During the past decade, several investigators reported effective application of intraoperative ultrasonography as a new diagnostic modality in surgery. Intraoperative ultrasonography has been successfully applied in the screening of the biliary tract and in the examination of the liver, pancreas, urinary tract, and endocrine organs. It has also been used successfully during vascular surgery. With the advent of minimal access surgery, the application of expensive preoperative diagnostic tests has visibly increased, particularly the use of ERCP procedures in patients with cholecystolithiasis. The loss of tactile feedback during laparoscopic surgery for gastrointestinal malignancy stimulated the increasing use of CT and MRI imaging. With our prior experience in intraoperative ultrasonography and in the advent of minimal access surgery, we were stimulated to introduce laparoscopic intraoperative ultrasonography (LIOU) in 1990 for screening the biliary tract for laparoscopic cholecystectomy. More reports on the use of laparoscopic intraoperative ultrasonography followed.