We reviewed CT of eight patients with malignant schwannomas arising in the thorax. Only one patient had neurofibromatosis. Five lesions occurred in the posterior mediastinum, one lesion was in the middle mediastinum, and two lesions were in the chest wall. Common CT findings were the presence of low-density areas (six of eight), compression of adjacent structures (six of eight), pleural abnormalities (six of eight), such as pleural effusion or pleural nodules, and metastatic pulmonary nodules (five of eight). Pleural abnormalities or pulmonary nodules were detected in seven of eight patients. These CT findings can help in differentiating malignant schwannoma from benign neurogenic tumor.