INDICATIONS: There are two types of indications for Langerhans islets transplantation, patients with type 1 diabetes mellitus who have a functional kidney graft but who cannot be candidates for total pancreas transplantation, and soon, patients without renal failure who develop particularly uncontrollable diabetes mellitus. SEVERAL BASIC CONDITIONS: Several conditions are required for the success of Langerhans islet transplantation: a laboratory with demonstrated skill is isolating islets, a sufficiently large number of islets for injection (600,000 for a 60-kg patient), fresh islets harvested within less than 24 hours before transplantation, effective immunosuppressive treatment with no toxic effect on Langerhans islets. The injection is a simple procedure performed under local anesthesia via transhepatic catheterization of the portal vein. RESULTS: Through 2000, 10% to 20% of implanted grafts were functional at 1 year. Islets survival has exceeded 80% at 1 year. The gold standard for success is withdrawal of insulin therapy and normal glucose control. Islets grafts will undoubtedly become the next important step in the treatment of type 1 diabetes mellitus, but other techniques are also envisaged for the future.