Background: Previous studies presented controversies in impact of body mass index (BMI) on perioper- ative complications in pancreatectomy, and mainly focused on West population. This study aimed to explore the impact of BMI on perioperative outcomes in Chinese patients undergoing pancreaticoduo-denectomy.Methods: Seven hundred and seven adult patients undergoing open pancreaticoduodenectomy between January 2005 and December 2016 at Ruijin Hospital were studied retrospectively and categorized as obese (BMI ≥25 kg/m 2 ), overweight (BMI ≥23 kg/m 2 and < 25 kg/m 2 ), or normal weight (BMI ≥18.5 kg/m 2 and < 23 kg/m 2 ). Associations of these BMI groups with perioperative outcomes were evaluated. Results: The overweight and obese groups experienced higher risk of clinically related postoperative pan- creatic fistula (CR-POPF) (7.6％ vs. 9.9％ vs. 17.6％, P = 0.002) and re-operation (1.1％ vs. 2.5％ vs. 5.1％, P = 0.017), and longer systemic inflammation response syndrome (SIRS) duration [2 (1–9) d vs. 2 (1–7) d vs. 3 (1–10) d, P = 0.003] and postoperative hospital stay [19 (2–84) d vs. 19 (7–158) d vs. 23 (8–121) d, P = 0.023] than the normal weight group did. The multiple logistic regression models showed obese as an independent risk factor for CR-POPF ( P = 0.013). The multiple linear regression analysis confirmed BMI as a predictor for prolonged postoperative hospital stay ( P = 0.005). Conclusions: Higher BMI results in higher morbidity of Chinese patients undergoing open pancreaticoduo- denectomy. Pancreaticoduodenectomy is still a safe surgery procedure for overweight and obese patients, with intensive perioperative management.