Evaluated the effectiveness of juvenile drug court for 161 juvenile offenders meeting diagnostic criteria for substance abuse or dependence and determined whether the integration of evidence-based practices enhanced the outcomes of juvenile drug court. Over a 1-year period, a four-condition randomized design evaluated outcomes for family court with usual community services, drug court with usual community services, drug court with multisystemic therapy, and drug court with multisystemic therapy enhanced with contingency management for adolescent substance use, criminal behavior, symptomatology, and days in out-of-home placement. In general, findings supported the view that drug court was more effective than family court services in decreasing rates of adolescent substance use and criminal behavior. Possibly due to the greatly increased surveillance of youths in drug court, however, these relative reductions in antisocial behavior did not translate to corresponding decreases in rearrest or incarceration. In addition, findings supported the view that the use of evidence-based treatments within the drug court context improved youth substance-related outcomes. Clinical and policy implications of these findings are discussed.