A cross sectional study was conducted in Addis Ababa from October 2011 to May 2012 to determine prevalence of bovine mastitis and discuss its public health implications. A total of 444 systematically selected lactating cows of different cattle breed from thirty seven (37) dairy farms were investigated. The herds were visited and the farmers interviewed about the management, housing, feed and feeding, and milking conditions. California Mastitis Test (CMT) was applied on milk samples collected from 1776 individual quarters. The overall prevalence of bovine mastitis was 68.0% (302/444) of which sub-clinical mastitis accounted for 46.8% (208/444) while 21.2% (94/444) were found to be clinical forms. There was significant difference (P<0.05) in the prevalence of mastitis among the different breeds, age groups, parity and lactation stage. Relatively higher number of farmers interviewed (20.8%) replied that they do not withhold milk from cows treated for mastitis and continue to avail it to the public without interruption. As it is economically damaging, the need to establish diagnostic facility to enable early detection for screening large number of samples was emphasized. Further work on identification of the causative agents and conducting public awareness creation about major zoonotic diseases were also recommended.