The paper summarizes various criteria that can be used in selecting material used in the construction, furnishing, maintenance, and operation of a building. It also summarizes the types of material and product testing that can be especially useful in the selection process. In broad terms, materials in buildings are classified as building materials, furnishings, maintenance materials, and other contents. At any given time, emissions from materials and products in any of these four categories can dominate the impact on indoor air quality (IAQ) in a building. Responsibility for the selection of these materials may be that of the designer, owner, or occupants. Information on IAQ impacts of materials therefore needs to be developed for a wide range of people.