Background: The best technique of radical prostatectomy - open versus robot-assisted approach - is controversially discussed. In this study, we compared the complication rates of open and robot-assisted radical prostatectomy during the introduction and subsequent routine use of a da Vinci® robotic device while open surgery remained the standard approach. Patients and Methods: Between January 1st, 2006, and June 4th, 2012, 2,754 men underwent radical prostatectomy at our department. Among them, 317 received robot-assisted and 2,438 open surgery. According to the requirements for prostate cancer centers certified by the Deutsche Krebsgesellschaft (German Cancer Society), a prospective database recording perioperative complications was built up. The complication rates of open and robot-assisted radical prostatectomy were compared with the χ2 or Fisher exact test. The distributions of quantitative variables were compared with U tests. Results: Whereas the demographic factors favored patients selected for robot-assisted radical prostatectomy, there were no differences between open and robot-assisted surgery concerning length of stay, autologous blood transfusion rates and the incidence of perioperative complications. Conclusions: Open and robot-assisted radical prostatectomy had comparable complication rates. With better patient- and tumor-related parameters as well as decreasing transfusion rates in the robot-assisted subgroup, this observation might reflect the learning curves of the involved robotic surgeons.