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                                                                    Exhibit 99.3

                           EXCHANGE AGENCY AGREEMENT



                                                              June __, 1998


State Street Bank and Trust Company
Corporate Trust Department
Two International Place - 4th Floor
Boston, Massachusetts 02110

Ladies and Gentlemen:

         Hadco Corporation, a corporation organized under the laws of the
Commonwealth of Massachusetts (the "Company") is offering to exchange (the
"Exchange Offer"), upon the terms and subject to the conditions set forth in the
Company's Form S-4 Registration Statement filed with the SEC on __________, 1998
(the "Prospectus"), and the accompanying Letter of Transmittal and instructions
thereto (the "Letter of Transmittal"), its 9-1/2% Senior Subordinated Notes Due
2008 (the "New Notes") for all of its outstanding 9-1/2% Senior Subordinated
Notes Due 2008 (the "Old Notes") of the Company of which $ 200,000.00 principal
amount is outstanding. The New Notes and the Old Notes are together referred to
herein as the "Notes". Capitalized terms used herein but not otherwise defined
herein shall have the meanings ascribed to them in the Prospectus or Letter of
Transmittal.

         You are hereby appointed and authorized to act as agent (the "Exchange
Agent") to effectuate the exchange of Old Notes for New Notes, on the terms and
subject to the conditions of this agreement (the "Agreement"). In that
connection, the following documents have been delivered to you:

         (i)      Prospectus;

         (ii)     the Letter of Transmittal accompanying the Prospectus, to be 
                  used by the holders of Old Notes ("Old Noteholders") in 
                  tendering their Old Notes; and

         (iii)    the Notice of Guaranteed Delivery to be used by Old
                  Noteholders whose Old Notes are not immediately available or
                  who cannot deliver their Old Notes, the


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                  Letter of Transmittal or any other required documents to you
                  prior to the expiration of the Exchange Offer.

         The Exchange Offer will expire at the time and on the date specified in
the Prospectus (the "Expiration Date") unless the Exchange Offer is extended by
the Company, in which case the term "Expiration Date" shall mean the latest date
to which the Exchange Offer is extended.

         You are hereby requested, and you hereby agree, to act as follows:

         1. You are to accept Old Notes which are accompanied by the appropriate
Letter of Transmittal or facsimile thereof, properly completed and duly executed
in accordance with the instructions thereon and any requisite collateral
documents or, in the case of Old Notes tendered by book-entry transfer, an
Agent's Message in lieu of the Letter of Transmittal, and all other instruments
and communications submitted to you in connection with the Exchange Offer and to
hold the same upon the terms and conditions set forth in this Agreement.

         2. You are to examine the Letters of Transmittal, or Agent's Message in
lieu thereof, Old Notes and other documents delivered or mailed to you by or for
Old Noteholders to ascertain whether (i) the Letters of Transmittal are properly
completed and duly executed in accordance with the instructions set forth
therein, (ii) the other documents are properly completed and duly executed, and
(iii) the Old Notes have otherwise been properly tendered. You need not pass on
the legal sufficiency of any signature or verify any signature guarantee.

                  The Exchange Agent's obligations with respect to receipt and
inspection of the Letter of Transmittal in connection with this Exchange Offer
shall be satisfied for all purposes hereof by inspection of the electronic
message transmitted to the Exchange Agent by Depository Trust Company ("DTC")
participants in accordance with the Automated Tender Offer Program ("ATOP") of
the DTC and by otherwise observing and complying with all procedures established
by DTC in connection with ATOP.

