Document:

EXHIBIT 10.4

                                                                  Execution Form

                          REGISTRATION RIGHTS AGREEMENT

      This Registration Rights Agreement (this "Agreement") is made and entered
into as of September 30, 2005, by and among Diomed Holdings, Inc., a Delaware
corporation (the "Company"), and the purchasers signatory hereto (the
"Purchasers").

      This Agreement is made pursuant to the Securities Purchase Agreement,
dated as of September 30, 2005, by and among the Company and the Purchasers (the
"Purchase Agreement").

      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 Company and the Purchasers,
intending to be legally bound, hereby agree as follows:

1.    Definitions.

      Capitalized terms used and not otherwise defined herein that are defined
in the Purchase Agreement shall have the meanings given such terms in the
Purchase Agreement. As used in this Agreement, the following terms shall have
the following meanings:

                  "Advice" shall have the meaning set forth in Section 6(d).

                  "AMEX" shall have the meaning set forth in Section 2(b).

                  "Effectiveness Date" means, with respect to the initial
      Registration Statement required to be filed hereunder, the 120th calendar
      day following the date hereof.

                  "Effectiveness Period" shall have the meaning set forth in
      Section 2(a).

                  "Event" shall have the meaning set forth in Section 2(b).

                  "Event Date" shall have the meaning set forth in Section 2(b).

                  "Filing Date" means, with respect to the initial Registration
      Statement required hereunder, the 45th calendar day following the date
      hereof.

                  "Holder" or "Holders" means the holder or holders, as the case
      may be, from time to time, of Registrable Securities.

                  "Indemnified Party" shall have the meaning set forth in
      Section 5(c).

                  "Indemnifying Party" shall have the meaning set forth in
      Section 5(c).

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                  "Inspectors" shall have the meaning set forth in Section 3(i).

                  "Losses" shall have the meaning set forth in Section 5(a).

                  "NASD" shall have the meaning set forth in Section 3(h).

                  "National Market" shall have the meaning set forth in Section
      2(b).

                  "NYSE" shall have the meaning set forth in Section 2(b).

                  "Prospectus" means the prospectus included in the Registration
      Statement (including, without limitation, a prospectus that includes any
      information previously omitted from a prospectus filed as part of an
      effective registration statement in reliance upon Rule 430A promulgated
      under the Securities Act or any preliminary prospectus if used prior to
      the date of the Registration Statement), as amended or supplemented by any
      prospectus supplement, with respect to the terms of the offering of any
      portion of the Registrable Securities covered by the Registration
      Statement, and all other amendments and supplements to the Prospectus,
      including post-effective amendments, and all material incorporated by
      reference or deemed to be incorporated by reference in such Prospectus.

                  "Records" shall have the meaning set forth in Section 3(i).

                  "Registrable Securities" means (i) all of the shares of Common
      Stock issuable upon exchange in full of the Preferred Stock, (ii) all
      Warrant Shares, (iii) any securities issued or issuable upon any stock
      split, dividend or other distribution recapitalization or similar event
      with respect to the foregoing and (iv) any additional shares issuable in
      connection with any anti-dilution provisions in the Warrants.

                  "Registration Statement" means the registration statements
      required to be filed hereunder, including the Prospectus, amendments and
      supplements to such registration statement or Prospectus, including pre-
      and post-effective amendments, all exhibits thereto, and all material
      incorporated by reference or deemed to be incorporated by reference in the
      registration statement.

                  "Registration Trigger Date" shall have the meaning set forth
      in Section 3(b).

                  "Rule 415" means Rule 415 promulgated by the Commission
      pursuant to the Securities Act, as such rule may be amended from time to
      time, or any similar rule or regulation hereafter adopted by the
      Commission having substantially the same purpose and effect as such rule.

                  "Rule 424" means Rule 424 promulgated by the Commission
      pursuant to the Securities Act, as such rule may be amended from time to
      time, or any similar rule or regulation hereafter adopted by the
      Commission having substantially the same purpose and effect as such rule.

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                  "Selling Holder Questionnaire" shall have the meaning set
      forth in Section 3(a).

                  "Small Cap Market" shall have the meaning set forth in Section
      2(b).

2.    Resale Registration.

      (a)   The Company shall prepare promptly and file with the Commission as
soon as practicable, but in no event after the Filing Date, a resale
Registration Statement covering the resale of the Registrable Securities on such
Filing Date for an offering to be made on a continuous basis pursuant to Rule
415. The Registration Statement shall be on Form SB-2 (except if the Company is
not then eligible to register for resale the Registrable Securities on Form
SB-2, in which case such registration shall be on another appropriate form in
accordance herewith) and shall contain (unless otherwise directed by the
Holders) substantially the "Plan of Distribution" attached hereto as Annex A.
Subject to the terms of this Agreement, the Company shall use its best efforts
to cause the Registration Statement to be declared effective under the
Securities Act as soon as practicable within 120 days from the Closing Date, but
in any event prior to the applicable Effectiveness Date, and shall use its best
efforts to keep such Registration Statement continuously effective under the
Securities Act until all Registrable Securities covered by such Registration
Statement have been sold or may be sold without volume restrictions pursuant to
Rule 144(k) as determined by the Company Counsel pursuant to a written opinion
letter to such effect, addressed and acceptable to the Company's transfer agent
and the affected Holders (the "Effectiveness Period"). Such Registration
Statement (including any amendments or supplements thereto and prospectuses
contained therein and all documents incorporated by reference therein) (A) shall
comply in all material respects with the requirements of the Securities Act and
the rules and regulations of the Commission promulgated thereunder and (B) shall
not contain any untrue statement of a material fact or omit to state a material
fact required to be stated therein, or necessary to make the statements therein
not misleading. The financial statements of the Company included in any such
Registration Statement or incorporated by reference therein (x) shall comply as
to form in all material respects with the applicable accounting requirements and
the published rules and regulations of the Commission applicable with respect
thereto, (y) shall be prepared in accordance with U.S. generally accepted
accounting principles, consistently applied during the periods involved (except
as may be otherwise indicated in such financial statements or the notes thereto
or, in the case of unaudited interim statements, to the extent they may not
include footnotes or may be condensed on summary statements) and (z) fairly
present in all material respects the consolidated financial position of the
Company and its consolidated subsidiaries as of the dates thereof and the
consolidated results of their operations and cash flows for the periods then
ended (subject, in the case of unaudited statements, to immaterial year-end
adjustments). At the time of effectiveness, the Company shall ensure that such
Registration Statement covers at least 125% of the Registrable Securities
issuable upon full exchange of the Preferred Stock (without giving effect to any
limitations on exchange) and exercise of the Warrants (without giving effect to
any limitations on exercise contained in the Warrants), including, if necessary,
by filing an amendment prior to the effective date of the Registration Statement
to increase the number of Registrable Securities covered thereby. The
Registration Statement filed hereunder, to the extent allowable under the
Securities Act and the Rules promulgated thereunder (including Rule 416), shall
state that such Registration Statement also covers such indeterminate number of
additional shares of Common Stock as may become issuable upon exchange of the
Preferred Stock and exercise of the Warrants to prevent dilution resulting from
stock splits, stock dividends or similar transactions. The Registration
Statement (and each amendment or supplement thereto, and each request for
acceleration of effectiveness thereof) shall be provided to the Holders and
their counsel prior to its filing or other submission, and shall be subject to
the reasonable approval of the Holders, provided, that such approval shall be
deemed to have been given if the Company or its counsel shall not have received
comments by the Holders or their counsel prior to 4:00 p.m. (Eastern Standard
Time) on the business day following the transmission of any such Registration
Statement, amendment or supplement or request for acceleration (other than the
initial Registration Statement, as to which such period shall be three business
days). The Company shall immediately notify the Holders via facsimile of the
effectiveness of the Registration Statement on the same day that the Company
receives notification of effectiveness from the Commission. Failure to so notify
the Holders within one Trading Day of such notification shall be deemed an Event
under Section 2(b).

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      (b)   If: (i) the Registration Statement is not filed on or prior to its
Filing Date, (ii) the Registration Statement filed or required to be filed
hereunder is not declared effective by the Commission by its Effectiveness Date,
(iii) during the Effectiveness Period the Registration Statement ceases for any
reason to remain continuously effective as to all Registrable Securities for
which it is required to be effective, or the Holders are not permitted to
utilize the Prospectus therein to resell such Registrable Securities for 20
consecutive Trading Days or more than an aggregate of 30 Trading Days during any
12-month period (which need not be consecutive Trading Days), or (iv) the Common
Stock is not listed or included for quotation on the Nasdaq SmallCap Market (the
"SmallCap Market"), the Nasdaq National Market (the "National Market"), the New
York Stock Exchange (the "NYSE") or the American Stock Exchange (the "AMEX") at
any time after the Effectiveness Date hereunder, then the Company will make
payments to each Holder in such amounts and at such times as shall be determined
pursuant to this Section as partial relief for the damages to the Holders by
reason of any such delay in or reduction of their ability to sell the
Registrable Securities (which remedy shall not be exclusive of any other
remedies available at law or in equity) (any such failure or breach being
referred to as an "Event", and for purposes of clauses (i), (ii) and (iv), the
date on which such Event occurs, or for purposes of clause (iii) the date on
which such 20 or 30 calendar day period, as applicable, is exceeded being
referred to as the "Event Date"), then in addition to any other rights the
Holders may have hereunder or under applicable law, until such date as the
applicable Event is cured, the Company shall pay each Holder an amount in cash
equal to 3.0% per month of the aggregate purchase price paid by such Holder
pursuant to the Purchase Agreement for any Registrable Securities then held by
such Holder, on demand by the Holder, as full liquidated damages and not as a
penalty (including, for this purpose, any shares of Preferred Stock that have
been exchanged into Underlying Shares then held by such Holder as if such shares
of Preferred Stock had not been so exchanged). The liquidated damages pursuant
to the terms hereof shall apply on a daily pro-rata basis for any portion of a
month prior to the cure of an Event.

