<Page>

                                                                   EXHIBIT 10.53

December 8, 2004
(REVISED DECEMBER 16, 2004)

Peter Delle Donne
34 Meachen Road
Sudbury MA 01776


Dear Peter:

In connection with your separation from employment with Iron Mountain,
Incorporated and/or its affiliated entities (collectively "Iron Mountain"), we
have agreed to the following:

1.   Your have resigned your employment with Iron Mountain as of December 31,
     2004 (the "Resignation Date"). Between now and the Resignation Date you
     will remain on a paid leave of absence and will provide such transition
     services as Iron Mountain may request. Effective upon your execution and
     non-revocation of this Agreement, and subject to the provisions of
     paragraph 6 below, Iron Mountain agrees that your resignation will be
     treated as a resignation for a "Qualifying Reason" as that term is defined
     in the employment agreement between you and Iron Mountain dated March 15,
     2001 (as revised on April 4, 2001), a copy of which is attached hereto (the
     "Employment Agreement"). In lieu of the any severance payments that you may
     be entitled to under the Employment Agreement, you agree that, commencing
     on the on the Resignation Date, and continuing until May 15, 2006 (the
     "Consulting Period"), you will provide consulting services to Iron Mountain
     at such times and with respect to such matters as Iron Mountain may
     request. These consulting services will be predominately phone matters
     pertaining to, but not limited to, customers, budget/financial items, and
     ESS personal matters. Iron Mountain will pay you a total consulting fee of
     $330,200.00 for your services during the Consulting Period, which amount
     will be paid to you as follows: (a) $297,180.00 for the period from January
     1, 2005, through December 31, 2005, in equal installments at such times as
     you would have received salary payments had you remain employed by Iron
     Mountain, and (b) $33,020.00 for the period from January 1, 2006, through
     May 15, 2006, again in equal installments at such times as you would have
     received salary payments had you remain employed by Iron Mountain. Any
     options previously granted to you pursuant to the Iron Mountain
     Incorporated 2002 Stock Incentive Plan shall continue to vest during the
     Consulting Period, and you shall have sixty (60) days after the expiration
     of the Consulting Period to exercise any options you may have. Iron
     Mountain shall be free to terminate the above consulting arrangement at any
     time for any reason, with the exception that the consulting arrangement
     cannot be terminated based on a change in Iron Mountain management;
     provided, however, that in the event of any such termination you shall
     remain entitled to receive the balance of the Consulting Fee and the

<Page>

Peter Delle Donne
Page 2

     payment referenced in paragraph five (5) at such times as you would have
     received it had Iron Mountain not terminated this consulting arrangement.
     If the agreement is terminated for any reason, all unvested options as of
     the date of termination will expire and you will have sixty (60) day from
     that termination date to exercise vested options. Additionally, subject to
     your execution and non-revocation of this Agreement, and subject to the
     provisions of paragraph 6 below, on or before March 31, 2005, Iron Mountain
     will pay you a bonus on account of calendar year 2004 in an amount equal to
     at least sixty percent (60%) of your base salary, minus withholdings as
     required by law. Any amount of such bonus in excess of sixty percent (60%)
     of your base salary shall be in Iron Mountain's sole discretion.

2.   On or shortly after the Resignation Date, Iron Mountain will pay you five
     (5) weeks of vacation pay, minus required withholdings, which you agree
     represents the balance of your vacation days accrued but not yet taken as
     of the Resignation Date. Iron Mountain will also reimburse you for any
     reasonable business expenses that you may have incurred on Iron Mountain's
     behalf prior to December 6, 2004, so long as you provide documentation of
     such expenses in form satisfactory to Iron Mountain prior to December 31,
     2004.

3.   On or before January 31, 2005, Iron Mountain shall make a lump sum payment
     to you of $10,000 (grossed up to permit you to pay federal and state
     payroll taxes on that amount) to assist you in purchasing outplacement
     services.

4.   Iron Mountain will provide you with a mutually agreeable reference from
     Richard Reese, John Kenny and/or Patricia Bowler to be used with future
     employers. You will provide a proposed draft of such a reference to
     Patricia Bowler for Iron Mountain's review.

5.   Except as set forth above, after the Resignation Date, you shall not be
     eligible to participate or continue to participate in any employee benefit
     plans or programs of Iron Mountain. Commencing on the Resignation Date and
     continuing during the Consulting Period, Iron Mountain will make a monthly
     payment to you of $530.66 to assist you in paying the cost of your medical
     and dental coverage and pension benefit that you have obtained through
     sources other than Iron Mountain.

