Acute urinary retention (AUR) is a common complication of benign prostatic hyperplasia (BPH) and the incidence varies widely from 0.4 to 25% per year in men seen in urology practices. It has been estimated that AUR is the indication for surgery in around 25-30% of patients undergoing transurethral resection of the prostate (TURP) and that emergency TURP for AUR is associated with greater morbidity than elective TURP. Risk factors for AUR include lower urinary tract symptoms (LUTS), depressed peak urinary flow rate, enlarged prostate, high postvoid residual (PVR) urine and old age. Alfuzosin has been shown to significantly increase maximum flow rate and relieve bladder outlet obstruction, resulting in a reduction in PVR urine. A pooled analysis of 11 placebo-controlled studies involving 1,470 patients with LUTS suggestive of BPH indicates that significantly greater improvements were observed in patients treated with alfuzosin than with placebo. A 6-month placebo controlled study of 518 patients reported a 0.4% incidence of AUR in the alfuzosin group compared with a 2.4% incidence with placebo (p = 0.04). These positive effects on PVR could be related to the reduction in incidence of AUR seen in alfuzosin-treated patients.