EXHIBIT 5.1

OPINION AND CONSENT OF DORSEY & WHITNEY LLP

April 2, 2010

BSD Medical Corporation

2188 West 2200 South

Salt Lake City, Utah 84119

Re: Registration Statement on Form S-8

Ladies and Gentlemen:

We have acted as counsel to BSD Medical Corporation, a Delaware corporation (the “Company”), in connection with a Registration Statement on Form S-8 (the “Registration Statement”) under the Securities Act of 1933, as amended (the “Act”), relating to the issuance by the Company from time to time of up to 3,160,000 shares of Common Stock, $0.001 par value, of the Company (the “Shares”), pursuant to the Third Amended and Restated 1998 Stock Incentive Plan and the Fourth Amended and Restated 1998 Director Stock Plan (collectively, the “Plans”).  This opinion is being furnished in accordance with the requirements of Item 8 of Form S-8 and Item 601(b)(5)(i) of Regulation S-K of the Act.

We have examined such documents and have reviewed such questions of law as we have considered necessary and appropriate for the purposes of the opinion set forth below. 

In rendering our opinion 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) and 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 opinion, 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 have been duly authorized and, upon issuance, delivery and payment therefor in accordance with the terms of the Plans and any agreements thereunder and in accordance with the Registration Statement, will be validly issued, fully paid and nonassessable.

Our opinion expressed above is limited to the Delaware General Corporation Law, and we express no opinion with respect to the applicability of any other laws. 

We hereby consent to the filing of this opinion letter as an exhibit to the Registration Statement.  In giving this consent, we do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Act, the rules and regulations of the Securities and Exchange Commission promulgated thereunder, or Item 509 of Regulation S-K.

BSD Medical Corporation

April 2, 2010

Page 2

This opinion letter is rendered as of the date first written above and we disclaim any obligation to advise you of facts, circumstances, events or developments which hereafter may be brought to our attention and which may alter, affect or modify the opinion expressed herein.  Our opinion is expressly limited to the matters set forth above and we render no opinion, whether by implication or otherwise, as to any other matters relating to the Company, the Plans or the Shares.

Very truly yours,

/s/ Dorsey & Whitney LLP

DFM/SPG