Aldehydes are irritants of the upper respiratory tract with symptoms such as eye, nose, and throat. Formaldehyde classified in Group 2A by the International Agency for Research on Cancer and a probable human carcinogen by the Unite States Environmental Protection Agency due to its carcinogenicity. Aldehydes may be emitted from many other consumer products, such as permanent press fabrics, cosmetics, fiberglass insulation, paints, and coatings. The purpose of this study was to examine the does-response relationship between aldehydes levels and symptoms (eyes, nose, throat, and respiratory) for 36 dwellings and 280 households in Korea. As a result, environmental factors affecting aldehydes level were indoor smoking, ventilation, using of carpet, bed, and new furniture, painting for renovation, and indoor humidity. There wat weakly positive correlation between symptom score and aldehydes level.