Hepatitis C is an infectious disease which is primarily blood borne and which is present in epidemic proportions amongst illicit drug injectors. The major risk factors for transmission amongst injectors are related to injecting behaviours, first and foremost the sharing of needle and syringes and other injecting equipment. However, the minutia of the injection process, when two or more people are injecting together, has not been investigated. Therefore the first aim of this study was to examine in detail, examined using a recorded observation technique, the process of injection to identify behaviours through which it might be possible to transmit hepatitis C. The second aim was to investigate the effect of a range of social, environmental and personal factors which impinge on the injecting behaviours of novice injectors. The observation of the injection process revealed a range of practices which increased the risk of transmission of hepatitis C. Furthermore, a range of social factors related to demographic characteristics, knowledge and networks characteristics were also found to be associated with increased risk. The findings were interpreted in relation to current hepatitis C prevention initiatives and recommendations made with regard to the future of hepatitis C prevention, in particular its content and delivery.