aim of this study was to determine allelic and genotypic frequency of two SNPs in ERα gene and evaluate the associations between ERα genetic variants and milk production traits in Holstein cattle. Analysis of the molecular mechanisms involved in the regulation of reproduction in connection with milk production and followed genotyping of the individuals with optimal genetic potential may facilitate the animal selection in dairy cattle farms. Genomic DNA was obtained in total from 150 hair root samples of Holstein cows. Two polymorphic sites in 5´region on ERα gene (BTA6) were analysed. Genotyping of animals was carried out by PCR-RFLP method using SnaBI and BglI restriction endonucleases. After restriction analyses was detected in population the presence of two ERα/SnaBI (GG, AG), and three ERα/BglI genotypes (GG, AG, AA). The highest proportion was found for individuals with ERα/SnaBI GG (85%) and ERα/BglI AA (83%) genotypes. The missing of ERα/SnaBI AA genotype was reflected to the higher distribution of G allele (0.92± 0.02). For the ERα/BglI polymorphism was observed the higher frequency of A allele (0.91±0.02). The differences between observed and expected genotype frequencies caused the deviations from HWE in locus ERα/SnaBI. The statistical analyses of ERα genotypes effect on milk production traits was performed with linear models (GLM procedure). Based on the selected effect we were able to estimate the variability of analyzed traits on 80%. The ERα/SnaBI and ERα/BglI genotypes affected the variability of milk, protein and fat yield only non-significant (P > 0.05).