OBJECTIVES: To gather information on helicopter emergency medical services (HEMSs) activities across Europe. METHODS: Cross-sectional data-collection on daily (15 November 2013) activities of a sample of European HEMSs. A web-based questionnaire with both open and closed questions was used, developed by experts of the European Prehospital Research Alliance (EUPHOREA). RESULTS: We invited 143 bases from 11 countries; 85 (60%) reported base characteristics only and 73 (51%) sample-day data too. The variety of base characteristics was enormous; that is, the target population ranged from 94.000 to 4.500.000. Of 158 requested primary missions, 62 (0.82 per base) resulted in landing. Cardiac aetiology (36%) and trauma (36%) prevailed, mostly of life-threatening severity (43%, 0.64 per mission). Had HEMS been not dispatched, patients would have been attended by another physician in 67% of cases, by paramedics in 24%, and by nurses in 9%. On-board physicians estimated to have caused a major decrease of death risk in 47% of missions, possible decrease in 22%, minor benefit in 17%, no benefit in 11%, and damage in 3%. Earlier treatment and faster transport to hospital were the main reasons for benefit. The most frequent therapeutic procedure was drug administration (78% of missions); endotracheal intubation occurred in 25% of missions and was an option hardly offered by ground crews. CONCLUSIONS: The study proved feasible, establishing an embryonic network of European HEMS. The participation rate was low and limits the generalizability of the results. Fortunately, because of its cross-sectional characteristics and the handy availability of the web platform, the study is easily repeatable with an enhanced network.