Between 1993 and 2004, 70 operations on patients with the diagnosis of mediastinal tumors were performed in the Cardiothoracic Surgery Department of Santa Maria Hospital. In this study we did not include diagnostic surgery of mediastinal tumors. In 70 patients treated, 63 p (90%) had the tumor located in the anterior mediastinum, 21 p with thymoma, 6 p with lymphoma, 4 p with carcinoid tumors, 1 p with sarcoma and 1 p with adenocarcinoma. 3 patients had tumors located in the medium and 4 patients in the posterior mediastinum. We analysed the results of the mediastinal tumors surgery during the 11-years period. Also, we evaluated the clinical effects of the thymectomy in myasthenia gravis.