We studied 111 myasthenic patients with thymoma followed over the last 20 years. Most patients were affected with severe myasthenia gravis (MG) and had been treated with immunosuppressive drugs. At the end of the follow-up, we observed good therapeutic results in 74% of patients, but a complete remission in only 10% of cases. The survival rate in thymoma patients was significantly lower than in nonthymoma cases. Clinical parameters, MG response to treatment and survival rate did not differ in patients with invasive and noninvasive thymic neoplasms. Patients with invasive thymoma showed slightly higher surgical mortality and a 10% incidence of tumor relapse.