We determined the seroprevalence of hepatitis B in Nahavand in a sample of 1824 subjects > 5 years in 2002. Face-to-face interviews were conducted and blood samples taken. The association between risk factor and hepatitis B was assessed using logistic regression. The prevalence of HBsAg positive cases was 2.3%, and HBcAb and HBsAb were isolated in 7.8% and 11.6% of the participants respectively; 11.9% were positive for both HBcAb and HBsAb. History of surgery and imprisonment were the major risk factors for infection with odds ratios of 2.14 (95% CI: 1.22–3.05) and 3.57 (95% CI: 1.68–5.4) respectively.