To evaluate the neutrophil-to-lymphocyte ratio (NLR) levels to predict the severity of inflammation in thyroid ophthalmopathy (TO).Fifty-six patients with TO and 40 healthy subjects were included in this study. TO patients were divided into two groups according to clinical activity score (CAS). Group 1 included 24 active TO patients and Group 2 included 32 inactive TO patients. The thyroid status, white blood cell (WBC), neutrophil, and lymphocyte counts were performed. NLR was calculated by dividing the neutrophil count by the lymphocyte count.The mean age was 53.6 ± 5.4 in active TO group, 54.2 ± 5.6 in inactive TO group, and 52.7 ± 5.2 in the control group. The WBC, neutrophil, lymphocyte and NLR levels were higher in patients with TO than in the control group (p < 0.05). A significant difference in NLR was found between the inactive and active TO groups (p < 0.05).NLR values were found to be higher in patients with TO than in controls. NLRvalues were also found higher in active TO patients than in inactive TO patients (Tab. 3, Ref. 26).