This project involves two studies focusing on the engagement and treatment of adolescents diagnosed with substance use disorders. Study 1 will evaluate a promising parent-based engagement intervention, Community Reinforcement Training, designed to facilitate the entry of resistant drug-abusing adolescents in treatment. The approach will be compared with an Engagement As Usual intervention condition. Study 2 involves a controlled clinical trial evaluating the efficacy of an HIV/AIDS prevention intervention embedded in family-based drug abuse treatment for reducing HIV/AIDS risk behaviors and substance use. Adolescents who are successfully engaged in treatment through Study 1 will be randomly assigned to receive either family therapy alone or family therapy with the integrated HIV/AIDS prevention intervention. Both studies are being conducted in Portland, Oregon.