3.    Registration Procedures.

      In connection with the Company's registration obligations hereunder, the
Company shall:

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      (a)   Cause its officers and directors, counsel and independent certified
public accountants to respond to such inquiries as shall be necessary, in the
reasonable opinion of respective counsel to conduct a "reasonable
investigation," within the meaning of the Securities Act. Each Holder agrees to
furnish to the Company a completed Questionnaire in the form attached to this
Agreement as Annex B (a "Selling Holder Questionnaire") not less than two
Trading Days prior to the Filing Date.

      (b)   The Company shall permit a single firm of counsel designated by the
Purchasers to review any Registration Statement required to be filed hereunder
and all amendments and supplements thereto a reasonable period of time prior to
its filing with the Commission and not file any document in a form to which such
counsel reasonably objects.

      (c)   (i) Prepare and file with the Commission such amendments, including
post-effective amendments, to the Registration Statement and the Prospectus used
in connection therewith as may be necessary to keep the Registration Statement
continuously effective as to the applicable Registrable Securities for the
Effectiveness Period; (ii) cause the related Prospectus to be amended or
supplemented by any required Prospectus supplement (subject to the terms of this
Agreement), and as so supplemented or amended to be filed pursuant to Rule 424;
(iii) respond as promptly as reasonably possible to any comments received from
the Commission with respect to the Registration Statement or any amendment
thereto, and as promptly as reasonably possible provide the Holders true and
complete copies of all correspondence from and to the Commission relating to the
Registration Statement; (iv) comply with the provisions of the Securities Act
and the Exchange Act with respect to the disposition of all Registrable
Securities covered by the Registration Statement during the applicable period in
accordance (subject to the terms of this Agreement) with the intended methods of
disposition by the Holders thereof set forth in the Registration Statement as so
amended or in the Prospectus as so supplemented and (v) submit to the
Commission, before the close of business on the second business day immediately
following the business day on which the Company learns (either by telephone or
in writing) that no review of such Registration Statement will be made by the
Commission or that the staff of the Commission has no further comments on such
Registration Statement, as the case may be, a request for acceleration of the
effectiveness of such Registration Statement to a time and date as soon as
practicable.

      (d)   In the event the number of shares available under a Registration
Statement filed pursuant to this Agreement is, for any three consecutive trading
days (the last of such three trading days being the "Registration Trigger
Date"), insufficient to cover 125% of the Registrable Securities then issued or
issuable upon exchange of the Preferred Stock (without giving effect to any
limitations on exchange of the Preferred Stock contained in the Exchange
Agreement) and exercise of the Warrants (without giving effect to any
limitations on exercise contained in the Warrants), the Company shall provide
each Holder written notice of such Registration Trigger Date within three
business days thereafter and shall amend the Registration Statement, or file a
new Registration Statement (on the short form available therefor, if
applicable), or both, so as to cover 125% of the Registrable Securities issued
or issuable upon exchange of the Preferred Stock (without giving effect to any
limitations on exchange) or exercise of the Warrants (without giving effect to
any limitations on exercise contained in the Warrants) as of the Registration
Trigger Date, in each case, as soon as practicable, but in any event within 15
days after the Registration Trigger Date.

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<PAGE>

      (e)   Notify the Holders of Registrable Securities to be sold (which
notice shall, pursuant to clauses (ii) through (vi) hereof, be accompanied by an
instruction to suspend the use of the Prospectus until the requisite changes
have been made) as promptly as reasonably practicable, and in any event within
one (1) Trading Day and (if requested by any such Holder) confirm such notice in
writing no later than one Trading Day following the day: (i)(A) when the
Prospectus or any Prospectus supplement or post-effective amendment to the
Registration Statement is proposed to be filed; (B) when the Commission notifies
the Company whether there will be a "review" of the Registration Statement and
whenever the Commission comments in writing on the Registration Statement (the
Company shall provide true and complete copies thereof and all written responses
thereto, as promptly as reasonably possible, to each of the Holders); and (C)
with respect to the Registration Statement or any post-effective amendment, when
the same has become effective; (ii) of any request by the Commission or any
other federal or state governmental authority for amendments or supplements to
the Registration Statement or Prospectus or for additional information; (iii) of
the issuance by the Commission or any other federal or state governmental
authority of any stop order suspending the effectiveness of the Registration
Statement covering any or all of the Registrable Securities or the initiation of
any Proceedings for that purpose; (iv) of the receipt by the Company of any
notification with respect to the suspension of the qualification or exemption
from qualification of any of the Registrable Securities for sale in any
jurisdiction, or the initiation or threatening of any Proceeding for such
purpose; (v) of the occurrence of any event or passage of time that makes the
financial statements included in the Registration Statement ineligible for
inclusion therein or any statement made in the Registration Statement or
Prospectus or any document incorporated or deemed to be incorporated therein by
reference untrue in any material respect or that requires any revisions to the
Registration Statement, Prospectus or other documents so that, in the case of
the Registration Statement or the Prospectus, as the case may be, it will not
contain any untrue statement of a material fact or omit to state any material
fact required to be stated therein or necessary to make the statements therein,
in light of the circumstances under which they were made, not misleading; and
(vi) the occurrence or existence of any pending corporate development with
respect to the Company that the Company believes may be material and that, in
the determination of the Company, makes it contrary to the best interest of the
Company to allow continued availability of the Registration Statement or
Prospectus; provided that any and all of such information shall remain
confidential to each Holder until such information otherwise becomes public,
unless disclosure by a Holder is required by law; provided, further, that
notwithstanding each Holder's agreement to keep such information confidential,
the Holders make no acknowledgement that any such information is material,
non-public information.

      (f)   Use its best efforts to avoid the issuance of, or, if issued, obtain
the withdrawal of (i) any order suspending the effectiveness of the Registration
Statement, or (ii) any suspension of the qualification (or exemption from
qualification) of any of the Registrable Securities for sale in any
jurisdiction, at the earliest practicable moment. The Company shall use its best
efforts to notify each Holder who holds Registrable Securities being sold (or,
in the event of an underwritten offering, the managing underwriters) of the
issuance of such order and the resolution thereof (and if such Registration
Statement is supplemented or amended, deliver such number of copies of such
supplement or amendment to each Holder as such Holder may reasonably request).

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      (g)   Furnish to each Holder, without charge, at least one conformed copy
of each such Registration Statement and each amendment thereto, including
financial statements and schedules, all documents incorporated or deemed to be
incorporated therein by reference to the extent requested by such Holder, and
all exhibits to the extent requested by such Holder (including those previously
furnished or incorporated by reference) promptly after the filing of such
documents with the Commission.

      (h)   Promptly deliver to each Holder, without charge, as many copies of
the Prospectus or Prospectuses (including each form of prospectus) and each
amendment or supplement thereto as such Holder may reasonably request in
connection with resales by the Holder of Registrable Securities. Subject to the
terms of this Agreement, the Company hereby consents to the use of such
Prospectus and each amendment or supplement thereto by each of the selling
Holders in connection with the offering and sale of the Registrable Securities
covered by such Prospectus and any amendment or supplement thereto, except after
the giving of any notice pursuant to Section 3(e).

      (i)   Prior to any resale of Registrable Securities by a Holder, use its
best efforts to register or qualify the Registrable Securities for the resale by
the Holder under the securities or Blue Sky laws of such jurisdictions within
the United States as any Holder reasonably requests in writing, to keep each
registration or qualification (or exemption therefrom) effective during the
Effectiveness Period and to do any and all other acts or things reasonably
necessary to enable the disposition in such jurisdictions of the Registrable
Securities covered by each Registration Statement; provided, that the Company
shall not be required to qualify generally to do business in any jurisdiction
where it is not then so qualified, subject the Company to any material tax in
any such jurisdiction where it is not then so subject or file a general consent
to service of process in any such jurisdiction.

      (j)   If requested by the Holders, cooperate with the Holders to
facilitate the timely preparation and delivery of certificates representing
Registrable Securities to be delivered to a transferee pursuant to the
Registration Statement, which certificates shall be free, to the extent
permitted by the Purchase Agreement, of all restrictive legends, and to enable
such Registrable Securities to be in such denominations and registered in such
names as any such Holders may request.

      (k)   Without limiting the generality of the foregoing, within three
business days after any Registration Statement that includes Registrable
Securities is declared effective by the SEC, the Company shall cause legal
counsel selected by the Company to deliver to the transfer agent for the
Registrable Securities (with copies to any Holder whose Registrable Securities
are included in such Registration Statement), an opinion of such counsel in the
form attached hereto as Exhibit A.

