Abstract The evidence for cannabis’s treatment efficacy across different conditions varies widely, and comprehensive data on the conditions for which people use cannabis are lacking. We analyzed state registry data to provide nationwide estimates characterizing the qualifying conditions for which patients are licensed to use cannabis medically. We also compared the prevalence of medical cannabis qualifying conditions to recent evidence from the National Academies of Sciences, Engineering, and Medicine report on cannabis’s efficacy in treating each condition. Twenty states and the District of Columbia had available registry data on patient numbers, and fifteen states had data on patient-reported qualifying conditions. Chronic pain is currently...