Air-ambulance services are extremely expensive to operate and maintain. The value of their existence has been questioned in this era of rationalization and downsizing. We examined the cost, safety, flight crew composition, types of trauma, and effectiveness of our air-ambulance program at the Children's Hospital of Eastern Ontario (CHEO) over a 3-year period, 1994-1997. During this time, 392 children were aeroevacuated to CHEO, 113 surgical (29%), 136 medical (35%), and 143 neonates (36%). Of the surgical cases, 43% were transferred for orthopaedic trauma, the commonest being fractured femur, 23% for general surgical cases, most common being thoracoabdominal trauma, and 22% for neurosurgical reasons, most commonly basilar skull fractures. The average response time (time from which the call was received to the time when the helicopter reached the patient site) for all of the cases was 46 min. The average travel time (time from departure of patient site to arrival at CHEO) for these same cases was 25.59 min. The air-ambulance program for children in the Ottawa-Carleton Eastern Ontario areas, was found to be safe, effective, and allowed earlier specialized medical care to be provided.