Two-dimensional gel electrophoresis followed by silver staining has been employed to study genetic variation of 59 red cell lysates in Korean (Cheju) population. Forty-nine polypeptides selected without respect to variability were considered suitable for scoring. Genetic variations were encounted in 6 of these polypeptides. Ninety-eight of total 2,891 polypeptides exhibited the combination of a normal and a variant polypeptide. The index of heterozygosity estimated in this study was 3.3±0.23%. the heterozygosity in Korean population was compared with those in other populations.