3.              Representations and Warranties of the Company .  The Company represents and warrants to the Placement Agents that:

(a)            Registration Statement.   The Company has filed with the Securities and Exchange Commission (the “Commission”) a “shelf” registration statement on Form S-3 (Registration No. 333-113500), which has become effective, relating to the Common Stock of the Company, under the Securities Act of 1933, as amended (the “Act”), and the rules and regulations (collectively referred to as the “Rules and Regulations”) of the Commission promulgated thereunder.  The registration statement, as amended as of the date of this Agreement, including the exhibits and information (if any) deemed to be part of the registration statement pursuant to Rule 430A or 434(d) under the Act, is hereinafter referred to as the “Registration Statement.”  No stop order suspending the effectiveness of the Registration Statement has been issued and, to the Company’s knowledge, no proceeding for that purpose has been initiated or threatened by the Commission.  The Company, if required by the Rules and Regulations of the Commission, proposes to file the Prospectus (as defined below) with the Commission pursuant to Rule 424(b) of the Rules and Regulations.  The Prospectus, in the form in which it is to be filed with the Commission pursuant to Rule 424(b) of the Rules and Regulations, or, if the Prospectus is not to be filed with the Commission pursuant to Rule 424(b), the Prospectus in the form included as part of the Registration Statement at the time the Registration Statement became effective, is hereinafter referred to as the “Prospectus,” except that if any revised prospectus or prospectus supplement shall be provided to the Placement Agents by the Company for use in connection with the offering and sale of the Shares which differs from the Prospectus (whether or not such revised prospectus or prospectus supplement is required to be filed by the Company pursuant to Rule 424(b) of the Rules and Regulations), the term “Prospectus” shall refer to such revised prospectus or prospectus supplement, as the case may be, from and after the time it is first provided to the Placement Agents for such use.  Any preliminary prospectus or prospectus subject to completion included in the Registration Statement or filed with the Commission pursuant to Rule 424 under the Act is hereafter called a “Preliminary Prospectus.”  Any reference herein to the Registration Statement, any Preliminary Prospectus or the Prospectus shall be deemed to refer to and include the documents incorporated by reference therein pursuant to Item 12 of Form S-3 which were filed under the Securities Exchange Act of 1934, as amended (the “Exchange Act”) on or before the last to occur of the effective date of the Registration Statement, the date of the Preliminary Prospectus, or the date of the Prospectus, and any reference herein to the terms “amend,” “amendment” or “supplement” with respect to the Registration Statement, any Preliminary Prospectus or the Prospectus shall be deemed to refer to and include (i) the filing of any document under the Exchange Act after the effective date of the Registration Statement, the date of such Preliminary Prospectus or the date of the Prospectus, as the case may be, which is incorporated therein by reference and (ii) any such document so filed.

(b)            Registration Statement and Prospectus.   When the Registration Statement became effective, upon the filing or first delivery to the Investors of the Prospectus, as of the date hereof, and at the Closing Date, the Registration Statement (and any post-effective amendment thereto) and the Prospectus (as amended or as supplemented if the Company shall have filed with the Commission any amendment or supplement to the Registration Statement or the Prospectus) complied and will comply in all material respects with the Act and the Rules and Regulations, and did not and 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 the light

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of the circumstances under which they were made, in the case of the Prospectus) not misleading, each Preliminary Prospectus, as of the date filed with the Commission, did not include 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 the light of the circumstances under which they were made, not misleading; except that no representation or warranty is made in this Section 3(b) with respect to statements or omissions made in reliance upon and in conformity with written information furnished to the Company expressly for inclusion in any Preliminary Prospectus, the Registration Statement, or the Prospectus, or any amendment or supplement thereto, as stated in Section 7(b) hereof.  The Company has not distributed any offering material in connection with the offering and sale of the Shares, other than the Registration Statement, the Preliminary Prospectus and the Prospectus.

(c)            Subsidiaries .  The Company has no significant subsidiaries (as such term is defined in Rule 1-02 of Regulation S-X promulgated by the Commission).  The Company owns, directly or indirectly, all of the capital stock of Dyax Holdings B.V., Dyax B.V., and Dyax S.A. (the “Subsidiaries”) free and clear of any lien, charge, security interest, encumbrance, right of first refusal or other restriction, and all the issued and outstanding shares of capital stock of the Subsidiaries are validly issued and are fully paid, nonassessable and free of preemptive and similar rights.

