Abnormal glucose metabolism and type 2 diabetes mellitus (T2DM) are becoming increasingly common. It has been recently confirmed that the period of time prior to the development of diabetes, when patients have impaired glucose tolerance, may also predispose them to increased cardiovascular risk. Therefore prevention and management of T2DM and its antecedents must have high priority when allocating healthcare resources. The present review summarises some information on detection, management and treatment of abnormal glucose metabolism in patients with established coronary artery disease, highlighting the importance of early detection of abnormal glucose metabolism in order to prevent the progression of prediabetes to T2DM and to delay the occurrence of those macrovascular and microvascular complications that impair quality of life and diminish survival.