      (l)   Upon the occurrence of any event contemplated by this Section 3, as
promptly as reasonably possible under the circumstances taking into account the
Company's good faith assessment of any adverse consequences to the Company and
its stockholders of the premature disclosure of such event, prepare a supplement
or amendment, including a post-effective amendment, to the Registration
Statement or a supplement to the related Prospectus or any document incorporated
or deemed to be incorporated therein by reference, and file any other required
document so that, as thereafter delivered, neither the Registration Statement
nor such Prospectus will contain an untrue statement of a material fact or omit
to state a material fact required to be stated therein or necessary to make the
statements therein, in light of the circumstances under which they were made,
not misleading. If the Company notifies the Holders in accordance with clauses
(ii) through (v) of Section 3(e) above to suspend the use of any Prospectus
until the requisite changes to such Prospectus have been made, then the Holders
shall suspend use of such Prospectus. The Company will use its best efforts to
ensure that the use of the Prospectus may be resumed as promptly as is
practicable. The Company shall be entitled to exercise its right under this
Section 3(l) to suspend the availability of a Registration Statement and
Prospectus, subject to the payment of partial liquidated damages pursuant to
Section 2(b), for a period not to exceed 15 consecutive days or 60 days (which
need not be consecutive days) in any 12 month period.

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      (m)   The Company shall use its best efforts to promptly cause all of the
Registrable Securities covered by any Registration Statement to be listed or
designated for quotation on the SmallCap Market, the National Market, the NYSE,
the AMEX or any other national securities exchange or automated quotation system
and on each additional national securities exchange or automated quotation
system on which securities of the same class or series issued by the Company are
then listed or quoted, if any, if the listing or quotation of such Registrable
Securities is then permitted under the rules of such exchange or automated
quotation system, and in any event, without limiting the generality of the
foregoing, to arrange for or maintain at least two market makers to register
with the National Association of Securities Dealers, Inc. (the "NASD") as such
with respect to the Registrable Securities.

      (n)   Comply with all applicable rules and regulations of the Commission.

      (o)   The Company shall make generally available to the Holders as soon as
practicable, but in no event later than 90 days after the close of the period
covered thereby, an earnings statement (in form complying with the provisions of
Rule 158 under the Securities Act) covering a twelve-month period beginning not
later than the first day of the Company's fiscal quarter next following the
effective date of the Registration Statement. The Company will be deemed to have
complied with its obligations under this Section 3(o) upon the Company's filing,
on an appropriate form, the appropriate report of the Company as required by the
Exchange Act of 1934, and the rules and regulations thereunder, or any similar
successor statute.

      (p)   At the request of any Holder, the Company shall prepare and file
with the Commission such amendments (including post-effective amendments) and
supplements to any Registration Statement required to be filed hereunder and the
prospectus used in connection with such Registration Statement as may be
necessary in order to change the plan of distribution set forth in such
Registration Statement.

      (q)   The Company shall make available for inspection by (i) each Holder,
(ii) any underwriter participating in any disposition pursuant to any
Registration Statement, (iii) one firm of attorneys and one firm of accountants
or other agents retained by the Holders, and (iv) one firm of attorneys retained
by all such underwriters (collectively, the "Inspectors") all pertinent
financial and other records, and pertinent corporate documents and properties of
the Company (collectively, the "Records"), as shall be reasonably deemed
necessary by each Inspector to enable such Inspector to exercise its due
diligence responsibility, and cause the Company's officers, directors and
employees to supply all information which any Inspector may reasonably request
for purposes of such due diligence; provided, however, that each Inspector shall
hold in confidence and shall not make any disclosure (except to a Holder) of any
Record or other information which the Company determines in good faith to be
confidential, and of which determination the Inspectors are so notified, unless
(A) the disclosure of such Records is necessary to avoid or correct a
misstatement or omission in any Registration Statement, (B) the release of such
Records is ordered pursuant to a subpoena or other order from a court or
government body of competent jurisdiction, or (C) the information in such
Records has been made generally available to the public other than by disclosure
in violation of this or any other agreement. Nothing herein shall be deemed to
limit any Holder's ability to sell Registrable Securities in a manner that is
otherwise consistent with applicable laws and regulations.

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      (r)   In the case of an underwritten public offering, at the request of
any Holder, the Company shall furnish, on the date of effectiveness of the
Registration Statement (i) an opinion, dated as of such date, from counsel
representing the Company addressed to any such Holder and in form, scope and
substance as is customarily given in an underwritten public offering and (ii) a
letter, dated such date, from the Company's independent certified public
accountants in form and substance as is customarily given by independent
certified public accountants to underwriters in an underwritten public offering,
addressed to the underwriters, if any, and any such Holder.

      (s)   At the option of the Company, require each selling Holder to furnish
to the Company a certified statement as to the number of shares of Common Stock
beneficially owned by such Holder and the person(s) having voting and
dispositive control over the shares. During any periods that the Company is
unable to meet its obligations hereunder with respect to the registration of the
Registrable Securities solely because any Holder fails to furnish such
information within three (3) Trading Days of the Company's request, any
liquidated damages that are accruing at such time shall be tolled (only as to
such Holder) and any Event that may otherwise occur solely because of such delay
shall be suspended (only as to such Holder), until such information is delivered
to the Company.

      (t)   The Company shall hold in confidence and not make any disclosure of
information concerning a Holder provided to the Company unless (i) disclosure of
such information is necessary to comply with federal or state securities laws,
(ii) the disclosure of such information is necessary to avoid or correct a
misstatement or omission in any Registration Statement that includes such
Holder's Registrable Securities, (iii) the release of such information is
ordered pursuant to a subpoena or other order from a court or governmental body
of competent jurisdiction, (iv) such information has been made generally
available to the public other than by disclosure in violation of this or any
other agreement, or (v) such Holder consents to the form and content of any such
disclosure. The Company shall, upon learning that disclosure of any information
concerning a Holder is sought in or by a court or governmental body of competent
jurisdiction or through other means, give prompt notice to such Holder prior to
making such disclosure, and cooperate with the Holder, at the Holder's expense,
in taking appropriate action to prevent disclosure of, or to obtain a protective
order for, such information.

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4.    Registration Expenses. All fees and expenses incident to the performance
of or compliance with this Agreement by the Company shall be borne by the
Company whether or not any Registrable Securities are sold pursuant to the
Registration Statement. The fees and expenses referred to in the foregoing
sentence shall include, without limitation, (i) all registration and filing fees
(including, without limitation, fees and expenses (A) with respect to filings
required to be made with the Trading Market on which the Common Stock is then
listed for trading, and (B) in compliance with applicable state securities or
Blue Sky laws reasonably agreed to by the Company in writing (including, without
limitation, fees and disbursements of counsel for the Company in connection with
Blue Sky qualifications or exemptions of the Registrable Securities and
determination of the eligibility of the Registrable Securities for investment
under the laws of such jurisdictions as requested by the Holders), (ii) printing
expenses (including, without limitation, expenses of printing certificates for
Registrable Securities and of photocopying), (iii) messenger, telephone and
delivery expenses, (iv) fees and disbursements of counsel for the Company, (v)
Securities Act liability insurance, if the Company so desires such insurance,
and (vi) fees and expenses of all other Persons retained by the Company in
connection with the consummation of the transactions contemplated by this
Agreement. In addition, the Company shall be responsible for all of its internal
expenses incurred in connection with the consummation of the transactions
contemplated by this Agreement (including, without limitation, all salaries and
expenses of its officers and employees performing legal or accounting duties),
the expense of any annual audit and the fees and expenses incurred in connection
with the listing of the Registrable Securities on any securities exchange as
required hereunder. In no event shall the Company be responsible for any broker
or similar commissions or, except to the extent provided for in the Transaction
Documents, any legal fees or other costs of the Holders.

5.    Indemnification.

      (a)   Indemnification by the Company. The Company shall, notwithstanding
any termination of this Agreement, indemnify and hold harmless each Holder, the
officers, directors, agents, members, partners, brokers (including brokers who
offer and sell Registrable Securities as principal as a result of a pledge or
any failure to perform under a margin call of Common Stock), investment advisors
and employees of each of them, each Person who controls any such Holder (within
the meaning of Section 15 of the Securities Act or Section 20 of the Exchange
Act) and the officers, directors, agents and employees of each such controlling
Person, to the fullest extent permitted by applicable law, from and against any
joint or several and all losses, claims, damages, liabilities, costs (including,
without limitation, reasonable attorneys' fees) and expenses (collectively,
"Losses"), as incurred, arising out of or relating to any untrue or alleged
untrue statement of a material fact contained in the Registration Statement, any
Prospectus or any form of prospectus or in any amendment or supplement thereto
or in any preliminary prospectus, or arising out of or relating to any omission
or alleged omission of a material fact required to be stated therein or
necessary to make the statements therein (in the case of any Prospectus or form
of prospectus or supplement thereto, in light of the circumstances under which
they were made) not misleading, or any violation or alleged violation by the
Company of the Securities Act, the Exchange Act or any other law (including,
without limitation, any state securities law), rule or regulation relating to
the offer or sale of the Registrable Securities except to the extent, but only
to the extent, that (i) such untrue statements or omissions are based solely
upon information regarding such Holder furnished in writing to the Company by
such Holder expressly for use therein, or to the extent that such information
relates to such Holder or such Holder's proposed method of distribution of
Registrable Securities and was reviewed and expressly approved in writing by
such Holder expressly for use in the Registration Statement, such Prospectus or
such form of Prospectus or in any amendment or supplement thereto (it being
understood that the Holder has approved Annex A hereto for this purpose) or (ii)
in the case of an occurrence of an event of the type specified in Section
3(c)(ii) through (vi), the use by such Holder of an outdated or defective
Prospectus after the Company has notified such Holder in writing that the
Prospectus is outdated or defective and Holder has acknowledge receipt of such
notice and prior to the receipt by such Holder of the Advice contemplated in
Section 6(d). The Company shall notify the Holders promptly of the institution,
threat or assertion of any Proceeding arising from or in connection with the
transactions contemplated by this Agreement of which the Company is aware.

