Objective To observe the clinical effects of combined islet cell and kidney transplantation in the treatment of insulin-dependent diabetes mellitus associated with end-stage renal failure.Methods Four patients with type I diabetes and ESRD received combined renal and islet cells transplantation.Clinical and metabolic data were studied during the follow-up.Results The cultured human adults islet cells were infused into the portal vein system of the 4 patients.Immunosuppression included CsA.azathioprine and prednisone.Metabolic follow-up comprised assessment of daily fasting and non-fasting blood glucose,basal C-peptide secretion,HbAIc,renal function and blood cell counts.Islet isolation yielded 25 000～48 000 equivalents(single or multiple donors).No adverse effects were seen subsequent to islet transplantation.Basal C-peptide secretion maintained at normal levels.and blood glucose and HbAIc levels were normalized throughout the observation period.The dosage of insulin were decreased by over 25% in all 4 patients after transplantation.Conclusions Combined adult islet cells and renal transplantation has a good effect in the treatment of the patients with type Ⅰ diabetes and ESRD and can be used as an effective way for treating ESRD secondary to the type Ⅰ diabetes.Postoperative efficacy is related not only to the quantlty and quality of the islet cells,but also to the rejection of the grafts.