A breathing tube for humidified gases ventilation system has an internal conduit and a surrounding conduit within which the internal conduit is disposed. A connector at one end of the internal conduit and the surrounding conduit has an inhalation gases port for connection to an inhalation gases supply port of a ventilator. A gases flow path leads from the inhalation gases port to the space between the internal conduit and the surrounding conduit. A spirally wound heater wire may be disposed between the internal conduit and the surrounding conduit with turns of the spirally wound wire passing around the internal conduit. <IMAGE>
