Objective:We aimed to evaluate the effect of simultaneous cholecystectomy on the short-term postoperative outcomes and nutritional status in patients with gastric cancer.Methods:We retrospectively reviewed data from 4,820 patients with gastric cancer who underwent gastrectomy from January 2011 to December 2016.Patients who underwent only gastrectomy (N=4,578) were matched to those who underwent simultaneous cholecystectomy during gastrectomy (N=242) at a 1:1 ratio using propensity score matching analysis.The nutritional status and inflammatory responses preoperatively and postoperatively and postoperative outcomes were compared between the groups.Results:The simultaneous cholecystectomy group showed more intraoperative blood loss and a longer operative time than the gastrectomy only group [150.0 (100.0,200.0) mL vs.100.0 (100.0,200.0) mL,P=0.006;176.0 (150.0,210.0) min vs.155.0 (128.0,188.0) min,P＜0.001,respectively].Intraoperative event rate,postoperative complication rate,and postoperative recovery did not differ between the groups.All parameters including body weight,the hemoglobin level,absolute lymphocyte count,total protein level,albumin level,fasting glucose level,and prognostic nutritional index excluding the cholesterol level were not significandy different between the groups,and their changing patts were similar.Although the cholesterol level was significantly lower in the simultaneous cholecystectomy group than in the gastrectomy only group at all follow-up points,the mean value of the decreased cholesterol level was within normal range.Conclusions:In gastric cancer patients with gallbladder disease,simultaneous cholecystectomy is safe and not associated with additional nutritional loss.