A 3-year-old boy with Treacher Collins syndrome had undergone tracheostomy and placement of a secured cannula at the age of 4 months. When he was 3 years old, he manually extracted the secured cannula by himself and choked to death. Autopsy revealed upper airway obstruction with posterior deviation and mucosal hyperplasia of the radix linguae, mandibular hyperplasia, and occlusion of the artifical airway owing to intratracheal granuloma due to the long-standing tracheotomy. For safe, long-term use of a tracheostomy to maintain the airway, children with craniofacial abnormalities should be carefully supervised by their families to prevent accidental decannulation.