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                                                                   EXHIBIT 10.6

                          CENTERPOINT PROPERTIES TRUST

                             STOCK OPTION AGREEMENT

         THIS STOCK OPTION AGREEMENT (the "Agreement") is dated as of May 20,
1999 between CenterPoint Properties Trust, a Maryland real estate investment
trust (the "Company"), and Martin Barber (the "Optionee").

         This Agreement is made pursuant to, and is governed by, the
CenterPoint Properties 1993 Stock Option Plan, as amended (the "Plan").
Capitalized terms not otherwise defined herein shall have the meanings set
forth in the Plan. The purpose of this Agreement is to establish a written
agreement evidencing an option granted in accordance with the terms of the
Plan. In this Agreement, "shares" means shares of the Company's Common Stock
or other securities resulting from an adjustment under Article 8 of the Plan.

         The agreement is as follows:

1.       GRANT OF OPTION. The Company hereby grants to the Optionee an option
         (the "Option") to purchase 6,500 shares under the terms and conditions
         hereof.

2.       TERM. The Option becomes exercisable and terminates in accordance with
         the schedule set forth in Section 5 hereof; provided, however, that in
         the event unemployment of the Optionee with the Company or a Subsidiary
         terminates for any reason, the Option shall terminate in accordance
         with the provisions of Section 7.2 of the Plan.

3.       PRICE. The price of each share purchased by exercise of the Option in
         $35.9375.

4.       PARTIAL EXERCISE. The Option, to the extent exercisable under Section 5
         hereof, may be exercised in whole or in part provided that the Option
         may not be exercised for less than 100 shares in any single transaction
         unless such exercise pertains to the entire number of shares then
         covered by the Option.

5.       EXERCISE PERIOD.

         (a)      Except as otherwise provided in the Plan or in this Agreement,
                  the Option shall become exercisable as follows:

<TABLE>
<CAPTION>
                  ----------------------------------------------------------------------- ---------------------------
                                               Time Period                                       Exercisable
                  ----------------------------------------------------------------------- ---------------------------
                  <S>                                                                     <C>
                  Prior to the first anniversary date of this Agreement                   None
                  ----------------------------------------------------------------------- ---------------------------
                  After the first anniversary date of this Agreement                      One-fifth
                  ----------------------------------------------------------------------- ---------------------------
                  After the second anniversary date of this Agreement                     Two-fifths
                  ----------------------------------------------------------------------- ---------------------------
                  After the third anniversary date of this Agreement                      Three-fifths
                  ----------------------------------------------------------------------- ---------------------------
                  After the fourth anniversary date of this Agreement                     Four-fifths
                  ----------------------------------------------------------------------- ---------------------------
                  After the fifth anniversary date of this Agreement                      All
                  ----------------------------------------------------------------------- ---------------------------
</TABLE>

         (b)      If it has not previously terminated pursuant to the terms of
                  the Plan or this Agreement, the Option shall terminate at the
                  close of business on the day before the tenth anniversary of
                  the date of this Agreement

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6.       METHOD OF EXERCISE. The Option shall be exercised by written notice by
         Optionee to the Company specifying the number of shares that such
         person elects to purchase, accompanied by full payment, in cash or
         current funds, for such shares.

7.       ISO TREATMENT. It is intended that the Option shall qualify as an
         "incentive stock option" as described in Section 422 of the Internal
         Revenue Code of 1986, as amended.

8.       RIGHTS OF STOCKHOLDER. No person, estate, or other entity will have the
         rights of a stockholder with respect to shares subject to the Options
         until a certificate or certificates for these shares have been
         delivered to the person exercising the option.

9.       RIGHTS OF THE COMPANY. This Agreement does not affect the Company's
         right to take any corporate action, including other changes in its
         right to recapitalize, reorganize or consolidate, issue bonds, notes or
         stock, including preferred stock or options therefor, to dissolve or
         liquidate, or to sell or transfer any part of its assets or business.

10.      CHANGES IN CAPITALIZATION. Upon the occurrence of an event described in
         Section 8.1(a) of the Plan, the Committee shall make the adjustments
         specified in Section 8.1(b) of the Plan.

11.      TAXES. The Company, if necessary or desirable, may pay or withhold the
         amount of any tax attributable to any shares deliverable under this
         Agreement, and the Company may defer making delivery until it is
         indemnified to its satisfaction for that tax.

12.      COMPLIANCE WITH LAWS. Options are exercisable, and shares can be
         delivered under this Agreement, only in compliance with all applicable
         federal and state laws and regulations, including without limitation,
         state and federal securities laws, and the rules of all stock exchanges
         on which the Common Stock is listed at any time. Options may not be
         exercised and shares may not be issued under this Agreement until the
         Company has obtained the consent or approval of every regulatory body,
         federal or state, having jurisdiction over such matters as the
         Committee deems advisable. Each person or estate that acquired the
         right to exercise an Option by bequest or inheritance may be required
         by the Committee to furnish reasonable evidence of ownership of the
         Option as a condition to the exercise of the Option. In addition, the
         Committee may require such consents and releases of taxing authorities
         as the Committee deems advisable.

13.      STOCK LEGENDS. Any certificate issued to evidence shares issued under
         the Option shall bear such legends and statements as the Committee
         deems advisable to assure compliance with all federal and state laws
         and regulations.

14.      ASSIGNABILITY. The Option shall not be transferable other than by will
         or the laws of descent and distribution. During the Optionee's
         lifetime, the Option shall be exercisable only by the Optionee, except
         as otherwise provided herein. The Option shall be transferable, on the
         Optionee's death, to the Optionee's estate and shall be exercisable,
         during the Optionee's lifetime, by the Optionee's guardian or legal
         representative.

15.      AMENDMENT OF OPTION. The Company may alter, amend, or terminate the
         Option only with the Optionee's consent, except for adjustments
         expressly provided by this Agreement.

16.      CHOICE OF LAW. The provisions of Section 9.6 of the Plan, concerning
         choice of law, shall govern this Agreement.

17.      MISCELLANEOUS. This Agreement is subject to and controlled by the Plan.
         Any inconsistency between this Agreement and said Plan shall be
         controlled by the Plan. This Agreement is the final, complete, and
         exclusive expression of the understanding between the parties and
         supersedes any prior or contemporaneous agreement or representation,
         oral or written, between them. Modification of this Agreement or waiver
         of a condition herein must be written and signed by the party to be
         bound. In the event that any paragraph or

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         provision of this Agreement shall be held to be illegal or
         unenforceable, such paragraph or provision shall be severed from the
         Agreement and the entire Agreement shall not fail on account thereof,
         but shall otherwise remain in full force and effect.

18.      NOTICES. All notices and other communications required or permitted
         under this Agreement shall be written, and shall be either delivered
         personally or sent by registered or certified first-class mail, postage
         prepaid and return receipt requested, or by telex or telecopier,
         addressed as follows: if to the Company, to the Company's principal
         office, and if to the Optionee or his successor, to the address last
         furnished by such person to the Company. Each such notice and
         communication delivered personally shall be deemed to have been given
         when delivered. Each such notice and communication given by mail shall
         be deemed to have been given when it was deposited in the United States
         mail in the manner specified herein, and each such notice and
         communication given by telex or telecopier shall be deemed to have been
         given when it is so transmitted and the appropriate answer back is
         received. A party may change its address for the purpose hereof by
         giving notice in accordance with the provisions of this Section 19.

         IN WITNESS WHEREOF, the Company has executed this Agreement as of the
         date first written above.

                                       CENTERPOINT PROPERTIES TRUST

                                       By:
                                            ------------------------------------
                                            John S. Gates, Jr., President