We evaluated the effects of extended-release alfuzosin HCl 10 mg once daily (q.d.) on sexual function in men with lower urinary tract symptoms associated with benign prostatic hyperplasia (BPH). In a randomized, double-blind, placebo-controlled study of men aged > or = 50 years, after a 28-day placebo run-in period, patients were randomized to receive alfuzosin 10 mg q.d. or matching placebo for 28 days. The mean change from baseline (day 1) in sexual function on day 29 was assessed using the Danish Prostate Symptom Score Sex (DAN-PSSsex) questionnaire. A total of 372 patients were randomized to receive alfuzosin (n=186) or placebo (n=186), with 355 completing the study. At baseline, 64% of the patients reported erectile dysfunction (ED) and 63% reported ejaculatory dysfunction (EjD). For the 320 patients who completed the DAN-PSSsex, alfuzosin treatment was associated with a significant improvement in the mean change from baseline in erectile function on day 29 compared with placebo (P=0.02). No significant difference was observed between the two treatment groups in the mean change from baseline in ejaculatory function on day 29. For patients with ED at baseline, a marginal improvement in erectile function was demonstrated with alfuzosin treatment (P=0.09 vs placebo). For patients with EjD at baseline, the mean change from baseline in ejaculatory function with alfuzosin was comparable to that with placebo. Dizziness was the most common adverse event with alfuzosin treatment (5 vs 0% with placebo), with other adverse events reported with comparable frequency in both treatment groups. After 1 month of treatment, alfuzosin 10 mg q.d. significantly improved erectile function in men with lower urinary tract symptoms/ benign prostatic hypertrophy and had no adverse effect on ejaculatory function.