EXHIBIT 5

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                         TESTA, HURWITZ & THIBEAULT, LLP
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                                ATTORNEYS AT LAW

                                 125 High Street
Office (617) 248-7000      Boston, Massachusetts 02110        Fax (617) 248-7100

                                December 19, 2002

Teradyne, Inc.
321 Harrison Avenue
Boston, MA 02118

    Re: Registration Statement on Form S-8 Relating to the
        Teradyne, Inc. 1996 Employee Stock Purchase Plan Filed December 19, 2002

Ladies and Gentlemen:

         Reference is made to the above-captioned Registration Statement on Form
S-8 (the "Registration Statement") filed by Teradyne, Inc. (the "Company") with
the Securities and Exchange Commission under the Securities Act of 1933, as
amended, relating to an aggregate of five million (5,000,000) shares of Common
Stock, $.125 par value, of the Company (the "Shares").

         We are counsel to the Company and are familiar with the proceedings of
its stockholders and Board of Directors. We have examined original or certified
copies of the Company's Restated Articles of Organization, as amended, the
Company's Amended and Restated Bylaws, and such other certificates, documents,
records and materials as we have deemed necessary in connection with this
opinion letter. We have relied, without independent investigation, upon a
certificate of an officer of the Company with respect to certain factual matters
relevant to this opinion letter.

         We are members only of the Bar of the Commonwealth of Massachusetts and
are not experts in, and express no opinion regarding, the laws of any
jurisdictions other than the Commonwealth of Massachusetts and the federal
securities laws of the United States of America.

         Based upon and subject to the foregoing, we are of the opinion that the
Shares proposed to be issued by the Company pursuant to the Teradyne, Inc. 1996
Employee Stock Purchase Plan (the "Plan") will be, upon receipt of the
consideration provided for in the Plan and when the Company's Board of Directors
shall have taken appropriate final action in connection with the issuance and
sale of such Shares, validly issued, fully paid and nonassessable after issuance
of such Shares in accordance with the terms of the Plan.

         We hereby consent to the filing of this opinion as Exhibit 5 to the
Registration Statement.

                                           Very truly yours,

                                           /s/  Testa, Hurwitz & Thibeault, LLP

                                           TESTA, HURWITZ & THIBEAULT, LLP