Tabinidae(horseflies), which are known worldwide as important mechanical vectors of virus, bacteria, protozoans, and helminths, cause disease in humans and animals. To the best of our knowledge, reports of horseflies associated with horse farms in Korea are rare, and knowledge of the horsefly fauna in Jeju is poor. The objective of this study was to evaluate the incidence of horseflies at a horse farm. Flies were collected using traps baited with natural attractants at a large horse farm during summer (Aug.-Sep. 2011). A total of 28,339 flies from 21 traps were collected on the large horse farm in Jeju. The most abundant were non-sucking flies (25,524; 90.07%) followed by sucking flies (2,226; 7.86%) and Tabanidae (589; 2.07%). Result of species analysis of 4 Tabanidae, ranked in descending order, are as follows: T. grisenus (45.2%), T. rufidens (25.3%), T. takasagoensis (21.6%), and Hybomitra bimaculata (7.9%). Although studies on vector ecology are essential to understanding, predicting, and controlling insect-borne diseases, relatively few studies on tabanids in Jeju have been reported. This paper presents the first comprehensive collection of data on the horse fly fauna of this part of the horse concentrated region. Further research is needed to investigate pathogens on the horse of horseflies.