Biliary tree of gastrectomized patients was examined with ultrasonography to investigate the factors affecting post-gastrectomy gallstone formation. Only gallbladder stone was found in 57 (18.9%). In 11 (20.0%) of 55 patients, stones had developed within 2 years after surgery, but no difference in incidence were observed by sex and age. Sixty four gastrectomized gallstone patients were examined in respect to the kind of gallstone. Patients with cholesterol gallstones were 18 (28.1%), patients with black gallstones were 29 (45.3%) and patients with calcium bilirubinate gallstones were 17 (26.6%). The incidence rate of cholesterol gallstones was lower and the rate of black gallstones and calcium bilirubinate gallstones was higher than that of non-gastrectomized patients. In conclusion, the incidence of pigment gallstones is very high in gastrectomized patients.