Among adolescents, those involved in the juvenile justice system are most likely to use and abuse drugs. Nearly 1 out of every 5 adolescents detained could be described as a heavy user, someone who takes drugs at least 30 times within a 30-day period. While nearly all are abusing alcohol and marijuana, some take cocaine, heroin, and psychedelics. The treatment model, the Portable Drug Treatment for the Juvenile Justice System, combines elements of the most promising cognitive-behavioral and family-centered therapies – approaches shown to be effective with young drug abusers. This approach will be tested in a three-year demonstration program serving approximately 130 juveniles each year. The goal is to demonstrate significant reductions in substance abuse; prevent delinquent and criminal behavior; and improve the physical, mental, social, and educational well being of the adolescents served. Research suggests that appropriate drug treatment provided without interruption should have a positive impact on the most serious drug abusers in the juvenile justice system. A demonstration project was launched in March 2001 in New York City. New York City has lagged far behind other parts of the country in recognizing and addressing the problem of substance abuse in the juvenile justice system. The goal of the demonstration is to test a clinical treatment model that, if proven effective, will inspire reforms not only locally, but also nationally. Clients and their families were served right away. The implementation evaluation of the program has also begun. Full capacity will be achieved by June 2001.