Studies of HIV seroprevalence have shown rate up to 50 percent among intravenous drug users in specific cities. Successful prevention efforts must recognize and address the social, psychology, and physiology of intravenous drug use and must recognize that drug users have some forms of social organization. Drug users tend to mistrust conventional society and have a precarious balance of trust and mistrust among one another. They also vary in their commitment to the values of the drug subculture. They rely on oral communications and share drug paraphernalia extensively for both social and economic reasons. However, contrary to common stereotypes, most intravenous drug users can be expected to change their behavior to avoid exposure to the AIDS virus. Specific target groups for prevention efforts should include drug users in treatment, persons at risk for initiation into intravenous drug use, current drug users who wish to enter treatment, drug users who do not wish to enter treatment, and the heterosexual partners and children of intravenous drug users. Prevention efforts should also recognize and respond to ethnic and racial differences among drug users. 38 references.