CABOT CORP — Director's Dealing 2007

Oct 2, 2007

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: CABOT CORP (CBT)
CIK: 0000016040
Period of Report: 2007-09-28

Reporting Person: CLARKESON JOHN S (Director)

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2007-09-28	Phantom Stock Units	$	A	598.0861	Acquired		Common Stock (598.0861)	Direct

Footnotes

F1: 1 for 1

F2: Immediately exercisable

F3: The shares of phantom stock become payable upon the reporting person's termination of service as a director.

F4: On July 13, 2007, Cabot's Board of Directors declared a dividend of $.18 per share on Cabot common stock, payable on September 14, 2007 to all holders of record of common stock on August 31, 2007. Mr. Clarkeson received a dividend on his phantom stock units totalling $1798.21, which was immediately reinvested in phantom stock units at a price of $37.53 per share. As a result, 47.9139 phantom stock units were allocated to Mr. Clarkeson on September 14, 2007.