Computer-assisted 99mTc-HIDA cholescintigraphy was performed before and after elective cholecystectomy in 24 patients. Preoperative cholecystography had shown gallstones in a well visualized gallbladder in 12 of the patients, and in 12 the gallbladder had not been visualized. Liver function tests gave normal results in all 24 patients, and peroperative cholangiography showed no common duct stones in any patient. In the series with functioning gallbladder, comparison of the preoperative and postoperative scintigrams showed that cholecystectomy was followed by significantly earlier visualization of the lower part of the common duct and of the duodenum. The number of times that passage of activity to the duodenum was observed also rose significantly. Comparison of the time-activity curves showed that after cholecystectomy the liver activity reached its maximum value significantly earlier post-injection as compared with the preoperative values. All of these changes were absent in the series with nonfunctioning gallbladder. Removal of a functioning gallbladder results in accelerated, though still irregular flow of activity to the duodenum.