The study of bloodsucking dipterans, including gadflies, was conducted mainly in the 60-70s of the last century, when the rapid development of oil and gas production began and was associated with the development of means and methods for the pro-tection of humans and animals. Since then, more than 40 years have passed. Dur-ing this time, there was a noticeable warming of the climate, and due to technical progress, the anthropogenic impact on nature increased. Currently, the interest of scientists and researchers to Diptera has significantly increased. Blood-sucking two-winged insects (midges) include mosquitoes (blood line Culicidae), gadflies (blood line Tabanidae), midges (blood line Simuliidae) and biting midges (blood line Cera-topogonidae). The main factors determining the high abundance of midges are favor-able climatic conditions for their reproduction and existence in combination with the abundance of biotopes of hatching (various water bodies and marsh formations) and the habitat of the imago (presence of tree, shrub or high grassy vegetation), as well as the presence of a sufficient number of warm-blooded animals – the source of blood saturation. The damage caused by horseflies to humans and animals is very great. The aim of our work was to summarize the information in the literature about the damage caused by horseflies to farm animals and their role in the transmission of pathogens of humans and animals.