The study comprised a research into the effect of milk production season on the content of fatty acids in milk fat. The study material consisted of milk fat isolated from a 30 % non-pasteurized sweet cream using an extraction method. The samples for analyses were taken 12 times per month during one year. The profile of fatty acids in milk fat was determined using a gas chromatography. The research performed shows that the milk production season significantly impacts both the profile of fatty acids in milk fat and the ratios of unsaturated (UFA, in it MUFA and PUFA) to saturated (SFA) fatty acids, as well as the content of hypocholesterolemic (DFA) and hypercholesterolemic acids (OFA).