This study was carried out to examine the genetic constitution of serum proteins and enzymes in Holstein Friesian cattle population. The genetic variants of post-transferrin-2(pTf-2), transferrin(Tf), post-albumin(pAlb), ceruloplasmin(Cp) and amylase-I(Am-I) were analyzed by using PAGE(polyacrylamide gel electrophoresis) and STAGE(starch gel electrophoresis). In serum proteins, the pTf-2 locus were observed to be controlled by codominant alleles designated F and S, and the distribution of genotypes were 76.34, 14.50 and 9.10% for pTf-2 FF, FS and SS types, respectively. The gene frequencies of the pTf-2 F and S allele were 0.836 and 0.164. The Tf locus were found to be controlled by four alleles, Tf A, D1, D2 and E at a single locus, and the distribution of genotypes were 6.11, 32.06, 19.08, 1.53, 10.69, 18.32, 9.92 and 2.29% for Tf AA, AD1, AD2, AE, D1D1, D1D2, D2D2 and D2E type, respectively. The gene frequencies of the Tf A, D1, D2 and E wee 0.321, 0.359, 0.298 and 0.019. The pAlb locus were identified to be genetically controlled by two alleles, pAlb F and S allele, and the distribution of genotypes were 32.06, 29.77 and 38.17% for pAlb FF, FS and SS types, respectively. The gene frequencies of the pAlb F and S allele were 0.461 and 0.531. The Alb locus were observed to be controlled by Alb A and B allele, and the gene frequencies of these were 0.996 and 0.004. In serum enzymes, the Cp locus were found to be controlled by F and S allele, and the distribution of genotypes were 46.57, 27.48 and 25.95% for Cp FF, FS and SS types, respectively. The gene frequencies of F and S allele were 0.603 and 0.394. The Am-I locus were observed to be controlled by Am-I B and C allele, and the distribution of genotypes were 39.69, 21.73 and 38.93% for Am-I BB, BC and CC types, the gene frequencies of Am-I B and C were 0.503 and 0.497, respectively.