The seasonal activity of the tabanids (Diptera: Tabanidae) was studied from May to September (2010-2011) in three localities on the territory of the Central Balkan Mountains. A total of 2232 specimens from 25 tabanid species and 8 genera were collected and processed. The first horse flies emerge in the first half of May and the last specimens were collected until mid-September. The tabanids reached their highest peak abundance in the first half of July. The most abundant species of the tabanid assemblages in the Central Balkan Mountains were Tabanus tergestinus Egg. (56.73 %), Tabanus bromius L. (12.71 %) and Haematopota pluvialis L. (8.87 %). The largest number of specimens of T. tergestinus was collected during the peak of the seasonal abundance of horse flies on the territory of the Central Balkan Mountains.