Diaphragmatic rupture is a potentially severe complication of blunt trauma which can easily be overlooked during initial emergency department evaluation. Delayed diagnosis is due to severe concurrent injuries and lack of specific clinical features and instrumental procedures. Clinical features of diaphragmatic herniation, in the early presentation, include respiratory symptoms, while abdominal symptoms and signs are late. Plain chest radiography repeated, if negative, is the main help in the diagnosis: especially in patients managed with intermittent positive-pressure ventilation. Experience in five cases of diaphragmatic hernia is reported.