The aim of this study was to determine the joint effects of CSN3 and LGB genotypes on parameters of production, quality and coagulation of milk in Czech Fleckvieh cows. Fifteen genotype combinations were detected, with ABAB (21.0 %) and AAAB (18.3 %) occurring as the most frequent. The observed genes significantly affected the contents of milk protein as well as solid non-fat in milk, casein number and curd quality. BBAA was found to be the genotype with the highest positive impact on most of the milk characteristics evaluated. Whereas ABBB, BBBB, BBAB and ABAB had a positive influence on milk quality and milk coagulation properties, genotypes containing CSN3 allele E had a negative effect. Results presented in this study are applicable in the selection of Czech Fleckvieh cattle.