Crimean -Congo Hemorrhagic Fever (CCHF) is a life-threatening viral infection. The pathogenesis of the disease is not well understood. The aim of this study was to determine the change in irisin concentrations in patients with CCHF. The study included a total of 30 patients with CCHF and 30 control participants. Irisin concentrations were determined using a commercial ELISA kit. Median irisin concentrations were 9.03 (5.81-12.22) mu g/mL and 4.2 (3.39-7.62) mu g/mL, respectively, in each group. There was no correlation between irisin and disease severity. Any correlations between irisin, and lactate dehydrogenase (LDH), international normalization ratio (INR), Alanine aminotransferase (ALT), aspartate aminotransferase (AST), platelets, activated partial thromboplastin time (aPTT), D-dimer and hemoglobin, were also investigated. There were statistically significant positive correlations between the values of irisin, and platelet (p = 0.005, r: 0.369), ALT (p = 0.049, r: 0.261), INR (p = 0.006, r: 0.359) and aPTT values (p = 0.002, r: 0.405). A negative correlation was also found between the values of irisin and LDH (p = 0.008, r: 0.348). No correlations were determined between the values of irisin, and AST, hemoglobin and D-dimer. These results suggest that irisin may have a role in CCHF.