Selective inhibitors of phosphodiesterase type 5 prevent the breakdown of cyclic guanosine monophosphate resulting in enhanced penile erection and are used for the treatment of erectile dysfunction. Those agents, by way of vasodilator effects could interact with the systemic vasculature and could potentially affect the cardiac patient. During sexual intercourse, heart rate and blood pressure increase as with other forms of exertion. Stress to the heart during sexual intercourse is similar than that observed during other common daily activities. This article reviews the literature and provides recommendations regarding the evaluation of patients with known or suspected cardiac disease in whom therapy for erectile dysfunction is being considered. Patients who seek therapy for erectile dysfunction should undergo to individualized medical evaluation before a prescription is issued. Patients requiring therapy with long-acting nitrates should not receive prescriptions for phosphodiesterase inhibitors. Patients who are likely to develop angina with sexual exertion should not take phosphodiesterase inhibitors, as they may be tempted to take sublingual nitroglycerin. Stress testing is indicated if exercise capacity is uncertain or if significant myocardial ischemia is suspected.