A prospective study was conducted on 102 patients (84 male), with a median age of 27 years, who had sustained a penetrating chest wound to evaluate the ability of physical examination in comparison with chest radiography to determine management of these injuries. Knife wounds accounted for 92% of the injuries. Fifty three patients had a small collection of air or fluid in their pleural cavity that was not drained. Fifty six hemithoraces had a large collection of fluid or air and were treated by tube thoracostomy. Physical examination at presentation detected large collections of air and fluid correctly and predicted appropriate management (sensitivity 96%, specificity 94%). Residual collections of air or fluid or both were also predicted correctly by clinical examination. Seven small collections increased in size and required intubation. Routine pre-extubation radiographs were found to be of little value in management and their routine use is not recommended. Four patients required late thoracotomy for decortication. By using a policy of selective intubation, frequent clinical reassessment, and chest radiography when relevant, experienced trauma surgeons can manage most penetrating pleural injuries with an acceptably low complication rate.