SecProbe.io

March 15 , 2013

Via E -mail
Eduardo E. Cordeiro
Executive Vice President and Chief Financial Officer
Cabot Corporation
Two Seaport Lane
Boston, MA  02210 -2019

Re: Cabot Corporation
 Form 10-K for the Year Ended September 30, 2012
Filed November 29, 2012
Response Dated March 1, 2013
File No. 1 -5667

Dear Mr. Cordeiro :

We have reviewed your response letter dated March 1, 2013  and have the following
comments.  In some of our comments, we may ask you to provide us with information so we
may better understand your disclosure.

Please respond to this letter within ten business days by prov iding the requested
information  or by advising us when you will provide the requested respon se.  If you do not
believe our comments apply to your facts and circumstances, please tell us why in your response.

After reviewing the information you provide in response to these  comments, we may
have  additional comments.

General

1. Where a comment below requests additional disclosures or other revisions to be made, please
show us in your supplemental response what the revisions will look like.  These revisions
should be included in your future filings, including your interim filings.

Item 8. Financial Statements and Supplementary Data, page 54

Note M. Venezuela, page 83

2. We note your response to comment six from our letter dated February 15, 2013.  On
February 8, 2013, the Venezuelan government devalued its currency to an official rate of  6.3
bolivars fuerte (BsF) to the U.S. dollar from 4.3 BsF and announced that it is shutting down
the SITME foreign exchange system.  Please address the following:
 Describe for us any instances in which you attempted to convert your bolivars into U.S.
dollars and were unable to.  Your response should explain when the failed attempt (or

Eduardo E. Cordeiro
Cabot Corporation
March 15 , 2013
Page 2

 attempts) was made, the amount you attempted to convert, and the reason w hy the
attempt was unsuccessful; and
 Tell us if you performed an updated impairment analysis of your  Venezuelan equity
investment as a result of the recent currency devaluation.  If so, please advise us of the
results of this analysis.  If not, please tell us why you do not believe such an analysis was
warranted.

3. As a related matter, please consider re vising your MD&A in future filings to address the
following and show us what your future filing disclosures will look like:
 Describe the timing and implications of the devaluation, from both an accounting and
operational standpoint;
 Provide an estimate of the financial impact of the devaluation, including any gains or
losses on monetary items or other -than-temporary impairments on your equity method
investment in Venezuela;
 Explain how the government actions regarding exchange rates and related restrictions
have affected your ability to settle transactions and repatriate cash;
 Discuss any changes in profitability related to the increase in the cost of imports and in -
country sales prices of imported goods due to the devaluation;
 Discuss any government pressures on vendors not to change sales prices and the expected
effect on profitability after the devaluation;
 Describe any business practices or policies that have changed or are expected to change
as a result of the devaluation; and
 If applicable, explain and quantify where possible the effect of the devaluation on your
compliance with any debt covenants.

Note V. Financial Information by Segment & Geographic Area, page 106

4. We note your response to comment eight from our letter dated February 15, 2013.  It appears
that the reported revenues for your Specialty Carbons and Compounds operating segment
were greater than 10 percent of the combined revenue for all your operating seg ments for all
periods presented.  As such, please tell us how you considered ASC 280 -10-50-10 and 50 -12
in determining that the Specialty Carbons and Compounds operating segment should not be
separately presented as its own reportable segment.

You may co ntact Lisa Etheredge, Staff Accountant,  at (202) 551 -3424 or Jeanne Baker,
Assistant Chief Accountant,  at (202) 551 -3691 .

Sincerely,

 /s/ Rufus Decker

Rufus Decker
Accounting Branch Chief