Introduction: In Sweden, several ambulance helicopter programs have been used during the past 3 decades. This article describes one of these programs. Setting: The catchment area of the helicopter system under study was a typical rural setting with a population density of less than 5 people per square kilometer. Methods: We describe in detail, with special reference to medical aspects, the activities of an helicopter ambulance program in 1997. Results: A total of 288 missions, including 328 patients (204 men), were analyzed. Trauma cases (29%) and patients with cardiovascular (24%) and neurologic problems (13%) dominated the missions. One-sixth of the cases occurred at night. The median response time was 12 minutes, and the median on-scene time was 28 minutes. The medical interventions performed included intubations; central venous catheter, arterial needle, and duodenal tube insertions; and medication administered intravenously, orally, and intrabronchially. Conclusion: We detected a higher rate of trauma cases than in previously published investigations, probably related to the outdoor activities of the area. We believe that the rapid institution of thrombolytic treatment in suspected acute myocardial infarction and a more rapid and flexible transport of trauma cases in a rural area are important. We estimate that, in most cases, the helicopter service could provide a quicker transport than a ground ambulance; however, for short distance transports, ground ambulance is faster than helicopter ambulance.