The data came from personal interviews. On average, participants first used heroin when they were just under 19 years old. Most became regular users within 2 years of first using the drug. Two-thirds of those who had used heroin for more than 10 years had experienced a heroin overdose. The majority of those who had used heroin for more than 5 years reported some kind of drug-related health problem. More than half reported that crime provided the main source of income for purchasing heroin. More than 70 percent had been arrested for a drug-related offense. Twenty-five percent had a drug-related court case pending at the time of the interview. More than 60 percent of those who were in methadone treatment rated avoiding more trouble with police or courts as an important or very important reason for entering treatment. Most participants also stated that they usually used heroin in a place where they felt safe from the police. Findings suggested that the ready availability of access to methadone maintenance treatment would make street-level drug law enforcement more effective in reducing drug-related property crime. In addition, police need to work more closely with health authorities in minimizing the risk their activities pose to public health. Moreover, treatment for heroin dependence needs to be redesigned to increase retention rates. Research recommendations, tables, figures, notes, appended instrument and tables, and 40 references