Gallbladder volume and contraction after a fatty meal was determined in 14 patients with gastric cancer before and 3-4 months after gastrectomy (7 total and 7 subtotal gastrectomies) with Roux-en-Y anastomosis. All patients had an increased gallbladder resting volume (p less than 0.001) and 10 of 14 patients (6 after total gastrectomy and 4 after subtotal gastrectomy) had an increased minimal residual volume after fatty meal stimulation (p less than 0.01) in the postoperative state, when compared to the preoperative values. It can be concluded that gastrectomy is followed by an impairment of gallbladder tone and contraction, both possibly increasing the risk of gallstone formation.