Exhibit 5.1

Michael Tenta

+1 650 843 5636

mtenta@cooley.com

March 1, 2017

Aduro Biotech, Inc.

740 Heinz Avenue

Berkeley, CA 94110

Ladies and Gentlemen:

We have acted as counsel to Aduro Biotech, Inc., a Delaware corporation (the “Company”), in connection with the filing of a Registration Statement on Form S-8 (the “Registration Statement”) with the Securities and Exchange Commission covering the offering of up to an aggregate of 3,395,911 shares of the Company’s Common Stock, par value $0.0001 per share, including (a) 2,716,729 shares of Common Stock (the “2015 EIP Shares”) issuable pursuant to the Company’s 2015 Equity Incentive Plan (the “2015 EIP”), and (b) 679,182 shares of Common Stock (the “ESPP Shares,” and together with the 2015 EIP Shares, the “Shares”) issuable pursuant to the Company’s 2015 Employee Stock Purchase Plan (the “2015 ESPP,” and together with the 2015 EIP, the “Plans”).

In connection with this opinion, we have examined and relied upon (a) the Registration Statement and related prospectuses, (b) the Plans, (c) the Company’s Amended and Restated Certificate of Incorporation and Amended and Restated Bylaws, each as currently in effect, and (d) such other documents, records, 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 and authenticity of all documents submitted to us as originals, and the conformity to originals of all documents submitted to us as copies thereof. As to certain factual matters, we have relied upon a certificate of an officer of the Company and have not sought to independently verify such matters.

Our opinion is expressed only with respect to the General Corporation Law of the State of Delaware. We express no opinion as to whether the laws of any particular jurisdiction are applicable to the subject matter hereof. We are not rendering any opinion as to compliance with any federal or state antifraud law, rule or regulation relating to securities, or to the sale or issuance thereof.

On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when sold and issued in accordance with the Plans and the Registration Statement and related prospectuses, will be validly issued, fully paid, and nonassessable (except as to Shares issued pursuant to certain deferred payment arrangements, which will be fully paid and nonassessable when such deferred payments are made in full).

Cooley LLP 3175 Hanover Street Palo Alto, CA 94304-1130

t: (650) 843-5000 f: (650) 849-7400 cooley.com

March 1, 2017

Page Two

We consent to the filing of this opinion as an exhibit to the Registration Statement.

Sincerely,

Cooley LLP

By:	/s/ Michael E. Tenta
	Michael E. Tenta

Cooley LLP 3175 Hanover Street Palo Alto, CA 94304-1130

t: (650) 843-5000 f: (650) 849-7400 cooley.com