Abstract: A sterilizer utilizes fluorocarbon liquid as the sterilizing medium. The fluorocarbon liquid is retained in the bottom of a sterilizer chamber. Instruments are placed within the chamber above the liquid level. The chamber is sealed and a heater causes the liquid within the chamber to vaporize. The fluorocarbon vapor is more dense than the air within the chamber and is not miscible with that air. Consequently, as the fluorocarbon vaporizes, the air within the chamber is displaced through a vent in the top of the chamber. A minor amount of fluorocarbon vapor is also displaced as all air is purged from the chamber. The discharged fluorocarbon vapor is recondensed through an expansion valve and collected for recycling. The chamber is sealed upon purging of all the air and is maintained in a pressurized state for a period of time. Subsequently the heater is turned off and the chamber is cooled by a fan.