Genetic polymorphisms of milk proteins, αs₁-casein (αs₁-CN) β-casein (β-CN), k-casein (k- CN) and β-lactoglobulin (β- LG), in milk samples from 175 Korean native cattle were analyzed by using starch gel elec-trophoresis. Their genotype and gene frequencies were estimated and their genetic relationships with other breeds were compared by using genetic distance and dendogram. The results obtained were summarized as fallows ; 1. Three genetic variants each were identified at αs₁-CN (BB, BC, and CC), k-CN (AA. AB and BB) and β-LG (AA, BB and BB) and nine genetic variants (A¹A¹, A²A², A¹A², A¹A⁴, A²A⁴, BA¹, BA², BA⁴ and BB) existed at β-CN. 2. Genotype distributions of the milk protein loci were as fallows: αs₁-CN BB 76% BC 21.1%, CC 2.9% β-CN A²A²40%, A¹A²38.3%, BA²11.4%, A¹A¹3.4%,, A²A⁴2.9%, BA¹1.7%, A¹A⁴1.1%, BA⁴0.6%, BB 0.6%, k-CN AB 52%, AA 37.1%, BB 10.9%, β-LG BB 76%, AB 23.4%, AA 0.6%. The distributions of genotypes in each milk protein locus were corresponded closely to expectations of Hardy-Weinberg equilibrium. 3. Gene frequencies of the milk protein loci were: αs₁-CN^B 0.866, αs₁-CN^C 0.134; β-CN^A2 0.660, β-CN^A1 0.235, β-CN^B 0.080, β-CN^A4 0.025: k-CN^A 0.631. k-CN^B 0.369; β-LG^A 0.877, β-LG^B 0.123. 4. From the analysis of` the genetic distance values and the dendogram drawn from the genetic distances matrix, the results indicate that there was a close relationship between Korean native cattle and Japanese native cattle, especially Japanese Brown. Consequently, it is supposed that Japanese native cattle originated from Korean native cattle.