Mastitis is an infection which often commits animals assigned for milk production. It has been the major price raise factor for dairy cattle breeding. Economical losses impact on professional fees, drugs, death and early discard of the animal as well as dairy companies as a result of the downturn in product end-quality, decrease of industrial procedure regarding dairy product manufacturing and changes in mastitic milk composition. Considering the relevance of such disease, this study verifies mastitis prevalence and etiology in the region of Nova Tebas, PR by analyzing 336 lactating dairy cows from 17 farms, totalizing 1324 mammary quarters through CMT, SCS and bacterial isolation. Negative (1120 mammary quarters - 84.6%) and positive (204 mammary quarters - 15.4%) results for CMT were verified. Among the positive quarters, 155 (75.9%) presented bacterial growth - higher prevalence of coagulase-negative Staphylococcus - SCN 51 (32.9%), Streptococcus sp. 49 (31.6%); Corynebacterium bovis 19 (12.3%), coagulase-positive Staphylococcus - SCP 19 (12.3%), Gram-negative bacilli (BGN) 12 (7.7%), Corynebacterium sp. 3 (1.9%), and Candida sp. 2 (1.2%). Results show that mastitis in the region of Nova Tebas is compatible to those found all over Brazil together with the highest prevalent etiological agents. Such profile of animals with mastitis can be noticed from screening tests used for mastitis such as CMT and SCS.