Exhibit 5


                        [Dorsey & Whitney LLP Letterhead]




Ancor Communications, Inc.
6130 Blue Circle Drive
Minnetonka, Minnesota 55343

         Re:  Registration Statement on Form S-3

Ladies and Gentlemen:

         We have acted as counsel to Ancor Communications, Inc., a Minnesota
corporation (the "Company"), in connection with a Registration Statement on Form
S-3 (the "Registration Statement") to be filed with the Securities and Exchange
Commission under the Securities Act of 1933, as amended, relating to the sale of
4,905,556 shares (the "Shares") of common stock of the Company, par value $.01
per share, which will be sold from time to time by the persons named in the
Registration Statement (the "Selling Shareholders"), on the Nasdaq SmallCap
Market, the Pacific Stock Exchange or otherwise, directly or through
underwriters, brokers or dealers.

         We have examined such documents and have reviewed such questions of law
as we have considered necessary and appropriate for the purposes of our opinions
set forth below. In rendering our opinions set forth below, we have assumed the
authenticity of all documents submitted to us as originals, the genuineness of
all signatures and the conformity to authentic originals of all documents
submitted to us as copies. We have also assumed the legal capacity for all
purposes relevant hereto of all natural persons and, with respect to all parties
to agreements or instruments relevant hereto other than the Company, that such
parties had the requisite power and authority (corporate or otherwise) to
execute, deliver and perform such agreements or instruments, that such
agreements or instruments have been duly authorized by all requisite action
(corporate or otherwise), executed and delivered by such parties and that such
agreements or instruments are the valid, binding and enforceable obligations of
such parties. As to questions of fact material to our opinions, we have relied
upon certificates of officers of the Company and of public officials.

         Based on the foregoing, we are of the opinion that the Shares to be
sold by the Selling Shareholders pursuant to the Registration Statement, upon
conversion of the Company's Series B Preferred Stock and exercise of the
warrants to purchase Common Stock issued by the Company on March 24, 1997 and to
be issued to purchasers of the Company's Series B Preferred Stock will be duly
authorized by all requisite corporate action, validly issued, fully paid and
nonassessable.

         Our opinions expressed above are limited to the laws of the State of
Minnesota.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement, and to the reference to our firm under the heading
"Legal Matters" in the Prospectus constituting part of the Registration
Statement.

Dated:  May 23, 1997

                                        Very truly yours,

                                        /s/  DORSEY & WHITNEY LLP

AEL