The clinical and radiographic findings of 11 patients with a chronic traumatic aneurysm were reviewed. Each patient had been under medical care at the time of injury but acute aortic rupture was not recognized in any, although several signs of mediastinal hemorrhage were present on the immediate posttraumatic radiographs. The average time between the initial trauma and the detection of the aneurysm was 5.3 years. Seven patients showed no or minimal specific complaints. Four patients showed more or less severe complaints of dysphagia, severe thoracic pain, hoarseness, and dyspnea. In all patients the chest radiograph was abnormal: Four patients showed a mass lesion at the level of the aortic knob. The other seven patients showed contour deformities of the descending aorta, sometimes subtle, with (five) or without (two) calcification. Esophagography and CT were useful in several patients. In the light of the unpredictable course of a chronic traumatic aneurysm and the low operative mortality, early operation after detection is recommended. Preoperative angiography is usually desirable.