This project evaluates the efficacy of brief interventions for individuals seeking treatment for substance use disorders who also have gambling problems. In total, 220 problem gambling substance abusers will be randomized to one of three conditions: (a) a control condition consisting of 10 minutes of psychoeducation about gambling, (b) 10 minutes of brief advice about problem gambling and how to reduce it, or (c) four session of motivational and cognitive-behavioral therapy. Gambling, substance use and psychosocial problems will be assessed using standardized instruments at pre-treatment, month 2, 5, 8, 12, 16, 20 and 24-month follow-up evaluations.