Oral cholecystography is still the basic modality for the diagnosis of gallbladder disease. Now, for the first time since the introduction of this procedure in 1924, this status is being challenged by another diagnostic technique, ultrasonography of the gallbladder. Ultrasound studies have major advantages over conventional cholecystography. These are sufficiently important that it can be safely predicted that ultrasonography will eventually become the primary diagnostic tool for evaluating the gallbladder. Just as the use of colonoscopy has provoked a new analysis of the barium enema examination in the evaluation of the colon, the introduction of ultrasound examination of the gallbladder has revealed the fact that falsenegative oral cholecystograms are not rare. Before ultrasonography this information was unobtainable, because of the surgeon's proper reluctance to perform a cholecystectomy in patients with normal oral cholecystograms. Ineed, the availability of an accurate alternate diagnostic procedure has stimulated a reevaluation of other difficulties associated with oral cholecystography. These include problems involved with nonvisualization and impaired visualization of the gallbladder after a single dose of contrast material, misunderstandings concerning the uses of oral cholecystography compared to those for intravenous cholangiography, and uncertainty regarding the value of cholecystokinin cholecystography in the diagnosis of acalculous cholecystitis. Knowledge of the pharmacokinetics of the oral cholecystographic contrast agents has been long overdue, considering the extensive use of these compounds in clinical practice for more than 50 years. However, information on this subject has finally reached a stage where the data can be applied to ensure that cholecystography is done with maximum efficiency and safety and with the least radiation exposure. The purpose of this report is to review the problems involved with imaging of the gallbladder by oral cholecystography and to discuss the indications, interpretation and accuracy of gallbladder imaging with ultrasonography. Data concerning the use of computerized tomography for evaluation of the gallbladder are still preliminary but are discussed.