Welcome to what I hope is a comprehensive list of startups using machine learning to research and develop drugs. I began this list in November 2017. At that time, it had 37 startups. I have updated it continuously since then. My focus is companies that (1) are new (I'm leaving this purposely vague, but typically founded post-2012); (2) use AI as a key differentiator; (3) develop products or drugs (I exclude service businesses); and (4) have demonstrated traction, such as via at least seed funding.