The treatment of drug offenders during their period of custody in correctional institutions is opportune, cost-effective and likely to be successful with the use of research-tested technologies for human change. These technologies may be sufficiently potent to treat violent offenders. Also, studies from diverse areas have demonstrated substantial reductions in recidivism after treatment. The article discusses the relationship between drugs and crime; the history of treating drug-using offenders, including national efforts in the past decade; and efforts underway in the Federal Correctional Options Program and the Federal Bureau of Prisons. In addition, the paper describes efforts in a number of States, and highlights important successful treatment results from California, Florida, Texas, New York, Oregon, and Delaware. Tables, references, notes