The simultaneous incremental increase in incidence of both obesity and hepatocellular carcinoma (HCC) will soon lead to more overweight and obese patients with cirrhosis needing surgery. At present, little is known about postoperative mortality and morbidity in such patients. This study investigated outcomes after hepatectomy in relation to obesity in a homogeneous cohort of patients with cirrhosis. Perioperative data from 235 patients with cirrhosis who had hepatectomy for HCC were related to the presence of normal bodyweight (body mass index (BMI) 18.5-24.9 kg/m(2)), overweight (BMI 25.0-29.9 kg/m(2)) and obesity (BMI at least 30 kg/m(2)). Complications after surgery were graded according to the expanded Accordion Severity Classification of Postoperative Complications (T92). One hundred and one patients (43.0 per cent) were of normal bodyweight, 88 (37.4 per cent) were overweight and 46 (19.6 per cent) were obese; none was underweight. Overweight and obese groups showed a male preponderance (P = 0.024), and metabolic disorders were frequently the cause of cirrhosis in these patients (P < 0.001 and P = 0.014 for non-B non-C hepatitis and alcoholic cirrhosis respectively). Liver function tests, tumour stage and extent of hepatectomy did not significantly differ between BMI groups. The intraoperative course and postoperative mortality were unaffected by BMI. Overweight and obese patients had significantly more mild respiratory complications (P = 0.044). Severe complications and organ system (including liver) failure were not significantly affected by BMI. Hepatic resection can be performed safely in overweight and obese patients with cirrhosis, although morbidity is increased in these patients. Copyright © 2011 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.