Bovine K-Casein genotypes were identified in 131 Austrian Fleckvieh-, 105 Austrian Braunvieh- and 23 Austrian Grauviehbulls by using a combined PCR-RFLP technique. In Fleckvieh, gene frequencies for K-Cn(A) and K-Cn(B) were 0,73 resp. 0,27, in Braunvieh 0.36 resp. 0,64 and in Grauvieh 0,54 resp. 0,46. The BB-genotype frequency was in Fleckvieh 5,3 %, in Braunvieh 42,9 % and in Grauvieh 17,4 %. The populations were in genetic equilibrium.