UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 20549

                                 SCHEDULE 13G/A

                   Under the Securities Exchange Act of 1934
                               (Amendment No.1 )*

                                Kerr McGee Corp.
- --------------------------------------------------------------------------------
                                (Name of Issuer)

                                     Common
- --------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    492386107
- --------------------------------------------------------------------------------
                                 (CUSIP Number)

                                  May 31, 2004
- --------------------------------------------------------------------------------
              (Date of Event which requires filing of this statement)

Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

[X] Rule 13d-1(b) [ ] Rule 13d-1(c) [ ] Rule 13d-1(d)

*The remainder of this cover shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).




Cusip No. 492386107             13G/A                       Page 2 of 5 Pages


1. NAME OF REPORTING PERSON
    S.S.  or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON NWQ Investment Management
          Company, LLC
          47-0875103


2.    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) (b)

3.    SEC USE ONLY


4.    CITIZENSHIP OR PLACE OF ORGANIZATION DELAWARE

NUMBER OF                5.  SOLE VOTING POWER                     9,268,732
SHARES
BENEFICIALLY             6.  SHARED VOTING POWER                   0
OWNED BY
EACH                     7.  SOLE DISPOSITIVE POWER                10,244,343
REPORTING PERSON
WITH                     8.  SHARED DISPOSITIVE POWER              0

9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 10,244,343



10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*


11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

       10.1%
12. TYPE OF REPORTING PERSON*

          IA




Cusip No. 492386107             13G/A                     Page 3 of 5 Pages

Schedule 13G Additional Information

Item #
1. (a)  Name of Issuer:
         Kerr-McGee Corp.

   (b)    Address of Issuer's Principal Executive Offices:
          123 Robert S. Kerr Ave.
          Kerr-McGee Center
          Oklahoma City, OK 73125

2. (a)  Name of Person Filing:
        NWQ Investment Management Company, LLC


   (b) Address of Principal Business Office for Each of the Above:

          2049 Century Park East, 4th Floor, Los Angeles, CA 90067

   (c)   Citizenship: Delaware, US


   (d)   Title of Class of Securities: Common


   (e)   CUSIP Number: 492386107


3. If this statement is filed pursuant to Rule 13d-1(b), or 13d-2(b). The person
   filing is a:
          Investment Adviser


4. Ownership:
   (a) Amount Beneficially Owned:                                     10,244,343
   (b) Percent of Class:                                              10.1%
   (c) Number of shares as to which such person has:
         (i) sole power to vote or to direct the vote 9,268,732 (ii) shared
         power to vote or to direct the vote 0 (iii) sole power to dispose or to
         direct the disposition of 10,244,343 (iv) shared power to dispose or to
         direct the disposition of 0


5.      Ownership of Five Percent or Less of a Class: N/A

6.        Ownership of More than Five Percent on Behalf of Another Person: N/A

7.  Subsidiary




Cusip No. 492386107                13G/A                   Page 4 of 5 Pages


8.     Identification and Classification of Members of the Group: Not applicable

9.     Notice of Dissolution of Group: Not applicable.

10.    Certification:

     By signing below I certify that, to the best of my knowledge and belief,
     the securities referred to above were acquired in the ordinary course of
     business and are held in the ordinary course of business and were not
     acquired and are not held for the purpose of and do not have the effect of
     changing or influencing the control of the issuer of the securities and
     were not acquired and are not held in connection with or as a participant
     in any transaction having such purpose or effect.

                                    SIGNATURE

     After reasonable inquiry and to the best of my knowledge and belief, I
     certify that the information set forth in this statement is true, complete
     and correct.

                                                   June 8, 2004


                                                   -----------------------
                                                   Jon D. Bosse, CFA
                                                   Chief Investment Officer,
                                                   Managing Director
The original statement shall be signed by each person on whose behalf the
statement is filed or his authorized representative. If the statement is signed
on behalf of a person by his authorized representative other than an executive
officer or general partner of the filing person, evidence of the
representative's authority to sign on behalf of such person shall be filed with
the statement, provided, however, that a power of attorney for this purpose
which is already on file with the Commission may be incorporated by reference.
The name and any title of each person who signs the statement shall be typed or
printed beneath his signature.


ATTENTION: INTERNATIONAL MISSATEMENTS OR OMISSIONS OF FACT CONSTITUTE FEDERAL
CRIMINAL VIOLATIONS (SEE 18 U.S.C. 1001)