Results of experimental and clinical xenotransplantation without immunosuppressive therapy in the treatment of insulin-dependent diabetes are summarized. Morphologic study demonstrated possibility of long-term preservation of macroencapsular xenogeneous culture of the insular cells in the blood of the recipients without immunosuppressive therapy. Thirteen patients with diabetes underwent surgery according to the developed method. Laboratory and clinical examinations demonstrated an increasing level of C-peptide, immunoreactive insulin, a decrease of fructozamine and insulin demand to 70-85%. It is concluded that intravascular xenotransplantation is an effective procedure, and it may be regarded as alternative to allotransplantation.