Routine preoperative chest X-rays

687 patients presenting for routine and emergency anaesthesia were studied. 297 were found to have a chest X-ray. Abnormalities on chest X-ray were scattered amongst most age groups. Patients in American Society of Anaesthesiologists grade I were found to have abnormalities in only 4% of cases, and the abnormalities were of no anaesthetic significance. The incidence of abnormalities increased to 25% in grade II, 52% in grade III and 81% in grades IV and V. Patients in American Society of Anaesthesiologists grades III, IV and V, and those suffering from trauma should have a preoperative chest X-ray.