UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
ANNUAL FILING
CABOT CORPORATION
(NAME OF ISSUER)
COMMON STOCK (CONV PFD STK HELD IN ESOP PORTION)
(CLASS OF SECURITIES)
127055101
(CUSIP NUMBER)
12/31/2005
(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 PAGE 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. 127055101 13G PAGE 2 OF 5 PAGES
1. NAME OF REPORTING PERSON
S.S. OR I.R.S. IDENTIFICATION NO. OF PERSON
STATE STREET BANK AND TRUST COMPANY, ACTING IN VARIOUS FIDUCIARY
CAPACITIES. 04-1867445
2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP.*
NOT APPLICABLE A __
B __
3. SEC USE ONLY
4. CITIZENSHIP OR PLACE OF ORGANIZATION
BOSTON, MASSACHUSETTS
5. SOLE VOTING POWER
876,925 SHARES
6. SHARED VOTING POWER
6,239,639 SHARES (INCLUDES 6,239,639 SHARES CNV PFD STK?VOTING
RATIO 1 PFD = 146.3782 COMMON)
7. SOLE DISPOSITIVE POWER
0 SHARES
8. SHARED DISPOSITIVE POWER
7,116,564 SHARES (INCLUDES 6,239,639 SHARES CNV PFD STK-DISP
RATIO-1 PFD =146.3782 COMMON SHS)
9. AGGREGATED AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
7,116,564 SHARES (INCLUDES 6,239,639 SHARES CNV PFD STK-DISP
RATIO-1 PFD =146.3782 COMMON SHS)
10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*
NOT APPLICABLE
11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
10.3%
12. TYPE OF REPORTING PERSON*
BK
SCHEDULE 13G PAGE 3 OF 5 PAGES
ITEM 1.
(A) NAME OF ISSUER
CABOT CORPORATION
(B) ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES
TWO SEAPORT LANE SUITE 1300
BOSTON MA 02109-1806
ITEM 2.
(A) NAME OF PERSON FILING
STATE STREET BANK AND TRUST COMPANY, TRUSTEE
(B) ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE,
RESIDENCE
225 FRANKLIN STREET, BOSTON, MA 02110
(C) CITIZENSHIP
BOSTON, MASSACHUSETTS
(D) TITLE OF CLASS OF SECURITIES
COMMON STOCK
(E) CUSIP NUMBER
127055101
ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULE 13D-1(B), OR
13D-2(B), CHECK WHETHER THE PERSON FILING IS A:
(B) _X_ BANK AS DEFINED IN SECTION 3(A)(6) OF THE ACT
SCHEDULE 13G PAGE 4 OF 5 PAGES
ITEM 4. OWNERSHIP
(A) AMOUNT BENEFICIALLY OWNED
7,116,564 SHARES
(B) PERCENT OF CLASS
10.3%
(C) NUMBER OF SHARES AS TO WHICH SUCH PERSON HAS:
(I) SOLE POWER TO VOTE OR TO DIRECT THE VOTE OF
876,925 SHARES
(II) SHARED POWER TO VOTE OR TO DIRECT THE VOTE OF
6,239,639 SHARES
(III)SOLE POWER TO DISPOSE OR DIRECT THE DISPOSITION OF
0 SHARES
(IV) SHARED POWER TO DISPOSE OR TO DIRECT THE DISPOSITION OF
7,116,564 SHARES
ITEM 5. OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS
NOT APPLICABLE
ITEM 6. OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER
PERSON.
EMPLOYEE STOCK OWNERSHIP PLAN = 9.0%
ITEM 7. IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH
ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT
HOLDING COMPANY
NOT APPLICABLE
ITEM 8. IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP
NOT APPLICABLE
ITEM 9. NOTICE OF DISSOLUTION OF GROUP
NOT APPLICABLE
SCHEDULE 13G PAGE 5 OF 5 PAGES
ITEM 10. CERTIFICATION
THE FOLLOWING CERTIFICATION SHALL BE INCLUDED IF THE
STATEMENT IS FILED PURSUANT TO RULE 13D-1(B):
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 WERE NOT ACQUIRED
FOR THE PURPOSE OF AND DO NOT HAVE THE EFFECT OF CHANGING OR
INFLUENCING THE CONTROL OF THE ISSUER OF SUCH SECURITIES AND WERE
NOT ACQUIRED IN CONNECTION WITH OR AS A PARTICIPANT IN ANY
TRANSACTION HAVING SUCH PURPOSES OR EFFECT.
THIS REPORT IS NOT AN ADMISSION THAT STATE STREET BANK AND
TRUST COMPANY IS THE BENEFICIAL OWNER OF ANY SECURITIES COVERED BY
THIS REPORT, AND STATE STREET BANK AND TRUST COMPANY EXPRESSLY
DISCLAIMS BENEFICIAL OWNERSHIP OF ALL SHARES REPORTED HEREIN
PURSUANT TO RULE 13D-4.
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.
14 FEBRUARY 2006
STATE STREET CORPORATION
STATE STREET BANK AND TRUST COMPANY,
TRUSTEE
/s/ SUSAN C. DANIELS
VICE PRESIDENT