The encouraging results of a pilot experiment had suggested that larger-scale methadone maintenance programs might provide a treatment alternative for a significant number of heroin addicts. On balance today, the projections of 10 yr ago were overly optimistic. The great majority of heroin addicts in cities remain on the streets and the programs have lost their ability to attract them to treatment. An unexpectedly favorable finding in the 10 yr experience with methadone was the absence of major toxicity or allergy. Patients have taken large doses (100 mg/day or more) for several years and remained in good health. Normal neuromotor coordination and intellectual acuity, correlated with their ability to do well in school and hold responsible jobs. The most serious pharmacological defect of methadone was the need for its daily administration. The introduction of a longer-acting derivative, methadyl acetate is now being tested in some clinics, although its 2 or 3 day period of action is not nearly long enough to solve the basic problem of attracting addicts to treatment while maintaining strict control of the medication. There is no provision for the rehabilitated person who needs continued medical treatment. The stringent controls imposed by the Food and Drug Administration [USA] have had the effect of creating a governmental monopoly of treatment facilities. Methadone maintenance is available in only a few overcrowded, governmentally licensed clinics. Law enforcement agencies, both police and regulatory, should reexamine the assumptions that underlie their activities. The statistics from New York City [USA] where methadone programs have operated for 10 yr are used to illustrate trends. Here, about 1/4 of the daily users of narcotics are treated, which saves the community at least $1,000,000/day in prevented crime and illicit drug traffic. In a follow-up study on .apprx. 6000 persons who entered treatment in 1972 and subsequently left treatment, 204 were located and classified; of these, 138 have relapsed to use of illicit opiates, intermittently or continuously. Of them, 36 had returned to a maintenance program for further treatment. Only 22 persons of the 204 could be classified by a lenient standard as being in satisfactory status. Methadone maintenance as part of a supportive program facilitates social rehabilitation, but clearly does not prevent opiate abuse after it is discontinued, nor does social rehabilitation guarantee freedom from relapse. Problems encountered in relation to addicts'' attitudes and political aspects are discussed.