As a part of researches for identifying the genetic composition of Korean population, authors have studied the phenotypes and allele frequencies of Coagulation Factor XIIIA (FXIIIA) and Coagulation Factor XIIIB (FXIIIB) in the plasma of Korean using agarose gel isoelectric focusing followed by immunoblotting. In the study of 329 individuals of Seoul, Kangreung and Kwangju, the identified phenotypes of FXIIIA were FXIIIA 1 (75.99%), FXIIIA 2-1 (23.40%) and FXIIIA 2 (0.61%). The allele frequencies of FXIIIA^*1 and FXIIIA^*2 were 0.8769 and 0.1231, respectively. And the phenotypes of FXIIIB were FXIIIB 1 (8.6%), FXIIIB 3 (46.9%), FXIIIB 3-1 (41.0%) and FXIIIB 3-2 (3.4%). Allele frequencies of FXIIIB^*1, FXIIIB^*2 and FXIIIB^*3 were calculated to be 0.2914, 0.0172 and 0.6914, respectively. The frequencies of FXIIIA^*1 and FXIIIA^*3 in Whites was slightly higher in Blacks, but that in Korean people were much higher than that in Blacks and Whites.