Abstract: The present invention is directed to a carbon monoxide detector tester and method for using the carbon monoxide detector tester to determine the operability of a carbon monoxide detector. The tester comprises a closable box adapted to receive and house a carbon monoxide detector and a carbon monoxide emitting material. In use, the closable box is opened and the carbon monoxide detector and carbon monoxide emitting material are inserted within. The carbon monoxide emitting material is ignited and the box is closed. A properly functioning carbon monoxide detector will then sound an alarm indicating a properly functioning detector whereas an improperly functioning detector will not sound an alarm, thus indicating a not properly functioning detector.