Abstract: This paper focuses on the prevalence and profile of opiate use, primarily heroin, in the United States and Europe. Methods include representative population surveys, which understate prevalence, and targeted approaches, which reflect more problematic use. In the United States and Europe, the lifetime prevalence of opiate use reported in surveys remained stable over the 1980s (around 1%), though young adults report higher rates. Estimates for the early 1990s suggest that the prevalence of problematic heroin use in the United States was double the average for western Europe. However, in a few European countries prevalence is now approaching that of the United States. Rates in major cities are considerably higher, especially in the north-east and south-west of the United States. Higher prevalence is often, although not always, associated with socio-economic deprivation. An important trend away from injecting is observed, notably in some European countries. Heroin availability and use, as well as serious heroin-related consequences, are increasing again in many European countries after an apparent pause in the mid-1980s. They are also increasing in parts of the United States. Heroin remains a public health priority, especially among vulnerable populations, including young people in central and eastern Europe.