Endoscopic retrograde cholangiopancreatography can become a safe and easy procedure by means of sterilization of the instruments. Administration of antibiotics or chemotherapeutic agents, both systemically and mixed with the contrast material, and measurement and control of the injection pressure of the contrast medium using a manometer are employed to achieve as aseptic an operation as possible. For diagnosis of pancreatic cancer in its early stage, as well as diagnosis of minimal and moderate chronic pancreatitis, opacification should extend into not only the main pancreatic duct, but also branches of the pancreatic duct and fine pancreatic ducts. The procedure is one of the most reliable methods for the detection of diseases of pancreatic and biliary systems, especially for the diagnosis of space-occupying lesions such as malignant tumors, and chronic inflammatory changes of the pancreas, as well as differential diagnosis in jaundiced patients.