OBJECTIVE • To assess the impact of body mass index (BMI) on the surgical outcomes of robotic partial nephrectomy (RPN). PATIENTS AND METHODS • Medical charts of 250 consecutive patients who underwent RPN at our institution between 2006 and 2010 were reviewed. • Patients were categorized based on their BMI into four groups per international classification of obesity into: normal (BMI < 25 kg/m 2 ), overweight (25-29.9), obese (30-39.9) and morbidly obese ( ≥ 40). • Preoperative characteristics as well as perioperative and postoperative outcomes were analysed and compared between the groups. RESULTS • Of the 250 patients, 43 (17.2% of the entire cohort) were non-obese, 104 (41.6%) were overweight, 75 (30%) were obese, and 28 (11.2%) were morbidly obese. • Groups were similar in terms of age, gender, history of previous surgery and nephrometry score ( P =0.5). • Patients with higher BMI had a higher American Society of Anesthesiologists (ASA) score (median 3 for obese and morbidly obese groups vs 2 for non-obese groups; P =0.002) and tumour size (median 3.6, 2.9, 2.5 and 2.3 cm in those who were morbidly obese, obese, overweight and with normal BMI, respectively; P =0.005). • Patients within the morbidly obese group had a higher estimated blood loss (median 250 mL) than other groups (median: 200, 200, 150 mL, respectively) ( P =0.03). • No significant difference was detected between the groups in terms of operation duration, warm ischaemia time, transfusion rate and postoperative complications. CONCLUSION • Robotic partial nephrectomy represents an effective treatment modality for renal tumours providing equivalent surgical outcomes even for patients with BMI up to 60 kg/m 2 . © 2012 THE AUTHORS.