This study was carried out to investigate epidemiology of tropicat theileriosis in vaccinated and non· vaccinated cattle in Malatya province between May-August 2000. Serum samples were collected from a total of 188 callie at varios ages and breeds. 01 these, 52 were from animals at pasture and vaccinated against Theileria annulata. 82 were from animals al haused and non-vaccinated, 54 were from animals at pasture and non-vaccinated, Serum antibodies against T.annulata were investigated by Indirect Fluorescence Antibody (IFA) test. In addition, peripheral blood smears were prepared and examined under microscope. The rates oblalned for seropositivity by IFA test in animals at pasture and vaccinated, at pasture and non-vaccinated, at haused and non-vaccinated were 46.15%, 31.48% and 12.19% respectively. The rales obtained lor piroplasm carrier by microscopical examination were 23.07%, 25.92% and 3.65% respectively. The rates obtained seroposillvity and piroplasm carrier was higher in animals at pasture and vaccinated and non-vaccinated than in animals al haused and non-vaccinated (P