Children`s small airway precludes the use of standard methods of bronchial separation. So, we performed the posterior thoracotomy under the prone position in 3 cases to avoid endobronchial gravity spillage of secretion and infected debris from the diseased lung to the contralateral sound lung. The advantages of the posterior thoracotomy under the prone position was discussed. In two cases, empyema with total collapse of left lung and congenital cystic adenomatoid malformation [CCAM] of right lung, copious secretion was spilled through the endotracheal tube but could be removed successfully by the endotracheal suction. In the third case of bilateral peripleural abscess, bilateral posterior thoractomy was done without position change. All procedures were performed without any technical difficulty and complication.