Multiple factors appear to be involved in the pathogenesis of type 2 (non insulin dependent) diabetes mellitus (DM). One of these factors may be iron overload. This critical review summarizes the major studies on the link between type 2 DM, insulin resistance, glycemic control, diabetic complications and hyperferritinemia. Although some studies suggested that plasma ferritin concentration is positively correlated with insulin resistance and with the risk of acquiring type 2 DM, substantial iron overload is not a typical feature of DM. There is no correlation between plasma ferritin level and glycemic control or diabetic microangiopathic complications.