We reviewed 39 national government- and nongovernment-sponsored data sets related to substance addiction policy. These data sets describe patients with substance use disorders (SUDs), treatment providers and the services they offer, and/or expenditures on treatment. Findings indicate the availability of reliable data on the prevalence of SUD and the characteristics of specialty treatment facilities, but meager data on financing and services. Gaps in information might be filled through agency collaboration to redesign, coordinate, and augment existing substance abuse and general health surveys. Despite noted gaps, these data sets represent an unusually rich set of resources for health services and policy research. (Contains 4 tables and 4 notes.)