Primary pericardial mesothelioma is a rare tumor of mesodermal origin that is infrequently diagnosed antemortem and survival is short. A 60 year old male case of pericardial mesothelioma(epitheloid type) is reported. He was admitted to Yeungnam University Hospital because of chest pain, dyspnea, orthopnea and nonproductive cough. Chest x-ray suggested pericardial effusion, 2-D echocardiography showed echo free spaces of massive pericardial effusion and areas of thick hyperrefractile echoes arising from the pericardium. Pericardiocentesis was attempted and aspirated fluid was bloody exudate. Pericardial window operation with biopsy was done. Swan-Ganz catheterization showed equalization between right atrial pressure and pulmonary capillary wedge pressure. The pathologic diagnosis was established by histologic finding at pericardial biopsy.