Milk composition depends mainly on feeding and farming methods of animals; those methods are different in the organic and conventional systems. Organic milk contains more beneficial proteins than conventional milk, i.e. such proteins as α-lactoalbumin, β-lactoglobulin, and lactoferrin. The milk from cows grazed on fresh grasses or fed fresh forage, both of them rich in multifarious plant species, has a considerably higher ratio of unsaturated (PUFA) to saturated (SFA) fatty acids and a better ratio of PUFA Ω-6 to Ω-3. Compared to the conventional milk, the organic milk has a higher content of PUFA, CLA, cis-9, trans-11 CLA, trans-vaccenic acid (TVA), and α-linolenic acid (LNA). The profile of fatty acids in the milk from cows fed grass silage is more beneficial than that in the milk from cows fed maize silage. Red clover, linseed, rape, and fish oil have a beneficial effect on the composition of fatty acids in the cow’s milk. During the pasture grazing period, the milk from cows bred in organic farms had a higher content of fat-soluble vitamins (A, D, E) than the milk from animals that were not grazed on pastures. The concentration of mineral elements in the milk from cows raised in organic farms depends on the concentrations thereof in soil and in green forage.