The diagnosis of inhalation injury in burn patients is of great importance as it is associated with a significant increase in morbidity and mortality. Although numerous methods of diagnosing inhalation injury have been recommended, it has been difficult to reach consensus as to the criteria for making the diagnosis as well as the grading of the severity of the injury to the airway and lungs. For clinical research into the outcomes and treatment of inhalation injury to be successful, it will be imperative that the codification of inhalation injury be consistent throughout all burn centers participating in these studies.