Introduction: Computed tomography (CT) scans are often used in the evaluation of patients with blunt trauma. This study identifies the clinical features associated with further diagnostic information obtained on a CT chest scan compared with a standard chest X-ray in patients sustaining blunt trauma to the chest. Methods: A 2-year retrospective survey of 141 patients who attended a Level 1 trauma centre for blunt trauma and had a chest CT scan and a chest X-ray as part of an initial assessment was undertaken. Data extracted from the medical record included vital signs, laboratory findings, interventions and the type and severity of injury. Results: The CT chest scan is significantly more likely to provide further diagnostic information for the management of blunt trauma compared to a chest X-ray in patients with chest wall tenderness (OR = 6.73, 95% Cl = 2.56, 17.70, p < 0.001), reduced air-entry (OR = 4.48, 95% CI = 1.33, 15.02, p = 0.015) and/or abnormal respiratory effort (OR = 4.05, 95% CI = 1.28, 12.66, p = 0.017). CT scan was significantly more effective than routine chest X-ray in detecting lung contusions, pneumothoraces, mediastinal haematomas, as well as fractured ribs, scapulas, sternums and vertebrae. Conclusion: In alert patients without evidence of chest wall tenderness, reduced air-entry or abnormal respiratory effort, selective use of CT chest scanning as a screening tool. could be adopted. This is supported by the fact that most chest injuries can be treated with simple observation. Intubated patients, in most instances, should receive a routine CT chest scan in their first assessment. (C) 2006 Elsevier Ltd. All rights reserved.