The total cost each year of the criminal activities of heroin users between 1983 and 1985 in England and Wales, together with the cost of law enforcement and criminal justice processing as well as the contribution to international efforts to reduce production of raw materials, is estimated at between 110 and 198 million pounds. Currently, there is no readily available information on the costs to the National Health Service or to other drug services of treating heroin users. Evidence from studies that have examined the effects of medical treatment suggest that more generous prescribing of heroin or methadone during treatment will not result in the elimination of the acquisitive offenses committed by heroin users. It is likely, however, that it would reduce the extent to which many steal to raise funds for illicit supplies of drugs. 20 references.