BACKGROUND: The following three helicopter-based medical evacuation platforms operate in Southern Afghanistan: the US Army emergency medical technician (basic)-led DUSTOFF, US Air Force paramedic-led PEDRO, and UK physician-led medical emergency response team (MERT). Nearly 90% of battlefield deaths occur in the prehospital phase, comparative outcomes for these en route care platforms are unknown. The objective of this investigation was to characterize the nature of injuries in patients transported by three evacuation platforms. In addition, it aimed to compare observed versus predicted mortality among these provider groups. METHODS: A performance improvement study involving 975 coalition patients injured in Southern Afghanistan, transported from the point of injury to a military hospital, was performed. All patients were alive on admission with prehospital documentation recorded in the US Department of Defense Trauma Registry from June 2009 to June 2011. The main outcome measure was in-hospital mortality and observed versus predicted (Trauma and Injury Severity Score [TRISS]) survival were the primary end points. RESULTS: MERT transported more amputation and polytrauma casualties and included patients with higher mean Injury Severity Score (ISS) compared with PEDRO and DUSTOFF (16  vs. 11  and 10  respectively; p < 0.001). DUSTOFF was excluded from the subgroup analysis owing to insufficient numbers of severely injured casualties with only one death. The overall mortality for MERT and PEDRO was similar (4.2% vs. 4.6%, p = 0.967). Stratifying by ISS, there was lower mortality in MERT compared with PEDRO in the range of 20 to 29 (4.8% vs. 16.2%, p = 0.021). The observed mortality among PEDRO casualties was as predicted with the exception of the range of 20 to 29, while mortality in MERT was lower than predicted for all ISS groups with greater than 10. CONCLUSION: MERT achieves greater than predicted survival, which may be related to the additional capabilities onboard. This supports the adoption of a versatile medical evacuation system with scalable crew and equipment configurations that adapt to meet the medical, tactical, and operational needs of future conflicts. LEVEL OF EVIDENCE: Therapeutic study, level IV.