Objective: We aimed to investigate neutrophil lymphocyte ratio (NLR), leukocyte count (WBC), mean platelet volume (MPV) and C-reactiveprotein levels (CRP) as inflammatory markers according to thyroid function status in hypo-hyperthyroidism patients.Methods: Data of patients (n=454, age>18) who applied to the Eskisehir Osmangazi University Hospital between March 2018 and December2018 were evaluated retrospectively. There were 79 patients in hyperthyroidism group (TSH<0.27 μIU/ml, group I), 297 patients in euthyroidgroup (TSH=0.27-4.2 μIU/ml, group II) and 78 patients in hypothyroidism group (TSH>4.2 μIU/ml, group III).Results: Serum TSH, fT4, fT3, anti-TG and anti-TPO levels were found statistically different between groups (p<0.001) but there were nosignificant difference in WBC, NLR and MPV between groups. There was a positive correlation between the NLR and CRP (r=0,295, p<0.01). Inaddition, NLR was positively correlated with WBC (r=0,412, p<0.001). Serum CRP levels were statistically higher in group I (3.5 mg/L [1.50-11])than group II (2.1 mg/L [0.86-5.42]), (p<0.001). Although CRP levels were higher in group III (2.5 mg/L [1.18-5.73]) than group II, there was nosignificant difference. CRP showed weak positive correlation with fT4 (r=0,118, p<0.05) and negative correlation with TSH (r=-0,108, p<0.05).Conclusion: High CRP levels may play an important role in the evaluation of hyperthyroidism in terms of thyroid dysfunction observed in thepresent study.