         3. In the event any Letter of Transmittal or other document has been
improperly executed or completed or any of the certificates are not in proper
form or have been improperly tendered or any book-entry delivery of Old Notes
has been improperly made, or if some other irregularity in connection with the
delivery of Old Notes by a holder thereof exists, you are authorized, upon
consultation with the Company or its counsel, to endeavor to take such action as
may be necessary to cause such irregularity to be corrected. You are authorized,
upon consultation with the Company or one of its representatives, to request
from any person tendering Old Notes such additional documents or undertakings as
you may deem appropriate. All questions as to the form of all documents and the
validity, eligibility


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(including time of receipt) and acceptance of tendered Old Notes will be
determined by the Company, in its sole discretion, whose determination will be
final and binding. The Company reserves the absolute right to reject any or all
tenders of any particular Old Notes, which would, in the opinion of the
Company's counsel, be unlawful. The Company also reserves the absolute right to
waive any of the conditions of the Exchange Offer or any defect or irregularity
in the tender of any Old Notes, and the Company's interpretation of the terms
and conditions of the Exchange Offer (including the Letter of Transmittal and
the instructions set forth therein) will be final. No tender of Old Notes will
be deemed to have been properly made until all defects and irregularities have
been cured or waived.

         4. Tenders of Old Notes may be made only as set forth in the Prospectus
and Letter of Transmittal, and Old Notes shall be considered properly tendered
to you only when:

                  a. a properly completed and duly executed Letter of
         Transmittal, with any required signature guarantees and any other
         required documents as set forth in the Letter of Transmittal, is
         received by you at your address set forth in the Prospectus and Letter
         of Transmittal, and Old Notes are received by you at such addresses or
         a timely confirmation of a book-entry transfer of such Old Notes, along
         with an Agent's Message is received by you at or prior to the
         Expiration Date at your address set forth in the Prospectus and Letter
         of Transmittal; or a properly completed and duly executed Notice of
         Guaranteed Delivery substantially in the form provided by the Company,
         with an appropriate guarantee of signature and delivery from an
         Eligible Institution, is received by you at or prior to the Expiration
         Date and Old Notes (in respect of which there have been delivered to
         you prior to the Expiration Date a properly completed and duly executed
         Notice of Guaranteed Delivery) in proper form for transfer together
         with a properly completed and duly executed Letter of Transmittal (or
         facsimile thereof) or Agent's Message, and any other required documents
         as set forth in the Letter of Transmittal, are received by you within
         three New York Stock Exchange trading days; and

                  b. the adequacy of the items relating to Old Notes, the Letter
         of Transmittal therefor and any Notice of Guaranteed Delivery has been 
         favorably passed upon as above provided.

         Notwithstanding the provisions of the preceding paragraph, Old Notes
which the Company shall approve as having been properly tendered shall be
considered to be properly tendered.

         5. Holders of Old Notes may make book-entry delivery of their
securities. You will establish in your name or the name of your nominee an
account with respect to the Old


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Notes at Depository Trust Company ("DTC") for purpose of the Exchange Offer to
permit book-entry transfers of Old Notes. Except as otherwise provided below,
Old Notes, or any book-entry transfer into your account at DTC of Old Notes
tendered electronically, as well as a properly completed and duly executed copy
of the Letter of Transmittal or Agent's Message, and any other documents
required by the Letter of Transmittal, must be received by you or, in the case
of tenders of book-entry transfer, confirmed to you by transfer to your account
on or prior to the Expiration Date.

         6. a. A tendering Old Noteholder may withdraw tendered Old Notes in
accordance with the procedures set forth in the Prospectus and Letter of
Transmittal, in which event, except as may be otherwise specified in the Old
Noteholder's notice of withdrawal, all items in your possession which shall have
been received from the Old Noteholder with respect to those Old Notes shall be
promptly returned to or upon the order of the Old Noteholder and the Old Notes
covered by those items shall no longer be considered to be properly tendered.

            b. A withdrawal may not be rescinded.  Withdrawn Old Notes may,
however, be tendered at anytime on or prior to the Expiration Date.

         7. You are to record and to hold all tenders received by you and to
promptly notify by telephone after the close of business on each business day,
the following person as to the total number of Old Notes tendered on such day
and the cumulative numbers with respect to the Old Notes received through the
time of such call:

             _____________________________________________________

Each daily report should identify: the number and principal amount of Old Notes
represented by (i) certificates, and (ii) Notices of Guaranteed Delivery
actually received by you through the time of the report. The foregoing
information should also be sent to Mr. in a daily letter. In addition, you will
also provide, and cooperate in making available to Mr. ________________________
____________________, such other information as he or the Company's counsel may
reasonably request upon oral request made from time to time. Your cooperation
shall include, without limitation, the granting by you to the Company, and such
other persons as it may reasonably request, of access to those persons on your
staff who are responsible for receiving tenders of Old Notes in order to insure
that immediately prior to the Expiration Date, the Company shall have received
information in sufficient detail to enable it to decide whether to extend the
Exchange Offer.

