1 EXHIBIT 5.1 GIBSON, DUNN & CRUTCHER 333 South Grand Avenue Los Angeles, California 90071-3197 Telephone: (213) 229-7000 Telecopier: (213) 229-7520 June 18, 1999 (213) 229-7000 C 62416-00001 MiniMed Inc. 12744 San Fernando Road Sylmar, California 91342 Ladies and Gentlemen: We have acted as counsel to MiniMed Inc., a Delaware corporation (the "Company"), in connection with the preparation and filing of the Registration Statement on Form S-3 (the "Registration Statement") of the Company to be filed with the Securities and Exchange Commission (the "Commission") under the Securities Act of 1933, as amended (the "1933 Act"), for the resale of up to 1,000,000 shares of the Common Stock, $0.01 par value, issued to Medtronic Asset Management, Inc. (the "Medtronic Shares"). This opinion is delivered to you in connection with the Registration Statement on Form S-3 for the aforementioned sales. In rendering the opinion set forth herein, we have made such investigations of fact and law, and examined such documents and instruments, or copies thereof established to our satisfaction to be true and correct copies thereof, as we have deemed necessary under the circumstances. Based upon the foregoing and such other examination of law and fact as we have deemed necessary, and in reliance thereon, we are of the opinion that the Medtronic Shares are duly authorized, validly issued, fully paid and nonassessable. 2 The Company is a Delaware corporation. We are not admitted to practice in Delaware. However, we are generally familiar with the Delaware General Corporation Law and have made such review thereof as we consider necessary for the purpose of this opinion. Subject to the foregoing, this opinion is limited to Delaware, California and federal law. We hereby consent to the filing of this opinion as an exhibit to the Registration Statement and to the reference to this firm under the caption "Legal Matters" in the Prospectus which is a part of the Registration Statement. Very truly yours, GIBSON, DUNN & CRUTCHER LLP RJS/HJH/SKH