Occupational and environmental health professionals are confronted with issues concerning the health effects of indoor fungal bioaerosol exposure. This article reviews current data on the health effects of indoor mold exposure and provides practical suggestions for occupational and environmental health practitioners regarding how best to manage these exposures based on published human studies. We conducted MEDLINE searches and reviewed all English language studies on indoor mold exposure (visible survey or objective sampling) and human health effects published from 1966 to November 2002. The main findings of the studies are analyzed in conjunction with plausible association of health effects and fungal exposure. Five case control studies, 17 cross-sectional surveys, and 7 case reports met the selection criteria. Current evidence suggests that excessive moisture promotes mold growth and is associated with an increased prevalence of symptoms due to irritation, allergy, and infection. However, specific human toxicity due to inhaled fungal toxins has not been scientifically established. Methods for measuring indoor bioaerosol exposure and health assessment are not well standardized, making interpretation of existing data difficult. Additional studies are needed to document human exposure-disease and dose-response relationships.