(d)            Financial Statements .  The consolidated financial statements and the related notes thereto included or incorporated by reference in the Registration Statement and the Prospectus comply with the applicable requirements of the Act and the Exchange Act, as applicable, and present fairly, the consolidated financial position of the Company as of the dates indicated and its results of operations and its consolidated cash flows for the periods specified; such financial statements and the related notes thereto have been prepared in conformity with generally accepted accounting principles applied on a consistent basis throughout the periods covered thereby (except as otherwise stated therein and subject, in the case of unaudited financial statements, to the absence of footnotes and normal year end adjustments), and the other financial information included or incorporated by reference in the Registration Statement and the Prospectus has been derived from the accounting records of the Company and its Subsidiaries and presents fairly the information shown thereby.  No other consolidated financial statements or schedules of the Company or any other entity are required by the Act or the Rules and Regulations to be included in the Registration Statement or the Prospectus.

(e)            No Material Adverse Change .  Except as set forth in or otherwise contemplated by the Registration Statement or the Prospectus, since the date of the most recent financial statements of the Company included or incorporated by reference in the Registration Statement and the Prospectus and prior to Closing, (i) there has not been any change in the capital stock of the Company (except for changes in the number of outstanding shares of Common Stock of the Company due to the issuance of shares, including without limitation shares issued under the Company’s employee stock purchase plan, upon the exercise or conversion of securities exercisable for, or convertible into, shares of Common Stock outstanding on the date hereof) or long-term debt of the Company or of its Subsidiaries or any dividend or distribution of any kind declared, set aside for payment, paid or made by the Company on any class of capital stock, or any material adverse change, or any development that would reasonably be expected to result in a material adverse change, in or affecting the business, properties, management, consolidated

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financial position, stockholders’ equity, or results of operations of the Company and its Subsidiaries taken as a whole (a “Material Adverse Change”); (ii) neither the Company nor its Subsidiaries have entered into any transaction or agreement, not in the ordinary course of business, that is material to the Company and its Subsidiaries taken as a whole or incurred or will incur any liability or obligation, direct or contingent, not in the ordinary course of business, that is material to the Company and its Subsidiaries taken as a whole; and (iii) neither the Company nor its Subsidiaries have sustained any material loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor disturbance or dispute or any action, order or decree of any court or arbitrator or governmental or regulatory authority.

(f)             Organization.   The Company and its Subsidiaries are duly organized, validly existing as a corporation and in good standing under the laws of their respective jurisdictions of organization.  The Company and its Subsidiaries are duly licensed or qualified as a foreign corporation for transaction of business and in good standing under the laws of each other jurisdiction in which their respective ownership or lease of property or the conduct of their respective businesses requires such license or qualification, and have all corporate power and authority necessary to own or hold their respective properties and to conduct their respective businesses as described in the Registration Statement and the Prospectus, except where the failure to be so qualified or in good standing or have such power or authority would not, individually or in the aggregate, have a material adverse effect or would reasonably be expected to have a material adverse effect on the business, properties, prospects, management, consolidated financial position, stockholders’ equity or results of operations of the Company and its Subsidiaries taken as a whole (a “Material Adverse Effect”).

(g)            Capitalization .  The issued and outstanding shares of capital stock of the Company have been validly issued, are fully paid and nonassessable and, other than as disclosed in or contemplated by the Registration Statement or the Prospectus, are not subject to any preemptive or similar rights.  The Company has an authorized, issued and outstanding capitalization as set forth in the Registration Statement and the Prospectus as of the dates referred to therein (other than the grant of additional options under the Company’s existing stock option plans, or changes in the number of outstanding shares of Common Stock of the Company due to the issuance of shares under the Company’s employee stock purchase plan or upon the exercise or conversion of securities exercisable for, or convertible into, shares of Common Stock outstanding on the date hereof) and such authorized capital stock conforms to the description thereof set forth in the Registration Statement and the Prospectus.  The description of the securities of the Company in the Registration Statement and the Prospectus is complete and accurate in all material respects.  Except as disclosed in or contemplated by the Registration Statement or the Prospectus, as of the date referred to therein, the Company did not have outstanding any options to purchase, or any rights or warrants to subscribe for, or any securities or obligations convertible into, or exchangeable for, or any contracts or commitments to issue or sell, any shares of capital stock or other securities.

(h)            Due Authorization and Enforceability .  The Company has full legal power and authority to enter into this Agreement and any other ancillary agreements associated with the transaction (together, the “Transaction Documents”) and to consummate the transactions contemplated hereby and thereby.  The Transaction Documents have been duly authorized,

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executed and delivered by the Company and constitute legal, valid and binding obligations of the Company enforceable against the Company in accordance with their respective terms except as rights to indemnity and contribution thereunder may be limited by federal or state securities laws and matters of public policy and except as such enforceability may be subject to the effect of applicable bankruptcy, insolvency, reorganization or similar laws affecting creditors’ rights generally and equitable principles of general applicability.

