The polymorphism of the PLG was studied in serum samples from healthy unrelated individuals of Korean population using the improved method consisting of IEF and immunoblotting. The five phenotypes, type 1(90.76%), 2-1(5.50%), 2(0.20%), 1-A(0.79%) and 1-B(2.75%) were found Rare phenotypes, PLG A and PLG B, were not discovered. The frequencies for the alleles are PLG*1=0.9529, PLG*2=0.0294, PLG*A=0.0039, and PLG*B=0.0138. Monogolian populations show higher PLG*1 frequency than those Caucasian and Negro populations, and at present, Korean population is the highest.