Pulmonary hypoplasia(PH) commonly occurs in association with oligohydramnios and other congenital anomalies, especially congenital diaphragmatic hernia (CDH). Pulmonary hypoplasia is an important factor, as persistent pulmonary hypertension, in the prognosis of CDH. In some reports, there is a decrement of pulmonary surfactant in PH accompanying CDH. Recently, there are some reports that exogenous pulmonary surfactant therapy is effective in experimental animal model and neonatal respiratory distress with PH. We report a case of a 5 day-old male neonate, who had shown dyspnea and diagnosed as left pulmonary hypoplasia accompanying CDH. The CDH was surgically treated and the ipsilateral PH, with intratracheal administration of exogenous pulmonary surfactant postoperatively. After exogenous pulmonary surfactant application, the left lung volume was increased on chest roentgenogram and lung perfusion scan findings, and there was an improvement in oxygenation and clinical manifestations. We suggest that postoperative exogenous pulmonary surfactant replacement therapy is effective in the case of PH and further trials are needed to clarify the optimal dose and timing of supplementation of surfactant for treatment of infants with PH accompanying CDH.