Four patients with diabetes mellitus of juvenile onset but without uremia were treated with segmental transplantation of the body and tail of the pancreas. The indications were hyperlabile diabetes or progressive loss of vision. The grafts were procured from cadaveric donors 4-16 min after circulatory arrest and were subsequently stored in the cold for approximately 4 h. In 1 patient the pancreatic duct was ligated, while in the other 3 drainage was attained by suturing the transected end of the pancreas into a jejunal Roux-en-Y loop. Three of the grafts failed within 6 wk as a result of irreversible rejection, and 1 graft failed because of the early onset of venous thrombosis. The 1st sign of graft rejection was an increase in the postprandial blood sugar level, an increase in the fasting blood sugar level occurring several days later. Neither hyperamylasemia nor fever was observed. Radioisotope scans and angiograms were of great value in establishing the diagnosis of graft rejection. All of the patients survived after graft removal.