Advances in fiberoptic duodenoscopy permit direct observation of interior of the duodenum and cannulation of the ampulla of Vater, and to perform endoscopic retrograde cholangiopancreatography. Authors analized the 30 cases of E.R.C.P. done at the Department of Radiology, Seoul National University Hospital between Feb. and Aug. 1979, which were compared with the final diagnosis. The results are as follows; 1. Out of 30 cases, successful visualization of the duct of concern was achieved in 23 cases. 2. Out of 10 cases of suspected pancreatic disease, pancreatic duct was visualized in 7 cases, and 5 cases revealed pathognomonic findings. All 5 cases were diagnosed as pancreatic cancer and their findings were encasement, local dilatation, poor filling and obstruction of pancreatic duct accompanying C.B.D. obstruction or stenosis, so called double dubt sign. 3. Out of 19 cases of suspected biliary tract disease, biliary tract was visualized in 16 cases and 14 cases revealed sugges ive abnormal findings. In biliary stones, filling defect with proximal dilatation and obstruction were noted. 4. Post-E.R.C.P. complications were vague abdominal pain, asymptomatic hyperamyasemia, elevated amylase clearance ratio and symptoms due to premedication or post-E.R.C.P. antibiotics therapy. Elevated serum amylase concentration or clearance ratio were within normal range and it dose not seem to have clinical significance.