Diabetic patients with end-stage renal disease have a high mortality rate. A combined kidney-pancreas transplant is associated with greater life expectancy. Pancreas islet transplantation is an alternative involving a lower degree of morbidity. We present two patients, of 41 and 37 years of age, with a long history of diabetes mellitus (C-peptide negative), both with a previous kidney transplant, who had been treated with 22 and 28 U of insulin/d, respectively. Both patients had frequent episodes of unawareness hypoglycemia. Pancreatic islets were infused to a total of 7809 and 19,180 IE/kg, respectively. Basal posttransplant C peptide levels were 2.9 and 1.3 ng/mL. After the implant, one patient required occasional doses of insulin, and the other patient more than 50% reduced dose. After the first implant neither patient had any episodes of unawareness hypoglycemia. HbA1c at 4 months were 6.2% and 6.9%. There were no transplant-related complications.