The article presents a genome-wide association study for tobiano spotting coat color in Korean Jeju x Thoroughbred horse population. The study is undertaken through the verification of the coat color patterns of 142 crossbred horses and the extraction of genomic DNA through the use of a DNeasy 96 blood DNA extraction kit. The results of the study show that horse chromosone ECA3 inversion locus variant is causative or is completely linked with tobiano coat color.