Objective: To compare the perioperative outcomes of robotic partial nephrectomy ( RPN ) with laparoscopic PN ( LPN ) performed for small renal masses ( SRM s), in a large multi‐institutional series and to define a new composite outcome measure, termed ‘optimal outcome’ for the RPN group. Patients and Methods: Retrospective review of 2392 consecutive cases of RPN and LPN performed in five high‐volume centres from 2004 to mid‐2013. We limited our study to SRMs and cases performed by surgeons with significant expertise with the technique. The Trifecta was defined as negative surgical margin, zero perioperative complications and a warm ischaemia time of ≤25 min. The ‘optimal outcome’ was defined as achievement of Trifecta with addition of 90% estimated glomerular filtration rate preservation and no chronic kidney disease stage upgrading. Univariable and multivariable analysis were used to identify factors predicting Trifecta and ‘optimal outcome’ achievement. Results: In all, 1185 RPN and 646 LPN met our inclusion criteria. Patients in the RPN group were older and had a higher median Charlson comorbidity index and higher R.E.N.A.L . nephrometry score. The RPN group had lower warm ischaemia time (18 vs 26 min), overall complication rate (16.2% vs 25.9%), and positive surgical margin rate (3.2% vs. 9.7%). There was a significantly higher Trifecta rate for RPN (70% vs 33%) and the rate of achievement of ‘optimal outcome’ for the RPN group was 38.5%. Conclusions: In this large multi‐institutional series RPN was superior to LPN for perioperative surgical outcomes measured by Trifecta. Patients in the RPN group had better outcomes for all three components of Trifecta compared with their LPN counterparts. Our more strict definition for ‘optimal outcome’ might be a better tool for assessing perioperative and functional outcomes after minimally invasive PN . This tool needs to be externally validated.