The study was carried out with 16 Red-and-White cows in a 4×4 Latin square design. In 4 periods of 21 days each, diets containing grass silage, maize silage, brewers grains and concentrate mixture containing calcium salts of fatty acids (CSFA) were given to cows at a rate of 0.28 kg/kg of milk obtained. Cows received CSFA at 0, 1.84, 3.54 or 5.40% of ration dry matter, which corresponded to 0, 316, 614 or 940 g of CSFA per day. The average milk yield of the cows was 27.2±0.55 kg/day and did not differ significantly between the groups. Feeding cows the CSFA supplement significantly increased the fat content of milk and daily fat production, while significantly reducing the protein content in milk and daily protein production, but significantly decreased the N-total, N-protein and N-casein contents of milk. The levels of stearic (C_18:0), oleic (C_18:0) and α-linolenic (C_18:3) acids significantly increased, the level of myristic (C_14:0) and palmitic acids (C_16:0) in milk significantly decreased. The differences in the levels of unsaturated fatty acids (UFA) in milk were significant (23.91, 27.31, 31.92 and 36.21 g/100 g of fatty acids in the respective groups). The level of monounsaturated (MUFA) and polyunsaturated (PUFA) acids in milk significantly increased. The level of n-3 PUFA in milk increased from 1.20 to 2.25 g/100 g of fatty acids, which corresponded to an increase in synthesis from 9.6 to 20.1 g acids/day. CSFA significantly reduced the n-6 PUFA-to-n-3 PUFA ratio from 3.5 to 2.2 (P<0.05). CSFA from linseed oil significantly increased the level of hypocholesterolemic acids (DFA) in milk (31.83, 36.31, 43.33 and 48.71 g/100 g of fatty acids, respectively). The plasma concentration of total cholesterol and high-density lipoproteins decreased significantly under the influence of increasing CSFA doses.