Since its introduction in 1924, oral cholecystography has been used as a screening method in the diagnosis of the gallbladder disease. Recently, intravenous cholangiography has become a most valuable method in the diagnosis of biliary tract pathology because of its advantage of simultaneous visualization of the gallbladder and bile ducts in a short time. However, opinions vary considerably as to the significance of nonvisualization of the gallbladder with oral cholecystography. In attempt to evaluate how much intravenous cholangography does contribute to the diagnosis in the cases that the gallbladder cannot be opacified or can only faintly visualized by the oral method, we have made a clinical observation in 168 patients, in whom intravenous cholangiography had been performed within a week following oral cholecystography, at Korea General Hospital during the last three years from January 1969 to December 1971. The results obtained are summarized as follows; 1. The results of ral cholecystography in 168 cases were as follows; well opacification of the gallbladder in 10 cases, faint opacification in 46 cases and nonopacification in 112 cases. 2. In 37.5% (42 cases) of 112 gallbladder not opacified by the oral method, the gallbladder was subsquently opacified by the intravenous method, and 11.6% (14 cases) turned out to be normal when examined by the intravenous method. 3. Further demonstration of abnormalities could be obtained with the aid of intravenous cholangiography in 28 cases (16.6%); cholelithiasis in 12 cases and choledocholithiasis in 16 cases. 4. In every cases of 14 patient whose gallbladder were virtually not opacified by both oral and intravenous methods but the common bile ducts could be opacified by intravneous cholangiography, definite abnormalities were identified in the gallbladder at surgery.