A method and device for high-pressure, high-temperature steam sterilization of endoscopes includes pressure resistant fittings to attach a steam generator to the ports of an endoscope. The method and device allows for high-pressure, high-temperature steam to circulate throughout the endoscope, exposing various surfaces to steam for sterilization. The method and device also allows for high-pressure, high-temperature steam to circulate selectively through the channels of the endoscope, selectively sterilizing the channels and allowing for use of this method with current high-level disinfection methods. The method and device also allows for movement of the scope elevator channel during the sterilization process, allowing for steam to reach the crevices around the elevator and other moving parts of an endoscope.