Tick-borne diseases like tick-borne relapsing fever are a public health problem in Iran. Its occurrence is more prevalent in north part of country. In order to determine the distribution of soft ticks, Argasidae, and their infection with Borrelia species in Hamadan province, 53 villages were selected randomly. A total of 4805 ticks were collected directly from human dwellings, poultries, and animal shelters. They belong to the genus Argas and Ornithodoros, among which 52.3% were Argas persicus, 2.6% A. reflexus, 2% Ornithodoros canestrinni, 41.4% O. lahorensis, and 1.77% O.tholozani . The most prevalent species was A.persicus and the least one O. lahorensis. Examination of ticks revealed that O.tholozani was infected with Borrelia persica. Infection rate and disease prevalence is coincident in the region. The results will be discussed in more details in terms of preventive measures.