9 subjects with myasthenia gravis, chronically treated with prednisone, underwent an open clinical trial with cyclosporine, an immunosuppressive and immunomodulator drug. Preliminary results after one year of treatment show that cyclosporine induces a further improvement of myasthenic symptoms, and that prednisone may be reduced or discontinued without relapse of clinical symptoms. Side effects of cyclosporine are very frequent and largely influence the treatment.