Objective: To determine the predictive and diagnostic value of thorax trauma severity score (TTSS) in a population of thoracic trauma patients admitted to a secondary level trauma center.Methods: A Retrospective analysis of patients admitted over a period of two years with IDC-9 codes related to thoracic trauma was undertaken. The association of TTSS with complications and mortality was evaluated. We also determined the predictive value of TTSS using receiver operating characteristic curve (ROC).Results: 238 patients with thoracic trauma, mostly middle-aged (62.2 ± 15 years), were included. The main mechanisms of injury were falls and traffic accidents. Thirty-three patients had important extra-thoracic injuries, but only 9 presented an ISS> 15. The average ISS was 3 ± 5; Morbidity was 2.5% and mortality was 2.1% as a result of thoracic injury and these patients had significantly higherTTSS values. Each score component was analyzed separately, showing significant association with complications and mortality. The area under the curve for TTSS was significant for predicting complications (0.848) and mortality (0.856) values. TTSS with a cut off value of 8 points had a sensitivity of 66% and specificity of 94% to predict complications and 80% sensitivity and 94% specificity for predicting mortality.Conclusions: The TTSS is an appropriate and feasible tool to predict the development of complications or mortality in a population of mostly mild thoracic trauma.