The vast majority of substitute prescribing to opiate addicts in England and Wales is of oral methadone. The prescription of diamorphine, dipipanone and cocaine to addicts is allowed subject to the 1971 Misuse of Drugs Act. Prescription of these drugs has aroused international interest and controversy in the United Kingdom although research is scanty. This report is a description of the current attitudes about, and practice of, prescribing diamorphine, dipipanone and cocaine by medical practitioners in the addiction field in England and Wales. A questionnaire was devised and sent to drug services in England and Wales which provided a prescribing service. Among respondents who reported that they currently hold a licence for heroin, dipipanone or cocaine, the number of patients treated by each doctor varied widely; from a handful of patients to 100 heroin patients. Dosage currently used ranged from a minimum of 10 mg to a maximum of 1000 mg daily for heroin. Doses of dipipanone were lower. More respondents thought that heroin and dipipanone were clinically justified in some situations than thought that they should never be prescribed, while the opinions were reversed in the case of cocaine.