Mediterranean theileriosis, caused by Theileria annulata, is endemic in Minorca (Balearic Islands, Spain). The present study analyzes the prevalence of piroplasm infections in cattle in Minorca using reverse line blot (RLB) macroarrays, as well as the effect of herd tick control on those prevalence levels. One hundred and nineteen animals from 12 herds were sampled in representative areas of the island. Information was gathered regarding tick control for the animals (frequency and acaricide used) in each herd. More than 87% of the animals were positive for the presence of piroplasm species. Theileria annulata and Theileria buffeli were observed in all sampled herds (mean prevalence 53.3% for T. annulata and 69.75% for T. buffeli). The mean prevalence was 5.7% for Babesia bigemina. A significantly higher prevalence of Theileria spp. was observed in herds that grazed in, or near, forested areas. Theileria annulata prevalence was significantly lower in herds that followed tick control and was related to the frequency of the applied treatments. Theileria buffeli and B. bigemina prevalences were not affected by tick control for the herds. The results indicate that despite tick control, Mediterranean theileriosis remains endemic in Minorca. Adequate control measures and vaccination approaches are required to improve the situation of Mediterranean theileriosis on the island. © 2009 American Society of Parasitologists.