This study allows us to draw up for the first time a detailed portrait of the situation of HCV infection among IDU in Quebec and Ottawa. [...] To study Quebec IDU’s intentions to get tested for hepatitis C. 1.2 SPECIFIC OBJECTIVES Epidemiological component 1. To determine the prevalence rate of hepatitis C and HIV-HCV coinfection among IDU; 2. To determine the incidence rate of hepatitis C among IDU at their time of entry into the SurvUDI network; 3. To identify the factors associated with the presence of infection among IDU (prevalence) [...] The goal of the hepatitis C epidemiological component is to measure the incidence of this infection. [...] By crossing the results of HCV screening tests on samples collected during the first interview selected with those of the HIV screening tests conducted on these samples within the ordinary course of the study, we came up with a profile of HIV-HCV co-infection among the participants. [...] In this analysis, each follow-up period delimited by two consecutive questionnaires was attributed to the recruitment district for the questionnaire at the end of the period in question.