Flies of the family Tabanidae are common, widespread pests, known to take blood meals from many mammals including humans, and are known vectors of a number of diseases. Tabanidae is wide family that represented with 165 species in Turkey, have possesion of great importance on economical and medical level. Allotype description of Tabanus karaosus, member of this family that was described on 1984 by Timmer, firstly accomplished on this study. Distribution of this species on Turkey is exhibited and variations demonstrated with collected samples comparison by holotype descriptions. In this study, taxonomical characterters of male specimens were offered repeatedly, also illustrations of male and female genitals were given, for the first time.