The aim of the research was to evaluate the morphological and physiological characteristics of the cow's udder quarters (n=1360) and to estimate the relationship with the productivity and health of the udder; to identify the main risk factors influencing sub clinical mastitis in dairy cows. Microbiological test of mastitis showed that 86.4% of cows and 60.2% of udder quarters (35.6% of the front and 50.8% of the rear quarters) milk samples were positive. The distance between the front teats of the cow's udder (on the average it was 2.51 times higher than the distance between the rear teats, P<0.001) influenced the productivity of cows and sub clinical mastitis rate (5.94% less positive samples from udder quarter and 12.8% higher milk yield in cows with the difference of up to 5 cm was found, P<0.05). The milk yield of the front quarters (X¯=41.80±0.46%) and the difference of productivity between udder quarters (X¯=14.09±0.51%.) were related with sub clinical mastitis (12.21% more positive samples from udder quarters when milk yield of cow's front quarters was up to 45%, P<0.05 and 3.1% less positive samples when the difference of milk yield between quarters was up to 11%). The substantial difference of milking time (X¯=26.17±0.70%) in udder quarters was estimated. We have found 15.4% less positive samples from udder quarters in milk of cows whose difference of the milking time in the quarters was up to 15% (P<0.05).