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 Mr. C. Richard Reese, Chief Executive Officer Iron Mountain Incorporated 745 Atlantic Avenue  Boston, Massachusetts 02111

Re: Iron Mountain Incorporated
 Form 10-K for the year ended December 31, 2007
Filed February 29, 2008
 File No. 001-13045

Dear Mr. Reese:

We have reviewed your filing and have th e following comments.  Unless otherwise
indicated, we think you should revise your document in future filings in response to these
comments.  If you disagree, we will consider your explanation as to why our comments
are inapplicable or a revision is unnecessary.  Please be as detailed as necessary in your
explanation.  In some of our comments, we may ask you to provide us with information so we may better understand your disclosure.  After reviewing this information, we may
raise additional comments.  Please understand that the purpose of our re view process is to assist you in your
compliance with the applicable disclosure requirements and to enhance the overall disclosure in your filing.  We look forward to  working with you in these respects.  We
welcome any questions you may have about our comments or any other aspect of our review.  Feel free to call us at the telephone numbers listed at the end of this letter.
 Please respond to confirm that such comments will be complied with, or, if certain of the
comments are deemed inappropriate, advise the staff of your reason.  Your response
should be submitted in electronic form, under the label “corresp” with a copy to the staff.
Please respond within ten (10) business days.

Mr. C. Richard Reese, CEO
Iron Mountain Incorporated
April 8, 2008 Page 2

Annual Report on Form 10-K for the year ended December 31, 2007

 Business, page 1

B.  Description of Business, page 2
Growth Strategy, page 9
International Acquisition Strategy, page 10

1. Please tell us why the $2 million for the jo int venture in Asia Pacific in 2007 does
not appear as a cash outflow item under inve sting activitie s within your cash flow
statement.  If no cash was used for the esta blishment of this joint venture, please
tell us how the consideration was paid.

Management’s Discussion and Analysis of Financial Condition and Results of
Operations, page 26
Results of Operations, page 35

2. In future filings, where changes in revenue  and expense amounts are attributed to
more than one factor, each significant fact or should be separately quantified and
discussed.  For example, each of the factor s contributing to the increase in general
and administrative costs listed on page 39 should be quantified and discussed.
(i.e. compensation expenses, reorganiza tion, and field operations meeting).
Please confirm your understanding and that you will comply in future filings in
your response to us.

Segment Analysis, page 44

3. We note your disclosure of depreciati on and amortization excluded from the
calculation of segment contri bution on pages 44, 45, and 46.  Please tell us, revise
future filings to describe how management uses this measure, and why it is useful
to investors given you have included such amounts in the tables as segment financial measures but have not provid ed a discussion of the changes in the
measure.  If you determine this measure is not relevant to an investor’s understanding of your segment analysis, please remove from future filings.

Mr. C. Richard Reese, CEO
Iron Mountain Incorporated
April 8, 2008 Page 3

Financial Statements, page 57

Notes to Consolidated Financial Statements, page 62
Note 2.  Summary of Significan t Accounting Policies, page 62
k.  Accrued Expenses, page 69

4. We note that Accrued Expenses - Other comprises approximately 19% of total
current liabilities.  Please tell us whether any amounts included in Accrued
Expenses – Other exceeds 5% of total curr ent liabilities.  If so, you are required to
state separately, in the balance sheet or  in a note, any item, included in other
current liabilities, which is in excess of 5 percent of total current liabilities in
accordance with Rule 5-02.20 of Regulation S-X.

 Note 6.  Acquisitions, page 94

5. Please reconcile for us the cash paid  for acquisitions in 2007 of $375,746 (i.e.
$200,295 for ArchivesOne, $45,400 for RMS, and $130,051 for Stratify) with the
amount presented within your cash flow st atement on page 61 under the line item
“Cash paid for acquisitions, net of cash acquired” of $481,526.  To the extent there are material differences, you should disclose such amounts in future filings.

6. We note from the last paragraph on page 96 that in connection with certain recent
acquisitions, the Company may be obligated to pay additional consideration if
certain earnings objectives are achieved.  We also note from the disclosures in
Note 2 that during 2007 and 2006, the Company paid $1.8 and $14.2 million,
respectively, of additional purchase consideration for acquisitions completed in prior years and the accrued  additional purchase consideration was recorded as
goodwill.  Please tell us and revise the notes to your financial statements in future
filings to explain in furt her detail the nature and terms of the conditions which
must occur for this contingent considerati on to become payable.  As part of your
response, please specifically address whet her any of these payments are or were
contingent upon the former shareholders  of the acquired entities remaining
employed with the Company.  Your response should also explai n in further detail
why you believe it is appropriate to acc ount for the accruals and payments made
as part of the purchase price for the ac quisitions rather than as compensation
expense.  Refer to the guidance outli ned in paragraphs 25 through 34 of SFAS
No.141 and EITF 95-8.

Mr. C. Richard Reese, CEO
Iron Mountain Incorporated
April 8, 2008 Page 4

Note 8.  Quarterly Results of Op erations (Unaudited), page 101

7. We note that net income increased significantly in the third quarter of 2007 and
decreased again in the fourth quarter of  2007.  Please note that the guidance in
Item 302(a)(3) of Regulation S-K requires that selected quarterly financial data
include a discussion of any extraordinary, unusual or infrequently occurring items
recognized in each full quarter of the fi scal years presented as well as the
aggregate effect and the nature of ye ar-end or other adjustments which are
material to the results of that quarter.  Please revise your footnote to comply with
the disclosure requirements of Item 302(a)(3) in future filings.

 Note 9.  Segment Information, page 101

8. We note as part of your segment footnot e on page 104 that you disclose revenues
by product and service line.  It is unclear  to us based upon your current disclosure
which service offerings comprise the phys ical records management and secure
shredding line as well as the physical tape rotation services line.  In this regard,
please clarify for us and in future filings di sclose the type of services offerings (as
described in your business section) incl uded in each of your product and service
lines.  Also, please tell us and describe  in future filings how such product and
service lines are classified within the re venue line items (i.e. storage and service
and storage material sales) presented on the face of your statements of operations.

*    *    *    *

We urge all persons who are responsible for th e accuracy and adequacy of the disclosure
in the filing to be certain that the fili ng includes all information required under the
Securities Exchange Act of 1934 and that they  have provided all information investors
require for an informed investment decision.  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 connection with responding to our comment s, please provide, in writing, a statement
from the company acknowledging that:  ‚ the company is responsible for the adequacy  and accuracy of the disclosure in the
filing;

Mr. C. Richard Reese, CEO
Iron Mountain Incorporated April 8, 2008 Page 5

‚ 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 federal securities laws of the United States.
 In addition, please be advise d that the Division of Enfo rcement has access to all
information you provide to the staff of the Divi sion of Corporation Fi nance in our review
of your filing or in response to our comments on your filing.  You may contact Heather Clar k at 202-551-3624 or Jean Yu  at 202-551-3305 if you have
questions regarding comments on the financial statements and related matters.  Please
contact me at 202-551-3813 w ith any other questions.

Sincerely,

Linda Cvrkel
Branch Chief