It may be the most important problem to keep the airway during general anesthetic procedure. The authors experienced a case of left segmental bronchial obstruction with foreign body during general anesthesia for right pneumonectomy on the position of left decubitus, which was successfully removed by fiberoptic bronchoscopic aspiration and atelectasis due to segmental bronchial obstrucion was completely cured by active management of I.P.P.B., inhalation of oxygen with humidification, endobronchial suction, and symptomatic medication.