In this study, we have tried to determine the age-specific seroprevalence of hepatitis B virus (HBV) infection and to make some conclusions about the mode of transmission and vaccination strategy which should be chosen in Turkey. Eight hundred and one patients between the ages of six months and 60 years of age were included in this study. According to the HBV serologic markers, (HBsAg, Anti-HBc and Anti-HBs), HBsAg positivity and HBV exposure rates were 6.5% and 32.8%, respectively. HBsAg positivity was 6.6% under one year of age. The highest rate of HBsAg positivity was in the 6-10 year age-group (p < 0.05). The prevalence of total hepatitis B virus seropositivity increased with age (p < 0.05). The HBV exposure rate was higher in males than in females (p < 0.05). It was concluded that HBV infection is an important infection in Turkey and is acquired very early in life. A mass hepatitis B vaccination strategy should be thus chosen in Turkey.