Objective: Contingency management (CM) is an evidence-based treatment, but few clinicians deliver this intervention in community-based settings. Method: Twenty-three clinicians from 3 methadone maintenance clinics received training in CM. Following a didactics seminar and a training and supervision period in which clinicians delivered CM to pilot patients, a randomized trial evaluated the efficacy of CM when delivered entirely by clinicians. Sixteen clinicians treated 130 patients randomized to CM or standard care. In both conditions, urine and breath samples were collected twice weekly for 12 weeks. In the CM condition, patients earned the opportunity to win prizes ranging in value from $1 to $100 for submitting samples negative for cocaine and alcohol. Primary treatment outcomes were retention, longest continuous period of abstinence, and proportion of negative samples submitted. Results: Patients randomized to CM remained in the study longer (9.5 plus or minus 3.6 vs. 6.7 plus or minus 5.0 weeks), achieved greater durations of abstinence (4.7 plus or minus 4.7 vs. 1.7 plus or minus 2.7 weeks), and submitted a higher proportion of negative samples (57.7% plus or minus 40.0% vs. 29.4% plus or minus 33.3%) than those assigned to standard care. Conclusions: These data indicate that, with appropriate training, community-based clinicians can effectively administer CM. This study suggests that resources ought to be directed toward training and supervising community-based providers in delivering CM, as patient outcomes can be significantly improved by integrating CM in methadone clinics. (Contains 4 tables and 1 figure.)