The role played by chest radiograph and CT scan in diagnosis of pneumothorax is analyzed in a retrospective study based on two years of activity in Intensive Care Unit. The sensibility of traditional chest radiography was 75% while the sensibility of CT scan resulted higher (87.5%). In the authors opinion, when pneumothorax is suspected, particularly in patients with polytrauma, CT scan of the chest is mandatory unless patient's conditions or logistic difficulties related with transport of the patient contraindicate it.