One-hundred-and-fifty injecting drug users were interviewed about their sexual behaviour, and types of sexual relationships and partners in the past year. The aims of the study were to assess the extent of changes in sexual HIV-risk behaviour patterns and to understand aspects of respondents' sexual relationships, as well as HIV/AIDS knowledge. We found few changes in sexual behaviour. The ability to assess personal HIV-risk varied widely across the sample and intoxication during sexual activity was widely reported. Whilst the use of condoms was infrequent, young respondents were more likely to use condoms, but have more sexual partners, hence a likely erosion of any net gain may have occurred. Over half of the respondents were in sexually monogamous relationships and there were no significant gender-related differences in respect of regular partners' IDU-status. Estimated rates of seroprevalence in Perth are low and with the effectiveness of deterrence dependent on visible negative outcomes, it may be difficult to ensure safer-sex messages are heeded. These concerns are raised and facilitation of safer-sex among IDUs are discussed. Further areas of research are recommended.