         8. Letters of Transmittal, Notices of Guaranteed Delivery and
telegrams, facsimile transmissions and letters submitted in lieu thereof
pursuant to the Exchange Offer


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shall be stamped by you as to the date and time of receipt and shall be retained
in your possession until the Expiration Date. As promptly as practicable after
the Expiration Date, you will deliver those items, together with all properly
tendered Old Notes to the Company.

         9. You are to follow up and to act upon any amendments, modifications
or supplements to these instructions mutually satisfactory to you and the
Company, and upon any further information in connection with the terms of the
Exchange Offer, any of which may be given to you by the Company, including
instructions with respect to (i) any extension or other modification of the
Exchange Offer, (ii) the amount or manner of payment for any Old Notes
exchanged, and (iii) the cancellation of the Exchange Offer.

         10. If under the conditions set forth in the Prospectus and Letter of
Transmittal, the Company becomes obligated to accept Old Notes tendered, it
will, as promptly as practicable thereafter, deposit with you certificates
representing New Notes in the amount determined according to the ratio
prescribed in the Prospectus and Letter of Transmittal. Unless otherwise
indicated under any Special Issuance Instructions or any Special Delivery
Instructions set forth in any Letter of Transmittal, you shall mail the
certificates representing the New Notes and the certificates for any Old Notes
submitted but not tendered for exchange to the registered owner of the
securities at the address shown in the Letter of Transmittal. In the event that
either or both the Special Issuance Instructions and the Special Delivery
Instructions are completed, you shall mail all certificates representing New
Notes (or Old Notes to be returned, if any) to the person or persons so
indicated in the Letter of Transmittal. Certificates shall be post-marked by you
within a reasonable period of time after certificates have been provided to you.

         11. No exchange shall be made as to any Old Notes unless and until such
Old Notes have been properly tendered as provided in Section 4 of this
Agreement.

         12. For performing your services hereunder, you shall be entitled to
receive from the Company a fee of $_______. You shall also be reimbursed by the
Company for all reasonable expenses, including counsel fees, if any, and mailing
costs you may incur in connection with the performance of your duties.

         13. As Exchange Agent hereunder you:

             (a) shall not have duties or obligations other than those
         specifically set forth or as may subsequently be agreed to by you and 
         the Company;



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                  (b) shall not be obligated to take any legal action hereunder
         which might in your judgment involve any expense or liability unless
         you have been furnished with reasonable indemnification;

                  (c) may rely on and shall be protected in acting upon any
         certificate, instrument, opinion, notice, letter, telegram or other
         document or security delivered to you and believed by you to be genuine
         and to have been signed by the proper party or parties;

                  (d) may rely on and shall be protected in acting or refraining
         from acting upon the written instructions of the Company; and

                  (e) may consult counsel satisfactory to you (including counsel
         to the Company), and the opinion of such counsel shall be full and
         complete authorization and protection with respect to any action taken,
         suffered, or omitted by you hereunder in good faith and in accordance
         with the opinion of such counsel.

                  (f) you shall not be deemed to have notice of any fact, claim
         or demand with respect hereto unless actually known by an officer
         charged with responsibility for administering this Agreement or unless
         in writing received by you and making specific reference to this
         Agreement.