(i)             The Shares .  The Shares have been duly authorized by the Company and, when issued and delivered and paid for as provided herein, will be validly issued, fully paid and nonassessable and will conform to the descriptions thereof in the Prospectus; and the issuance of the Shares is not subject to any preemptive or similar rights that have not been waived.

(j)             No Violation or Default .  Neither the Company nor its Subsidiaries are (i) in violation of its charter or by-laws or similar organizational documents; (ii) in default, and no event has occurred that, with notice or lapse of time or both, would constitute such a default, in the due performance or observance of any term, covenant or condition contained in any indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which the Company or its Subsidiaries are a party or by which the Company or its Subsidiaries are bound or to which any of the property or assets of the Company or its Subsidiaries are subject; or (iii) in violation of any law or statute or any judgment, order, rule or regulation of any court or arbitrator or governmental or regulatory authority, except, in the case of each of clauses (ii) and (iii) above, for any such violation or default that would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(k)            No Conflicts .  The execution, delivery and performance by the Company of each of the Transaction Documents, the issuance and sale by the Company of the Shares and the consummation by the Company of the transactions contemplated by the Transaction Documents will not (i) conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default under, or result in the creation or imposition of any lien, charge or encumbrance upon any property or assets of the Company or its Subsidiaries pursuant to, any indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which the Company or its Subsidiaries are a party or by which the Company or its Subsidiaries are bound or to which any of the property or assets of the Company or its Subsidiaries are subject; (ii) result in any violation of the provisions of the charter or by-laws or similar organizational documents of the Company or its Subsidiaries; or (iii) result in the violation of any law or statute or any judgment, order, rule or regulation of any court or arbitrator or governmental or regulatory authority, except, in the case of each of clauses (i) and (iii) above, for any such conflict, breach, violation, default, lien, charge or encumbrance that would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(l)             No Consents Required .  No consent, approval, authorization, order, registration or qualification of or with any court or arbitrator or governmental or regulatory authority is required for the execution, delivery and performance by the Company of each of the Transaction Documents, the issuance and sale by the Company of the Shares and the consummation by the Company of the transactions contemplated by the Transaction Documents, except for the registration of the Shares under the Act and such consents, approvals, authorizations, orders and registrations or qualifications as may be required under applicable state securities laws or by the

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by-laws and rules of the National Association of Securities Dealers, Inc. (“NASD”) in connection with the distribution of the Shares by the Placement Agents.

(m)           Legal Proceedings .  There are no legal, governmental or regulatory actions, suits or proceedings pending, nor, to the Company’s knowledge, any legal, governmental or regulatory investigations, to which the Company or its Subsidiaries are a party or to which any property of the Company or its Subsidiaries is the subject that, individually or in the aggregate, if determined adversely to the Company or its Subsidiaries, would reasonably be expected to have a Material Adverse Effect or materially and adversely affect the ability of the Company to perform its obligations under the Transaction Documents; to the Company’s knowledge, no such actions, suits or proceedings are threatened or contemplated by any governmental or regulatory authority or threatened by others; and (i) there are no current or pending legal, governmental or regulatory investigations, actions, suits or proceedings that are required under the Act to be described in the Prospectus that are not so described; and (ii) there are no contracts or other documents that are required under the Act to be filed as exhibits to the Registration Statement that are not so filed.

(n)            Independent Accountants .  PricewaterhouseCoopers LLP, who have audited certain consolidated financial statements of the Company, is an independent registered public accounting firm (the “Accountants”) with respect to the Company as required by the Act.

(o)            Title to Real and Personal Property .  The Company and its Subsidiaries own no real property.  Except as disclosed in Notes 4 and 8 to the Company’s consolidated financial statements for the year ended December 31, 2004 that are incorporated by reference into the Registration Statement, the Company and its Subsidiaries have good and valid title to all personal property owned by them, in each case free and clear of all liens, encumbrances and claims except those that (i) do not materially interfere with the use made and proposed to be made of such property by the Company and its Subsidiaries or (ii) would not reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect.  Any real property leased by the Company and its Subsidiaries is held by them under valid, existing and enforceable leases, except those that (A) do not materially interfere with the use made or proposed to be made of such property by the Company or its Subsidiaries or (B) would not be reasonably expected, individually or in the aggregate, to have a Material Adverse Effect.

