Chronic pancreatitis was induced in 22 piglets by dividing all pancreatic attachments to the duodenum; five sham-operated piglets served as controls. Two piglets died of postoperative complications. The animals were autopsied 2, 4, or 6 weeks postoperatively. All operated animals developed chronic pancreatitis. Concomitant with the development of interstitial fibrosis, an increasing progressive atrophy of the exocrine parenchyma occurred, with preservation of the islets of Langerhans. This atrophy and fibrosis were considerable already after 2 weeks. In one piglet only there was some acute inflammation and fat necrosis, whereas all showed at least moderate chronic inflammation, which did not change with time. The growth of the piglets stopped, and all had diarrhoea, which was thought to reflect exocrine insufficiency. Two animals (9%) developed a large pancreatic pseudocyst, and all animals had wide pancreatic ducts. The endocrine function was undisturbed. Intravenous glucose tolerance tests showed that the animals did not become diabetic. This model is appropriate for the study of experimental pancreatitis.