SecProbe.io

February 15, 2012
 Via E-mail

Mr. Eduardo Cordeiro Executive Vice President and Chief Financial Officer Cabot Corporation Two Seaport Lane, Suite 1300 Boston, MA  02210
RE: Cabot Corporation
Form 10-K for the Year ended September 30, 2011
Filed November 29, 2011 Form 10-Q for the Quarter ended December 31, 2011
Filed February 8, 2012
  File No. 1-5667

Dear Mr. Cordeiro:
 We have reviewed your filings 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 te n business days by providing the requested
information or by advising us when you will provide the requested response.  If you do not believe our comments apply to your facts and circum stances, please tell us w hy in your response.

After reviewing the information you provide in response to these comments, we may
have additional comments.               Form 10-K for the Year Ended September 30, 2011

 Item 7 – Management’s Discussion and Analys is of Financial Condition and Results of
Operations, page 30
 Results of Operations, page 37

1. You present total segment EBIT on page 42.  Since total segment EBIT represents a non-
GAAP measure when it is presen ted or discussed outside of your SFAS 131 footnote, in
future filings you should ensure either: (a) Total segment EBIT it is not presente d outside of your SFAS 131 footnote or
(b) If you choose to present total segment EBIT outside of your SFAS 131, you must
include all the disclosures required by Item  10(e) of Regulation S-K including the
following:

Mr. Eduardo Cordeiro Cabot Corporation February 15, 2012 Page 2

  reconcile from total segment EBIT to in come (loss) from continuing operations
before taxes and then on to net income to highlight the differences between the
non-GAAP measure and operating income,
 identify this amount as a non-GAAP performance measure,
 state the material limitations associat ed with use of the non-GAAP financial
measure as compared to the use of the most directly comparable GAAP financial
measure,
 state the manner in which management compensates for these limitations when
using the non-GAAP financial measure,
 explain why your management believes that this measure provides useful
information to investors,
 state how your management uses the non-GAAP measure,
 provide cautionary disclosure that th e non-GAAP measure presented may not be
comparable to similarly titled m easures used by other entities and
 state that this non-GAAP measure should not be considered as an alternative to
net income, which is determined in accordance with GAAP.
See also Question 104.04 of the SEC Complia nce and Disclosure Interpreta tions: Non-
GAAP Financial Measures.  Please show us  in your supplemental response what the
revisions will look like.
 Item 8 – Financial Statements and Supplementary Data, page 54

 Note A – Significant Acc ounting Policies, page 62

 General

2. Please disclose in future filings the types of e xpenses that you include in the cost of sales
line item and the types of expenses that you include in the selling and administrative
expenses line item.  Please also disclose  whether you include i nbound freight charges,
purchasing and receiving costs, inspection co sts, warehousing costs,  internal transfer
costs, and the other costs of your  distribution network in the co st of sales line item.  With
the exception of warehousing cost s, if you currently exclude a portion of these costs from
cost of sales, please disclose:
 in a footnote the line items that these ex cluded costs are included in and the amounts
included in each line item for each period presented, and
 in MD&A that your gross margins may not be  comparable to thos e of other entities,
since some entities include all of the costs re lated to their distribution network in cost
of sales and others like you exclude a porti on of them from gross margin, including
them instead in a line item such as selling and administrative expenses.
Please show us in your supplemental response what the revisions will look like.

Mr. Eduardo Cordeiro Cabot Corporation February 15, 2012 Page 3

 Inventories, page 62

3. You use both the average cost and FIFO methods to determine the cost of your
inventories for all non-U.S. inventories a nd certain U.S. inventories.  You should
generally use one inventory method for similar t ypes of inventories.  Please disclose in
future filings which types of inventory you use each method for, and disclose whether
you use both methods for any similar types of in ventory.  If so, pleas e also disclose your
basis for doing this.  Please show us in your  supplemental response what the revisions
will look like.
 Note S – Income Taxes, page 97

4. We note that you repatriated $24 million of high tax income in response to recent
changes in U.S. tax legislation.  Please tell us and revise your disclosure in future filings
to address how you concluded, in light of your  repatriation, that you have the ability and
intent to invest $887 million of undistributed earnings of non-U.S. subsidiaries indefinitely as of September 30, 2011.  Please refer to ASC 740-30-25-17 though 19.

