A survey was conducted during the months of April-June 2003 in the northeast Portugal (Bragança district) in order to characterize the hemoparasite population of an autochthonous Mirandesa breed of Bos taurus. The polymerase chain reaction (PCR) analysis of the bovine blood revealed that 3 out of 116 animals were infected with Theileria and/or Babesia parasites, while reverse line blot hybridisation (RLB) analysis showed that these animals were infected with Theileria buffeli/orientalis. Cloning and sequencing confirmed the RLB results. Database sequence searches combined with phylogenetic analysis of the partial 18S ribosomal RNA gene sequences obtained enabled us to place the parasites in question as members of the T. buffeli/orientalis group, confirming the PCR/RLB diagnosis.