Exhibit 3.1
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                             Amendment to By-Laws of
                               Cognex Corporation

     The By-laws of Cognex Corporation, a Massachusetts corporation, are hereby
amended by deleting Sections 3.4 and 3.7 in their entirety and replacing such
sections respectively with the following:

          "Section 3.4 Notice of Meetings. A written Notice of the place, date
     and hour of all meetings of stockholders stating the purposes of the
     meeting shall be given at least seven (7) days before the meeting to each
     stockholder entitled to vote thereat. Notice may be given to a stockholder
     by any means permitted under applicable law, including, without limitation,
     by leaving such Notice with him or at his residence or usual place of
     business, or by mailing, postage prepaid, and addressed to such stockholder
     at his address as it appears in the records of the Corporation. Such Notice
     shall be given by the Secretary, or in the case of the death, absence,
     incapacity or refusal of the Secretary, by any other officer or by a person
     designated either by the Secretary, by the person or persons calling the
     meeting or by the Board of Directors. Without limiting the generality of
     the foregoing, notice may be given to a stockholder by electronic
     transmission in a manner specified by the stockholder, including, without
     limitation, by facsimile transmission, electronic mail or posting on an
     electronic network. Whenever Notice of a meeting is required to be given a
     stockholder under any provision of law, of the Articles of Organization, or
     of these By-Laws, a written Waiver thereof, executed before or after the
     meeting by such stockholder or his attorney thereunto authorized, and filed
     with the records of the meeting, shall be deemed equivalent to such
     Notice."

          "Section 3.7 Proxies and Voting. Except as may otherwise be provided
     in the Articles of Organization, stockholders entitled to vote shall have
     one vote for each share of stock entitled to vote owned by them.
     Stockholders entitled to vote may vote in person or by proxy. No proxy
     dated more than six (6) months before the meeting named therein shall be
     valid and no proxy shall be valid after the final adjournment of such
     meeting. A proxy with respect to stock held in the name of two or more
     persons shall be valid if executed by any one of them unless at or prior to
     the exercise of the proxy the Corporation receives specific written notice
     to the contrary from any one of them. A proxy purporting to be executed by
     or on behalf of a stockholder shall be deemed valid unless challenged at or
     prior to its exercise and the burden of proving invalidity shall rest on
     the challenger. Proxies shall be filed with the Secretary, or person
     performing the duties of Secretary, at the meeting, or any adjournment
     thereof, before being voted. Any stockholder's proxy may be transmitted by
     facsimile or other electronic means in a manner complying with applicable
     law.

          The Corporation shall not, directly or indirectly, vote upon any share
     of its own stock. Both abstentions and broker non-votes are to be counted
     as present for the purpose of determining the existence of a quorum for the
     transaction of business at any meeting. However, for purposes of
     determining the number of shares voting on a particular proposal,
     abstentions and broker non-votes are not to be counted as votes cast or
     shares voting."




     The foregoing is certified as an Amendment to the By-laws of Cognex
Corporation as adopted by the Board of Directors on March 1, 2008.

                                                    /s/ Anthony J. Medaglia, Jr.
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                                                    Anthony J. Medaglia, Jr.
                                                    Secretary


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