An initial efficacy test of an innovative behavioral outpatient treatment model for adolescents with problematic use of marijuana enrolled 69 adolescents, aged 14-18, and randomly assigned them to one of two treatment conditions. Both conditions received individualized Motivational Enhancement and Cognitive Behavioral Therapy (MET/CBT) and a twice-weekly drug-testing program. The experimental contingency management condition involved a clinic-delivered, abstinence-based incentive program, and weekly behavioral parent training sessions that included a parent-delivered, abstinence-based, substance monitoring contract. The comparison condition included an attendance-based incentive program, and weekly psychoeducational parent sessions. Follow-up assessments were performed at 3, 6, and 9 months post-treatment. The experimental condition showed greater marijuana abstinence during treatment, e.g., 7.6 vs. 5.1 continuous weeks and 50% vs. 18% achieved > or = 10 weeks of abstinence. Improvements were found in parenting and youth psychopathology across treatment conditions, and improvements in negative parenting uniquely predicted post-treatment abstinence. The outcomes observed in the experimental condition are consistent with adult substance-dependence treatment literature, and suggest that integrating CM abstinence-based approaches with other empirically based outpatient interventions provides an alternative and efficacious treatment model for adolescent substance abuse/dependence. Replication and continued development of more potent interventions remain needed to further advance the development of effective substance abuse treatments for adolescents.