The Y-linked tetranucleotide microsatellite locus DYS19(Y-27H39) has been examined in samples from a total of 505 unrelated Korean males to study the population structure and genetic affinities between Koreans and different ethnic groups. All five common alleles at the DYS19 locus were identified in this study. The C allele is the most frequent (220/505), followed by the D(134/505), B(86/505), E(44/505) and A(21/505) allele and the DYS19, allelic diversity was estimated as 0.703 in the Korean population. This predominance of the C allele is similar to the previous reports from other survey of Asian, Australian and African population. On the basis of results for the Allele frequency of the DYS19, Japanese show a close genetic relationship with Koreans rather than with other ethnic groups. This result could reflect an evidence for the gene flow and the large infusion of genes with the Yayoi migration from Korea to Japan