We aimed to determine the seroprevalence of poliovirus antibody in Korea by using the cell culture neutralization method recommended by the WHO. A total of 500 sera collected from children at eight primary schools in Kyunggi province were used for this study. We found that 82·2% of children were positive for all three types of poliovirus and antibody-positive rates for types I, II and III were 94·4, 96·6 and 86·8% respectively, indicating that seropositive rates for types I and II were considerably higher than for type III (P<0·0001). This result implies that the type III component of the oral polio vaccine should be evaluated further. Although a greater number of children, including young infants, need to be tested for seroprevalence, this study still provides us with valuable information on the effectiveness of vaccination against polioviruses in Korea.