EXHIBIT 10.34

                                                                  Execution Form

                      AMENDMENT TO FIRST EXCHANGE AGREEMENT

      THIS AMENDMENT TO FIRST EXCHANGE AGREEMENT (this "Amendment"), is dated as
of May 28, 2003 and amends the Exchange Agreement (the "First Exchange
Agreement"), dated as April 22, 2003, into by and among Diomed Holdings, Inc., a
Delaware corporation, with headquarters located at One Dundee Park, Andover, MA
01810 (the "Company"), Diomed, Inc., a Delaware corporation and a wholly-owned
subsidiary of the Company ("Diomed"), each entity named on the signature page
hereto as a Note Purchaser (each, a "Note Purchaser") and Gibralt US, Inc., a
Colorado corporation (the "Designated Note Purchaser"). Capitalized terms used
but not defined herein shall have their respective meanings set forth in the
First Exchange Agreement, unless the context clearly indicates otherwise.

                              W I T N E S S E T H:

      WHEREAS, the Company, Diomed, the Note Purchasers and the Designated Note
Purchaser have entered into the First Exchange Agreement pursuant to which the
parties consummated the Exchange Transaction and under which the Company and
Diomed made certain agreements and granted certain rights to the Note
Purchasers; and

      WHEREAS, as a result of developments regarding the Company's annual
meeting and the Company's ability to consummate the Contemplated Equity
Financing by June 30, 2003, the Company and the Note Purchasers have agreed to
make certain modifications to the agreements and rights granted to the Note
Purchasers under the First Exchange Agreement to (i) extend the deadline for the
Company to consummate the Contemplated Equity Financing without triggering the
Note Purchasers' right to rescind the Exchange Transaction from June 30, 2003 to
July 31, 2003; and (ii) to provide that the Company shall seek AMEX listing of
the Common Stock underlying the Class D Convertible Preferred Stock issued under
the First Exchange Agreement at a future Special Meeting of the stockholders at
which stockholder approval of the issuance of Common Stock under the
Contemplated Equity Offering will be sought, rather than at its 2003 Annnual
Meeting of Stockholders.

      NOW THEREFORE, in consideration of the premises and the mutual covenants
contained herein and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties agree to amend the
First Exchange Agreement as follows:

      1. Section 1(b) of the First Exchange Agreement is hereby amended and
restated in full to read as follows:

      "(b) Rescission Rights. The Note Purchasers may rescind the Exchange
Transaction by providing written notice with the Lenders' Approval to the
Company (the "Rescission Notice") and surrendering therewith to the Company for
cancellation the originally executed Class C Notes and the Exchange Conversion
Shares within five (5) days, in the case of clause (i) below, or ten (10) days,
in the case of clause (ii) below, after the later of the following events
occurs:

                  (i) the issuance of the Exchange Shares underlying the
Exchange Conversion Shares and the Common Shares underlying the Commitment
Shares shall not have been approved by the Company's stockholders at the
Company's special meeting of stockholders called for the purposes of approving
the issuance of the Exchange Shares and the Common Shares and the Common Stock
or Common Stock underlying the securities to be issued (directly

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or upon conversion or exchange) under the terms of the securities sold in the
Contemplated Equity Financing; or

                  (ii) the Company shall not have consummated the Contemplated
Equity Financing on or prior to July 31, 2003."

      2. Section 4(g) of the First Exchange Agreement is hereby amended and
restated to read as follows:

      "(g) AMEX Listing of Common Shares. The Company shall seek approval at a
special meeting of stockholders of the issuance of the Exchange Shares upon
conversion of the Exchange Conversion Shares and the Common Shares upon
conversion of the Commitment Shares, pursuant to the rules and regulations of
the AMEX (specifically, Section 713 of the Listing Standards, Policies and
Requirements of the AMEX). Said special meeting shall be held as promptly as is
practicable after the consummation of the Contemplated Equity Offering, whereat
the Company shall also seek stockholder approval of the issuance of the Common
Stock or other securities to be issued (directly or upon conversion or exchange)
under the terms of the securities sold in the Contemplated Equity Financing."

      3. Section 4(i) of the First Exchange Agreement is hereby amended and
restated to read as follows:

      "(i) Lenders' Approval of Financing Transactions Not Required. The Note
Purchasers expressly acknowledge and agree that the Approval Rights originally
granted to them under the Note Agreement are hereby terminated, and accordingly
the Company may at any time after the Closing consummate any Financing
Transaction without obtaining the Lenders' Approval of such Financing
Transaction. Notwithstanding the foregoing, the Company and Diomed agree that
prior to July 31, 2003, they shall not consummate any Financing Transaction
other than the Contemplated Equity Financing and the transactions contemplated
hereby and by the Secured Loan Agreement and the other Documents.

      4. All other terms and conditions of the First Exchange Agreement and the
Class D Notes shall remain in full force and effect.

                            [Signature page follows.]

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      IN WITNESS WHEREOF, this Amendment has been duly executed by the Note
Purchasers, the Designated Note Purchaser, Diomed and the Company as of the date
set forth below.

Date: May 28, 2003

                                         COMPANY:

                                         Diomed Holdings, Inc.

                                         By: _____________________________
                                             Name:  James A. Wylie, Jr.
                                             Title: Chief Executive Officer

                                         DIOMED:

                                         Diomed, Inc.

                                         By: ______________________________
                                             Name:  James A. Wylie, Jr.
                                             Title: Chief Executive Officer

                                         DESIGNATED NOTE PURCHASER

                                         Gibralt US, Inc.

                                         By: _______________________________
                                             Name:  Johnny Ciampi
                                             Title: Authorized Person

                                         NOTE PURCHASER
                                         Gibralt US, Inc.

                                         By: ________________________________
                                             Name:  Johnny Ciampi
                                             Title: Authorized Person

                                         NOTE PURCHASER
                                         Morris Belzberg

                                         _______________________________________

                                         NOTE PURCHASER
                                         Charles Diamond

                                         _______________________________________

                                         NOTE PURCHASER
                                         Steven Shraiberg

                                         _______________________________________