Holsteins are known for the world's highest-milk producing dairy cattle. The purpose of this study was to identify genetic regions strongly associated with milk traits (milk production, fat and protein) using Korean Holstein data. This study was performed using SNP chip data (Illumina BovineSNP50 Beadchip) of 911 Korean Holstein individuals. We inferred each gEBVs based on BLUP and ridge regression using BLUPF90 and R. And then we performed genome-wide association study and identified genetic regions related to milk traits. We identified 9, 6 and 17 significant genetic regions related to milk production, fat and protein, respectively. These genes are newly reported on the genetic association with milk traits of Holstein. It complements a recent Holstein GWAS that identified other SNPs and genes as the most significant variants. These results will help to expand the knowledge of the polygenic nature of milk production in Holsteins.