Type-I diabetes is considered an autoimmune disease, directed against pancreatic beta cells. Diabetes recurrence after pancreas transplantation is theoretically possible, and some cases have been reported after isotransplantation of segmental grafts in HLA-identical twins, where no rejection phenomenon is possible and where no immunosuppression was used. Diabetes recurrence has never been observed in a cadaveric allograft recipient, probably because immunosuppression efficiently blocks the autoimmune mechanism. Autoreactivity against beta cells exists life-long in type-I diabetes, and the immunosuppression used after transplantation becomes an advantage y preventing the recurrence of the disease.