OBJECTIVES: Obesity has been proposed as a risk factor for reduced disease-specific survival, increased positive surgical margin (PSM) and biochemical recurrence (BCR) after radical prostatectomy (RP) in patients with prostate cancer. The aim of this study was to clarify the relationship between obesity and surgical outcomes in patients undergoing RP. METHODS: Medical records of 491 patients who underwent RP from 2004 to 2007 were retrieved from our institutional database. Patients were divided into three groups based on their body mass index (BMI): <25, 25-30 (overweight) and >30 kg/m (obese). Outcomes after RP were compared between the groups in terms of length of stay, perioperative complications, BCR, PSM and Gleason scores. RESULTS: Age, stage and preoperative prostate-specific antigen were similar between BMI categories. Operating time was prolonged in obese patients (146 vs 135 min, P = 0.01) and blood loss was greater (mean estimated blood loss 640 vs 504 mL, P = 0.02), but did not translate into higher transfusion rates. Early complication rates, PSM rates and Gleason scores were not statistically different between the groups. Significant differences in late outcomes, such as the need for adjunct procedures or BCR (hazard ratio 0.44, 95% CI 0.18-1.09), were not shown. CONCLUSION: As surgical experience with high BMI patients has developed, RP appears to be a well tolerated procedure in contemporary series, irrespective of BMI. In particular, early outcome parameters, such as PSM and BCR rates, are similar.