tBackground: Data regarding Hepatitis B and C viruses (HBV and HCV) prevalence among mil-itary personnel in Brazil are lacking, but the work-related risk of exposure can be high. Theobjective of this study was to estimate the seroprevalence of HBV and HCV and the riskfactors associated to HBV exposure among Brazilian military personnel.Methods: A cross-sectional study was conducted and included 433 male military adults aged18–25 years old working in Rio de Janeiro during October 2013. All individuals completed aquestionnaire to assess their risk of exposure and provided a blood sample to HBV and HCVtesting.Results: None of the participants presented HBsAg or anti-HBc IgM, 18 (4.1%) were positive fortotal anti-HBc, 247 (57.0%) were positive for anti-HBs, and 3 (0.7%) were anti-HCV reactive.The majority of military personnel with past HBV infection (anti-HBc reactive) and HBVimmunity (anti-HBs reactive) had a history of prior dental procedures (88.9% and 77.3%),consumption of alcohol at least once a week (50% and 55.9%), and practiced oral sex (61.1%and 58.3%, respectively). In addition, anti-HBc positivity was common among individualswith a history of surgery (44.4%) and practice of anal sex (50%). At univariate analysis, agegroup was associated to anti-HBc and anti-HBs positivity.Conclusions: Low rates of HBV and HCV infection were observed among Brazilian militarypersonnel in comparison to the general Brazilian population. HBV immunity rates wererelatively low indicating the need for vaccination campaigns in this group.