The influence of the transport mode, i.e. Helicopter Emergency Medical Service (HEMS) versus ground-based Emergency Medical Service (EMS) on the mortality of multiple trauma patients is still controversially discussed in the literature. In this study a total of 333 multiple trauma patients treated over a 1-year period in a level I trauma center in Switzerland were analyzed. Using the newly established revised injury severity classification (RISC) score there was a tendency towards a better outcome for patients transported by HEMS (standardized mortality ratio 1.06 for HEMS versus 1.29 for EMS). Overall a short preclinical time and the presence of an emergency physician (EP) were associated with a better outcome.