This proposal is in response to RFA-DA-04-008, Group Treatment for Individuals in Drug Abuse or Alcoholism Treatment. Of particular interest to the agencies are group therapies for Conduct Disordered adolescents, reducing the spread of infectious disease, and mechanisms of action. This proposal targets these areas of interest. This study will focus on treating substance abusing incarcerated teens using 2 individually administered Motivational Interviewing (MI) sessions followed by 10 group sessions of Cognitive Behavior Therapy (CBT). MI is conceptualized as preparation for group CBT. The control group receives individualized Relaxation Training (RT) followed by group Treatment as Usual (TU). Currently, there is little research regarding effective group treatments for incarcerated teens and this study will address this gap in our knowledge base. In this proposed randomized trial, a one-way design (MI/CBT vs. RT/TU) will be used to determine whether MI/CBT enhances group therapy participation and reduces substance use and related problems (such as crime, injuries and unprotected sex) post discharge in substance-involved juvenile delinquents. RT/TU is based on the 12-step model and includes psycho-educational components. Participants are followed during incarceration and for 12 months post incarceration. Primary outcome variables include alcohol and marijuana use, as well as related behaviors (illegal activity, sex or injuries while drunk or high). It is hypothesized that in comparison to teens in RT/TU, youth receiving MI/CBT will participate more in therapy (according to teen, facility staff, and counselor ratings) and will show lower levels of substance use and related problems after discharge. Frequently, substance abuse treatment is unavailable to youths in the juvenile justice system, and when treatment is available, it may be provided in group format using untested therapies. A motivation/skills-based intervention (delivered in group format) may prove efficacious in enhancing motivation and in reducing substance abuse and related problems. This study extends previous research by rigorously evaluating group treatment for incarcerated teens. We will examine processes contributing to the efficacy of group MI/CBT, and the influence of race and ethnicity on treatment effects. The development of effective interventions for substance using juvenile offenders has the potential to reduce substance abuse and crime in this population.