Aim: Partial nephrectomy is the standard treatment for small renal tumors; however, it remains unclear which surgical approach from among robot-assisted partial nephrectomy (RAPN) and open partial nephrectomy (OPN) is superior. This study aimed to compare perioperative outcomes of RAPN and OPN performed at a single institution after adjusting for preoperative patient and tumor characteristics using propensity score matching (PSM). Methods: In this retrospective cohort study, patients who underwent RAPN or OPN for a renal mass of cT1-2 N0 M0 between 2005 and 2020 at our institution were recruited. The study outcomes were perioperative outcomes, complications, and pathological and functional outcomes. PSM was used to account for baseline covariates. Results: Overall, 131 RAPN and 71 OPN cases were extracted; in addition, 58 cases of RAPN and OPN were selected via PSM. RAPN was superior to OPN in terms of estimated blood loss (10 g vs. 160 g, P < 0.001), ischemia time (23 min vs. 34 min, P < 0.001), and hospital duration (7 days vs. 12 days, P < 0.001). There were no significant differences in the incidence of perioperative complications or in the rate of positive surgical margins (both P > 0.05). With respect to functional outcomes, the rates of preservation of renal function at both 1 day and 3 months postoperatively were higher with RAPN than with OPN (85.3% vs. 69.1% and 93.3% vs. 85.6% respectively, both P < 0.001). Conclusion: In selected cases, RAPN with warm ischemia appears to preserve renal function equally well or better compared to OPN with cold ischemia.