This study was performed to offer the basic and applicable data for improvement of Korean cattle and dairy cattle, according to finding the genetic construction obtained from analysis of genetic polymorphisms of ${\beta}$-lactoglobulin and ${\kappa}$-casein loci related Korean cattle and Holstein cows using PCR-RFLP. Genomic DNA used in this study was prepared from the blood of 253 individuals of Korean cattle in Korean Native Cattle Improvement Center, NLCF, and the blood of 113 individuals of Holstein cows in National Livestock Research Institute. The results obtained are summarized as follows : 1. This study confirmed amplified products of 530bp and 262bp fragments obtained from the amplification of ${\beta}$-lactoglobulin and ${\kappa}$-casein loci in Korean cattle and Holstein breed by PCR. 2. The ${\beta}$-lactoglobulin AA genotype showed 153bp and 109bp fragments, and ${\beta}$-lactoglobulin AB genotype showed 153bp, 109bp, 79bp and 74bp fragments, and BB genotype showed 109bp, 79bp and 74bp fragments in amplified products of ${\beta}$-lactoglobulin loci with the restricted enzyme digestion of Hae III. 3. The ${\kappa}$-casein AA genotype showed a 530bp fragment, and ${\kappa}$-casein AB genotype showed 530bp, 344bp and 186bp fragments, and BB genotype showed 344bp and 186bp fragments in amplified products of ${\kappa}$-casein loci with the restricted enzyme digestion of Taq I. 4. On ${\beta}$-lactoglobulin genotypes and gene frequencies, Korean cattle were 6.72%, 26.09% and 67.19% for AA, AB and BB genotypes, and ${\beta}$-lactoglobulin A and B alleles were 0.197 and 0.803, and Holstein were 35.40%, 56.64% and 7.96% for AA, AB and BB genotypes, and ${\beta}$-lactoglobulin A and B alleles were 0.637 and 0.363, respectively. 5. On ${\kappa}$-casein genotypes and gene frequencies, Korean cattle were 46.25%, 39.13% and 14.62% for AA, AB and BB genotypes, and ${\kappa}$-casein A and B alleles were 0.658 and 0.342, and Holstein were 60.18% and 38.94% and 0.88% for AA, AB and BB genotypes, and ${\kappa}$-casein A and B alleles were 0.796 and 0.204, respectively. 6. As a consequence, the gene frequency was 0.197 and 0.803 for ${\beta}$-lactoglobulin A and B alleles, and 0.658 and 0.342 for ${\kappa}$-casein A and B alleles in Korea cattle, but was 0.637 and 0.363 for ${\beta}$-lactoglobulin A and B alleles, and 0.796 and 0.204 for ${\kappa}$-casein A and B alleles in Holstein, respectively.