A rare case of metastatic tonsillar malignant mesothelioma is reported. In May 1990, a 63-year-old man presented with a solitary mass in the right frontal brain ten months after he had undergone right pleuropneumonectomy due to pleural malignant mesothelioma. In June 1990, the brain tumor which was a metastatic malignant mesothelioma was removed successfully. However, in June 1990 while receiving postoperative radiation therapy, he visited our department with complaints of a sore throat and slight fever. A necrotic tumor in the right tonsil and the right neck lymph node swelling were observed. Histological examination revealed metastatic malignant mesothelioma. In September 1990, tonsillar tumor extirpation and the right neck dissection were performed, and the defect was reconstructed by a cervical musculocutaneous flap. Follow up studies for 26 months have revealed no signs of local recurrence or distant metastasis.