The aim of this study was to determine the antibody response to influenza vaccination in children with nephrotic syndrome (NS). Nineteen children with NS and 10 healthy controls were vaccinated with a 19992000 influenza vaccine. A dose of 0.25 ml was used for those under 6 years and 0.5 ml for those over 6 years. All children were given two doses with a month between each dose. Antibody titers were measured before vaccination and 1 month after vaccination in both groups and 6 months after vaccination in 8 patients with NS. The proportion of subjects in the nephrotic group with protective antibody titers before immunization (10.5%) was significantly lower than the proportion at 1 (78.9%) and 6 months (87.5%) post vaccination. The mean concentration of specific IgG antibodies to influenza A in the NS group increased 6-fold at 1 month and approximately 14-fold at 6 months. These results suggest that pediatric patients with NS have an adequate antibody response to influenza A vaccine. Protective antibody titers to influenza A were maintained at 6 months after immunization in 8 patients with NS.