This study was carried out to determine the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) markers among adolescents aged between 10 and 16 years old, who are elementary school students in the city of Chapecó, Santa Catarina State, Brazil. The study involved a cross-sectional survey that included 418 volunteers, from March to July, 2008. Serology comprised HBsAg, anti-HBc, anti-HBs and anti-HCV. Tests were performed using automated Microparticle Enzyme Immunosorbant Assay (Abbott, AxSYM System, Wiesbaden, Germany). The prevalence of HBsAg was found to be 0.2% (95%CI: 0.0-1.3), and the prevalence of anti-HBc was found to be 1.4% (95%CI: 0.5-3.1). Regarding anti-HBs, 48.6% had titers greater than 10UI/L. None of the volunteers presented reactive results for anti-HCV. This study showed a low prevalence of HBV and HCV markers of infection and a great number of volunteers immunized against HBV. Finally this study shows the importance of proper health campaigns and policies in reducing those prevalences.