Abstract: A continuous flow of gas plasma is supplied to a space at a very low pressure in which the object to be sterilized is located. Cool plasma of a suitable gas such as argon is produced continually by being subjected to a radio-frequency field. Complex shapes such as capillary passages through a blood oxygenator can be sterilized by passing the gas plasma through them. The exterior of objects to be sterilized can be subjected to gas plasma in a space at a very low pressure either confined or unconfined. The space may, for example, be a packaging envelope, and subsequent to sterilization such envelope can be evacuated and collapsed onto the object to preserve its sterile character.