6.   Any severance or consulting payments due you under this Agreement shall be
     made to your estate or legal representative in the event of your death.

7.   You reaffirm and acknowledge that you remain bound by your obligations
     under the enclosed Employee Confidentiality and Non-Competition Agreement.
     For the avoidance of doubt, the two (2) year period referenced in paragraph
     3 of the Employee Confidentiality and Non-Competition Agreement shall run
     from January 1, 2005 through and including December 31, 2006.

8.   You agree that Iron Mountain has informed you of your right to consult, and
     that you should consult, an attorney with respect to this Agreement. You
     have until twenty-one (21) days from the receipt of this letter to decide
     whether or not to sign this Agreement. If the Agreement has not been
     returned to me within twenty-one (21) days of your receipt of this
     Agreement, this Agreement shall not be valid. In the event that you execute
     and return this Agreement to me within twenty-one (21) days of the date of
     its delivery to you, you shall

<Page>

Peter Delle Donne
Page 3

     have seven (7) days after executing this Agreement to revoke your execution
     of this Agreement, which can be accomplished by delivering a written notice
     of revocation to me before the expiration of the seven (7) day revocation
     period. This Agreement shall not be effective (and Iron Mountain shall have
     no obligations hereunder) until the expiration of the seven (7) day
     revocation period.

9.   After your employment at Iron Mountain, you will treat as strictly
     confidential all proprietary or other confidential information of Iron
     Mountain. All documents (electronic, paper or otherwise), records
     (electronic, paper or otherwise), materials, software, equipment, and other
     physical property, and all copies of the foregoing, whether or not
     otherwise subject to the Confidentiality Agreement, that have come into
     your possession or been produced by you in connection with your employment
     ("Property"), have been and remain the sole property of Iron Mountain or
     the Iron Mountain Affiliates, as applicable. You agree that you have
     returned all such Property to Iron Mountain or the Iron Mountain
     Affiliates, as applicable (or, to the extent that you have not, that you
     immediately will do so); provided, however, that you may keep your current
     laptop computer.

10.  You agree to hold as secret and confidential all details of this Separation
     Agreement, including its terms and the negotiations leading to it and the
     contents of the Memorandum ("Agreement-Related Matters"), except as
     required to seek legal counsel, financial, or tax advice. Further, you
     agree not to discuss any Agreement-Related Matters with any employee or
     ex-employee of Iron Mountain, or with any other third parties, without Iron
     Mountain's written authorization. You may, however, disclose the Agreement,
     if required to do so by law, provided, however, that if you anticipate
     making such a disclosure, you agree to provide Iron Mountain with at least
     10 days written notice (or, if such notice is not practicable under the
     circumstances, with as much notice as is practicable) of the anticipated
     disclosure and the reasons therefore .

11.  You agree not to take any action or to make any statement, written or oral,
     that disparages or criticizes the business or management of Iron Mountain,
     or any of its respective directors, officers, agents, or employees. You
     further agree not to take any action that is intended to, or that does in
     fact, damage the business or reputation of Iron Mountain, or the personal
     or business reputations of any of its respective directors, officers,
     agents, or employees, or that interferes with, impairs or disrupts the
     normal operations of Iron Mountain.

12.  You, your heirs, successors, and assigns, hereby knowingly and voluntarily
     remise, release and forever discharge Iron Mountain, together with all of
     its respective current and former officers, directors, agents,
     representatives and employees, and each of its predecessors, successors and
     assigns (collectively, the "Releasees"), from any and all debts, demands,
     actions, causes of actions, accounts, covenants, contracts, agreements,
     claims, damages, omissions, promises, and any and all claims and
     liabilities whatsoever, of every name and nature, known or unknown,
     suspected or unsuspected, both in law and equity ("Claims"), which you ever
     had, now have, or may hereafter claim to have against the Releasees by
     reason of any matter, cause or thing whatsoever arising from the beginning
     of time to the time you sign this Agreement (the "General Release"). This
     General Release of Claims shall apply to any Claim of any type, including,
     without limitation, any and all Claims of any type that you may have
     arising under the common law, under Title VII of the Civil Rights Act of

