Since IV drug users are the second largest risk group for AIDS in the United States and are the primary source of transmission to heterosexual partners and children, control of the AIDS epidemic will require control within the IV drug-use group. Because of the social organization of IV drug users in the United States, there are greater constraints on prevention efforts with this group than with others. Current research shows, however, that IV drug users in New York City and elsewhere do modify their behavior in response to the threat of AIDS. Prevention efforts begun within the IV drug-use subculture need to be reinforced by programs undertaken by public health and drug abuse treatment and prevention personnel. Although research has not yet identified the most effective AIDS prevention tactics among IV drug users, tentative generalizations are that behavior can be modified though media information campaigns that provide specific information. Face-to-face communication should also be used. 38 references.