                                       10
<PAGE>

      (b)   Indemnification by Holders. In connection with any Registration
Statement in which a Holder is participating, each Holder shall, severally and
not jointly, indemnify and hold harmless the Company, its directors, officers,
agents and employees, each Person who controls the Company (within the meaning
of Section 15 of the Securities Act and Section 20 of the Exchange Act), and the
directors, officers, agents or employees of such controlling Persons, to the
fullest extent permitted by applicable law, from and against all Losses, as
incurred, to the extent arising out of or based solely upon: (x) such Holder's
failure to comply with the prospectus delivery requirements of the Securities
Act or (y) any untrue or alleged untrue statement of a material fact contained
in any Registration Statement, any Prospectus or any form of prospectus, or in
any amendment or supplement thereto or in any preliminary prospectus, or arising
out of or relating to any omission or alleged omission of a material fact
required to be stated therein or necessary to make the statements therein not
misleading (i) to the extent that such untrue statement or omission is contained
in any information so furnished in writing by such Holder to the Company
specifically for inclusion in such Registration Statement or such Prospectus or
(ii) to the extent that (A) such untrue statements or omissions are based solely
upon information regarding such Holder furnished in writing to the Company by
such Holder expressly for use therein, or to the extent that such information
relates to such Holder or such Holder's proposed method of distribution of
Registrable Securities and was reviewed and expressly approved in writing by
such Holder expressly for use in the Registration Statement (it being understood
that the Holder has approved Annex A hereto for this purpose), such Prospectus
or such form of Prospectus or in any amendment or supplement thereto or (B) in
the case of an occurrence of an event of the type specified in Section 3(c)(ii)
through (vi), the use by such Holder of an outdated or defective Prospectus
after the Company has notified such Holder in writing that the Prospectus is
outdated or defective and prior to the receipt by such Holder of the Advice
contemplated in Section 6(d). In no event shall the liability of any selling
Holder hereunder be greater than the dollar amount of the gross proceeds
received by such Holder upon the sale of the Registrable Securities giving rise
to such indemnification obligation.

      (c)   Conduct of Indemnification Proceedings. If any Proceeding shall be
brought or asserted against any Person entitled to indemnity hereunder (an
"Indemnified Party"), such Indemnified Party shall promptly notify the Person
from whom indemnity is sought (the "Indemnifying Party") in writing, and the
Indemnifying Party shall have the right to assume the defense thereof, including
the employment of counsel reasonably satisfactory to the Indemnified Party and
the payment of all fees and expenses incurred in connection with defense
thereof; provided, that the failure of any Indemnified Party to give such notice
shall not relieve the Indemnifying Party of its obligations or liabilities
pursuant to this Agreement, except (and only) to the extent that it shall be
finally determined by a court of competent jurisdiction (which determination is
not subject to appeal or further review) that such failure shall have prejudiced
the Indemnifying Party.

                                       11
<PAGE>

      An Indemnified Party shall have the right to employ separate counsel in
any such Proceeding and to participate in the defense thereof, but the fees and
expenses of such counsel shall be at the expense of such Indemnified Party or
Parties unless: (1) the Indemnifying Party has agreed in writing to pay such
fees and expenses; (2) the Indemnifying Party shall have failed promptly to
assume the defense of such Proceeding and to employ counsel reasonably
satisfactory to such Indemnified Party in any such Proceeding; or (3) the named
parties to any such Proceeding (including any impleaded parties) include both
such Indemnified Party and the Indemnifying Party, and such Indemnified Party
shall reasonably believe that it would be inappropriate due to actual or
potential conflicts of interest that are likely to exist if the same counsel
were to represent such Indemnified Party and the Indemnifying Party (in which
case, if such Indemnified Party notifies the Indemnifying Party in writing that
it elects to employ separate counsel at the expense of the Indemnifying Party,
the Indemnifying Party shall not have the right to assume the defense thereof
and the reasonable fees and expenses of one separate counsel shall be at the
expense of the Indemnifying Party). The Indemnifying Party shall not be liable
for any settlement of any such Proceeding effected without its written consent,
which consent shall not be unreasonably withheld. No Indemnifying Party shall,
without the prior written consent of the Indemnified Party, effect any
settlement of any pending Proceeding in respect of which any Indemnified Party
is a party, unless such settlement includes an unconditional release of such
Indemnified Party from all liability on claims that are the subject matter of
such Proceeding.

      Subject to the terms of this Agreement, all reasonable fees and expenses
of the Indemnified Party (including reasonable fees and expenses to the extent
incurred in connection with investigating or preparing to defend such Proceeding
in a manner not inconsistent with this Section) shall be paid to the Indemnified
Party, as incurred, within ten Trading Days of written notice thereof to the
Indemnifying Party; provided, that the Indemnified Party shall promptly
reimburse the Indemnifying Party for that portion of such fees and expenses
applicable to such actions for which such Indemnified Party is not entitled to
indemnification hereunder, determined based upon the relative faults of the
parties.

      (d)   Contribution. If a claim for indemnification under Section 5(a) or
5(b) is unavailable to an Indemnified Party (by reason of public policy or
otherwise), then each Indemnifying Party, in lieu of indemnifying such
Indemnified Party, shall contribute to the amount paid or payable by such
Indemnified Party as a result of such Losses, in such proportion as is
appropriate to reflect the relative fault of the Indemnifying Party and
Indemnified Party in connection with the actions, statements or omissions that
resulted in such Losses as well as any other relevant equitable considerations ,
provided, however, (a) no contribution shall be made under circumstances where
the maker would not have been liable for indemnification under the fault
standards set forth in Section 5(a) or 5(b), as the case may be, (b) no person
guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of
the Securities Act) shall be entitled to contribution from any seller of
Registrable Securities who was not guilty of such fraudulent misrepresentation.
The relative fault of such Indemnifying Party and Indemnified Party shall be
determined by reference to, among other things, whether any action in question,
including any untrue or alleged untrue statement of a material fact or omission
or alleged omission of a material fact, has been taken or made by, or relates to
information supplied by, such Indemnifying Party or Indemnified Party, and the
parties' relative intent, knowledge, access to information and opportunity to
correct or prevent such action, statement or omission. The amount paid or
payable by a party as a result of any Losses shall be deemed to include, subject
to the limitations set forth in this Agreement, any reasonable attorneys' or
other reasonable fees or expenses incurred by such party in connection with any
Proceeding to the extent such party would have been indemnified for such fees or
expenses if the indemnification provided for in this Section was available to
such party in accordance with its terms.

                                       12
<PAGE>

      The parties hereto agree that it would not be just and equitable if
contribution pursuant to this Section 5(d) were determined by pro rata
allocation or by any other method of allocation that does not take into account
the equitable considerations referred to in the immediately preceding paragraph.
Notwithstanding the provisions of this Section 5(d), no Holder shall be required
to contribute, in the aggregate, any amount in excess of the amount by which the
net proceeds actually received by such Holder from the sale of the Registrable
Securities subject to the Proceeding exceeds the amount of any damages that such
Holder has otherwise been required to pay by reason of such untrue or alleged
untrue statement or omission or alleged omission.

      The indemnity and contribution agreements contained in this Section are in
addition to any liability that the Indemnifying Parties may have to the
Indemnified Parties.

6.    Miscellaneous.

      (a)   Remedies. In the event of a breach by the Company or by a Holder, of
any of their obligations under this Agreement, each Holder or the Company, as
the case may be, in addition to being entitled to exercise all rights granted by
law and under this Agreement, including recovery of damages, will be entitled to
specific performance of its rights under this Agreement. The Company and each
Holder agree that monetary damages would not provide adequate compensation for
any losses incurred by reason of a breach by it of any of the provisions of this
Agreement and hereby further agrees that, in the event of any action for
specific performance in respect of such breach, it shall waive the defense that
a remedy at law would be adequate.

      (b)   No Piggyback on Registrations by the Company. Except as set forth on
Schedule 6(b) attached hereto, neither the Company nor any of its security
holders (other than the Holders in such capacity pursuant hereto) may include
securities of the Company in the Registration Statement other than the
Registrable Securities. The Company shall not file any other registration
statements until the initial Registration Statement required hereunder is
declared effective by the Commission, provided that this Section 6(b) shall not
prohibit the Company from filing amendments to registration statements already
filed.

                                       13
<PAGE>

      (c)   Compliance. Each Holder covenants and agrees that it will comply
with the prospectus delivery requirements of the Securities Act as applicable to
it in connection with sales of Registrable Securities pursuant to the
Registration Statement.

