Theileria species infect wild and domestic ruminants. Bovine Theileria species causing serious problems in dairy and beef industry are common across the world. Theileria parva and Theileria annulata, cause lymphoproliferative disease with high morbidity and mortality in susceptible cattle. The other bovine Theileria species cause mild disease in cattle. The taxonomy, pathogenicity and nomenclature of these species are ambiguous. In Turkey, tropical theileriosis is considered to be a major threat to the cattle industry. However, data on the other Theileria species are limited.