A small task force of State and local police began the crackdown in Lynn in September 1983. The task force almost completely eradicated the market. In addition, the demand for treatment increased 87 percent, and property and personal crimes dropped substantially. However, crime and heroin dealing did not increase in surrounding communities. In contrast, a similar program begun in Lawrence in September 1984 suppressed some of the most flagrant heroin dealing and increased demand for treatment, but did not eliminate the heroin market or influence the rates of violent and property crime. Differences in the tactics and geographic spread of the efforts probably affected the results. A further effort focused on drug abstinence for drug-involved offenders in Lawrence was unsuccessful due to implementation difficulties. Tables, figures, and appended analyses of street crime and heroin treatment.