PURPOSE: The purpose of this study was to investigate the prevalence rate of HBsAg and the epidemiological characteristics of hepatitis B virus (HBV) infection from 1998 to 2005. National Health and Nutrition Examination Survey (NHANES) data of 1998, 2001 and 2005 were analyzed. METHOD: Study population was consisted of 24,093, aged 10 year or over who performed NHANES self reported surveys and blood tests. Statistical analysis was performed by age, sex, and the year of survey. Also the prevalence of HBsAg was compared by self reported family history of liver disease. RESULTS: The prevalence rate of HBsAg was reduced from 4.5% in 1998 to 3.7% in 2005. Also age-specific prevalence rate of HBsAg was significantly decreased in persons born after introduction of the hepatitis B virus vaccination. HBsAg seropositivity was slightly higher in male than in female. Among the people with the family history of liver diseases, the risk of HBsAg seropositive was much higher than those without. Study subjects with mother's liver disease history showed much higher HBsAg serepositive rate. Although after the implementation of hepatitis B virus vaccination program prevalence of HBsAg decreased, but persons with history of liver disease showed still higher rate Of HBsAg seropositive rate. CONCLUSION: Although the introduction of the HBV vaccination program has resulted in a decline of HBV infection, the family history of liver diseases was still an important factor for transmission of HBV in Korea. In addition to the mother-to-child transmission prevention program from 2002, it might be advisable to introduce a screening program for persons with family history of liver diseases for further reduction of HBV infection.