In order to study exocrine pancreas graft function and cytological findings, a technique of vascularized pancreas transplantation with special reference to a pancreatic juice collecting system has been developed in the rat model. For this purpose, a catheter is introduced into the common bile duct, which is ligated close to the duodenum, thus covering all pancreatic ducts. This catheter is connected to a reservoir implanted subcutaneously, from which pancreatic juice can easily be aspirated. The amount of 0.7-1.2 cc of juice produced over a 24-h period has proven to be sufficient for various analyses and cytological examination.