To examine the efficacy of bleomycin on the local control of malignant pericardial effusion, we prospectively conducted a clinical trial consisting of continuous pericardial drainage and a local instillation of bleomycin. In the current study, we treated 7 patients, who suffered from malignant pericardial effusion with cardiac tamponade due to advanced-stage non-small cell carcinoma of the lung. The pericardial effusions were continuously drained through an echo-guided inserted catheter. After the effusions were drained as completely as possible, 5 mg of bleomycin were instilled locally via the catheter. In all patients but one, the draining catheter could be successfully removed. The duration of drainage ranged from 4 to 13 days (mean: 9.2 days). Five of the 7 patients achieved a complete remission of pericardial effusions, which was maintained until death or the last day of follow-up. Intrapericardial bleomycin treatment was thus found to be effective on malignant pericardial effusions without any adverse effects. However, a further study comparing the effect of pericardial instillation of bleomycin versus drainage alone would be needed for the determination of the usefulness of bleomycin.