The crucial principles for effective treatment include an accurate assessment of clients' needs, matching of clients to treatment services, adequate duration of treatment, continuity of care, behavioral change through leverage, treatment integrity, and linkages with other services through models such as Treatment Alternatives to Street Crime and case management. Specific treatment approaches that have reasonably strong research support include cognitive and behavioral treatments focusing on cognitive skills, training in relapse prevention, and contingency contracting; pharmacotherapy for opiate dependence; and behavioral and neurobehavioral models for treating cocaine dependence. Recommended policies include acceptance of the role of treatment for drug abuse, recognition that community supervision alone is insufficient for offenders with serious drug problems, realistic treatment goals, creative and flexible policies, and cooperation among agencies to promote efficiency. 70 references