PURPOSE: There is little data evaluating the changes of severity of bladder outlet obstruction after 80 W-potassium-titanyl-phosphate (KTP) photoselective laser vaporization prostatectomy (PVP) by pressure-flow study. We evaluated the efficacy of PVP to relieve the obstruction in benign prostate hyperplasia (BPH) compared with transurethral resection of the prostate (TURP). MATERIALS AND METHODS: This is a prospective, non-randomized single center study. The inclusion criteria were as follows: Men suffering from lower urinary tract symptoms (LUTS) secondary to BPH, age > or =50 years, International Prostatic Symptom Score (IPSS) > or =13, maximum flow rate (Qmax) < or =15 ml/s, and ability to give fully informed consent. Patients with neurogenic cause or detrusor underactivity were excluded. The IPSS, bother score, Qmax, postvoid residual volume (PVR), detrusor pressure at maximum flow rate (PdetQmax), bladder outlet obstruction index (BOOI), and prostate volume were measured before and 6 months after surgery and compared between PVP and TURP. RESULTS: Sixty-seven patients (53 in PVP, 14 in TURP) were evaluable. In both groups, the IPSS, bother score, Qmax, and PVR had significantly improved (p<0.05), and there were no differences between the changes in those parameters. PVP could effectively reduce the PdetQmax, prostate volume, and BOOI from baseline (from 68.7+/-23.3 to 40.6+/-11.2 cmH2O, 49.5+/-16.3 to 31.3+/-12.1 ml, 49.8+/-25.6 to 9.8+/-20.7), similar to TURP. There were no differences in postoperative PdetQmax, prostate volume, or BOOI between the two groups. The percentage of patients with BOOI > or =40 was decreased from 64% to 4% in the PVP group and from 86% to 14% in the TURP group. CONCLUSIONS: PVP could reduce the prostate volume effectively and relieve bladder outlet obstruction similar to TURP by the 6-month follow up in men with BPH.