Twenty consecutive patients with diabetes who were dependent upon insulin underwent simultaneous pancreatic-duodenal and renal transplantation at our center between March 1984 and August 1985. Eighteen patients are alive, 17 have functioning renal allografts and 13 have normal fasting blood sugar levels and are free of insulin use. Pancreatic graft loss was secondary to venous thrombosis in four instances and inadequate perfusion in one. Graft versus host disease occurred in three patients with composite pancreatic and splenic grafts, which led to a policy of not including the spleen as part of the graft. Serum creatinine levels were a more sensitive indicator of rejection than blood sugar levels which represent a distinct advantage of the simultaneous pancreatic and renal procedure, as compared with pancreatic transplantation after renal transplantation. Duodenal intestinal anastomosis appeared to be a satisfactory way of establishing exocrine pancreatic drainage. As results of pancreatic transplantation continue to improve, this procedure should no longer be considered as experimental.