The present studies were carried out in 1999–2004 in 43 herds belonging to private farmersThe present studies were carried out in 1999–2004 in 43 herds belonging to private farmersspecializing in milk production in the Lublin Voivodeship (district). Taking into consideration thedata collected from 22.736 trial cow milkings, the properties such as: 24-hour milk efficiency, fatand protein content in the milk, SCC in milk and quality distribution of the milk samples accordingto milk classification (in %) in full lactations in relation to cows genotype and origin wereanalysed. The animals were divided into black and white (bw), Holstein-Frisian (hf) and hf x bwcrossbreds with a contribution of hf race genes of <50, 50–75 i 75.1–99.9% and cows from Polandand imported from Holland, Germany and France. The data collected were analysed using theleast squares method, while the percentage share of milk in individual classes of milk quality wasanalysed by means of a chi2 test. It was found that crossing of bw cows with hf race as well asimport of animals from other countries are efficient methods of increasing milk efficiency as wellas fat and especially protein content in milk. The highest milk efficiency and the most favourablefat and protein content was observed in the purebred hf animals and cows imported from Holland. It was observed that in the cow herds analysed, the genotype and the country of origin differentiated the number of somatic cells in milk and depending on their amount, the percentage share of milk in individual milk quality classes. The highest number of somatic cells in milk and the lowest percentage share of milk samples in the extra class was observed in the case of purebred hf cows and cows imported from Holland.