Diabetes mellitus is a chronic illness frequently associated with cardiovascular complications. The cardiologist must therefore play an important role in the management of diabetic patients, aware of the different natural history of the insulin-dependent and non-insulin-dependent forms, as well as of the pathophysiological peculiarities of the disease which requires particular diagnosis and therapy. Unfortunately, treatments which have proved to be most effective are still underused. Cardiovascular complications in diabetic patients are aggravated by higher morbidity and mortality rates than in the general population. In an attempt to prevent major cardiovascular events, the cardiologist must identify those patients at greater risk, particularly those with asymptomatic coronary heart disease.