The article is devoted to actulal problem of endocrinology and surgery-treatment of severe diseases of the thyroid gland. Results of plasmapheresis application in complex preoperative preparation in 90 patients, aged from 20 to 60 yrs, in severe course of the disease, were adduced. After plasmapheresis preparation conduction the reduction of the autoimmune processes in the patients organisms, the antibodies titer lowering were noted, witnessing the stable remission achievement. Plasmapheresis application in complex of treatment of patients with autoimmune thyroiditis and diffuse toxic goiter causes significant positive influence on hormonal and immune state.