This article reviews the potential role of dietary supplementation with coenzyme Q10 (CoQ10) for the management of patients with type 2 diabetes. The rationale for supplementation with CoQ10 is based on its key roles in cellular energy metabolism and as an antioxidant, and its potential mediation of oxidative stress and inflammation, which have been implicated in the pathogenesis of diabetes. Randomised controlled clinical trials have demonstrated that supplementation with CoQ10 can significantly improve glycaemic control, as well as improving vascular dysfunction. Supplementation with CoQ10 may be of particular importance in type 2 diabetics prescribed statins and in those with fatty liver disease. Supplemental CoQ10 is usually well tolerated, with no significant adverse effects reported in long-term use. The importance of product quality and bioavailability cannot be over-emphasised, since this may be a factor in the disparity of findings from clinical trials supplementing CoQ10.