Genetic variations of human plasma α₁B-glycoprotein (α₁B) was observed using two-dimensional agarose gel electrophoresis (pH 5.4) - horizontal polyacrylamide gel electrophoresis (PAGE), pH 9.0 or one-dimensional PAGE (pH 9.0) followed Western blotting with specific antiserum to α₁B as alternative method. Among the 612 unrelated individuals living in Seoul (205 individuals), Kangreung (200 individuals) and Cheju (207 individuals) of Korea, four different α₁B phenotypes (1-1, 1-2, 2-2 and 1-3) were identified. Also, to conform whether each types are the same protein, peptide mapping of these proteins was performed. The frequencies of A1B^*1, A1B^*2 and A1B^*3 alleles were calculated to be 0.8897, 0.1021 and 0.0082, respectively. Mongoloid populations showed a higher degree (polymorphism information content) of α₁B variations than Caucasian populations that have been studied except Swedish Lapps population.