Endoscopic retrograde cholangiopancreatography (ERCP) as well as upper-abdominal ultrasonography were performed on 134 patients. Organ structure was optimally demonstrated by ultrasonography in 94 patients (70.2%) and partially in 29 (21.6%) Comparing the diagnostic assessment in 62 patients who had undergone 73 tests and had subsequently been operated on (57) or examined post-mortem (5) there was a statistically significant advantage of ERCP in diseases in which the choledochal duct had been involved. The method was successful in 95% of cases of choledocholithiasis (20 cases) compared with 45% by ultrasound and in 85% of cases of gall-bladder carcinoma which also involved the choledochal duct (38% by ultrasound). In clinically manifest carcinoma of the head of the pancreas (9 cases) and cholecystolithiasis (19 cases) ultrasonography provided the correct diagnosis in 89%, while the results for ERCP were 56% and 74%, respectively.