Growth hormone (GH) and insulin-like growth factor-I are involved in heart development and in maintaining cardiac structure and performance. Cardiovascular disease has been reported to reduce life expectancy both in GH deficiency (GHD) and in GH excess. Patients with GHD suffer from abnormalities of left ventricular performance, ie reduced diastolic filling and impaired response to peak exercise. Patients with GHD also have increased intima-media thickness at the common carotid arteries, associated with a higher occurrence of atherosclerotic plaques, which may further aggravate the haemodynamic conditions. This may contribute to increased cardiovascular and cerebrovascular risk. These cardiovascular abnormalities can be reversed, at least partially, with GH replacement therapy. In recent years, GH therapy has been used to increase cardiac mass in ischaemic or dilated cardiomyopathy, but the results have produced contradictory data.