The article discusses the emission of organic substances from indoor surface materials. A wide variety of surface materials in buildings (e.g., Building and maintenance materials, furnishings, clothing, and paper products) can release organic compounds. These sources contribute substantially to the hundreds of organic compounds that have been measured in indoor air. Their emissions have been directly connected to complaints of odors or hyperreactivity, and are presumed to contribute to the problems in many 'sick buildings' where the cause of complaints is uncertain. Significant progress has been made in the past decade in developing procedures for measuring emissions from such materials, in controlled experiments where factors affecting emission rates can be determined and quantified. Emissions data are still limited, but are being accumulated gradually by research groups in Europe and North America. Recent data gathered in research and modeling studies indicate that one of the most effective ways to limit indoor concentrations of organic compounds is to limit the content of volatile compounds in materials that are used in buildings. Limiting the original residual content of such compounds in the materials, or conditionining such materials prior to use in buildings, or (perhaps) conditioning such materials in place before occupancy is most likely to prevent excessive levels.