We have analysed retrospectively the pancreatic ultrasound scans (using a bistable machine) in 138 consecutive patients, and have related the results to the clinical status and the final diagnosis in each case. The scans were read without knowledge of the patient's clinical state. When technically unsatisfactory scans were excluded from consideration, the overall diagnostic accuracy of ultrasonography proved to be 82%, with a false positive rate of 8%. The scan was abnormal in all 10 patients with cancer of the pancreas: a positive diagnosis of cancer was made in six. All patients with chronic pancreatitis in relapse had abnormal scans, but in 53% the scans were normal in patients in whom the disease was in clinical remission. In seven patients with chronic pancreatitis who suffered relentless pain, the head of the pancreas was swollen and contained cystic areas or emitted abnormal echoes. In acute pancreatitis ultrasonic scanning proved useful in following the progression of the disease to final resolution, or to development of complicating pseudocyst, abscess, or ascites. Random echoes in the early stages of acute pancreatitis are features of haemorrhagic necrosis. In alcoholic relapsing pancreatitis the persistence of abnormal echoes, disposed linearly along the axis of major ducts, suggests the presence of chronic pancreatitis.