Relationships between milk β-carotene concentrations and the cytological quality of cow’s milk. The objective of the study was to describe the relationship between milk β-carotene concentration and the cytological quality of milk of high yielding cows. The experiment was carried out at the research dairy farm of the Warsaw University of Life Sciences (WULS). From a herd of 320 Polish Holstein Friesian cows maintained in a free–stall dairy shed 58 cows were selected taking into consideration the stage of lactation (15±14 days). Cows were fed a total mixed ration (TMR) diet provided ad libitum. Four groups of cows taking into consideration concentration of β–carotene in milk has been created: 1) <150 mg L-1; 2) 151-250 mg L-1; 3) 251-450 mg L-1; 4) > 450 mg L-1. The content of β–carotene and SCC amounted at the herd level: 192 tys ml-1 and 0.312 mgL -1 respectively. The β–carotene content ranged from 0.150 to 0.451 mgL-1. The highest content of β–carotene, 0.451 mgL-1, was found in milk of cows with the lowest level of somatic cells count (SCC). The lowest level, 0.150 mgL-1, was found in milk of cows with the highest level of SCC. Milk SCC varies significantly with the concentration of β-carotene in cow’s milk. Researchers should consider monitoring for this variable as potential cofounder when exploring the relationship between mastitis, intramammary infection and nutritional management.