133Xenon lung scanning post-thermal injury was used to detect inhalation injury in 86 patients admitted to the United States Army Institute of Surgical Research during 1974. Inhalation injury was indicated by the 37 (43%) positive scans. Based on all available clinicopathologic evidence, 11 (13%) of the scans were erroneous with seven (8%) falsely positive and four (5%) falsely negative. Eighty-six per cent of the scans were "appropriate." Addition of bronchoscopy and/or pulmonary function testing appeared to improve diagnostic accuracy. By using any pair of tests, falsely negative diagnoses were virtually eliminated. Inhalation injury, as expected, had an adverse effect on survival rates. The group of patients whose expected mortality lay between 40 and 59% were most notably affected. One hundred per cent (five of five) of those with inhalation injury died; only one of eight without inhalation injury died.