This protocol is designed for screening of patients with renal failure and/or diabetes who may be eligible for kidney, kidney-pancreas, or islet cell transplantation. Its purpose is to allow detailed investigation into the renal and endocrine function of these patients, and the status of other organ systems that would determine their ability to safely tolerate specific aspects of other therapeutic research protocols. After completion of this screening process, the patient will either be offered a chance to participate in an active treatment protocol, or if no appropriate protocol is identified, will have recommendations for other treatment options relayed to the primary or referring physicians.