In Congo, it is estimated that between 9 to 11% of the general population present hepatitis B surface antigen (HBsAg). Little data are available on the seroprevalence of markers and risk factors for this virus in blood donors in Brazzaville. This study aimed to determine the prevalence markers and factors associated with HBV infection in blood donors. Six hundred and forty eight healthy blood donors samples collected from October 2013 to June 2014 were tested by enzyme-linked immunosorbent assay for HBsAg, HBeAg, anti-HBe, anti-HBs and anti-HBc. Demographic data of these donors was also studied. Out of 648 patients included, overall prevalence estimates were 6,6%(95%CI:4.8-8.8) for HBsAg, 1,1%(95%CI:0.3-2) for HBeAg, 8.2%(95%CI:6.2-10.5) for anti-HBe, 13.6%(95%CI:11-16.4) for anti-HBs and 62.7%(95%CI:59-66.2) for anti-HBc. HBV infection was significant associated with Categories of blood donors (adjusted OR=1.70; 95%CI:1.08-2.67), age (adjusted OR=17.61; 95%CI:9.67-32.02), occupation (adjusted OR=2.25; 95%CI:1.53-3.31), sexual risk (adjusted OR=6.14; 95%CI:2.42-15.61) and families with a history HBV (adjusted OR=5.87; 95%CI:2.68-12.85). The seroprevalence rates found in this study were higher than those in other countries, suggesting high rates of HBV infection and a persistent risk of transmission of HBV in blood donors in Brazzaville.