5. Based on your disclosure on pages 97 and 98, it appears that (i) you ge nerate a significant
amount of income from continuing operations  before income taxes and equity in net
earnings of affiliated companies from locati ons outside of the United States, (ii) a
significant portion of your pr ovision (benefit) for income taxes is composed of non-U.S.
amounts, and (iii) the difference between inco me tax provision as calculated using the
U.S. statutory rate and your effective tax rate  is due, in part to adjustments related to
foreign income.  Please tell us what countries  comprise a material amount of your foreign
taxes and whether you generate a disproportiona te amount of taxable income in countries
with very low tax rates.
 Note T – Commitments and Contingencies, page 101

 Contingencies-Environmental Matters, page 102

6. We have reviewed the tables representing your estimated future undiscounted payments
related to your respirator re serves you presented in your Forms 10-K for the years ended
September 30, 2010, 2009 and 2008.  In 2008, you estimated those payments to be $1 million, $1 million and $2 million for the years ended September 30, 2009, 2010 and 2011.  In 2009, you estimated those payments to be $1 million and $2 million for the years ended September 30, 2010 and 2011.  In 2010, you estimated those payments to be $4 million for the year ended September 30, 2011.  We further note that you have made
payments of $5 million, $2 million, $2 million a nd $2 million for the four fiscal years
ended September 30, 2011.  In light of the fact that you have consistently paid more than
what you had estimated for these payments, te ll us you basis for your estimated future
undiscounted payments as reflected on page 48.  Tell us why the $5 million payment in 2011 is not indicative of potential future payments.

Mr. Eduardo Cordeiro Cabot Corporation February 15, 2012 Page 4

Item 15 – Exhibits, Financial Statement Schedules, page 117

 Exhibit 10(a) – Credit Agreement dated August 26, 2011

7. Please refer to comment 10 in our letter  dated January 25, 2010.  We note that you
continue to omit the schedules and exhibits  from the public filing of the new credit
agreement.  Please file a complete copy of the credit agreement, including all schedules
and exhibits, with your next Exchange Act report .  In addition, please be advised that this
agreement should have been filed as an e xhibit to the Form 8-K dated August 26, 2011
reporting the entry into this material defin itive agreement.  See Footnote (2) to Exhibit
Table of Item 601 of Regulation S-K, which st ates that a Form 8–K exhibit is required
only if relevant to the subject matter reported on the Form 8–K report.
 Form 10-Q for the Quarter Ended December 31, 2012

 General

8. Please address the above comments in your in terim filings as well, as applicable.

We urge all persons who are responsible for th e accuracy and adequacy of the disclosure
in the filing to be certain that the filing include s the information the Securities Exchange Act of
1934 and all applicable Exchange Act rules requir e.  Since the company and its management are
in possession of all facts relating to a company’s disclosure, they are responsible for the accuracy
and adequacy of the disclosures they have made.
 In responding to our comments, please provi de a written statement from the company
acknowledging that:
 the company is responsible for the adequacy an d accuracy of the disclo sure in the filing;

 staff comments or changes to disclosure in response to staff comments do not foreclose
the Commission from taking any action with respect to the filing; and

 the company may not assert staff comments as  a defense in any proceeding initiated by
the Commission or any person under the federa l securities laws of  the United States.

Mr. Eduardo Cordeiro Cabot Corporation February 15, 2012 Page 5

 You may contact Era Anagnosti, Staff Attorn ey, at (202) 551-3369 or, in her absence,
Pamela Long, Assistant Director, at (202) 551-3765 if you have any questions regarding legal or
disclosure matters.  Please contact Jeffrey Gor don, Staff Accountant, at (202) 551-3866 or, in his
absence, Jeanne Baker, Assistant Chief Acc ountant, at (202) 551-3691 if you have questions
regarding comments on the financial st atements and related matters.
      Sincerely,   /s/ Rufus Decker       Rufus Decker  Accounting Branch Chief