Objective: To evaluate the surgical performance of the new Greenlight XPS-180W laser system (American Medical Systems, Minnetonka, MI) and the effect of prostate volume (PV), in comparison with the former HPS-120W system, for the treatment of benign prostatic hyperplasia by photo-selective vaporization of the prostate. Methods: Between July 2007 and March 2012, 1809 patients underwent laser photo-selective vaporization of the prostate (1187 patients with the use of HPS-120W and 622 patients with the use of XPS-180W) at 7 international centers. All data were collected prospectively. Comparative analysis was performed between XPS and HPS according to PV measured by transrectal ultrasound. Results: The XPS compared with HPS, allowed significantly reduced laser and operative time (29.6 minutes vs 65.8 minutes and 53 minutes vs 80 minutes, respectively; P <.01 for both). The number of fiber used during the procedures was significantly reduced with the XPS system (1.11 vs 2.28; P <.01), whereas total energy delivered was lower (250.2 kJ vs 267.7 kJ; P =.043). Overall, the mean operative time, mean laser time, and mean energy were all significantly increased according to PV >80 mL vs <80 mL. However, when stratified according to PV, XPS demonstrates significant advantages compared with HPS, regardless of prostate size in all operative parameters (P <.01). Conclusion: The new XPS-180W system exhibits significant advantages in all surgical parameters compared with the HPS-120W system. Overall, with XPS-180W and HPS-120W, mean operative time, laser time, and energy usage increased according to PV. This suggests that preoperative evaluation of PV by transrectal ultrasound should be mandatory.