Data were obtained from the Community Epidemiology Work Group, the Drug Enforcement Administration, the Drug Abuse Warning Network (DAWN), the Treatment Episode Data Set, the National Household Survey on Drug Abuse (NHSDA), and the Monitoring the Future project of the National Institute on Drug Abuse. NHSDA data indicated that approximately 428,000 persons had used heroin at least once during the past year; 61 percent of past year heroin users were male, 25 percent were between 12 and 17 years of age, 53 percent were white, 48 percent lived in a large metropolitan area, 27 percent had less than a high school education, and 22 percent worked full-time. Among heroin-related deaths reported by medical examiners to DAWN in 1994, 83 percent involved males and 68 percent involved persons 35 years of age and older. Among persons admitted to publicly funded treatment programs for heroin abuse in 1994, 66 percent were male, 55 percent were 35 years of age and older, and 43 percent were white. Methadone programs designed to treat heroin addicts reported 112,000 clients in treatment in 1993; about 23 percent were in New York and another 17 percent were in California. Data demonstrated a rise in heroin use among young persons who smoked or sniffed heroin instead of injecting it. In particular, data from the Monitoring the Future project showed a rise in heroin use among 8th, 10th, and 12th graders. Between 1991 and 1995, the annual number of heroin-related emergency department visits increased from 36,000 to 76,000. There were an estimated 122,000 new heroin users in 1994. It was determined that heroin purity and fear of AIDS may be responsible for the shift from injecting to smoking or sniffing heroin. 16 references and 10 tables