CABOT CORP — Director's Dealing 2006

May 31, 2006

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: CABOT CORP (CBT)
CIK: 0000016040
Period of Report: 2006-05-26

Reporting Person: Mason Jonathan P (Executive Vice President, CFO)

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2006-05-26	Employee Stock Option (right to buy)	$35.23	A	15000	Acquired	2011-05-11	Common Stock (15000)	Direct

Footnotes

F1: Option grant.