Broken tracheostomy tube as a foreign body in the trachea is one of the rare complications of tracheostomy and it's incidence is very low. Authors experienced one case of broken tracheostomy tube(outer canula) in the trachea, occuring in 8 years old patient, removed as a foreign body in the trachea. We report about this patient with review of the literatures. Causes of broken tube were mainly suggested as follows : 1) Aging & deterioration of the tube which result from prolonged usuage. 2) Chemical erosion of metal tube which result from prolonged contact with tracheobronchail secretion. 3) Difference of materials used in the manufacture of the tube and acturing manufacturing process. 4) Methods employed in the care and sterilization of the tube. And some preventive measures are suggested as follows : (1) Choice of appropriate tube as patient's condition. (2) Closed observation when manufacturing of the tube. (3) Frequently sterilization & change of the tube. (4) Frequently follow-up at hospital.