A 32-year-old man with lung cancer involving pericarditis carcinomatosa underwent pericardiotomy, using an Inoue balloon dilating catheter, to create a non-surgical pericardial window. The procedure was performed from the thoracic wall to the left pleural effusion and parietal pericardium under local anesthesia. The effects of non-surgical pericardial window had been maintained until this patient died from his primary disease. It is concluded that percutaneous balloon pericardiotomy is helpful in the management of massive pericardial effusions particularly in patients with malignancies and poor clinical condition.