A method and device for producing blow-molded containers which are sterile at least in some areas. A preform made of a thermoplastic material is first heated and then supplied with a pressurized fluid, and the preform is supplied with a sterilizing radiation at least in some areas. A radiation source for the sterilizing radiation is arranged at a distance to the preform, and a supplying device is moved into the preform. The supplying device conducts the sterilizing radiation from the radiation source into the preform and emits the sterilizing radiation onto the preform inner wall.