The sample consisted of 253 subjects (72 percent male). Subjects were interviewed at least three times, at admission to the program and then every 6 months. The reference period for all three measurement points was 6 months. Data on property offenses was obtained from self-reported delinquency, victimization data, and police statistics. During the last 6 months before admission to the program and during the first 6 months under treatment, the overall drop in contacts recorded by the police was 76 percent. For offenses that are particularly relevant to public safety, burglary and robbery for example, the decrease was consistent with the trends in self-report data. For drug trafficking, the incidence rate dropped 61 percent; use of drugs other than heroin decreased by approximately the same proportion. Although illegal heroin use, as recorded by the police, declined 83 percent, the general drop in illegal drug use supports the conclusions of the medical evaluation, which found that, contrary to expectation, heroin prescription tended to reduce the use of other drugs that are not under prescription. The analysis shows that the recorded drops in drug-related crimes and behavior was not due to the reduced probability of the police recording offenses committed by participants after their admission to the heroin prescription program. 3 tables and 5 references