In the 7 years since sildenafil citrate (VIAGRA) was introduced as the first oral phosphodiesterase type 5 inhibitor therapy for erectile dysfunction, it has been used to treat nearly 27 million men with erectile dysfunction worldwide. Patient populations with erectile dysfunction of varying etiologies and with diverse comorbidities have benefited from sildenafil treatment. This update focuses on relatively recent research that further defines the response and effectiveness profiles of sildenafil and provides additional insight into optimizing treatment. In addition to providing recent data on sildenafil efficacy and safety/tolerability, the update provides data on assessments of erection hardness, measures of psychosocial outcomes (e.g., emotional well-being and treatment satisfaction), and treatment approaches to maximize response and effectiveness (e.g., by titrating to the maximum tolerated dose). Increased understanding of the sildenafil response and effectiveness profiles and optimal sildenafil treatment are central to the appropriate management of erectile dysfunction using sildenafil.