      (d)   Discontinued Disposition. Each Holder agrees by its acquisition of
such Registrable Securities that, upon receipt of a notice from the Company of
the occurrence of any event of the kind described in Section 3(c), such Holder
will forthwith discontinue disposition of such Registrable Securities under the
Registration Statement until such Holder's receipt of the copies of the
supplemented Prospectus and/or amended Registration Statement, or until it is
advised in writing (the "Advice") by the Company that the use of the applicable
Prospectus may be resumed, and, in either case, has received copies of any
additional or supplemental filings that are incorporated or deemed to be
incorporated by reference in such Prospectus or Registration Statement. The
Company will use its best efforts to ensure that the use of the Prospectus may
be resumed as promptly as it practicable. The Company agrees and acknowledges
that any periods during which the Holder is required to discontinue the
disposition of the Registrable Securities hereunder shall be subject to the
provisions of Section 2(b).

      (e)   Piggy-Back Registrations by the Holders. If at any time during the
Effectiveness Period there is not an effective Registration Statement covering
all of the Registrable Securities and the Company shall determine to prepare and
file with the Commission a registration statement relating to an offering for
its own account or the account of others under the Securities Act of any of its
equity securities, other than on Form S-4 or Form S-8 (each as promulgated under
the Securities Act) or their then equivalents relating to equity securities to
be issued solely in connection with any acquisition of any entity or business or
equity securities issuable in connection with the stock option or other employee
benefit plans, then the Company shall send to each Holder a written notice of
such determination and, if within fifteen days after the date of such notice,
any such Holder shall so request in writing, the Company shall include in such
registration statement all or any part of such Registrable Securities such
holder requests to be registered; provided, that, the Company shall not be
required to register any Registrable Securities pursuant to this Section 6(e)
that are eligible for resale pursuant to Rule 144(k) promulgated under the
Securities Act or that are the subject of a then effective Registration
Statement.

      (f)   Amendments and Waivers. The provisions of this Agreement, including
the provisions of this sentence, may not be amended, modified or supplemented,
and waivers or consents to departures from the provisions hereof may not be
given, unless the same shall be in writing and signed by the Company and each
Holder of the then outstanding Registrable Securities. Notwithstanding the
foregoing, a waiver or consent to depart from the provisions hereof with respect
to a matter that relates exclusively to the rights of Holders and that does not
directly or indirectly affect the rights of other Holders may be given by
Holders of all of the Registrable Securities to which such waiver or consent
relates; provided, however, that the provisions of this sentence may not be
amended, modified, or supplemented except in accordance with the provisions of
the immediately preceding sentence.

                                       14
<PAGE>

      (g)   Notices. Any and all notices or other communications or deliveries
required or permitted to be provided hereunder shall be delivered as set forth
in the Purchase Agreement.

      (h)   Successors and Assigns. This Agreement shall inure to the benefit of
and be binding upon the successors and permitted assigns of each of the parties
and shall inure to the benefit of each Holder. The Company may not assign its
rights or obligations hereunder without the prior written consent of all of the
Holders of the then-outstanding Registrable Securities. Each Holder may assign
their respective rights hereunder in the manner and to the Persons as permitted
under the Purchase Agreement.

      (i)   No Inconsistent Agreements. Neither the Company nor any of its
subsidiaries has entered, as of the date hereof, nor shall the Company or any of
its subsidiaries, on or after the date of this Agreement, enter into any
agreement with respect to its securities, that would have the effect of
impairing the rights granted to the Holders in this Agreement or otherwise
conflicts with the provisions hereof. Except as set forth on Schedule 6(b),
neither the Company nor any of its subsidiaries has previously entered into any
agreement granting any registration rights with respect to any of its securities
to any Person that have not been satisfied in full.

      (j)   Execution and Counterparts. This Agreement may be executed in any
number of counterparts, each of which when so executed shall be deemed to be an
original and, all of which taken together shall constitute one and the same
Agreement. In the event that any signature is delivered by facsimile
transmission, such signature shall create a valid binding obligation of the
party executing (or on whose behalf such signature is executed) the same with
the same force and effect as if such facsimile signature were the original
thereof.

      (k)   Governing Law. All questions concerning the construction, validity,
enforcement and interpretation of this Agreement shall be determined with the
provisions of the Purchase Agreement.

      (l)   Cumulative Remedies. The remedies provided herein are cumulative and
not exclusive of any remedies provided by law.

      (m)   Severability. If any term, provision, covenant or restriction of
this Agreement is held by a court of competent jurisdiction to be invalid,
illegal, void or unenforceable, the remainder of the terms, provisions,
covenants and restrictions set forth herein shall remain in full force and
effect and shall in no way be affected, impaired or invalidated, and the parties
hereto shall use their commercially reasonable efforts to find and employ an
alternative means to achieve the same or substantially the same result as that
contemplated by such term, provision, covenant or restriction. It is hereby
stipulated and declared to be the intention of the parties that they would have
executed the remaining terms, provisions, covenants and restrictions without
including any of such that may be hereafter declared invalid, illegal, void or
unenforceable.

      (n)   Headings. The headings in this Agreement are for convenience of
reference only and shall not limit or otherwise affect the meaning hereof.

                                       15
<PAGE>

      (o)   Independent Nature of Holders' Obligations and Rights. The
obligations of each Holder hereunder are several and not joint with the
obligations of any other Holder hereunder, and no Holder shall be responsible in
any way for the performance of the obligations of any other Holder hereunder.
Nothing contained herein or in any other agreement or document delivered at any
closing, and no action taken by any Holder pursuant hereto or thereto, shall be
deemed to constitute the Holders as a partnership, an association, a joint
venture or any other kind of entity, or create a presumption that the Holders
are in any way acting in concert with respect to such obligations or the
transactions contemplated by this Agreement. Each Holder shall be entitled to
protect and enforce its rights, including without limitation the rights arising
out of this Agreement, and it shall not be necessary for any other Holder to be
joined as an additional party in any proceeding for such purpose.

                              ********************
                            [SIGNATURE PAGE FOLLOWS]

                                       16
<PAGE>

      IN WITNESS WHEREOF, the parties have executed this Registration Rights
Agreement as of the date first written above.

                                     DIOMED HOLDINGS, INC.

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

                       [SIGNATURE PAGE OF HOLDERS FOLLOWS]

                                       17
<PAGE>

                           [SIGNATURE PAGE OF HOLDERS]

Name of Investing Entity:
                          ---------------------------

By:
    --------------------------------------------------------
     (Signature of Authorized Signatory of Investing Entity)

Name of Authorized Signatory:
                              ------------------------------
Title of Authorized Signatory:
                              ------------------------------

                           [SIGNATURE PAGES CONTINUE]

                                       18
<PAGE>

                                                                         Annex A

                              Plan of Distribution

      Each selling stockholder (each "Selling Stockholder") of the common stock
("Common Stock") of Diomed Holdings, Inc., a Delaware corporation (the
"Company") and any of their pledgees, transferees, donees, assignees and
successors-in-interest may, from time to time, sell any or all of their shares
of Common Stock on the market or exchange on which the Common Stock is listed or
quoted for trading (the "Trading Market") or any other stock exchange, market or
trading facility on which the shares are traded or in private transactions.
These sales may be at fixed or negotiated prices. A Selling Stockholder may use
any one or more of the following methods when selling shares:

      o     ordinary brokerage transactions and transactions in which the
            broker-dealer solicits purchasers;

      o     block trades in which the broker-dealer will attempt to sell the
            shares as agent but may position and resell a portion of the block
            as principal to facilitate the transaction;

      o     "at the market" to or through market makers into an existing market
            for the shares;

      o     purchases by a broker-dealer as principal and resale by the
            broker-dealer for its account;

      o     an exchange distribution in accordance with the rules of the
            applicable exchange;

      o     privately negotiated transactions;

      o     settlement of short sales entered into after the date of this
            prospectus;

      o     broker-dealers may agree with the Selling Stockholders to sell a
            specified number of such shares at a stipulated price per share;

      o     a combination of any such methods of sale;

      o     through transactions in options, swaps or other derivative
            securities, whether exchange-listed or otherwise; or

      o     any other method permitted pursuant to applicable law.

      The Selling Stockholders may also sell shares under Rule 144 under the
Securities Act of 1933, as amended (the "Securities Act"), if available, rather
than under this prospectus.

      Broker-dealers engaged by the Selling Stockholders may arrange for other
broker-dealers to participate in sales. Broker-dealers may receive commissions
or discounts from the Selling Stockholders (or, if any broker-dealer acts as
agent for the purchaser of shares, from the purchaser) in amounts to be
negotiated. Each Selling Stockholder does not expect these commissions and
discounts relating to its sales of shares to exceed what is customary in the
types of transactions involved.

