Introduction and objectives: To analyze postoperative complications and to assess for significant predictive factors during partial nephrectomy (PN) using a large multicenter dataset. Methods: Patients who underwent PN for clinical T1 renal tumors at 19 urological Italian centers (Registry of Conservative Renal Surgery [RECORd] project) were evaluated between 2009 and 2012. Anthropometric data, comorbidities and perioperative outcomes were analyzed. Complications were divided as intra- and postoperative, medical and surgical, as appropriate. The severity of postoperative complications was graded according to the modified Clavien classification system. Patients who experienced intraoperative complications were excluded from the analyses for the potential confounding effect in the evaluation of predicting factors for postoperative complications. Results: Overall, 979 patients were analyzed: open, laparoscopic and robot-assisted (available since 2011) surgical approaches were used in 522 (56.4%), 286 (30.9%) and 117 (12.6%) cases, respectively. Surgical postoperative complications were reported in 121 (13.1%) cases (32 (3.5%) were Clavien 3), medical were reported in 52 (5.6%) cases (3 (0.3%)wereClavien 3).No Clavien 4 complicationswere reported. Atmultivariable analysis, ECOG score 1 (OR 1.98; p ¼ 0.002), lower preoperative hemoglobin (OR 0.71; p