The investigations included total 515 milk samples which were collected from 309 cows of the main dairy cows’ breeds used in Poland, i.e. Polish Holstein-Friesian Black-White variety (<i>n</i>=150), Polish Holstein-Friesian Red-White variety (<i>n</i>=77) and Simmental (<i>n</i>=82). There was determined a content of fat, protein and dry matter, a share of fat globules ranging in size, i.e. <6 μm, 6-10 μm and >10 μm as well as a fatty acids profile. It was shown that milk gained from Holstein-Friesian cows was characterized with a higher level of fat dispersion (over 70 % globules of <6 μm diameter and a higher percentage of short- and long-chain fatty acids (ca. 19 %). The Simmentalers’ milk had a higher protein : fat ratio (about 0.89), a lower fat dispersion level (8.21 % globules of >10 μm diameter) and the highest share of the polyunsaturated fatty acids (3.28 %). Cows nutrition included pasture forage during summer (independently on the breed) had a significant influence (<i>P</i>≤0.01) on increased polyunsaturated fatty acids percentage (mean by 0.51 %). The winter milk, however, showed a significantly higher content of dry matter, fat and protein as well as a higher share of big-sized milk globules.