Adults with growth hormone deficiency (GHD) have moderate hypercholesterolemia, characterized by elevated levels of total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B. Adults with GHD have visceral adiposity, which predisposes them to insulin resistance. Intimal thickening and increases of plaque formation have been observed in adults with GHD compared with healthy subjects, and abnormalities in fibrinolytic factors have been noted. These data, along with results from epidemiologic studies of rates of cardiovascular mortality and morbidity, suggest that adults with GHD have a higher risk of cardiovascular events and death than do healthy subjects. Growth hormone (GH)-replacement therapy in adults with GHD improves all elements of the dyslipidemia but can result in transient worsening of insulin resistance. In addition, small increases in resting left ventricular end-diastolic and stroke volumes and increases in cardiac output at rest and during exercise, with improved maximal and sub-maximal exercise performance, have been observed after the initiation of GH-replacement therapy. The long-term effects of GH-replacement therapy on cardiovascular mortality rates in adults with GHD remain to be determined.