Case of bronchogenic cyst associated with extralobar pulmonary sequestration is presented in a 10-month-old baby. At thoracotomy, the tumor was an extralobar pulmonary sequestration with a central cyst surrounded by two pulmonary lobes vascularised by systemic vessels. Resection was easy. The cyst had a respiratory mucosa and was benign. The pathogenesis of the malformation is discussed.