There is no experimental basis for transplantation of the pancreas in patients with non-insulin-dependent diabetes mellitus. We compared results in normal and grafted non-insulino-dependent Lewis rats. A heterotopic pancreatico-duodenal graft was implanted with end-to-side anastomosis of the coeliac artery and the portal vein of the donner on the infrarenal aorta and inferior vena cava of the recipient. The diabetic rats showed weight loss, high blood glucose levels (3.30 +/- 1.25 milligrams), moderate insulinopenia and significantly elevated liver production of glucose. Glycaemia, weight and liver production of glucose were the same as those in the group of normal animals. We concluded that transplantation of the pancreas in an isogenic model without immunosuppression can correct glucose levels and insulino-resistance. It could be suggested in man.