England now has more than 200 needle-exchange programs designed to prevent HIV transmission. However, this and other AIDS prevention strategies are unavailable to inmates, in whom the HIV infection rates are unknown. Community studies have revealed declining levels of syringe-sharing among drug users who take part in needle-exchange programs. Other studies have indicated that at least one-fourth of imprisoned intravenous drug users reported that they had injected drug in prison. To limit the spread of HIV in correctional facilities, the current disincentives that inmate drug abusers face should be removed so that they will identify themselves and seek drug treatment. Systematic data collection efforts about drug injectors and their risk behaviors is also needed, both in and out of prisons. Author photograph and 17 references