The records of 141 patients with myasthenia gravis who had thymomas were reviewed. In this series there were 69 non-invasive tumors and 52 invasive tumors. The five year survival for all patients was 60%, with the invasive group demonstrating a poorer prognosis than the noninvasive. The remission rates for the whole group (both invasive and non-invasive) of myasthenics was quite low (7%). Although the overall survival of this series of patients was relatively high, it is felt that by earlier diagnosis and a more aggressive surgical approach their prognosis will be even better.