Methadone maintenance has been evaluated since its development in 1964 as a medical response to the post-World War II heroin epidemic in New York City. The findings of major early studies have been consistent. Methadone maintenance reduces and/or eliminates the use of heroin, reduces the death rates and criminality associated with heroin use, and allows patients to improve their health and social productivity. In addition, enrollment in methadone maintenance has the potential toreduce the transmission of infectious diseases associated with heroin injection, such as hepatitis and HIV. The principal effects of methadone maintenance are to relieve narcotic craving, suppress the abstinence syndrome, and block the euphoric effects associated with heroin. A majority of patients require 80-120 mg/d of methadone, or more, to achieve these effects and require treatment for an indefinite period of time, since methadone maintenance is a corrective but not a curative treatment for heroin addiction. Lower doses may not be as effective or provide the blockade effect. Methadone maintenance has been found to be medically safe and nonsedating. It is also indicated for pregnant women addicted to heroin. Reviews issued by the Institute of Medicine and the National Institutes of Health have defined narcotic addiction as a chronic medical disorder and have claimed that methadone maintenance coupled with social services is the most effective treatment for this condition. These agencies recommend reducing governmental regulation to facilitate patients access to treatment. In addition, they recommend that the number of programs be expanded, and that new models of treatment be implemented,if the nationwide problem of addiction is to be brought under control. The National Institutes of Health also recommend that methadone maintenance be available to persons under legal supervision, such as probationers, parolees and the incarcerated. However, stigma and bias directed at the programs and the patients have hindered expansion and the effective delivery of services. Professional community leadership is necessary to educate the general public if these impediments are to be overcome.