Pancreas transplantation, when successful, is the only reproducibly effective method to normalize glycemia without the use of exogenous insulin treatment in patients with diabetes mellitus. Worldwide success rates for combined pancreas and kidney transplantation are approximately 70%, and patient survival rates are approximately 90% one year postoperatively, although certain institutions have higher rates. Benefits of this procedure include normalization of fasting plasma glucose, hemoglobin A1C, glucose-induced insulin secretion, and intravenous glucose tolerance. Improvements are observed in glucose recovery following insulin-induced insulin hypoglycemia, glucagon secretion during hypoglycemia, kidney structure, and both motor and sensory nerve function. However, no benefits are accrued in pancreatic polypeptide secretion, kidney function, and the retinal pathology of diabetes mellitus. Further progress in these therapeutic results must await improvements in drugs for induction of immunosuppression, methods to induce immune tolerance, or provision of the operative procedure to patients less compromised preoperatively with secondary complications of diabetes.