The family Tabanidae transmits bacteria that have a negative impact on animal and public health. Female of most Tabanidae species are a mechanical vector that causes many diseases. In order to expand the information on this area, it has been isolated and identified bacteria that have been transmitted in the digestive system Tabanidae in the around of Eskişehir and Kütahya province. In this study, 17 female flies and 1 male flies were caught both on the cattle and in the trap and 310 isolates were obtained from the digestive systems of these flies. This is in line with the results of the tests with the aim of defining the different isolates 83 isolates were identified and 36 different species of microorganisms, believed to be determined. Among these microorganisms 30 species caught on the body of the host by hand; 6 species were isolated from Tabanidae that were collected by Malaysian type trap. All of these species identified from Tabanidae species within this study are reported for the first time. Tabanus bromius and Tabanus tinctus were the most frequent Tabanidae, 22.2% and 16.6% respectively. The most frequent species of bacteria found in the flies were Serratia marcescens and Enterobacter amnigenus biogrup 2. The isolation of highly important bacteria from some of the investigated Tabanidae species once again demonstrates the importance of their vector properties.