                                       19
<PAGE>

      In connection with the sale of Common Stock or interests therein, the
Selling Stockholders may enter into hedging transactions with broker-dealers or
other financial institutions, which may in turn engage in short sales of the
common stock in the course of hedging the positions they assume. To the extent
permitted by the applicable rules of the American Stock Exchange, the Selling
Stockholders may also sell shares of Common Stock short and deliver these
securities to close out their short positions, or loan or pledge the Common
Stock to broker-dealers that in turn may sell these securities. The Selling
Stockholders may also enter into option or other transactions with
broker-dealers or other financial institutions or the creation of one or more
derivative securities which require the delivery to such broker-dealer or other
financial institution of shares offered by this prospectus, which shares such
broker-dealer or other financial institution may resell pursuant to this
prospectus (as supplemented or amended to reflect such transaction).

      The Company is required to pay certain fees and expenses incurred by the
Company incident to the registration of the shares. The Company has agreed to
indemnify the Selling Stockholders against certain losses, claims, damages and
liabilities, including liabilities under the Securities Act.

      Each Selling Stockholder has advised us that they have not entered into
any agreements, understandings or arrangements with any underwriter or
broker-dealer regarding the sale of the resale shares. There is no underwriter
or coordinating broker acting in connection with the proposed sale of the resale
shares by the Selling Stockholders.

      We agreed to keep this prospectus effective until the earlier of (i) the
date on which the shares may be resold by the Selling Stockholders without
registration and without regard to any volume limitations by reason of Rule
144(e) under the Securities Act or any other rule of similar effect or (ii) all
of the shares have been sold pursuant to the prospectus or Rule 144 under the
Securities Act or any other rule of similar effect. The resale shares will be
sold only through registered or licensed brokers or dealers if required under
applicable state securities laws. In addition, in certain states, the resale
shares may not be sold unless they have been registered or qualified for sale in
the applicable state or an exemption from the registration or qualification
requirement is available and is complied with.

      Under applicable rules and regulations under the Exchange Act, any person
engaged in the distribution of the resale shares may not simultaneously engage
in market making activities with respect to our common stock for a period of two
business days prior to the commencement of the distribution. In addition, the
Selling Stockholders will be subject to applicable provisions of the Exchange
Act and the rules and regulations thereunder, including Regulation M, which may
limit the timing of purchases and sales of shares of our common stock by the
Selling Stockholders or any other person. We will make copies of this prospectus
available to the Selling Stockholders, and have informed them of the need to
deliver a copy of this prospectus to each purchaser at or prior to the time of
the sale.

                                       20
<PAGE>

                                                                         Annex B

                              Diomed Holdings, Inc.

                 Selling Securityholder Notice and Questionnaire

      The undersigned beneficial owner of common stock, par value $0.001 per
share (the "Common Stock"), of Diomed Holdings, Inc., a Delaware corporation
(the "Company"), understands that the Company has filed or intends to file with
the Securities and Exchange Commission (the "Commission") a registration
statement on Form SB-2 (the "Registration Statement") for the registration and
resale under Rule 415 of the Securities Act of 1933, as amended (the "Securities
Act"), of the Registrable Securities, in accordance with the terms of the
Registration Rights Agreement, dated as of September 30, 2005 (the "Registration
Rights Agreement"), among the Company and the Purchasers named therein. A copy
of the Registration Rights Agreement is available from the Company upon request
at the address set forth below. All capitalized terms not otherwise defined
herein shall have the meanings ascribed thereto in the Registration Rights
Agreement.

      Certain legal consequences arise from being named as a selling
securityholder in the Registration Statement and the related prospectus.
Accordingly, holders and beneficial owners of Registrable Securities are advised
to consult their own securities law counsel regarding the consequences of being
named or not being named as a selling securityholder in the Registration
Statement and the related prospectus.

                                     NOTICE

      The undersigned beneficial owner (the "Selling Securityholder") of
Registrable Securities hereby elects to include the Registrable Securities owned
by it and listed below in Item 3 (unless otherwise specified under such Item 3)
in the Registration Statement.

                                       21
<PAGE>

The undersigned hereby provides the following information to the Company and
represents and warrants that such information is accurate:

                                  QUESTIONNAIRE

1.    Name.

      (a)   Full Legal Name of Selling Securityholder:

            --------------------------------------------------------------------

      (b)   Full Legal Name of Registered Holder (if not the same as (a) above)
            through which Registrable Securities listed in Item 3 below are
            held:

            --------------------------------------------------------------------

      (c)   Full legal name of natural control person (which means a natural
            person who directly you indirectly alone or with others has power to
            vote or dispose of the securities covered by this Questionnaire):

            --------------------------------------------------------------------

2.    Address for Notices to Selling Securityholder:

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
Telephone:
          ----------------------------------------------------------------------
Fax:
     ---------------------------------------------------------------------------
Contact Person:
               -----------------------------------------------------------------

3.    Beneficial Ownership of Registrable Securities:

      (a)   Type and principal amount of Registrable Securities beneficially
            owned:

            --------------------------------------------------------------------

            --------------------------------------------------------------------

            --------------------------------------------------------------------

            --------------------------------------------------------------------

                                       22
<PAGE>

4.    Broker-Dealer Status:

      (a)   Are you a broker-dealer?

                                    Yes |_|  No  |_|

      Note: If yes, the Commission's staff has indicated that you should
            be identified as an underwriter in the Registration Statement.

      (b)   Are you an affiliate of a broker-dealer?

                                    Yes |_|  No  |_|

      (c)   If you are an affiliate of a broker-dealer, do you certify that you
            bought the Registrable Securities in the ordinary course of
            business, and at the time of the purchase of the Registrable
            Securities to be resold, you had no agreements or understandings,
            directly or indirectly, with any person to distribute the
            Registrable Securities?

                                    Yes |_|  No  |_|

      Note: If no, the Commission's staff has indicated that you should be
            identified as an underwriter in the Registration Statement.

5.    Beneficial Ownership of Other Securities of the Company Owned by the
      Selling Securityholder.

      Except as set forth below in this Item 5, the undersigned is not the
      beneficial or registered owner of any securities of the Company other than
      the Registrable Securities listed above in Item 3.

      State the type and Amount of Other Securities beneficially owned by the
      Selling Securityholder:

            --------------------------------------------------------------------
            --------------------------------------------------------------------

                                       23
<PAGE>

6.    Relationships with the Company:

      Except as set forth below, neither the undersigned nor any of its
      affiliates, officers, directors or principal equity holders (owners of 5%
      of more of the equity securities of the undersigned) has held any position
      or office or has had any other material relationship with the Company (or
      its predecessors or affiliates) during the past three years.

      State any exceptions here:

      --------------------------------------------------------------------------
      --------------------------------------------------------------------------

      The undersigned agrees to promptly notify the Company of any inaccuracies
or changes in the information provided herein that may occur subsequent to the
date hereof at any time while the Registration Statement remains effective.

      By signing below, the undersigned consents to the disclosure of the
information contained herein in its answers to Items 1 through 6 and the
inclusion of such information in the Registration Statement and the related
prospectus. The undersigned understands that such information will be relied
upon by the Company in connection with the preparation or amendment of the
Registration Statement and the related prospectus.

      IN WITNESS WHEREOF the undersigned, by authority duly given, has caused
this Notice and Questionnaire to be executed and delivered either in person or
by its duly authorized agent.

Dated:                                    Beneficial Owner:
      -------------------------------                     ----------------------

                                          By:
                                             -----------------------------------
                                             Name:
                                             Title:

PLEASE FAX A COPY OF THE COMPLETED AND EXECUTED NOTICE AND QUESTIONNAIRE, AND
RETURN THE ORIGINAL BY OVERNIGHT MAIL, TO:

      Diomed Holdings, Inc.
      1 Dundee Park
      Andover, MA  01810
      Attn:  Christopher Geberth, Vice President, Finance
      Fax 978-475-8488

                                       24EXHIBIT 10.5

                              DIOMED HOLDINGS, INC.

                           ---------------------------

                         CERTIFICATE OF DESIGNATIONS OF
                                PREFERRED STOCK,
                           PAR VALUE $0.001 PER SHARE

                           ---------------------------

       Pursuant to Section 151(g) of the Delaware General Corporation Law

                           ---------------------------

IT IS HEREBY CERTIFIED that:

      1. The name of the company (hereinafter called the "Corporation") is
Diomed Holdings, Inc., a corporation organized and now existing under the
Delaware General Corporation Law ("DGCL").

      2. The Certificate of Incorporation of the Corporation (as amended, the
"Certificate of Incorporation") authorizes the issuance of Twenty Million
(20,000,000) shares of preferred stock, par value $0.001 per share (the
"Authorized Preferred Stock"), and expressly vests in the Board of Directors of
the Corporation the authority to issue any or all of said shares by resolution
or resolutions.

      3. The Board of Directors of the Corporation, pursuant to the authority
expressly vested in it as aforesaid, and pursuant to the provisions of Section
151 of the DGCL, has adopted the resolution set forth below to create Authorized
Preferred Stock to be designated as Preferred Stock. Pursuant to said Section
151, the approval of the Corporation's shareholders was not required.

