The goal of the scientific research was to establish the differences between fatty acid composition in conventional milk and milk produced according to the organic production principles. In the period between February and December in 2009, the samples of raw conventional milk were analysed using the gas chromographic method to determine the fatty acid composition. Conventional milk was produced at the farm with around 700 dairy cows of Holstein breed. The farm is located in the Vrbas municipality. Organic milk was sampled from ten smaller farms with 12 dairy cows of Simmental breed on the average, located in clean environment of Fru ka Gora slopes (Grabovo settlement). The results of fatty acids content were processed with the statistical package (Statistica 9), and a significant differences were determined with t-test and shown as statistically significant (p<0.05) and highly statistically significant (p<0.01). Conventional milk had a higher content of the monounsaturated fatty acids in comparison with organic milk (p<0.05). In terms of polyunsaturated and omega-3 fatty acids content, organic milk was richer in comparison with conventional milk and these differences were statistically highly significant (p<0.01). The differences in the content of saturated and omega-6 fatty acids were not shown as statistically significant (p>0.05). The ratio of omega-6 to omega-3 in organic milk was lower than in conventional milk, which is crucial to human health. The differences in fatty acid composition between conventional and organic milk may result from different feeding practices, because the organic breeding of cows is primarily based on grazing, while the conventional breeding implies mixed ration.