Multiple imaging modalities are available for the preoperative diagnosis of diaphragmatic injury. Chest radiographs are the initial and most commonly performed imaging study to evaluate the diaphragm after trauma. When chest radiography is indeterminate, spiral computed tomography (CT) with thin sections and reformatted images is the next study of choice, particularly because most hemodynamically stable patients with blunt diaphragm injury will require an admission CT examination to evaluate the extent and anatomical sites of coexisting thoracoabdominal injuries. Magnetic resonance imaging is used to evaluate the diaphragm for patients with clinical suspicion but an indeterminate diagnosis after chest radiography and spiral CT.