Implementation of the first Danish helicopter emergency medical service (HEMS) was associated with reduced time from first medical contact to treatment at a specialized centre for patients with suspected ST elevation myocardial infarction (STEMI). We aimed to investigate effects of HEMS on mortality and labour market affiliation in patients admitted for primary percutaneous coronary intervention (PCI).In this prospective observational study, we included patients with suspected STEMI within the region covered by the HEMS from January 1, 2010, to April 30, 2013, transported by either HEMS or ground emergency medical services (GEMS) to the regional PCI centre. The primary outcome was 30-day mortality.Among the 384 HEMS and 1220 GEMS patients, time from diagnostic ECG to PCI centre arrival was lower with HEMS (median 71 min vs. 78 min with GEMS; P = 0.004). Thirty-day mortality was 5.0% and 6.2%, respectively (adjusted OR = 0.82, 95% CI 0.44–1.51, P = 0.52. Involuntary early retirement rates were 0.62 (HEMS) and 0.94 (GEMS) per 100 PYR (adjusted IRR = 0.68, 0.15–3.23, P = 0.63). The proportion of patients on social transfer payments longer than half of the follow-up time was 22.1% (HEMS) vs. 21.2% (adjusted OR = 1.10, 0.64–1.90, P = 0.73).In an observational study of patients with suspected STEMI in eastern Denmark, no significant beneficial effect of helicopter transport could be detected on mortality, premature labour market exit or work ability. Only a study with random allocation to one system vs. another, along with a large sample size, will allow determination of superiority of helicopter transport.