan Stanley & Co. Incorporated
                  1585 Broadway
                  New York, New York  10036
                  Telecopy No.:  (212)761-0783
                  Attention:  Fixed Income Syndicate Desk

                  Citigroup Global Markets Inc.
                  388 Greenwich Street
                  New York, New York  10013
                  Telecopy No.:  (212) 816-7912
                  Attention:  Jeanne Campanelli

                  with a copy to:

                  Sidley Austin Brown & Wood LLP
                  787 Seventh Avenue
                  New York, New York  10019
                  Telecopy No.:  (212) 839-5599
                  Attention:  John H. Newman

                                      16
<Page>

         If to the Company:

                  Packaging Corporation of America
                  1900 West Field Court
                  Lake Forest, Illinois 60045
                  Telecopy No.:  (847) 482-4545
                  Attention:  Chief Financial Officer

                  with a copy to:

                  Kirkland & Ellis
                  200 East Randolph Drive
                  Chicago, Illinois 60601-6636
                  Telecopy No.:  (312) 861-2200
                  Attention:  James S. Rowe

or, in each case, at such other address as may be specified in writing by a
party to the other parties hereto.

All such notices, requests, demands, waivers and other communications shall be
deemed to have been received (w) if by personal delivery, on the day after such
delivery, (x) if by certified or registered mail, on the seventh business day
after the mailing thereof, (y) if by next-day or overnight mail or delivery, on
the day delivered, (z) if by telecopy, on the next day following the day on
which such telecopy was sent, provided that a copy is also sent by certified or
registered mail with postage prepaid.

         14.      HEADINGS. The headings of the sections of this Agreement have
been inserted for convenience of reference only and shall not be deemed a part
of this Agreement.

                            [SIGNATURE PAGE FOLLOWS]

                                      17
<Page>

                                    Very truly yours,

                                    PACKAGING CORPORATION OF AMERICA

                                    By: /s/ Richard B. West
                                       -----------------------------------------
                                        Name:  Richard B. West
                                        Title: Senior Vice President,
                                               Chief Executive Officer
                                               and Corporate Secretary

Accepted as of the date hereof

Morgan Stanley & Co. Incorporated
Citigroup Global Markets Inc.

     Acting severally on behalf of themselves and
     the several Initial Purchasers
     named in Schedule I hereto.

Morgan Stanley & Co. Incorporated

By:  /s/ Harold J. Hendershot III
   ---------------------------------
   Name:  Harold J. Hendershot III
   Title: Executive Director


Citigroup Global Markets Inc.



By: /s/ John Chrysikopoulous
   ---------------------------------------
   Name:  John Chrysikopoulous
   Title: Managing Director

                                      18