This is a report on our first 2 years' experience of operating a helicopter emergency medical service in the Canary Islands, Spain. The two advanced life-support helicopters are staffed full time by a physician and a nurse. For the transport protocol, inter-hospital transport patients (secondary missions) were classified into three groups: group A, minor illnesses or injuries; group B, modified or middle critical condition; and group C, critical condition. On-scene patients (primary missions) were also divided into critical and non-critical condition. Cardiovascular and respiratory stabilization were necessary before transport. One thousand and fifty-four patients were transported, 19% of whom were primary missions and 81% of whom were secondary missions. Thirty per cent of the first group were in critical condition. The distribution of secondary missions was group A 16%, group B 44% and group C 40%. In group C, 60% of patients were mechanically ventilated, 70% needed cardiovascular drug support and 84% needed stabilization before transport. Thirty-two per cent were trauma patients and 12% neonates. The overall mortality rate was 0.8%. The cost per mission was US$2300. In the interests of safety and rationalization of the use of resources, transport of non-critical patients should be reduced. The presence of a trained physician and nursing crew and stabilization before transport could be responsible for the low mortality rate.