BACKGROUND Juveniles in custody are affected by sexually transmitted infections due to risky behaviors. Therefore, they have a disproportionate burden of hepatitis B virus (HBV) and human immunodeficiency virus (HIV). In this study, the prevalence and associated characteristics of hepatitis B and HIV infections were assessed in young prisoners. METHODS In this cross-sectional study, prevalence of HBV and HIV infections was assessed among young prisoners during 2008-2009. A checklist consisting of demographic, social, and risk factors was filled out and blood was drawn for their tests. Sera were analyzed for hepatitis B surface antigen (HBs Ag), hepatitis B surface antibody (HBs Ab), hepatitis B core antibody (HBc Ab) and HIV Ab, and Western blot test was performed on antibody-positive HIV. RESULTS A total number of 160 young prisoners (147 boys and 13 girls) were evaluated. The mean age of the subjects was 16.59 ± 1.24 year. HBs Ag, HBc Ab, HBs Ab, and HIV Ab were detected in 1 (0.63%), 1 (0.63%), 52 (32.5%), and 1 (0.63%), respectively. CONCLUSIONS With respect to national vaccination program against HBV infection, the juvenile prisoners had low prevalence of HBs Ab.