SummaryIntraoperative ultrasonography during laparoscopic cholecystectomy is a new procedure for examining the bile duct. The ultrasonic probe used in this study utilized a 7.5-MHz convex array designed for easy insertion through a 10-mm cannula. This probe was 90 cm long, had a 10-mm diameter, and was equipped with an angulation system controlled by levers. Additionally, this ultrasound system could detect the direction of the blood flow using a color Doppler display. Both laparoscopic ultrasound and laparoscopic cholangiography were attempted in 45 patients. In 41 of the 45 patients, laparoscopic ultrasound was successful in visualizing the first-order hepatic branches and the common bile duct. On the other hand, laparoscopic cholangiography was successful only in 38 of the 45 patients. The color Doppler capability helped to distinguish the bile duct from the portal vein and hepatic artery. Visualization of the bile duct was achievable by laparoscopic ultrasound. Also, the color Doppler system easily identified the bile duct. However, further design improvements in the ultrasound probe are required to establish laparoscopic ultrasound as an effective intraoperative routine procedure.