This study was carried out to clarify the genetic constitution of biochemical polymorphic loci controlling blood protein and enzymes as genetic rnarkers in Korean native chicken(KNG) population Blood samples were collected from 230 KNG representing three colored-lines(reddish-, yellowish- and blackish- brown) raised in Daejeon branch of National Livestock Research Institute. Eight blood marker loci, transferrin(Tf), post-albumin(Pas), albumin(Alb), amylase-1(Arny-1), es-terase-1(Es-1), alkaline phosphatase(Akp), catalase(Cat) and hemoglobin(Hh) were analyzed by using starch, agarose and polyacrylamide gel electrophoresis. Based on the gene frequencies of polymorphic marker loci, the genetic characteristics of KNF population was analyzed, and the genetic ariability within population was quantified. The genetic relationships between KNC and other native fowls or improved breeds were also estimated. The gene frequencies of Tf, Pas and AIb loci were similar to those of improved breeds among the seven biochemical polymorphic loci, while gene frequencies of Cat and Es-i loci were remarkably different between KNC and improved breeds. Gene frequencies of amy-i and Akp loci were similar to those of New Hampshire and Rhode Island Red and White Leghorn, respectively. However in comparison with other improved breeds, great differences were observed in gene frequencies of these loci The average heterozygosity, effective number of alleles and homogeneity index for the seven loci combined were estimated to be .334, 1.639 and .373, respectively. Based on the dendrogram and genetic distances, the KNC was genetically closer to New Hampshire, Plymouth Rock and Rhode Island Red breeds than to the White Leghorn breed.