Objectives: To quantify complications to surgery in patients treated with robot-assisted radical prostatectomy (RARP) and open retropubic radical prostatectomy (RRP) at our institution. Radical prostatectomy is associated with specific complications that can affect outcome results in patients. Methods: Between January 2002 and August 2007, a series of 1738 consecutive patients underwent RARP (n = 1253) or RRP (n = 485) for clinically localized prostate cancer. Surgery-related complications were assessed using a prospective hospital-based complication registry. The baseline characteristics of all patients were documented preoperatively. Results: Overall, 170 patients required blood transfusions (9.7%), 112 patients (23%) in the RRP group compared with 58 patients (4.8%) in the RARP group. Infectious complications occurred in 44 RRP patients (9%) compared with 18 (1%) in the RARP group. Bladder neck contracture was treated in 22 (4.5%) patients who had undergone RRP compared with 3 (0.2%) in the RARP group. Clavien grade IIIb-V complications were more common in RRP patients (n = 63; 12.9%) than in RARP patients (n = 46; 3.7%). Conclusions: The introduction of RARP at our institution has resulted in decreased number of patients with Clavien grade IIIb-V complications, such as bladder neck contractures, a decrease in the number of patients who require blood transfusions, and decreased numbers of patients with postoperative wound infections.