Purpose: To compare the results of open radical prostatectomy (OP) and robotic prostatectomy (RP) for a single surgeon's experience of 219 radical prostatectomy cases. Materials and Methods: Between June 2002 and June 2007, 133 patients underwent OP and between July 2005 and June 2007, 86 patients underwent RP. To compare the surgeon's experience-related differences, we divided the OP cases into 73 early cases (OP-I) and 60 late cases (OP-II), and the RP cases into 30 early cases (RP-I) and 56 late cases (RP-II). The clinical characteristics, perioperative results, and early clinical outcomes were evaluated. Results: There were no significant differences in the preoperative characteristics between the four groups. For the RP cases, the mean estimated blood loss was decreased, a normal diet was started earlier, the mean duration of hospital stay and the mean duration of bladder catheterization was shorter than for the OP cases. The frequency of intraoperative complications significantly decreased in the RP-II group as compared to the RP-I group. Although there was no significant statistical difference in the positive surgical margin rates between the four groups, the rates were slightly decreased in the RP-II group. The recovery period of continence was shorter in the RP-II group than in the OP group and for patients 60 years or older, recovery of potency was also better in the RP-II group than the OP group. Conclusions: Our results suggest that RP at the hands of an experienced surgeon may decrease the positive surgical margin rate to some degree. Additionally, performance of RP may lead to a shorter duration of bladder catheterization and hospital stay and a better recovery of continence and potency than obtainable by OP.