During June and July 2007, about 3125 adult ticks were collected from humans, animals, and vegetation in a hyperendemic region (Sivas and Tokat) of Turkey. A total of 2193 ticks were pooled in 225 pools and screened for the Crimean Congo hemorrhagic fever virus (CCHFV) presence by antigen-capture enzyme-linked immunosorbent assay. Infection rates were calculated as the maximum likelihood estimation with 95% confidence intervals (CI). The dominant tick species was found to be Hyalomma marginatum with the following infestation rates in human, cattle and sheep, respectively: 47.43%, 66.07%, and 30.12%. Maximum likelihood estimation values of CCHFV in H. marginatum ticks collected from human, cattle, and sheep were 0.91% (CI 0.05-4.42), 2.10% (CI 1.12-3.64), and 3.11% (CI 1.18-6.87), respectively. CCHFV antigens were also demonstrated in Hyalomma excavatum, Haemaphysalis parva, and Boophilus annulatus ticks collected from cattle and Rhipicephalus bursa ticks from sheep. Our results suggest that the studied area might maintain its endemic properties in the near future unless effective tick control measures are implemented.