Improvements in the operative management of acute traumatic thoracic aortic aneurysm have resulted in safe and expeditious repair. Nonetheless, multisystem injuries continue to inflict significant numbers of deaths. From 1970 to 1990, 108 patients with acute traumatic thoracic aortic aneurysm were evaluated. Mean injury severity score, excluding aortic injury, was 17.5. Ninety-three patients (86%) survived beyond initial resuscitation and came to operation. Median interval from injury to aortic repair was 8 hours (range, 2 hours to 19 days); there were five operative deaths. Lethal nonaortic injuries included 18 closed head injuries, four myocardial contusions, two intraabdominal vascular injuries, and one pulmonary contusion. The overall mortality rate was 39% of total admissions (42 of 108), and 29% of survivors of resuscitation (27 of 93). It is significant that only 11 of the 42 deaths (26%) were directly attributable to thoracic aortic aneurysm. Adjuncts to prevent spinal cord ischemia (shunt/bypass) were used in 76 patients, whereas 12 underwent clamp/repair. Postoperative paraplegia developed in 5 of 79 patients (6.8%, including 4 of 68 (5.9%) repaired with shunt/bypass and 1 of 11 (9.1%) repaired with clamp/repair (p = NS). Among those who developed paraplegia, the injury severity score was 27.0, and the median interval from injury to repair was 4.9 hours (range, 2 to 6.5). Intraoperative hypotension occurred in three of five patients with paraplegia. Death in patients with thoracic aortic aneurysm is due primarily to associated injuries and has remained relatively constant over the 20-year period of review. Overall injury severity, intraoperative hypotension, and extensive aortic tissue destruction may correlate with the development of postoperative paraplegia; however, a larger population sample is required to confirm this conclusion. A plea is made for standardized reporting of all patients with thoracic aortic aneurysm.