EX-5.1

Exhibit 5.1

LOGO

Charles J. Bair

+1 858 550 6142

cbair@cooley.com

October 8, 2021

Cidara Therapeutics, Inc.

6310 Nancy Ridge Drive, Suite 100

San Diego, California 92121

Ladies and Gentlemen:

We have acted as counsel to Cidara Therapeutics, Inc., a Delaware corporation (the “Company”), and you have requested our opinion with respect to certain matters in connection with the offering by the Company of (i) up to 17,064,511 shares (the “Common Shares”) of the Company’s Common Stock, $0.0001 par value per share (“Common Stock”), including up to 2,225,805 Common Shares that may be sold pursuant to the exercise of an option to purchase additional Common Shares contained in that certain Underwriting Agreement (the “Common Agreement”), dated October 7, 2021, by and between the Company and Cantor Fitzgerald & Co. (“Cantor”), as representative of the underwriters named in Schedule A thereto, and pursuant to Registration Statement No. 333-228268 (the “Registration Statement”), filed with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Act”), the prospectus included in the Registration Statement (the “Base Prospectus”), and the prospectus supplement, dated October 7, 2021, relating to the Common Shares filed with the Commission pursuant to Rule 424(b) of the Rules and Regulations of the Act (together with the Base Prospectus, the “Common Prospectus”), and (ii) up to 774,194 shares (the “Preferred Shares”, and together with the Common Shares, the “Shares”) of the Company’s Series X Convertible Preferred Stock, $0.0001 par value per share, which Preferred Shares will be convertible into up to 7,741,940 shares of Common Stock (the “Conversion Shares”), contained in that certain Series X Preferred Stock Underwriting Agreement (together with the Common Agreement, the “Agreements”), dated October 7, 2021, between the Company and Cantor, as representative of the underwriters named in Schedule A thereto, and pursuant to the Registration Statement, the Base Prospectus, and the prospectus supplement, dated October 7, 2021, relating to the Preferred Shares filed with the Commission pursuant to Rule 424(b) of the Rules and Regulations of the Act (together with the Base Prospectus and the Common Prospectus, the “Prospectuses”).

In connection with this opinion, we have examined and relied upon the Registration Statement and the Prospectuses, the Company’s certificate of incorporation and bylaws, each as currently in effect, the Agreements and originals or copies certified to our satisfaction of such records, documents, certificates, memoranda and other instruments as in our judgment are necessary or appropriate to enable us to render the opinion expressed below. We have assumed the genuineness of all signatures; the authenticity of all documents submitted to us as originals, the conformity to originals of all documents submitted to us as copies; the accuracy, completeness and authenticity of certificates of public officials; and the due authorization, execution and delivery of all documents by all persons other than the Company where authorization, execution and delivery are prerequisites to the effectiveness thereof. As to certain factual matters, we have relied upon a certificate of an officer of the Company and have not independently verified such matters.

COOLEY LLP 4401 EASTGATE MALL SAN DIEGO, CA 92121

T: (858) 550-6000 F: (858) 550-6420 COOLEY.COM


Very truly yours,

Cooley LLP

By:		/s/ Charles J. Bair
		Charles J. Bair