Serum ferritin level is related to body iron stores and is influenced by several diseases. We aimed to evaluate the association between serum ferritin concentration and the complications and nature of diabetes mellitus (DM). We examined association of ferritin concentration, fasting and post-prandial glucose levels and glyeated hemoglobin in 329 patients with type 2 diabetes mellitus and 269 healthy controls. In the present study, 41 of 150 poorly controlled diabetic patients and 31 of 119 cases had hyperferritinemia. We confirmed that serum ferritin was increased in diabetic patients as long as glycemic control is not achieved. There was also a correlation between ferritin level and diabetic retinopathy. In conclusion, this study showed an independent positive association between serum ferritin concentration and markers of glucose homeostasis.