Abstract This exploratory report examines the risk of selected organic air pollutants measured in homes in the United States and the Netherlands. After several theoretical assumptions, estimates are made for the carcinogenic potency of each chemical; combined with the exposure measurements these give estimates of cancer risk. These estimates are compared with risks of these same pollutants outdoors and in drinking water and also with other well known indoor air pollutants: cigarette smoke, radon gas and formaldehyde. These comparisons indicate priorities for action. Some suggestions are made for future studies.