Fungi are a ubiquitous presence in the indoor environment. The level of indoor fungi in typical households is a matter of considerable debate. The allowable level of indoor fungi has not been established. Our aim is to investigate fungal levels present in typical Midwest homes. Subject households were recruited from the greater Kansas City area. Parents of asthmatic children seen in the Allergy /Asthma Clinic were asked if they had friends whose children had no respiratory disease who might like to have their homes inspected. Subjects were extensively screened by telephone and only those households containing at least 3 persons (at least one child) with no history of respiratory disease (asthma, bronchitis, COPD, rhinitis, etc) were enrolled. Homes were inspected using a standard protocol. Non-viable air samples were taken with an Allergenco MK-3 viable samples were taken with a SP rotating stage impactor. Dust samples were taken for evaluation of fungal allergens by immunoassay. There were 18 homes recruited into the study. Of these, 17 homes were inspected. There was an average of 3.75 persons per household. Single family homes comprised 94% of the structures and 81% of the homes had basements. All of the structures were heated with gas forced air furnaces, 93% had central air and about 43% of the floor space in the homes was carpeted. Cladosporium was the most common spore on viable collections (100% of homes) and Aspergillus/Penicillium was the most numerous spore on the viable collections (mean 175 CFU/m³). Cladosporium was also the most common spore on non-viable collections (100% of homes) and the most numerous spore type (mean 500/ M3). The mean of the mean spore level for all collections in these typical homes was 1097/m³ with a 95% CI of 9 to 2184. Detectable levels of antigenic material were found in the dust of all houses tested for Cladosporium, Aspergillus and Penicillium. There is a low level of fungal spores in typical homes from the Midwestern US. There is also a low level of allergenic material in these homes. The upper end of the 95% CI for nonviable spores in these houses is around 2000/m³.