The acaricidal activity of an essential oil obtained from aerial parts of Origanum bilged P.H. Davis (Lamiaceae), an endemic species in Turkey, and its major constituents, carvacrol was evaluated against unfed adults Rhipicephalus turanicus Pomerantzev (Acari: Ixodidae) collected from Kepez, Antalya. The composition of the essential oil was analyzed by GC/MS. The major compound identified in the oil was carvacrol (93.02%). Generally, tick mortalities to the O. bilged distillate and carvacrol increased with concentrations. O. bilged oil produced >83% mortality at 48 h at a concentration of 0.8% and mortality was higher than 63% at a carvacrol concentration of 0.4%. Our results have shown that O. bilged essential oil and its major component, carvacrol, may have potential as acaricidal agents against R. turanicus. (C) 2012 Elsevier B.V. All rights reserved.