Twenty-six youth received six months of treatment (mean of 15 sessions) after random assignment to either a supportive counseling program or to a newly designed behavioral treatment. The behavioral program included several procedures to restucture family and peer relations and to control urges. Drug use was measured by urinalysis, supplemented by family report and self-report. The results showed that during the last month, 9% of youth receiving supportive counseling were abstinent vs. 73% of youth receiving the new behavioral treatment. A greater reduction of drug use was also apparent when measured in terms of urinalysis data alone, days per month of drug use, or overall number of months of abstinence. Improved functioning of youths in the behavioral program was evidenced by significantly greater school/work attendance, improved youth- and partent-relationship satisfaction ratings, improved conduct ratings, decreased depression, and decreased frequency of alcohol use as compared to youth in the supportive counseling program.