OBJECTIVE Nonresponse to hepatitis B vaccine in the perinatal period occasionally occurs. This report documents the results of reimmunization of nonresponders to perinatal immunization. METHODS From a cohort of 1154 infants immunized with plasma-based vaccine in the perinatal period and followed up for more than 8 years, 45 nonresponders were identified. These children were reimmunized at 4 years of age. Each child received a yeast-derived recombinant hepatitis B vaccine on a 0-, 1-, and 5-month schedule, 33 children with 10-micrograms and 12 with 5-micrograms doses. Blood was sampled 1 month after the third vaccination and thereafter at 1, 2, and 4 years. METHODS The follow-up clinic where the cohort of children was regularly seen. METHODS Forty-five 4-year-old children who had no antibody to hepatitis B despite perinatal immunization. METHODS Antibody levels to hepatitis B surface antigen. RESULTS Seroconversion with titers higher than 10 mIU/mL occurred in all children. More than 70% still had titers higher than 10 mIU/mL 4 years after vaccination. CONCLUSIONS Nonresponders to perinatal hepatitis B vaccination respond well to subsequent vaccination.