Background: Body heat loss during anaesthesia may result in increased morbidity, particularly in high-risk populations such as children. To avoid hypothermia, a novel thermoregulatory system (Allon) was devised. We tested the safety and efficacy of this system in maintaining normothermia in children undergoing routine surgical procedures. Methods: The system consists of a computerized body, which receives continuous afferent data, i.e. core (rectal) temperature. These data are then compared with a preset temperature (37°C) and a microprocessor heating/cooling unit warms/cools the temperature of circulating water in a garment that is specially designed to allow maximal coverage of body surface area, without impingement on the surgical field. Water temperature to the garment was limited to a maximum of 39.5°C. Continuous perioperative monitoring of skin and rectal temperature, heart rate and blood pressure was performed. Postoperative shivering and adverse effects were also assessed. Results: The Allon system was used in 38 patients aged 3 months to 14 years undergoing surgery under general anaesthesia lasting more than 30 min. Fifty to 80% body surface area was covered by the garment. Mean operative and postoperative core temperatures were 36.9 ± 0.5°C and 36.7 ± 0.5°C, respectively. Intraoperative skin temperatures were maintained at 34.4 ± 2.7°C. The average core-to-periphery intraoperative gradient was 2.9 ± 4.9°C. Postoperative shivering was absent in 36 cases and mild in two cases. No device-related adverse effects were observed. Conclusions: Perioperative thermoregulation using the Allon system is safe and effective in maintaining body temperature within a narrow range in children undergoing brief surgical procedures.