Surgical correction of patent ductus arteriosus is,under most circumstances,highly successful and carries a low mortality. But infected PDA is yet potentially dangerous due to its frequent recurrence and resistant organisms to antibiotics. And,in surgical correction,surgeon may face the possibility of tearing of ductus arteriosus arterial end due to friability and adhesion of its surrounding tissue.This report demonstrats another problem in treatment of infected patent ductus arteriosus.This thirteen years old female patient received susceptible combined antibiotics intravenously from the day of admission and remitted from 4th.week of therapy.This remission state continued for 12days without relapse.But the pulmonary artery ruptured in this remission period.In autopsy,bacteria was not found in ductal vegetation.Also,there was no pulmonary artery aneurysm,Our experience show that in infected PDA,pulmonary artery can rupture spontaneously during remission period without aneurysmal formation.