Our study attempts to define the role of pancreatic duct ligation for segmental pancreas transplantation. Five groups of dogs were studied. Group 1 (n = 6) included the sham-operated animals; group 2 (n = 8) included pancreatectomized animals that did not receive any transplant; group 3 (n = 8) consisted of animals with ligated pancreatic ducts after transplantation; group 4 (n = 8) consisted of dogs with unligated pancreatic duct transplants; and group 5 (n = 8) included dogs with anastomosed pancreatic duct transplants to a small bowel loop. All of the transplant groups received pancreatic autotransplantation in the iliac vessels. Pancreatectomized animals survived for an average of 11.5 ± 2.8 days (mean ± SD). Six of eight animals survived for more than 2 months after grafting in the anastomosed pancreatic duct transplant group, and they had normal glucose and insulin response after i.v. glucose tolerance test (IVGTT). Five of eight animals with ligated pancreatic duct transplants survived for 2 months post-transplantation, and at this time there was a diabetic IVGTT response with moderate pancreatic fibrosis at histological examination. Six of eight unligated pancreatic duct transplants survived for more than 2 months. They had a glucose response similar to that of the anastomosed pancreatic duct transplants after IVGTT. Serum amylase was moderately elevated in the 1st week after transplantation in the unligated group and remained within normal limits thereafter. There were no infections or other associated abnormalities with duct-free drainage of the pancreatic secretions into the abdominal cavity. Besides, no disrupture of the vascular anastomoses was seen after free pancreatic duct drainage. Several animals in the various groups of pancreatic transplants were followed for 1 year after grafting. The unligated and anastomosed pancreatic duct transplants had a normal endocrine response and no evidence of pancreatic fibrosis in the histological examination. Contrarily, the ligated pancreatic duct transplants had a diabetic response after IVGTT with clear evidence of pancreatic fibrosis at histological examination. Our study seems to indicate that unligated pancreas duct transplants do as well as the ones that received technically satisfactory pancreatic duct anastomosis. We believe that this is a good technique to be used when segmental pancreatic transplantation is indicated.