Power of Attorney for Theodora Ross

This filing concerns a Power of Attorney granted by Theodora Ross, Chief Development Officer at IDEAYA Biosciences, Inc., to specific company officers. The appointed officers, including the CEO, Chief Legal Officer, CFO, and Chief Accounting Officer, are authorized to execute and file SEC forms (3, 4, 5, and ID) on behalf of Ms. Ross. This authorization covers all necessary actions to complete and file these forms accurately and timely, including making any necessary amendments. The Power of Attorney also grants the attorneys-in-fact broad discretion in determining the content and terms of the filed documents. Ms. Ross acknowledges that the attorneys-in-fact and the company are not assuming her reporting responsibilities under Section 16 of the Securities Exchange Act of 1934. She agrees to indemnify them against any losses or liabilities arising from inaccurate or incomplete information she provides. This Power of Attorney revokes any prior authorizations and remains in effect until Ms. Ross is no longer required to file such forms, or until it is revoked or superseded by a new document.