Abstract: A disposable cartridge assembly is provided for use with a rodent trap of the kind having a movable spring-loaded striker bar operable in response to a trigger mechanism. The disposable cartridge with a generally flat base and a flexible sleeve with a rigid opening at least at one end is mounted on a rodent trap so that the sleeve is disposed adjacent to the trigger of the trap. The rodent enters the sleeve and activates the trigger to be trapped. The entire cartridge assembly is then disposed.