Clinical datas of 20 patients with severe Guillain-Barre syndrome were evaluated retrospectively. The diagnosis was established on the electrophysiological and histopathological examinations (electroneurography, electromyography, sural nerve and muscle biopsy) and the analysis of the cerebrospinal fluid. All of the patients were treated with plasma exchange and some of them with other immunomodulant therapies (intravenous immunoglobuline, steroid, cyclophosphamide), too. To judge the clinical state correctly we used the modified Rankin scale. The patient's follow up went on for maximum 4 years. The improvement was satisfactory in 7 cases (35%) and good in 6 patients (30%). The last 6 patients had pure motor neuropathy. Six patients (30%) remained in severe residual condition. All of them had long-term course of disease, serious sensory symptoms and predominantly axonal degeneration of the peripheral nerves. One patient had died. The plasma exchanges were well tolerated, without any serious adverse event. This therapy would be safe and effective help in Guillain-Barre syndrome.