SCHEDULE 14A INFORMATION

           Proxy Statement Pursuant to Section 14(a) of the Securities
                      Exchange Act of 1934 (Amendment No. )

                           Filed by the Registrant (X)
                 Filed by a Party other than the Registrant ( )

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                  |_|   Preliminary Proxy Statement
                  |_|   Confidential, for Use of the Commission Only (as
                        permitted by Rule 14a-6(e)(2))
                  |_|   Definitive Proxy Statement
                  |X|   Definitive Additional Materials
                  |_|   Soliciting Material Pursuant to Section 240.14a-11(c) or
                        Section 240.14a-12

                              DIOMED HOLDINGS, INC.
                (Name of Registrant as Specified in its Charter)

(Name of Person(s) Filing Proxy Statement, if other than Registrant)

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|X| No fee required

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            fee was paid previously. Identify the previous filing by
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                      [Letterhead of Diomed Holdings, Inc.]
September 20, 2006

                           YOUR VOTE IS IMPORTANT!!!!


Dear Stockholder:

Our latest records indicate that we have not yet received your vote in
connection with the very important Special Meeting of Stockholders scheduled for
September 27, 2006. If at that meeting we have insufficient votes to approve the
equity financing, we will adjourn the meeting until a later date. Therefore,
your vote is very important.

As stated in our proxy statement, the Company requires working capital to
operate our business and protect our intellectual property. To obtain
$10,010,000 of capital, we have entered into agreements for a proposed financing
(the "Financing Transaction"). You are being asked to vote on a proposal that
approves the Financing Transaction and a second proposal that will provide us
with the authorized share capital to complete the Financing Transaction.

If stockholders do not approve Proposal 1 and Proposal 2, we will not be able to
complete the Financing Transaction. We are not likely to have sufficient funds
to operate and protect our intellectual property and this may affect the value
of your shares.

Please refer to the proxy statement for detailed information regarding the
proposals to be voted upon at the Annual Meeting. For ease of reference, the
proxy statement can be viewed at our website, www.diomedinc.com.

Your vote is critical no matter how many or how few shares you may own.
Accordingly, please refer to the enclosed voting form and vote TODAY. Remember,
you may vote by telephone or internet. Simply follow the easy instructions on
the enclosed form. If you have any questions, or need assistance in voting your
shares, please call our proxy solicitor, Innisfree M&A Incorporated at
1.888.750.5834. If you have already voted, we thank you for your participation.

Thank you for your continued support.

Very truly yours,

/s/ David Swank
David Swank
Secretary