The mortality of 128 consecutive severely brain-injured patients (Glasgow Coma Score less than or equal to 8) treated by a land advanced life support system and transported to a trauma center was compared to the mortality of 104 consecutive severely brain-injured patients treated during the same time period by an advanced care rotorcraft aeromedical emergency service and transported to the same trauma center. The two patient groups had statistically similar distribution of CNS lesions and Glasgow Coma Scores. The mortality of the patients treated by the land ALS system was 40%. The mortality of the patients treated by the aeromedical service was 31%. The 9% reduction in mortality in the patients treated by the aeromedical service was statistically significant (p less than 0.001). There was also a statistically significant (p less than 0.05) reduction in the Glasgow Outcome Scores of the patients treated by the aeromedical service compared with patients treated by the land advanced life support system.