This study aimed to determine the effect of parity, age and season on somatic cell count of dairy cows. For this purpose, 310 milk samples were collected from 9 different dairy farms located around Tekirdao. The milk samples were examined in terms of California Mastitis Test (CMT), Somatic Cell Count (SCC) and Total Viable Bacteria Counts (T VBC). According to CMT examination, 256 milk samples were evaluated as CMT + and the average age of the cows was 3.84 years, 46 samples were evaluated as CMT ++, the average age of the cows was 5.61 years and 8 samples were evaluated as CMT +++ while their average age of the cows was 6 years. In conclusion, it is seen that when the age and the parity of dairy cows increase, CMT and SCC increase thus mastitic milk incidence may be rise up. This affects the quality of milk thus the dairy industries should be more sensitive about this issue and they should take extra cautions for mastitis control in order to obtain healthy milk and milk products. © Medwell Journals, 2013.