Four patients of acute purulent pericarditis were seen at the Jeonbug National University Hospital between January, 1979 and December 1983. All patients were proven to have acute purulent pericarditis by clinical evaluation, bacterial study, and biopsy. Three patients were male and one female. The three patients were in pediatric age. The primary focuses were meningitis, Rt. coxitis, lobar pneumonia, and gastro-enteritis. The causative organisms were staphylococcus aureus in two patients. In the other two patients, organisms were not cultured from the pericardial pus. The reason why the causative organisms were not cultured in pericardial pus was probably due to massive antimicrobial treatment before pus collection. All patients were treated with systemic antibiotic therapy and pericardiostomy with normal saline irrigation. The three patients were treated without specific complication. The one patient developed the chronic constrictive pericarditis. In this patient, pericardiectomy was performed.