Malignant pericardial mesothelioma was successfully resected in a 70-year-old man, who had been admitted complaining of palpitation. Chest X-ray films showed slight cardiac enlargement. A moderate amount of pericardial effusion was noted by echocardiography. Chest X-ray commputed tomography and MRI revealed a localized pericardial tumor. Total excision of the tumor was accomplished through a left thoracotomy approach because the tumor showed neither invasion to the myocardium nor dissemination to the pericardium. The patient was discharged following an uneventful postoperative course. No sign of recurrence has been encountered for nine months after surgery. However careful observation is needed.