      RESOLVED, that Four Million Two Hundred Thousand (4,200,000) shares of the
Twenty Million (20,000,000) shares of the Authorized Preferred Stock of the
Corporation which are authorized but unissued shares as of the date of this
certificate shall hereby be designated Preferred Stock, par value $0.001 per
share (the "Preferred Stock"), and shall possess the preferences and voting
rights set forth below:

      1. Dividends.

                                    Page 1
<PAGE>

      (a) Subject to Article 1(b), the holders of outstanding shares of
Preferred Stock shall be entitled to receive, as, when and if declared by the
Board of Directors of the Corporation (the "Board of Directors"), cumulative
dividends ("Dividends"): (i) for the first eighteen (18) months following the
closing date of the initial sale and issuance by the Corporation of the
Preferred Stock (as to the issuance of each such share of Preferred Stock, the
"Closing Date"), at the annual rate of six percent (6%); (ii) from the
nineteenth (19th) month through the twenty fourth (24th) month following the
Closing Date, at the annual rate of ten percent (10%); and (iii) after the
twenty fourth (24th) month following the Closing Date, at the annual rate of
fifteen percent (15%). Such Dividends shall accrue from day to day on each share
of Preferred Stock from the Closing Date of such share, whether or not earned or
declared, and shall accrue until paid (a) quarterly in arrears as of the end of
each fiscal quarter of the Corporation (payable on the first business day of the
subsequent fiscal quarter), (b) upon the exchange of the Preferred Stock for
common stock, par value $0.001 per share, of the Corporation (the "Common
Stock") or redemption of the Preferred Stock by the Corporation, or (c) upon
liquidation, dissolution or winding up of the Corporation (as applicable, the
"Dividend Payment Date"). Such Dividends shall be cumulative so that if
Dividends in respect of any previous or current quarterly dividend period, at
the annual rate specified above, shall not have been paid or declared and a sum
sufficient for the payment thereof has not been set aside by the Corporation,
the deficiency shall first be fully paid before any dividend or other
distribution shall be paid or declared and set aside for the Common Stock.
Dividends shall be payable in cash or shares of Common Stock, or a combination
of cash and shares of Common Stock, at the election of the Corporation,
provided, that no shares of Common Stock may be issued in payment of Dividends
unless (a) a registration statement covering the resale by the holders of the
shares of Common Stock to be issued as a Dividend shall have been filed by the
Corporation and declared effective by the United States Securities and Exchange
Commission, and such registration statement continues to be effective up through
and including the Dividend Payment Date, (b) all shares of Common Stock to be
issued as a Dividend are then authorized and reserved for issuance, and listed
or traded on a Trading Market (as defined below), (c) no event entitling the
holder of any shares of Preferred Stock to cause the Corporation to be required
to redeem any such shares of Preferred Stock (a "Redemption Event") under that
certain written agreement (the "Purchase Agreement") by and among the
Corporation and the purchasers identified on the signature pages thereto (the
"Purchasers"), pursuant to which the Preferred Stock shall be issued and sold,
or under those further written agreements by and among the Corporation and the
Purchasers in connection with the sale and purchase of the Preferred Stock by
the Corporation to the Purchasers (together with the Purchase Agreement, the
"Transaction Documents") shall have occurred without such Redemption Event
having been cured within the cure period (if any) provided by the applicable
Transaction Documents and (d) all other amounts, if any, then accrued and
payable by the Corporation under this Certificate of Designations or any
Transaction Document shall have been paid unless such unpaid amounts do not
exceed, in the aggregate, $15,000. If the Corporation elects to issue shares of
Common Stock in payment of Dividends, such shares shall be issued on the
following basis:

                                    Page 2
<PAGE>

            (i) Dividends shall be paid in Common Stock on a per share basis
      valued at the average of the VWAP for the ten Trading Day period
      immediately prior to the applicable Dividend Payment Date. For purposes
      hereof, "VWAP" means, for any Trading Day, the price determined by the
      first of the following clauses that applies: (a) if the Common Stock is
      then listed or quoted on a Trading Market, the daily volume weighted
      average price of the Common Stock for such date on the Trading Market on
      which the Common Stock is then listed or quoted as reported by Bloomberg
      Financial L.P. (based on a Trading Day from 9:30 a.m. Eastern Time to 4:02
      p.m. Eastern Time); (b) if the Common Stock is not then listed or quoted
      on a Trading Market and if prices for the Common Stock are then quoted on
      the OTC Bulletin Board, the volume weighted average price of the Common
      Stock for such date on the OTC Bulletin Board; (c) if the Common Stock is
      not then listed or quoted on the OTC Bulletin Board and if prices for the
      Common Stock are then reported in the "Pink Sheets" published by the
      National Quotation Bureau Incorporated (or a similar organization or
      agency succeeding to its functions of reporting prices), the most recent
      bid price per share of the Common Stock so reported; or (c) in all other
      cases, the fair market value of a share of Common Stock as determined by
      an independent appraiser selected in good faith by the holders of the
      Preferred Stock and reasonably acceptable to the Corporation, where
      "Trading Day" means a day on which the Common Stock is traded on a Trading
      Market, and "Trading Market" means the following markets or exchanges on
      which the Common Stock is listed or quoted for trading on the date in
      question: the Nasdaq SmallCap Market, the American Stock Exchange, the New
      York Stock Exchange or the Nasdaq National Market.

            (ii) If the Corporation elects to issue Common Stock in the payment
      of Dividends, not less than twenty (20) Trading Days prior to the
      applicable Dividend Payment Date (in each such case, the "Dividend Payment
      Notice Date"), the Corporation shall provide the Holder with irrevocable
      written notice of its election to pay as Dividends shares of Common Stock
      (or partly in cash and partly in Common Stock), and, if Dividends are to
      be paid in a combination of cash and Common Stock, the exact combination
      thereof. Subject to the aforementioned conditions, failure to timely
      provide such written notice shall be deemed an election by the Corporation
      to pay the Dividends on such Dividend Payment Date in cash. The
      Corporation's determination of whether to pay Dividends in cash or shares
      of Preferred Stock shall be applied pro rata among all holders of Common
      Stock. Notwithstanding anything to the contrary set forth herein, in no
      event shall the Corporation issue Common Stock to any holder of Preferred
      Stock as payment of any Dividend to the extent that such payment of a
      Dividend would violate the Limitations on Ownership (as defined in the
      Purchase Agreement) applicable to such holder. For purposes of this
      provision, beneficial ownership shall be determined in accordance with
      Section 13(d) of the Securities Exchange Act of 1934, as amended, and
      Regulation 13D-G thereunder. The restriction contained in this provision
      may not be altered, amended, deleted or changed in any manner whatsoever
      unless the holders of a majority of the outstanding shares of Common Stock
      and the holders of at least 51% of the then outstanding Preferred Stock
      (the "Required Holders") shall approve, in writing, such alteration,
      amendment, deletion or change. In the event the Corporation is prohibited
      from issuing Common Stock to any holder of Preferred Stock as payment of
      any Dividend, it shall pay such Dividend to such holder in cash.

      (b) Notwithstanding anything to the contrary set forth in Article 1(a), on
any day on which each of the Dividend Suspension Conditions (as defined below)
are satisfied (a "Dividend Suspension Day"), Dividends shall not accrue on the
Preferred Stock for such day; provided, however, that in the event a Dividend
Payment Date occurs on a Dividend Suspension Day, the Corporation shall be
required to pay all accrued but unpaid Dividends otherwise payable on such
Dividend Payment Date. For purposes of determining whether a day is a Dividend
Suspension Day pursuant this Article 1(x), the "Dividend Suspension Conditions"
shall mean:

                                    Page 3
<PAGE>

            (i) the VWAP for the thirty (30) consecutive Trading Days
      immediately prior to such date equals or exceeds $6.25 (as adjusted for
      stock splits, stock dividends or similar events);

            (ii) a registration statement covering the resale by the holders of
      the shares of Common Stock issuable upon exchange of the Preferred Stock
      pursuant to the Transaction Documents shall have been filed by the
      Corporation and declared effective by the United States Securities and
      Exchange Commission, and such registration statement continues to be
      effective up through and including such date;

            (iii) all shares of Common Stock issuable upon exchange of the
      Preferred Stock for shares of Common Stock pursuant to the Transaction
      Documents and upon exercise of the Warrants (as defined in the Purchase
      Agreement) are then authorized and reserved for issuance, and listed or
      traded on a Trading Market;

            (iv) no Redemption Event, shall have occurred without having been
      cured; and

            (v) all other amounts, if any, then accrued or payable by the
      Corporation under this Certificate of Designations and the Transaction
      Documents shall have been paid, unless such unpaid amounts do not exceed,
      in the aggregate, $15,000 as of such date.

2. Voting.

      (a) Except as otherwise expressly provided elsewhere in this Certificate
of Designation or as otherwise required by the Delaware General Corporation Law
(the "DGCL"), (i) each holder of Preferred Stock shall be entitled to one vote
per share of the issued and outstanding share of Preferred Stock owned by such
holder on the record date for the determination of stockholders entitled to vote
on all matters submitted to a vote of the stockholders of the Corporation or, if
no such record date is established, at the date such vote is taken or any
written consent of stockholders is solicited, and (ii) the holders of shares of
Preferred Stock and Common Stock shall vote together (or tender written consents
in lieu of a vote) as a single class on all matters submitted to the
stockholders of the Corporation. Fractional votes shall not, however, be
permitted and any fractional voting rights available on an as-exchanged ed basis
(after aggregating all shares of Common Stock into which shares of Preferred
Stock held by each holder could be exchanged) shall be rounded to the nearest
whole number.

