Common bile duct (CBD) exploration is often indicated when cholecystectomy is performed for gallstone disease. Choledochoscopy may help to decrease the incidence of retained common duct stones. The present study reviews 97 consecutive CBD exploration cases performed between 1980 and 1988, in order to evaluate the authors' experience with flexible choledochoscopy and CBD exploration. Fifty-nine patients had CBD exploration plus flexible choledochoscopy and 38 underwent CBD exploration alone. Retained stones were found postoperatively in ten per cent of the patients who had only CBD exploration versus four per cent in the choledochoscopy group. The retained stones in five patients were later removed by percutaneous basket retrieval (3), flush irrigation (1), and choledochoscopy (1). Flexible choledochoscopy detected additional stones after routine CBD exploration in 12 patients, clarified T-tube cholangiograms in four patients, and aided stone extraction in two patients. For these reasons, and because choledochoscopy was associated with a lower incidence of retained stones, the authors believe this procedure is a worthwhile addition in most cases of CBD exploration.