This chapter focuses on evidence-based treatment for illicit drug use disorders. The treatments addressed are motivational interviewing, treatments based on cognitive behavioral principals such as cue exposure, coping skills training and contingency management, and 12-step orientated treatment programs. Contingency management approaches are probably the most effective interventions for drug dependent patients. There is consistent evidence that treatments based on coping skills training and relapse prevention are more effective than inactive control conditions, but effect sizes are slightly smaller than those of contingency management approaches. There are a few studies that show that the combination of community reinforcement and coping skills training/relapse prevention is slightly more effective than stand-alone community reinforcement. The results with respect to the value of motivational interviewing in drug-using patients are mixed. In less motivated patients, motivational interviewing led to a better adherence and increased motivation in some, but not in all, studies and generally did not decrease drug use. Given the fact that very few studies have specifically focused on illicit drugs other than cocaine, conclusions with respect to the 12-step approaches are inconclusive.