(p)            Title to Intellectual Property .  The Company and its Subsidiaries own or possess adequate rights to use all patents, patent applications, trademarks, service marks, trade names, trademark registrations, service mark registrations, copyrights, licenses and know-how (including trade secrets and other unpatented and/or unpatentable proprietary or confidential information, systems or procedures) (collectively, the “Intellectual Property”), necessary for the conduct of their respective businesses as conducted as of the date hereof, except to the extent that the failure to own or possess adequate rights to use such Intellectual Property would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect; and the Company and its Subsidiaries have not received any written notice of any claim of infringement or conflict which asserted Intellectual Property rights of others, which infringement or conflict, if the subject of an unfavorable decision, would result in a Material Adverse Effect.

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(q)            No Undisclosed Relationships .  No relationship, direct or indirect, exists between or among the Company or its Subsidiaries, on the one hand, and the directors, officers and stockholders of the Company, on the other, which is required by the Act to be disclosed in the Registration Statement and the Prospectus and is not so disclosed.

(r)             Investment Company Act .  The Company is not and, after giving effect to the offering and sale of the Shares to be sold by the Company and the application of the proceeds thereof as described in the Prospectus, will not be an “investment company” within the meaning of the Investment Company Act of 1940, as amended, and the rules and regulations of the Commission promulgated thereunder.

(s)            Taxes .  The Company and its Subsidiaries have filed all federal, state, local and foreign tax returns (or timely filed applicable extensions therefor) which have been required to be filed and paid all taxes shown thereon through the date hereof, to the extent that such taxes have become due and are not being contested in good faith; and, except as otherwise disclosed in or contemplated by the Registration Statement or the Prospectus, no tax deficiency has been determined adversely to the Company or its Subsidiaries which has had, or would reasonably be expected to have, individually or in the aggregate, a Material Adverse Effect.

(t)             Licenses and Permits .  The Company and its Subsidiaries possess or have obtained all licenses, certificates, permits and other authorizations issued by, and have made all declarations and filings with, the appropriate federal, state, local or foreign governmental or regulatory authorities that are necessary for the ownership or lease of their respective properties or the conduct of their respective businesses as described in the Registration Statement and the Prospectus (the “Permits”), except where the failure to possess, obtain or make the same would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect; and except as disclosed in or contemplated by the Registration Statement or the Prospectus, neither the Company nor its Subsidiaries have received written notice of any proceeding relating to revocation or modification of any such Permit or has any reason to believe that such Permit will not be renewed in the ordinary course, except where the failure to obtain any such renewal would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(u)            No Labor Disputes .  No labor disturbance by or dispute with employees of the Company or its Subsidiaries exists or, to the knowledge of the Company, is threatened which would reasonably be expected to result in a Material Adverse Effect.

(v)            Compliance With Environmental Laws .  The Company and its Subsidiaries (i) are in compliance with any and all applicable federal, state, local and foreign laws, rules, regulations, decisions and orders relating to the protection of human health and safety, the environment or hazardous or toxic substances or wastes, pollutants or contaminants (collectively, “Environmental Laws”); (ii) have received and are in compliance with all permits, licenses or other approvals required of them under applicable Environmental Laws to conduct their respective businesses as described in the Registration Statement and the Prospectus; and (iii) have not received notice of any actual or potential liability for the investigation or remediation of any disposal or release of hazardous or toxic substances or wastes, pollutants or contaminants, except, in the case of any of clauses (i), (ii) or (iii) above, for any such failure to comply or

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failure to receive required permits, licenses, other approvals or liability as would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(w)           Compliance With ERISA .  Each material employee benefit plan, within the meaning of Section 3(3) of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), that is maintained, administered or contributed to by the Company or any of its affiliates for employees or former employees of the Company and its Subsidiaries has been maintained in material compliance with its terms and the requirements of any applicable statutes, orders, rules and regulations, including but not limited to ERISA and the Internal Revenue Code of 1986, as amended (the “Code”); no prohibited transaction, within the meaning of Section 406 of ERISA or Section 4975 of the Code, has occurred which would result in a material liability to the Company with respect to any such plan excluding transactions effected pursuant to a statutory or administrative exemption; and for each such plan that is subject to the funding rules of Section 412 of the Code or Section 302 of ERISA, no “accumulated funding deficiency” as defined in Section 412 of the Code has been incurred, whether or not waived, and the fair market value of the assets of each such plan (excluding for these purposes accrued but unpaid contributions) exceeds the present value of all benefits accrued under such plan determined using reasonable actuarial assumptions.

