INTRODUCTION: Given the anatomic constraints of obese patients, concern exists as to whether robotic assisted laparoscopic prostatectomy (RALP) is appropriate in patients with higher body mass index (BMI). We reviewed a large RALP database to determine if clinical outcomes are related to BMI. METHODS: The records of patients who underwent a RALP from 2003-2009 were reviewed. BMI stratifications were concordant with the Centers for Disease Control (CDC) standards: ? 30, ? 25 and < 30, and < 25 were classified as obese, overweight, and normal weight, respectively. Baseline, perioperative, histopathologic, and functional outcome data were collected. RESULTS: A total of 1420 patients were identified and BMI information was available for 1112 patients. Median BMI in the three strata was 23.5 (n = 270), 27.3 (n = 600), and 32.1 (n = 242). There were no significant differences in preoperative prostate specific antigen (PSA), clinical staging, and preoperative Gleason scores. Operating time was 6 minutes longer in the obese (p < 0.001) and prostate weight was 8 g greater (p < 0.001). Other perioperative factors were similar, including: EBL, pathologic stage and Gleason score and rates of positive surgical margins. The overall incidence of postoperative complications was similar between the three groups. Biochemical recurrence rates were similar among all patients, although there was a trend toward increased recurrence in the obese (p = 0.09). Recovery of erectile function and continence was similar regardless of BMI. CONCLUSIONS: RALP is an effective approach to prostatectomy in obese patients as perioperative and functional outcomes are almost identical across BMI strata. This supports the continued utilization of RALP in obese and overweight men.