During the period from January 1987 to December 1989, admissions for biliary tract disease at the New York Infirmary--Beekman Downtown Hospital were split almost evenly between Chinese immigrants from southeast Asia and all other ethnic groups (Caucasian, Hispanic, black, et cetera). However, the incidence of choledocholithiasis in patients undergoing cholecystectomy for cholelithiasis was much higher in the Chinese immigrant population, 37.2 versus 11.8 per cent, a highly significant difference (p = 0.001). In addition, we often found the disease to be of greater severity in Chinese patients. They were more likely to have large numbers of stones in the duct and more likely to have significant ductal enlargement. This increased risk was essentially constant regardless of age. Because of this threefold risk of choledocholithiasis when operating on a Chinese immigrant from southeast Asia for cholelithiasis, intraoperative cholangiography is mandatory, even in those without other indications for common bile duct exploration.