This exploratory study, undertaken to inform new prevention strategies, assessed the willingness of community members and drug users to advise drug‐using relatives about various HIV prevention strategies. Participants were 421 adult community members and 67 adults in treatment for drug abuse in San Francisco, with approximately equal numbers of Hispanics and non‐Hispanic Whites in each group. Participants answered questions about whether they would advise an imagined relative who injects drugs about various strategies to prevent transmission of HIV, such as cleaning needles with bleach and condom use. Multivariate analyses revealed generally high willingness to provide AIDS prevention advice, with few differences between community members and those in drug treatment. The families of drug users are underutilized potential resources in AIDS education and prevention efforts.