(x)             Listing .  The Company has not, in the two years preceding the date hereof, received any notice (written or oral) from the Nasdaq National Market, any stock exchange, market or trading facility on which the Common Stock is or has been listed (or on which it has been quoted) to the effect that the Company is not in compliance with the listing or maintenance requirements of such exchange, market or trading facility.  The Company shall comply with all requirements of the Nasdaq National Market with respect to the issuance of Shares and shall use its best efforts to have the Shares listed on the Nasdaq National Market on or before the Closing Date.

(y)            Sarbanes-Oxley Act .  There is and has been no failure on the part of the Company, or to its knowledge after due inquiry, and any of the Company’s directors or officers, in their capacities as such, to comply with any applicable provisions of the Sarbanes Oxley Act of 2002 and the rules and regulations promulgated therewith (the “Sarbanes Oxley Act”).  Each of the principal executive officer and the principal financial officer of the Company (or each former principal executive officer of the Company and each former principal financial officer of the Company as applicable) has made all certifications required by Sections 302 and 906 of the Sarbanes-Oxley Act with respect to all reports, schedules, forms, statements and other documents required to be filed by it with the Commission.  For purposes of the preceding sentence, “principal executive officer” and “principal financial officer” shall have the meanings given to such terms in the Sarbanes-Oxley Act.

(z)             Internal Controls .  The Company and its Subsidiaries maintain systems of internal accounting controls sufficient to provide reasonable assurance that (i) transactions are executed in accordance with management’s general or specific authorizations; (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain asset accountability; (iii) access to assets is permitted only in accordance with management’s general or specific authorization; and (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and

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appropriate action is taken with respect to any differences.  The Company has established disclosure controls and procedures (as defined in Exchange Act Rules 13a-14 and 15d-14) for the Company and designed such disclosure controls and procedures to ensure that material information relating to the Company and its Subsidiaries is made known to the certifying officers by others within those entities, particularly during the period in which the Company’s Annual Report on Form 10-K or Quarterly Report on Form 10-Q, as the case may be, is being prepared.  The Company’s certifying officers have evaluated the effectiveness of the Company’s controls and procedures as of the end of the period covered by the Form 10-Q for the quarter ended March 31, 2005 (such date, the “Evaluation Date”).  The Company presented in its Form 10-Q for the quarter ended March 31, 2005 the conclusions of the certifying officers about the effectiveness of the disclosure controls and procedures based on their evaluations as of the Evaluation Date.  Since the Evaluation Date, there have been no significant changes in the Company’s internal controls (as such term is defined in Item 307(b) of Regulation S-K under the Exchange Act) or, to the Company’s knowledge, in other factors that could significantly affect the Company’s internal controls.

(aa)          Operations .  The operations of the Company and its Subsidiaries are and have been conducted at all times in material compliance with applicable financial record keeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended, the money laundering statutes of all jurisdictions to which the Company or its Subsidiaries are subject, the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency (collectively, the “Money Laundering Laws”) and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its Subsidiaries with respect to the Money Laundering Laws is pending or, to the best knowledge of the Company, threatened.

(bb)          Off-Balance Sheet Arrangements .  There are no transactions, arrangements and other relationships between and/or among the Company, and/or, to the knowledge of the Company, any of its affiliates and any unconsolidated entity, including, but not limited to, any structural finance, special purpose or limited purpose entity (each, an “Off Balance Sheet Transaction”) that could reasonably be expected to affect materially the Company’s liquidity or the availability of or requirements for its capital resources, including those Off Balance Sheet Transactions described in the Commission’s Statement about Management’s Discussion and Analysis of Financial Conditions and Results of Operations (Release Nos. 33-8056; 34-45321; FR-61), required to be described in the Prospectus which have not been described as required.

(cc)          Foreign Corrupt Practices .  Neither the Company, nor any of its Subsidiaries, nor, to the knowledge of the Company, any director, officer, agent, employee or other Person acting on behalf of the Company or any of its Subsidiaries have, in the course of its actions for, or on behalf of, the Company (i) used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expenses relating to political activity; (ii) made any direct or indirect unlawful payment to any foreign or domestic government official or employee from corporate funds; (iii) violated or is in violation of any provision of the U.S. Foreign Corrupt Practices Act of 1977, as amended; or (iv) made any unlawful bribe, rebate, payoff, influence payment, kickback or other unlawful payment to any foreign or domestic government official or employee.

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(dd)          Insurance .  The Company and its Subsidiaries carry, or are covered by, insurance in such amounts and covering such risks as the Company and its Subsidiaries reasonably believe are adequate for the conduct