Transferrin(Tf) and group-specific component(Gc) variants were studied in Korean population by the polyacrylamide gel isoelectric focusing and immunofixation. Among the 1,085 unrelated samples, 4 heterozygous phenotypes of transferrin variants, C1B1, C2B1, C2B1-2, and C2-variant, were detected. The numbers of each variant were 5, 1, 1, and 1, respectively. Gene frequencies of the variants were 0.0028, 0.00046, and 0.00046 for B1, B1-2, and unknown variant, respectively. On the other hand, among the 1,227 unrelated samples, 6 kinds of variants of group-specific component, 1F-1A8, 2-1A8, 2-1A12, 2-1A9, 1S-1A9, and 1A5-1A8, were detected, and the gene frequencies were 0.00041(1A12), 0.00122(1A9), 0.0024(1A8), and 0.00041(1A5).