Indoor air pollution is a critical problem in Saudi Arabia. Because of the hot weather air conditioning is widely used. Incense burning is intensively used as aroma in Saudi homes. This involves incomplete combustion with liberation of carbon monoxide. The present study aims to detect the levels of carbon monoxide emitted from incense burning. Three different situations were studied: the use of charcoal, charcoal briquettes and electrical device for burning incense. The effect of air conditioning was also studied. Results revealed that using charcoal briquettes and air conditioning increase the levels of carbon monoxide emitted from burning incense. The highest levels of carbon monoxide [82.3 ± 33.8 ppm] have been obtained. It has been concluded that exposure to carbon monoxide represents a serious health risk in Saudi homes. Preventive measures must be taken.