Acute purulent pericarditis, though not common in incidence after introduction of antibiotics, is still potentially life treating isease. Since 1971, we have experienced 14 cases of acute purulent pericarditis with successful treatment. Among these 14 cases, 9 cases were male and they had high occurrence on their third to fifth decades in age distribution. Isolation of causative organisms were obtained in 11 cases through the bacterial culture of infectious source which was mainly pericardial effusion or blood, and the most frequently recovered organism was the staphylococcus aureus. Pre-existing inflammatory disease preceding to pericarditis, named as antecedent disease, were proved in 12 cases, and among which contiguous extension from the intrathoracic infection such as pneumonia or empyema accounted for the majority of antecedent disease. Pericardiocentesis with administration of antibiotics were tried in all cases, but result in recovery in 1 patient only. Remaining 13 cases had persistent picture of pericarditis and necessitated surgical drainage procedure. Ten of these 13 cases were underwent the open pericardial window using a mode of anterior approach in 4 and subxiphoid approach in 6 cases respectively. Two cases of subxiphoid group were reoperated by the anterior interphrenic pericardiectomy, due to insufficient drain of too thick effusion. In remaining 3 cases, anterior interphrenic pericardiectomy was performed initially because of purulent effusion already changed into fibrinopurulent peel with thickened pericardium. Through the experience of this series, we recommended that pericardiectomy should not be reluctant in purulent pericarditis as a initial surgical procedure for advantage of complete removal of infected space and avoidance of late constrictive pericarditis.