The purpose of this study is to establish the psychometric properties of a noncommercial, publicly available, modular screening and assessment system for adolescents in substance abuse treatment. Data were collected in 2011-2012 from 1,189 adolescents admitted to eight residential treatment programs in urban and rural locations in the United States. Results from three sets of analyses documented the instruments to be reliable. Females reported more problems than males, and younger adolescents reported more problems than older youth. Implications and limitations are discussed, and suggestions for future research are provided.