Introduction: While the effects of increasing body mass index on prostate cancer epidemiology and surgical approach have recently been studied, its effects on surgical outcomes are less clear. We studied the perioperative outcomes of obese (BMI >= 30) men treated with daVinci-assisted laparoscopic radical prostatectomy (DLP) and compared them to those treated with open radical retropubic prostatectomy (RRP) in a contemporary time frame. Method: After Institutional Review Board approval, we used the Mayo Clinic Radical Prostatectomy database to identify patients who had undergone DLP by a single surgeon and those who had undergone open RRP by a single surgeon between December 2002 and March 2005. Baseline demographics, peri- and post-operative courses, and complications were collected by retrospective chart review, and variables from the two cohorts compared using chi-square method and least-squares method of linear regression where appropriate. Results: 59 patients who had DLP and 76 undergoing RRP were available for study. Baseline demographics were not statistically different between the two cohorts. Although DLP had a significantly lower clinical stage than RRP (p=0.02), pathological stage was not statistically different (p=0.10). Transfusion rates, hospital stay, overall complications, and pathological Gleason were also not significantly different, nor were PSA progression, positive margin rate, or continence at 1 year. After bilateral nerve-sparing, erections suitable for intercourse with or without therapy at 1 year was 88.5% (23/26) for DLP and 61.2% (30/49) for RRP (p=0.01). Follow-up time was similar. Conclusion: For obese patients, DLP appears to have similar perioperative, as well as short-term oncologic and functional outcomes when compared to open RRP.