Abstract:A survey was undertaken in Sydney in 1989 to identify factors associated with behaviour involving risk for human immunodeficiency virus infection. Self‐report data on needle‐sharing and sexual practices were collected from 91 heroin users entering a residential, drug‐free detoxification unit. Data were analysed using polytomous and ordinal logistic regressions. Heroin‐dependent subjects who also had a current alcohol problem were significantly more likely than others to report high risk needle‐sharing behaviour. Subjects with more than one sexual partner in the last three months were significantly more likely to use condoms while those with a current benzodiazepine problem were significantly less likely to use condoms. Qualitative data suggest that high risk needle‐sharing behaviour most often occurred around the time of relapse to injecting drug use and among homeless drug users occupying derelict buildings in inner