PURPOSE Erectile dysfunction (ED) is a common sequel of pelvic fracture urethral disruption (PFUD). After repair of the urethral injury ED may be the most devastating long-term effect for the patient. Some patients with ED may regain normal erectile function. We prospectively studied the response to sildenafil and the erectile function of patients with ED due to PFUD. MATERIALS AND METHODS The erectile function of patients referred to us with PFUD for urethroplasty were prospectively evaluated before surgery. Patients underwent nocturnal penile tumescence testing and, if results were abnormal, penile duplex ultrasonography with intracavernous injection and arteriography were performed to diagnose the etiology of ED. Patients were questioned about erectile function every 3 months after surgery and if they complained of ED they were offered 100 mg sildenafil. Patients were followed for at least 18 months after surgery. RESULTS A total of 29 consecutive patients were evaluated and 22 (76%) of them had ED before surgery. Sufficient followup was available for 15 of the patients. Overall 47% of these patients responded favorably to sildenafil. Of the patients 60% with neurogenic ED and 20% of those with arterial ED responded to this treatment. In 33% of the patients ED resolved within the followup period. All patients with spontaneous resolution of ED previously responded to sildenafil (71% of sildenafil responders). CONCLUSIONS In patients with ED due to PFUD, those with neurogenic ED are more likely to respond to sildenafil than those with arterial damage. Favorable response to sildenafil may predict spontaneous resumption of normal erectile function over time.