We gathered exposure data on indoor air pollution, and investigated the dose-response slope factor for indoor air pollutants, such as volatile organic compounds, aldehydes and radon. Population cancer risks (that is the theoretical cancer deaths) were estimated from exposure to the pollutants. In addition, the damage costs, due to their risks, were estimated using WTP (willingness to pay) and VSL (value of a statistical life), which were investigated by a dichotomous contingent valuation method (DCVM). As a priority for human health risks and damage costs, management strategies are required for both radon and formaldehyde as indoor air pollutants. When the numeric results of human risks and damage costs are applied for other purposes, some assumptions and uncertainties have to be considered to use the results as useful screening tools for the administration of practical risk-based priorities. Keywords：Indoor air pollution, Excess cancer risk, Willingness to pay, Value of a statistical life, Damage costs