The physiological significance of adequate temperature and humidity of respiratory gases and the problems of technical realization were demonstrated. Humidifying and warming of gases by bubbling through a heated waterbath was the accepted method. The problems with this technique (e.g., dependence of temperature and relative humidity of the gases delivered to the patient on respiratory minute volume, tubing material and room temperature) were shown. A simple solution to these problems without the need of electrically heated tubing was offered. A new electronically controlled humidifier (HRP[Hygienic Respiratory Products]-Humidifier 2000) with specially developed tubing was presented. Optimal temperature and relative humidity of the respiratory gases was guaranteed by the high efficiency humidifier and additional temperature measurement and regulation of the patient''s tracheal tube. The problem of increased amounts of condensed water in the tubing was solved by the HRP special tracheal tube adapter with an automatic water exhaust. The hygienic problems of artificial respiration can best be solved by combination with the complete HRP-System 2000.