Exhibit 5.1
Divakar Gupta
T: +1 212 479 6474
dgupta@cooley.com
January 13, 2026
CG Oncology, Inc.
400 Spectrum Center Drive, Suite 1040
Irvine, CA 92618
Ladies and Gentlemen:
We have acted as counsel to CG Oncology, Inc., a Delaware corporation (the “Company”), in connection with the offering by the Company of shares (the “Shares”) of its common stock, par value $0.0001 per share (the “Common Stock”), having aggregate offering price of up to $550,000,000 pursuant to the Registration Statement on Form S-3 (File No. 333-283260) (the “Registration Statement”) filed with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”), the prospectus relating to the Shares included in the Registration Statement (the “Prospectus”), and the prospectus supplement filed with the Commission pursuant to Rule 424(b) under the Securities Act on January 13, 2026 (together with the Prospectus, the “ATM Prospectus”). The Shares are to be sold by the Company in accordance with that certain Open Market Sale Agreement, dated March 28, 2025 by and between the Company and Jefferies LLC (the “Agreement”), as described in the ATM Prospectus.
In connection with this opinion, we have examined and relied upon (a) the Registration Statement and the ATM Prospectus, (b) the Agreement, (c) the Company’s certificate of incorporation and bylaws, each as currently in effect, and (d) such other records, documents, opinions, certificates, memoranda and 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. As to certain factual matters, we have relied upon a certificate of an officer of the Company and have not independently verified such matters.
We have assumed (i) that each sale of Shares will be duly authorized by the Board of Directors of the Company, a duly authorized committee thereof or a person or body pursuant to an authorization granted in accordance with Section 152 of the General Corporation Law of the State of Delaware (the “DGCL”), (ii) that no more than 55,000,000 Shares will be sold under the Agreement pursuant to the ATM Prospectus and (iii) that the price at which the Shares are sold will equal or exceed the par value of the Shares. We express no opinion to the extent that future issuances of securities of the Company, anti-dilution adjustments to outstanding securities of the Company or other matters cause the number of shares of Common Stock issuable under the Agreement to exceed the number of shares of Common Stock available for issuance by the Company.
Our opinion is expressed solely with respect to the DGCL. We express no opinion to the extent that any other laws are applicable to the subject matter hereof and express no opinion and provide no assurance as to compliance with any federal or state securities law, rule or regulation.
On the basis of the foregoing, in reliance thereon and subject to the assumptions, qualifications, limitations and exceptions set forth herein, we are of the opinion that the Shares, when sold and issued against payment therefor in accordance with the Agreement, the Registration Statement and the ATM Prospectus, will be validly issued, fully paid and nonassessable.
Cooley LLP 55 Hudson Yards New York, NY 10001-2157
t: (212) 479-6000 f: (212) 479-6275 cooley.com