A simplified method of simultaneous genotyping of bovine growth hormone (bGH) and prolactin (bPRL) has been developed. The method is based on simultaneous amplification of fragments of the two genes by multiplex PCR, and subsequent digestion of the products by two restriction enzymes (Alu I and Rsa I). Digestion with Alu I distinguished growth hormone L and V alleles and did not cut within the prolactin fragment, while digestion with Rsa I allowed the differentiation between the A and B alleles of bovine prolactin. All combinations of the known alleles could be detected by electrophoretic separation on the same agarose gel. Frequency of the allele L of the bovine growth hormone gene in Slovak Pied, Slovak Pinzgauer and Holstein was 0.55, 0.55 and 0.72, respectively. Frequency of the allele A of the bovine prolactin gene in the same breeds was 0.87, 0.68 and 0.95, respectively.