Karyotypic features of Tabanidae (Diptera: Insecta) are largely unexplored. In this study, karyotypes of some horse fly species, Tabanus quatuornotatus Meigen, 1820, T. sudeticus Zeller, 1842, Dasyrhamphis umbrinus (Meigen, 1820), Atylotus loewianus (Villeneuve, 1920) and Haematopota italica Meigen, 1804 are described for the first time, and also, karyotypes of T. autumnalis Linnaeus, 1761, T. bromius (Linnaeus, 1761), T. bifarius Loew, 1858, T. unifasciatus (Loew, 1858), A. fulvus (Meigen, 1820) are confirmed. Karyotypic differences between six genera in Tabanidae will be discussed. Adult and larval specimens were collected, injected cholchicine and brought to the laboratory. After 24-48 hours tissues were dissected, fixed and dyed, respectively. After dying, preparations were made by squashing tissues and investigated with light microscope and photographed. Based on the results of the present study, the chromosome number in the following reads as follows; T. autumnalis 2n=14, T. bromius 2n=10, T. bifarius 2n=16, T. quatuornotatus 2n=16, T. sudeticus 2n=14, T. unifasciatus 2n=12, D. umbrinus 2n=10, A. fulvus 2n=18, A. loewianus 2n=18 and H. italica 2n=14 chromosome number. Chromosome number, chromosome arm length and arm ratio, location of centromere of these species is reported and evaluated.