Limited evidence exists regarding the value of robot-assisted radical prostatectomy (RARP) in promoting health outcomes in patients with prostate cancer (PCa) in Korea, prompting a study to determine its clinical impact. The study included 15,501 patients with PCa who underwent RARP (n = 12,268) or radical prostatectomy (RP) (n = 3,233) between 2009 and 2017. The outcomes were compared using a Cox proportional hazards model after propensity score matching. Hazard ratios of all-cause overall mortality after RARP compared to that after RP within 3 and 12 months were (6.72, 2.00–22.63,p= 0.002) and (5.55, 3.31–9.31,p< 0.0001), respectively. The RARP group in four hospitals with the largest PCa surgery volume during the study period had worse percentile deaths than the total RARP patients within 3- (1.6% vs. 0.63%) and 12-month post-op (6.76% vs. 2.92%). The RARP group showed specific surgical complications, like pneumonia and renal failure, more than the RP group. A significantly higher short-term mortality and only modestly lower surgical complications occurred in RARP than RP group. RARP performance status may not be superior to that of RP as previously reported and perceived, possibly due to increased robotic surgery in the elderly. More meticulous measures are needed for robotic surgery in the elderly.