Microscopic examination of Giemsa-stained peripheral blood smears collected from three naturally infected dogs originating from Turkey revealed the presence of large (around 4.5-5.0 mu m) intraerythrocytic Babesia parasites in all dogs. DNA was extracted from the three infected blood samples and an around 410 bp portion of the 18 S rDNA gene of Babesia species was PCR amplified for subsequent molecular characterization. RFLP analysis of the PCR products suggested the presence of the species B. vogeli in all infected dogs and sequencing of the PCR products from two of the three samples revealed 100% identity among the two Turkish isolates. Comparisons with the equivalent 4 10 bp portions of the 18 S rDNA gene of Babesia species confirmed the affiliation of these isolates to the B. vogeli species. This is the first report and molecular characterization of dog infection with a large Babesia species in Turkey. (c) 2006 Elsevier B.V. All rights reserved.