The relationships between genotypes of milk protein genes (alphaS1 casein, beta casein, kappa casein and beta lactoglobulin) and parameters of milk technological quality, milk coagulation, milk production and breeding values for milk production were analysed in this work. The most significant effect of CSN3 gene was proved on contents of protein and casein, and mainly on curd quality, curd firmness, and coagulation time. Also the effect on breeding values for protein content and protein yield was found. Significant effect of LGB gene was found on content of whey proteins and casein proteins. The effect of CSN2 was proved on casein content and breeding values for milk, protein, and fat production. CSN1S1 gene affected the breeding value for milk production.