Aisyah DN, et al. - Considering the substantially increase risk of hepatitis C virus (HCV) infection with injecting drugs which is common in the homeless and prisoners, the prevalence of HCV was estimated in these populations. Recruiting 491 individuals who were homeless (40.7%), 205 drug users (17%) and 511 prisoners (42.3%), they recognized active HCV infection in 8% of patients and past HCV infection in 3% of patients. In this study, one quarter (51/205) of people recruited in drug treatment services, 13% (65/491) of people from homeless residential sites and 4% (20/511) prisoners were anti-HCV positive. Seventy-seven of the 136 of HCV infected participants identified displayed a history of all three risk factors (homelessness, imprisonment and drug use), 27.3% (95% CI: 20.1%-35.6%) displayed 2 overlapping risk factors, and 15.4% displayed one risk factor. For identifying hepatitis C-infected individuals, drug treatment services, prisons and homelessness services seems to provide good opportunities.