The purpose of this study was to review whether air ambulance transportation of trauma patients to the Brooke Army Medical Center (BAMC) level I trauma center contributed to maintaining national mortality standards in the trauma care of these patients. Aeromedical transportation is considered a standard-of-care component of regional trauma systems throughout the United States. Pooled trauma database information from 792 consecutive ambulance-transported trauma patients received at BAMC during the fiscal year from October 1, 1995, to September 30, 1996, were reviewed. The 792 trauma patients were composed of 687 patients transported by ground ambulance and 105 patients who received helicopter aeromedical evacuation. Aeromedical evacuation was associated with increased levels of prehospital medical care and faster transportation than ground ambulance service. The mortality rates (immediate, early, and late deaths) of both ambulance groups were compared with national mortality standards using the internationally recognized Trauma and Injury Severity Score methodology, based on the Major Trauma Outcome Study in 1986 and validated in 1992. The Z test for independent populations demonstrated no statistically significant difference between BAMC trauma mortality rates for either ambulance group compared with national trauma mortality rates. The results suggest that aeromedical evacuation of the more severely injured patients farthest from the BAMC trauma center resulted in mortality rates that met national standards.