Endothelial dysfunction precedes the clinical stage of atherosclerotic disease and is recognized as an additional risk factor when detecting symptomatic patients. Endothelial function is largely mediated by nitric oxide, and this vasodilatory mechanism is also responsible for the venous and arterial dilatation required to obtain and maintain an erection. The physiological effects and clinical aspects of sexual function have been extensively studied and reported in patients who have angina or who have experienced a myocardial infarction and in those who have undergone coronary artery bypass graft surgery or heart transplant. The relationship between erectile dysfunction (ED) and the risk factors for coronary heart disease was noted in the Massachusetts Male Aging Study (MMAS). MMAS included 1290 men (aged 40-70 years) and reported a 52% incidence of some degree of ED. Sildenafil and other PDE-5(Phosphodiesterase type-5) inhibitors will eventually be developed for a number of cardiovascular indications including essential hypertension, endothelial dysfunction, ischemia/reperfusion injury, myocardial infarction, ventricular remodelling and heart failure. A recent clinical study suggested that PDE-5 inhibitors might be a new class of drug that can potentially be used for the treatment of essential hypertension. The unique mechanism of action and high efficacy of PDE5 inhibitors has generated immense interest among researchers dealing with sexual dysfunction. The recognition of ED as a warning sign of silent vascular disease has led to the concept that a man with ED and no cardiac symptoms is a cardiac (or vascular) patient until proven otherwise.