Exhibit 23

                  CONSENT OF REGISTERED PUBLIC ACCOUNTING FIRM



We hereby consent to the incorporation by reference in the Registration
Statements on Form S-8 (No. 333-19103 and 333-19099) of Cabot Corporation of our
report dated June 25, 2004 relating to the financial statements of the Cabot
Retirement Savings Plan, which appears in this Form 11-K.




/s/ PricewaterhouseCoopers LLP


Boston, MA
June 28, 2004