The hepatitis C virus is highly infectious and furthermore is highly prevalent among injecting drug users. Due to these two factors, the most subtle of injecting practices and the smallest of breaches of infection control are a risk for the transmission of hepatitis C. Social and injecting drug use research over the past decade has demonstrated that the spread of hepatitis C among IDUs is unlikely to be reduced without substantial behaviour change. The generic messages about sharing, designed to address HIV/AIDS among IDU are inadequate when it comes to hepatitis C. Brief interventions, successful in reducing HIV/AIDS risk among gay men and injecting drug users, represent a potentially effective strategy for achieving such change. The aim of the current project was to evaluate the efficacy of a brief hepatitis C prevention intervention using a randomised controlled trial method. Forty-five current injecting drug users were recruited from Perth, Western Australia and underwent pre- and post-test assessment injecting assessment using a Risk Assessment Checklist (RAC). The RAC is a five domain instrument addressing environmental, contextual, social factors as well as injecting behaviours. Participants were randomly allocated to control or intervention group and were followed-up at 4 weeks. The efficacy of the intervention was assessed by comparing the summed RAC scores. The mean summed pre-test score for the control and intervention groups were 7.1 (median 7; mode 7; range 13) and 6.5 (median 7; mode 8; range 8) respectively. When these scores were compared no significant difference was detected (F=0.435; sig. =0.513). The mean post-test scores for the control and intervention groups were 6.6 (median 6.7; mode 9; range 12) and 5.0 (median 5; mode 5; range 10) respectively. The mean score for the intervention group was lower than that found for the control group at the 0.10 level (F = 3.792; sig. 0.058). Furthermore, the summed score for the specific domain covering injecting behaviours for the intervention group score was significantly lower than the control group scores at the 0.05 level (F=6.18; sig. = 0.017). While the study group for this pilot study was small and the follow-up time limited to one month the findings indicate that the brief intervention as delivered was effective in reducing the risk of hepatitis C transmission from injecting drug use among the intervention group. While these findings are encouraging further research with a larger study group and a follow-up period of between 3 and 6 months will be required before this intervention can used on a wider scale.