The objective of this study was to determine the efficacy and safety of sildenafil in patients with erectile dysfunction (ED) and associated organic risk factors in a multispecialty clinic. Patients (n = 521) were diagnosed with ED based on self-assessment. Associated risk factors were managed by medication or life-style modifications, or both, before treatment with sildenafil for ED. Patients received a 50-mg dose of sildenafil that could be adjusted to 100 mg or 25 mg based on tolerability and efficacy. Patients recorded the number of successful intercourse encounters for 6 to 8 weeks, and the number of adverse events. Overall, there was an 82% successful intercourse rate with sildenafil treatment. The predominant associated risk factors for ED were hypertension (39%), hypogonadism (37%), and multiple medications (34%). Common adverse events due to sildenafil treatment were mild to moderate in nature and resulted in <2% patient discontinuation. Clinicians should be particularly careful to evaluate patients presenting with ED because the condition can be accompanied by a wide spectrum of risk factors requiring monitoring and treatment. However, with adequate treatment and control of these risk factors, the use of sildenafil in a representative population of men with ED in a multispecialty clinic can achieve a higher efficacy rate than previous studies have indicated.