Background: The pathogenesis of the Crimean-Congo hemorrhagic fever (CCHF) and the cause of the hemorrhage are not yet fully understood. However, the endothelium plays a key role in the pathogenesis. The purpose of this study was to investigate endothelial dysfunction markers [asymmetrical dimethyl arginine(ADMA), endothelin 1(ET-1), thrombomodulin(TM), von Willebrand factor(vWf) and intercellular adhesion molecule(ICAM-1)] in serum in patients with CCHF and their associations with hemorrhage. Method: Seventy-three patients with CCHF were included in the study. All patients' endothelial dysfunction markers were studied using routine biochemical and hematological tests. The data obtained were then subjected to statistical analysis. Results: Statistically significant differences were determined between the patients and healthy control groups at time of presentation to hospital in terms of ADMA (p
