Almost all respondents in both cities knew that AIDS is spread by shared needles, but few realized that AIDS can also be spread by homosexual and heterosexual relations. The media was cited by most respondents as the source of their information about AIDS; although more respondents in New York had learned about AIDS from governmental information or from a counselor. The high level of fear among respondents was consistent with the behavior modifications that they reported. While a wide range of preventive activities was noted, practicing safe sex was more often cited in New York. Because this sample consisted of intravenous drug users in treatment, the findings suggest that fear of AIDS may prompt drug users to enter treatment programs. 2 tables and 7 references