We performed percutaneous balloon pericardial window (PBPW) in 8 patients (age 40 to 70 yrs; 4 men, 4 women) with malignant pericardial effusion and tamponade. Pericardial window was indicated because they continued to drain greater than 100 ml/day of pericardial fluid through the pigtail catheter for greater than or equal to 3 days. A 0.038 inch guidewire was advanced through the pigtail catheter into the pericardial space and then the catheter was removed. A 20 mm diameter, 3 cm long balloon dilating catheter was advanced to straddle the parietal pericardium. Manual inflations were performed until the waist produced by the pericardium disappeared. All patients tolerated the procedure well with minimal discomfort and with no complications. A left or bilateral pleural effusion occurred in all patients after PBPW. No patient developed recurrent pericardial tamponade at a mean follow-up of 6 +/- 2 months. Thus, PBPW is a useful and safe technique to avoid surgery in patients with malignant pericardial effusion and tamponade.