Purpose : The aim of this study was to assess the clinical utility of the known CT signs of the traumaticrupture of the diaphragm. Materials and Methods : CT scans and chest radiographs were retrospectively reviewed in13 patients who had diaphragmatic rupture confirmed by surgery. On chest radiographs, the elevation of thediaphragm was evaluated. On CT, 1) discontinuity of the diaphragm, 2) lack of depiction of the diaphragmsurrounding the herniated intraabdominal organs (absent diaphragm sign), and 3) fat seen lateral to the diaphragm(fat sign) were evaluated. Results : Chest radiographs showed the elevation of the diaphragm in 11 patients (85%).CT scan showed absent diaphragm sign in 11 patients (85%), discontinuity of the diaphragm in 8 (62%), and fat signin 7 (54%). All of 12 patients who had the left diaphragmatic rupture had one or more of the above findings.Conclusion : Discontinuity of the diaphragm, absent diaphragm sign, and fat sign may be helpful CT findings in thediagnosis of the traumatic rupture of the left diaphragm.