Type 2 diabetes mellitus is one of the most common chronic metabolic diseases characterized by hyperglycemia, with either lack of insulin secretion or decreased sensitivity to insulin metabolic effects. Prediabetes is an intermediate stage between normal glucose metabolism and diabetes mellitus with high prevalence rate of diabetes mellitus developments. We aimed in this study to evaluate serum irisin level among patients with type 2 diabetes mellitus and individuals with prediabetes. A cross-sectional study was done on 214 participants, who were attend to the Azadi Teaching Hospital, Diabetic unit at Duhok city between October 2021 and April 2022. The participants were classified to three groups; 94 patients with type 2 diabetes mellitus, 60 prediabetic individuals and 60 apparently healthy control. We collected blood samples in the morning after overnight fasting from all participants. All parameters were measured by cobas 6000 (Hitachi, Roche) and including glucose, insulin, total cholesterol, triglyceride, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol and blood HbA1c% except serum irisin that was measured by ELISA instrument. Serum irisin levels was lower in type 2 diabetic patients and prediabetic individuals compared to healthy control (P<0.001). There was a negative relation between serum irisin and total cholesterol, triglyceride, low-density lipoprotein-cholesterol, poor glycemic control and atherogenic indices, with positive relation of serum irisin with high-density lipoprotein-cholesterol -c. We found lower level of circulating serum irisin in type 2 diabetic patients and prediabetic individuals compared to healthy controls.