Malignant pericardial effusions (MPEs), which are commonly associated with cardiac tamponade, make oncologic emergencies requiring prompt drainage. In lung cancer patients, MPE is one of the most unpleasant terminal events. Drainage usually results in prompt palliation of symptoms, but recurrent effusions often occur. Sclerosis with pericardial instillation of various agents is reported to prevent the recurrence, and bleomycin is the most commonly used drug, with fewer toxicities compared with others. There is, however, no prospective trial of pericardial sclerosis as compared with drainage alone for MPEs, and it is far from clear whether sclerosis really benefits these patients in terminal stages.