Knipper S, et al. - Within the National Inpatient Sample database (2008-2015), obese vs non-obese robot-assisted and open radical prostatectomy (RARP and ORP) subjects were recognized by the researchers in order to test the influence of obesity (body mass index ≥30 kg/m²) on perioperative outcomes and total hospital charges (THC) at RARP vs. ORP. A total of 53,626 (60%) underwent RARP and 35,757 underwent ORP. In comparison with 6.9% at ORP, 8.6% were obese at RARP. RARP rate progressed significantly over time. In overtime at both, RARP and ORP, the obesity rate progressed markedly. Obesity prognosticated five of eleven and nine of eleven unfavorable perioperative complications at RARP and at ORP, respectively, in multivariable logistic regression models. At RARP and ORP, obesity significantly supplemented to THC in linear regression models. Hence, at RP, obesity may predispose to higher rates of adverse outcomes. Moreover, its impact differed according to the surgical approach.