POWER OF ATTORNEY WITH RESPECT TO FORMS 3, 4 and 5
The undersigned hereby constitutes and appoints each of
Kelly R. Welsh, James I. Kaplan, Rose A. Ellis, Victoria Antoni,
and Eileen C. Ratzka, signing singly, as the undersigned's true
and lawful attorneys-in-fact to:
(1)	execute for and on behalf of the undersigned, in the
(2)	undersigned's capacity as an
officer and/or director of Northern Trust Corporation, a Delaware
corporation (the "Corporation"), Forms 3, 4, and 5 in accordance
with Section 16(a) of the Securities Exchange Act of 1934 and the
rules thereunder;
   (2)do and perform any and all acts for and on behalf of the
undersigned that may be necessary or desirable to complete and
execute any such Form 3, 4, or 5 and timely file such Form with
the United States Securities and Exchange Commission, either manually
or through the use of EDGAR, the Electronic Data Gathering, Analysis,
and Retrieval system, and with any stock exchange or similar authority;
and
   (3)take any other action of any type whatsoever in connection
with the foregoing which, in the opinion of such attorney-in-fact,
may be of benefit to, in the best interest of, or legally required
by, the undersigned, it being understood that the documents executed
by such attorney-in-fact on behalf of the undersigned pursuant to
this Power of Attorney shall be in such form and shall contain such
terms and conditions as such attorney-in-fact may approve in such
attorney-in-fact's discretion. The undersigned hereby grants to
each such attorney-in-fact full power and authority to do and perform
any and every act and thing whatsoever requisite, necessary,
or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned
might or could do if personally present, with full power of
substitution or revocation, hereby ratifying and confirming all that such
attorney-in-fact, or such attorney-in-fact's substitute or substitutes,
shall lawfully do or cause to be done by virtue of this Power of Attorney
and the rights and powers herein granted.  The undersigned acknowledges
that the foregoing attorneys-in-fact, in serving in such capacity
at the request of the undersigned, are not assuming, nor is the
Corporation assuming, any of the undersigned's responsibilities to
comply with Section 16 of the Securities Exchange Act of 1934.
This Power of Attorney shall remain in full force and effect until
the undersigned is no longer required to file Forms 3, 4, and 5 with
respect to the undersigned's holdings of and transactions in
securities issued by the Corporation, unless earlier revoked by the
undersigned in a signed writing delivered to the foregoing
attorneys-in-fact.
IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney
to be executed as of this 15th day of December, 2006.
				/s/Nicholas D. Chabraja


Section 16 POA.doc
Section 16 POA.doc