<Page>

Peter Delle Donne
Page 4

     1964, the Civil Rights Act of 1991, the Age Discrimination in Employment
     Act of 1967, the Older Workers Benefit Protection Act, the Americans With
     Disabilities Act of 1967, the Family and Medical Leave Act of 1993, the
     Employee Retirement Income Security Act of 1974, or Mass. Gen. Laws ch.
     151B, each as amended, and any other federal, state or local statutes,
     regulations, ordinances or common law creating employment-related causes of
     action, or under any policy, agreement, understanding or promise, written
     or oral, formal or informal, between any of the Releasees and you, and
     shall further apply, without limitation, to any and all Claims in
     connection with, related to or arising out of your employment, or the
     termination of your employment, with Iron Mountain, and all Claims for
     alleged tortious, defamatory or fraudulent conduct. You also hereby waive
     any Claim for reinstatement, severance pay, attorney's fees, or costs. By
     signing this Agreement, you agree and represent that you will not be
     entitled to any personal recovery in any action or proceeding that may be
     commenced on your behalf arising out of any of the matters that are the
     subject of the General Release; PROVIDED, HOWEVER, that nothing in this
     General Release shall prevent you from seeking to enforce your rights under
     this Agreement.

13.  During and after the termination of your employment, you agree to cooperate
     fully with Iron Mountain concerning requests for information about the
     business of Iron Mountain or your involvement and participation therein;
     the defense or prosecution of any claims or actions now in existence or
     which may be brought in the future against or on behalf of Iron Mountain
     which relate to events or occurrences that transpired while you were
     employed by Iron Mountain. Your full cooperation shall include, but not be
     limited to, being available to meet and speak with officers or employees of
     Iron Mountain and/or their counsel at reasonable times and locations,
     executing accurate and truthful documents and taking such other actions as
     may reasonably be requested by Iron Mountain and/or their counsel to
     effectuate the foregoing. Iron Mountain agrees to reimburse you for any
     reasonable, out-of-pocket travel; hotel and meal expenses incurred in
     connection with your performance of obligations for which you have obtained
     prior approval from Iron Mountain. In addition, Iron Mountain will consider
     reimbursing you for your time spent in performing your obligations under
     paragraph 13 other than for routine matters or for time spent in testifying
     on Iron Mountain's behalf, the terms of such reimbursement to be negotiated
     on a case-by-case basis.

14.  This Agreement is intended to operate as a contract under seal and shall be
     governed by, and enforced and interpreted in accordance with, the law of
     the Commonwealth of Massachusetts, and you hereby consent to jurisdiction
     in courts located in the Commonwealth of Massachusetts with respect to all
     matters arising out of or related to this Agreement.

15.  Other than the enclosed Employee Confidentiality and Non-Competition
     Agreement, this Agreement constitutes the entire agreement and
     understanding between you and Iron Mountain and supersedes all other
     agreements between you and Iron Mountain. This Agreement (and its
     enclosures) may be modified, altered or amended only by a document signed
     by you and an authorized representative of Iron Mountain. Iron Mountain, in
     its sole discretion, will consider waiving restrictions of the Employee
     Confidentiality and Non-Competition Agreement on a case-by-case basis in
     response to a written request for a waiver

<Page>

Peter Delle Donne
Page 5

     from you that describes in detail all of the facts and circumstances as to
     which you are requesting a waiver.

16.  It is the desire and intent of the parties that the provisions of this
     Agreement shall be enforced to the fullest extent permissible under the
     laws and public policies applied in each jurisdiction in which enforcement
     is sought. In the event that any one or more of the provisions of this
     Agreement shall be held to be invalid, illegal or unenforceable, the
     validity, legality and enforceability of the remaining provisions shall not
     in any way be affected or impaired thereby. Moreover, if any one or more of
     the provisions contained in this Agreement shall be held to be excessively
     broad as to duration, scope, activity or subject, such provisions shall be
     construed by limiting or reducing them so as to be enforceable to the
     maximum extent compatible with applicable law.

17.  By signing this Agreement, you acknowledge that you are doing so knowingly
     and voluntarily, and that you are receiving compensation and benefits
     hereunder to which you are not otherwise entitled. You also acknowledge
     that you are not relying on any representations or promises by me or any
     other representative of Iron Mountain concerning the meaning or any aspect
     of this Agreement.

If the terms of this Agreement are agreeable to you, please sign and return one
copy of this letter to me indicating your understanding of this Agreement. The
other copy of this Agreement is for your records.

Sincerely,

Iron Mountain Records Management


By /s/ Patricia M. Bowler
  -----------------------
Patricia M. Bowler


Agreed and Accepted:


/s/ Peter Delle Donne                          12-20-04
-------------------------                      --------------------
Peter Delle Donne                              Date


Enclosures