Exposure to fungi in the indoor environment may trigger hypersensitivity to a variety of fungi and is known to be an influencing factor in allergic rhinitis and asthma. A wide list of airborne fungal spores and dust containing fungi have been described for different environments; however, their clinical relevance is seldom clear. In this survey we measure levels of fungi indoor and outdoor of domestic dwellings of 10 patients with known chronic allergic respiratory disease to fungi. To measure hypersensitivity to fungi, Prick (sensitivity to fungi), RAST (specific serum IgE levels) and PAR (persistent allergic rhinitis) severity are assessed in relation to fungal load in the environment. Only association of PAR and indoor fungal load were found to be significant (P = 0.1648). No direct causality with sensitivity to the amount of exposure, or a hypersensitivity to a specific fungal genus could be established. There is still no consensus on the most relevant methods for measuring personal exposure and 'no safe levels' have been established yet.