         14.      You undertake the duties and obligations imposed herein upon
the following additional terms and conditions:

                  (a) you shall perform your duties and obligations hereunder 
         with due care;

                  (b) you shall not be under any responsibility in respect of
         the validity or sufficiency (not only as to genuineness, but also as to
         its due execution, the genuineness of signatures appearing thereon and
         as to the truth and accuracy of any information therein contained) of
         any Letter of Transmittal, certificate representing Old Notes,
         book-entry transfer of Old Notes or Notice of Guaranteed Delivery; and

                  (c) neither you nor any of your directors, officers or
         employees shall be liable to anyone for any error of judgment, or for
         any act done or step taken or omitted to be taken by you or any of your
         directors, officers or employees, or for any mistake of fact or law, or
         for anything which you or any of your directors, officers or employees,
         may do or refrain from doing in connection with or in the
         administration of this Agreement, unless and except to the extent the
         same constitutes gross negligence or willful misconduct on your part.


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         15. You are not authorized to make any recommendation on behalf of the
Company as to whether a holder of Old Notes should or should not tender his, her
or its Old Notes.

         16. All certificates representing New Notes shall be forwarded by (i)
first-class mail under a blanket surety bond protecting you and the Company from
loss or liability arising out of the non-receipt or non-deliver of such
certificates or (ii) registered mail, insured separately for the replacement
value of such certificates.

         17. You are authorized to cooperate with and furnish information to any
organization (and its representatives) designated from time to time by the
Company, in any manner reasonably requested by any of them and acceptable to you
in connection with the Exchange Offer.

         18. The Company covenants and agrees to reimburse, indemnify and hold
you harmless against any costs, expenses (including reasonable expenses of your
legal counsel), losses or damages which, without negligence, misconduct or bad
faith on your part may be paid, incurred or suffered by you or to which you may
become subject by reason of or as a result of the administration of your duties
hereunder or by reason of or as a result of your compliance with the
instructions set forth herein or with any written or oral instructions delivered
to you pursuant hereto, or liability resulting from your actions as Exchange
Agent pursuant hereto, including any claims against you by any Old Noteholder.

         19. You hereby acknowledge receipt of each of the documents listed in
items (i) through (iii) of the introduction to this Agreement and further
acknowledge that you have examined the same. The Company shall supply you with a
sufficient number of copies of such documents to enable you to perform your
services hereunder. Any inconsistency between this Agreement on the one hand and
the documents listed in items (i) through (iii) of the introduction of this
Agreement, as they may from time to time be amended, on the other, shall be
resolved in favor of the latter, except with respect to the duties, liabilities
and indemnification of you as Exchange Agent.

         20. All notices, statements and other communications hereunder shall be
in writing, signed by a duly authorized officer of the party sending such
notices, and shall be deemed given when delivered by hand or by certified mail,
postage prepaid, addressed as follows:


                  To the Company:           Hadco Corporation
                                            12A Manor Parkway
                                            Salem, New Hampshire 03079



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                           Attention: ________________________________

                           Facsimile: ________________________________

                           Telephone:       (603) 898-8000


                  to you:

                           State Street Bank and Trust Company
                           Corporate Trust Division
                           Two International Place
                           Boston, MA 02110-0778

                           Attention:       Hadco Corporation

                           Facsimile:       (617) 664-5607
                           Telephone:       (617) 664-5371

or to such other address as either party may furnish hereunder by notice;
provided that notice of change of address shall be deemed given only when
received.

         21. This agreement shall be construed and enforced in accordance with
the law of the State of New York applicable to agreements made and to be
performed in the State of New York and shall inure to the benefit of, and the
obligations created hereby shall be binding upon, the successors and assigns of
the parties hereto.

         22. These instructions may be reasonably modified or supplemented by
the Company or by any officer thereof authorized to give notice, approval or
waiver on its behalf.

         23. As used herein, "business day" shall mean any day other than a
Saturday or Sunday, or any other day on which you are authorized or required to
be closed for business.



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         Please acknowledge receipt of this letter and confirm the arrangements
herein provided by signing and returning the enclosed copy.


                                        Very truly yours,


                                        HADCO CORPORATION


                                        By:_________________________________
                                        Name:
                                        Title:



ACCEPTED AS OF   June __, 1998

STATE STREET BANK AND TRUST COMPANY
As Exchange Agent


By:_________________________________________
Name:
Title:



PABOS2:LKF:148771_1