A seven-year-old boy with a history of recurrent aspiration pneumonia was admitted to the Seoul National University Hospital for suspension examination. Anesthesia was induced through the T-cannula with oxygen and enflurane, and ventilation of the lungs was performed easily and resulted in good bilateral breathing sounds. After administration of thiopental, atropine, and vecuronium, endotracheal intubation was administered through the tracheostomy site with an endotracheal tube. Manual ventilation through the pediatric circuit system failed to raise the chest wall. Breathing sounds were absent. Manual assessment of the reservoir bag revealed extremely poor compliance. Immediately, we examined the trachea via ventilation-assisted bronchoscopy and a 2 cm-long diverticulum located in the posterior wall 1.5 cm below the tracheostomy site was discovered. we could therefore understand the reason for the ventilation impairment. The tip of the tube impinged through the diverticulum. After widening the pathway, endotracheal intubation was accomplished successfully into the tracheostomy site and ventilation of the lung was performed easily and resulted in good bilateral breathing sounds. After suspension examination and T-cannula insertion the patient recovered from anesthesia and was transfered to the recovery room.