A new biodegradable tracheal prosthesis was developed using hydroxyapatite rings as the artificial tracheal cartilage, a carbon fiber tube as the tracheal tube; it was then implanted into the cervical trachea in dogs. Morphologic examination revealed that the hydroxyapatite ring was anchored firmly to the tracheal cartilage by ingrowth of cartilaginous tissue into the macropores of the hydroxyapatite.