Purpose: Improvements to photoselective vaporization of the prostate (PVP) have been made over time, particularly with the introduction of higher power systems. Few studies however have compared the performance of these systems to their predecessors. The purpose of this study was to compare the clinical and perioperative outcomes of 80 W vs. 120 W PVP. Materials and Methods: A series of 267 and 209 consecutive patients underwent 80 W and 120 W PVP, respectively, from September 2001 to May 2009 at Weill Cornell Medical College (GreenLightTM laser system, American Medical Systems, Inc., Minnetonka, MN). Data were collected on patient demographics, International Prostate Symptom Score (IPSS), prostate-specific antigen (PSA), and perioperative parameters. Maximum flow rate (Qmax), postvoid residual (PVR), and transrectal ultrasound prostate volume were recorded. Statistical analyses were carried out utilizing the Shapiro-Wilk, Mann-Whitney, Wilcoxon and unpaired t tests (SPSS 15.0, SPSS Inc., Chicago, IL, USA). Results: Baseline parameters were similar between the two groups except for greater median age (72.8 vs. 69.2 years, p = 0.01) and lower median PSA (2.0 vs. 3.3, p = 0.01) in the 80 W group. Median laser time was longer in the 80W group (85 vs. 51 minutes, p < 0.001) with a higher median energy utilized (253 vs. 210 kJ, p = 0.001). Final IPSS, Qmax, PVR, and PSA were equivalent between the two groups. Conclusions: In our series, PVP was safe and effective. Durable and similar improvements in symptoms and objective parameters were achieved in patients with both 80 W and 120 W laser systems. PVP with the 120 W system, however, provided faster and more efficient vaporization compared to the 80 W system.