Much attention has been focused on indoor molds; resulting in modest amounts of new research. There is strong evidence of respiratory effects. Although mechanisms are disputed, some of the effect (but not all) is likely to be allergy related. There is some evidence that atopic individuals may be more affected, but many nonatopic individuals also are affected. This area needs more general research and specific research on exposure measures (such as what fungal components should be measured) and on health-effect mechanisms. It is worthwhile to emphasize the practical knowledge that is readily available. Buildings should be designed, built, operated, and occupied so that the buildings stay dry. When this situation does not occur, the environmental and clinical aspects that are observed by competent professionals should both be considered when determining causal relationships.