The aim of this study was to investigate the relationship between the β-casein CSN2 genotypes (A1A1, A1A2, A2A2) and the biochemical characters and fatty acid composition of milk. Twenty-four milk samples from Jersey cows from the same herd from a farm in Hungary were studied. Animals were grouped according to β-casein genotype variants A1A1, A1A2 and A2A2. A1A1 milk had a significantly higher content of monounsaturated fatty acids (