AIM:To evaluate the impact of obesity on the postoperative outcome after hepatic resection in patients with hepatocellular carcinoma (HCC).METHODS:Data from 328 consecutive patients with primary HCC and 60 patients with recurrent HCC were studied.We compared the surgical outcomes between the non-obese group (body mass index:BHI＜25 kg/m2)and the obese group(BHI≥25 kg/m2).RESULTS:Following curative hepatectomy in patients with primary HCC,the incidence of postoperative complications and the long-term prognosis in the nonobese group(n=240) were comparable to those in the obese group(n=88).Among patients with recurrent HCC,the incidence of postoperative complications after repeat hepatectomy was not significantly different between the non-obese group(n=44) and the obese group(n=16).However,patients in the obese group showed a significantly poorer long-term prognosis than those in the non-obese group(P＜0.05,five-year survival rate;51.9% and 92.0%,respectively).CONCLUSION:Obesity alone may not have an adverse effect on the surgical outcomes of patients with primary HCC.However,greater caution seems to be required when planning a repeat hepatectomy for obese patients with recurrent HCC.