Inflammation of mammary glands of cows or mastitis is one of the most common infectious diseases of dairy cattle, which causes significant economic losses to livestock and affects the quality of dairy products. This work was aimed at monitoring the presence of hemolytic streptococci and Staphylococcus aureus as the main causative agents of mastitis in the high producing dairy cows and identifying relationship between the milk somatic cell count (SCC) and the infection with S. aureus.