Studies were reviewed with respect to three different target groups for preventing AIDS among intravenous (IV) drug users by (a) providing drug abuse treatment for those who want to stop injecting drugs, (b) providing "safer" injection for those who are likely to continue injecting, and (c) preventing drug injection among those who are at high risk for beginning to inject. The studies reviewed were limited to those that include "hard" data: validated self-reports, seroprevalence outcomes, or self-reports of behavior that is the opposed to any of the demand characteristics generated by the research setting. For two groups of current IV drug users--those entering drug treatment and those continuing to inject--these hard data studies show rapidly induced AIDS risk reduction but suggest a need for large-scale change maintained over long time periods. In terms of preventing initial injection, alternative forms of intense drug use have emerged but have not supplanted drug injection, and basic knowledge of AIDS does not appear to deter initial drug injection.