      (b) The Corporation shall provide each holder of Preferred Stock with
prior notification of any meeting of the stockholders (and copies of proxy
materials and other information sent to stockholders). If the Corporation takes
a record of its stockholders for the purpose of determining stockholders
entitled (i) to receive payment of any dividend (other than Dividends, as to
which Section 1(a) shall apply) or other distribution, any right to subscribe
for, purchase or otherwise acquire (including by way of merger, consolidation or
recapitalization) any share of any class or any other securities or property, or
to receive any other right, or (ii) to vote in connection with any proposed
sale, lease or conveyance of all or substantially all of the assets of the
Corporation, or any proposed merger, consolidation, liquidation, dissolution or
winding up of the Corporation, the Corporation shall mail a notice to each
holder of Preferred Stock, at least 15 days prior to the record date specified
therein (or 45 days prior to the consummation of the transaction or event,
whichever is earlier, but in no event earlier than public announcement of such
proposed transaction), of the date on which any such record is to be taken for
the purpose of such vote, dividend, distribution, right or other event, and a
brief statement regarding the amount and character of such vote, dividend,
distribution, right or other event to the extent known at such time.

                                    Page 4
<PAGE>

      (c) To the extent that under the DGCL the vote of the holders of the
Preferred Stock, voting separately as a class or series, as applicable, is
required to authorize a given action of the Corporation, the affirmative vote or
consent of the holders of at least a majority of the then outstanding shares of
the Preferred Stock represented at a duly held meeting at which a quorum is
present or by written consent of the Required Holders (except as otherwise may
be required under the DGCL) shall constitute the approval of such action by the
class.

3. Liquidation.

      (a) The Preferred Stock shall be preferred over the Common Stock and any
class or series of capital stock of Corporation hereafter created as to the
assets of the Corporation available for distribution to its stockholders upon
the occurrence of any Liquidating Event (as defined below), whether voluntary or
involuntary, or from the net proceeds from a sale, lease, exchange or other
disposition of the assets of the Corporation (in any such case, the "Proceeds").
In the case of any Liquidating Event (as defined below), upon the consummation
of such Liquidating Event, all then-outstanding shares of Preferred Stock shall
be extinguished automatically and in lieu of such shares of Preferred Stock the
holders of the Preferred Stock so extinguished shall be entitled to receive out
of the Proceeds, and before any distribution or payment is made to any holders
of any shares of Common Stock or any other class or series of capital stock of
the Corporation, an amount equal to the greater of: (i) $3.00 per share of
Preferred Stock, plus all accrued and unpaid Dividends thereon, whether or not
earned or declared, up to and including the date full payment shall be tendered
to the holders of the Preferred Stock with respect to such Liquidating Event
(which amount per share shall be payable in cash) and (ii) such amount per share
of Preferred Stock as would have been payable had each such share been tendered
by the holder thereof for exchange into Common Stock pursuant to the Transaction
Documents (without giving effect to any limitations on exchange set forth
therein) immediately prior to such Liquidating Event (which amount per share
shall be payable in cash, securities and/or other property in the same amount
and proportion as would be paid to the holders of Common Stock).

      (b) If, upon any Liquidating Event, the Proceeds available for
distribution to the holders of the Preferred Stock shall be insufficient to
permit payment to such holders of the full preferential amounts as provided for
above, then such holders shall share ratably in any distribution of available
assets according to the respective amounts which would otherwise be payable with
respect to the shares of Preferred Stock held by them upon such Liquidating
Event distribution if all amounts payable on or with respect to said shares were
paid in full, based upon the aggregate liquidation value of all Preferred Stock
outstanding immediately prior to such Liquidating Event.

                                    Page 5
<PAGE>

      (c) After such payment shall have been made in full to the holders of the
Preferred Stock, the remaining Proceeds shall be distributed ratably among the
holders of the shares of Common Stock.

      (d) The amounts to be paid or set aside for payment as provided above in
this Section 3(a) of this Certificate of Designations shall be proportionately
increased or decreased in inverse relation to the change in the number of
outstanding shares resulting from any consolidation or combination of capital
stock, stock split, stock dividend, subdivision of shares, recapitalization,
reclassification or similar event.

      (e) Liquidating Event. Any of the following, whether voluntary or
involuntary, shall be considered a "Liquidating Event" and shall entitle the
holders of the Preferred Stock and the Common Stock to receive promptly after
the Corporation's realization thereof, in cash, securities or other property,
those amounts specified in Section 3(a) of this Certificate or Designations in
accordance with the terms of Section 3(a) hereof:

            (i) any liquidation, dissolution or winding up of the Corporation;

            (ii) the Corporation shall sell, convey or dispose of all or
      substantially all of its assets (the presentation of any such transaction
      for stockholder approval being conclusive evidence that such transaction
      involves the sale of all or substantially all of the assets of the
      Corporation); or

            (iii) the Corporation shall merge or consolidate with or into, or
      engage in any other business combination with, any other person or entity,
      in any case, which results in either (x) the holders of the voting
      securities of the Corporation immediately prior to such transaction
      holding or having the right to direct the voting of fifty percent (50%) or
      less of the total outstanding voting securities of the Corporation or such
      other surviving or acquiring person or entity immediately following such
      transaction or (y) the members of the board of directors or other
      governing body of the Corporation comprising fifty percent (50%) of less
      of the members of the board of directors or other governing body of the
      Corporation or such other surviving or acquiring person or entity
      immediately following such transaction.

4. Uncertificated Shares.

      The shares of the Preferred Stock shall be uncertificated shares;
provided, that in accordance with Section 158 of the DGCL every holder of
uncertificated shares shall be entitled to have a certificate signed by, or in
the name of, the Corporation representing the number of shares owned of record
by such holder in certificated form if such holder so requests.

5. Cancellation of Preferred Stock.

      If any shares of Preferred Stock are exchanged for Common Stock, redeemed
or repurchased by the Corporation, the shares so exchanged, redeemed or
repurchased shall be canceled, shall return to the status of shares of
authorized, but unissued, Authorized Preferred Stock and shall not be issuable
by the Corporation as Preferred Stock.

                                    Page 6
<PAGE>

6. Payment of Cash; Defaults.

      Whenever the Corporation is required to make any cash payment to a holder
under this Certificate of Designations (as payment of any Dividend or
otherwise), such cash payment shall be made to the holder within five business
days after the earlier of (a) the date for such payment provided for in this
Certificate of Designations or (b) delivery by such holder of a notice
specifying that the holder elects to receive such payment in cash and the method
(e.g., by check, wire transfer, including instructions therefor) in which such
payment should be made and any supporting documentation reasonably requested by
the Corporation to substantiate the holder's claim to such cash payment or the
amount thereof. If such payment is not delivered within such five business day
period, such holder shall thereafter be entitled to interest on the unpaid
amount at a per annum rate equal to the lower of eighteen percent (18%) and the
highest interest rate permitted by applicable law until such amount is paid in
full to the holder.

7. Remedies Cumulative.

      The remedies provided in this Certificate of Designations shall be
cumulative and in addition to all other remedies available under this
Certificate of Designations, at law or in equity (including a decree of specific
performance and/or other injunctive relief), and nothing herein shall limit a
holder's right to pursue actual damages for any failure by the Corporation to
comply with the terms of this Certificate of Designations. The Corporation
acknowledges that a breach by it of its obligations hereunder will cause
irreparable harm to the holders of Preferred Stock and that the remedy at law
for any such breach may be inadequate. The Corporation therefore agrees, in the
event of any such breach or written threatened breach, that the holders of
Preferred Stock shall be entitled, in addition to all other available remedies,
to an injunction restraining any breach, without the necessity of showing
economic loss and without any bond or other security being required.

8. Waiver.

      Notwithstanding any provision in this Certificate of Designations to the
contrary, any provision contained herein and any right of the holders of
Preferred Stock granted hereunder may be waived as to all shares of Preferred
Stock (and the holders thereof) upon the written consent of the Required
Holders, unless a higher percentage is required by applicable law, in which case
the written consent of the holders of not less than such higher percentage of
shares of Preferred Stock shall be required.

9. Notices.

      Any notices required or permitted to be given under the terms hereof shall
be sent by certified or registered mail (return receipt requested) or delivered
personally, by nationally recognized overnight carrier or by confirmed facsimile
transmission, and shall be effective five days after being placed in the mail,
if mailed, or upon receipt or refusal of receipt, if delivered personally or by
nationally recognized overnight carrier or confirmed facsimile transmission, in
each case addressed to a party. The addresses for such communications are (i) if
to the Corporation to Diomed Holdings, Inc., One Dundee Park, Andover, MA 01810,
Attn: Chief Executive Officer, Telephone: (978) 475-7771, Facsimile: (978)
475-8488, with a copy to McGuireWoods LLP, 1345 Avenue of the Americas, 7th
Floor, New York, NY 10105, Attn: William A. Newman, Esq., Telephone (212)
548-2160, Facsimile (212) 548-2170, and (ii) if to any holder to the address set
forth under such holder's name on the books and records of the Corporation.

                                    Page 7
<PAGE>

      IN WITNESS WHEREOF, the undersigned has executed this Certificate of
Designations as the act and deed of the Corporation.

Dated:  September 30, 2005

                                         By: /s/  David B. Swank
                                         ---------------------------------------
                                         Name: David B. Swank
                                         Title:   Secretary

                                    Page 8

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