A case of selective kidney allograft rejection with stable pancreas function in a patient who received simultaneous kidney-pancreas allograft from the same donor is reported. Pancreas function was shown to be normal within the first month posttransplant by both a glucose tolerance test (despite a high corticosteroid dose) and stable urinary amylase values during biopsy-proven acute renal allograft rejection. This patient subsequently rejected his kidney allograft as documented by histopathologic evidence of severe chronic vascular rejection and acute tubulointerstitial rejection, yet his pancreas function remained intact. He subsequently received a six-antigen-matched kidney, continues to have normal fasting glucose and normal glucose tolerance by oral glucose tolerance test, and is without evidence of glucosuria. He has never had a clinical rejection of his pancreas, as evidenced by either a decline in urinary amylase or hyperglycemia, and has not required insulin except in the perioperative period of his second kidney transplant, at which time he was receiving high doses of both corticosteroids and cyclosporin. It is suggested that preferential rejection and subsequent loss of the kidney, although infrequent, do occur in combined renal-pancreas allografts and that maintenance of immunosuppression is justified until retransplant of kidney is available.