Korea is now classified as an area of intermediate endemicity for hepatitis B virus (HBV), due to the implementation of universal HBV vaccination and national preventive programs for HBV infection. A national program of HBV vaccination was launched in Korea in 1988 for school-going children and was listed on a vaccination guideline in 1991. In 1995, universal vaccination for newborn infants was started for the prevention of perinatal HBV transmission. The prevalence of HBsAg among Korean middle school students has shown marked decreased from 3.2% in the late 1990s to 0.44% in 2007. HBsAg positivity in preschool children was 0.9% in 1995, decreased to 0.2% in 2007 by national prevention program of hepatitis B vertical transmission, launched in 2002. Vaccine failure rate of HBV immunoprophylaxis is 4.2% by this program. The infected children should be monitored per 6-12 months interval. Lamivudine and interferon are approved therapies for children with chronic hepatitis B in immune-clearance phase in Korea.