An evaluation of intra-operative B-mode ultrasound scanning of the extra-hepatic biliary tree and pancreas shows that it is a useful, noninvasive method of detecting bileduct calculi and assessing pancreatic disease. In 50 patients undergoing cholecystectomy for gallstones, ultrasound scanning was an accurate as per-operative cholangiography; the decision to explore the bileduct, made on ultrsound findings, was correct in 49/50 cases, and that made on X-ray findings was correct in 46/47 cases; there was 1 false-positive in each group. Scans of 5 patients with pancreatic disease were compared with 28 normal pancreatic scans. Infiltration of the portal vein by tumour was easily detected. Differentiation of carcinoma from chronic pancreatitis by ultrasound scanning might with more experience be possible, whilst identification of other pancreatic lesions, such as cysts, calculi, or endocrine tumours, will certainly be facilitated by this new technique.