OBJECTIVE To determine a) if clinical examination can accurately predict radiological change and b) if routine chest radiography is efficacious. METHODS All mechanically ventilated patients admitted to the Surgical Intensive Care Unit over a 4-week period were enrolled into the study. A physical examination was undertaken by two clinicians to predict significant (radiographic features which alter management) and insignificant (radiographic features which do not alter management) changes. The radiographs were then reviewed by a radiologist who noted any changes from previous radiographs. The clinical findings were then correlated with the radiographical findings. METHODS The study was conducted in a 16-bedded Surgical Intensive Care Unit which admits approximately 800 patients per year. The majority of these patients require mechanical ventilation. METHODS All patients who required mechanical ventilation were included. Thirty-four patients were studied. The patients were young adults admitted primarily following trauma with a low incidence of pre-existing disease. METHODS There were no interventions in this study. RESULTS One hundred sixty-four radiographs were evaluated. Both examiners were efficient in predicting significant changes (sensitivity of 93 and 97%), but less efficient at predicting insignificant changes (sensitivity of 74 and 70%). Two significant radiographical changes were missed on clinical examination: one catheter malposition and one pneumothorax, representing a yield from radiography of 1%. A 52% reduction in the number of radiographs would have resulted if the need for radiography had been determined by clinical examination. CONCLUSIONS Clinical examination can effectively predict the need for radiography. Routine chest radiography is, therefore, not indicated for ventilated patients in our Surgical Intensive Care Unit.