The presented study concerned mycological analysis of buildings in Lódź and evaluation of the role between filamentous fungi contaminated flats and inhabitants health (allergic airway diseases). 49 inhabitants of 20 flats with signs of moulds contamination were examined. Air samples were collected in houses and outdoors. In all inhabitants skin prick tests (SPT) to common allergens and to standardized particular fungal extracts were performed. Moreover, total and serum specific IgE to moulds, rest spirometry were measured in all subjects. Level of moulds contamination in the air of flats was high and in 75% cases exceed accepted limits. The most frequent species isolated from examined rooms were: Penicillium, Cladosporium, Aspergillus, Acremoniu and Alternaria. The most frequent symptoms reported by examined subjects were rhinitis (N = 29, 59.2%), conjunctivitis (N = 29, 59.2%), chronic cough (N = 24, 49%), dyspnea (N = 15, 30.6%) and skin symptoms (N = 24, 49%). Elevated IgE level was found in 12 subjects (24.5%) and in three patients (6.1%) mould specific serum IgE were detected. Nineteen out of all subjects (38.8%) had positive SPT to common allergens (house dust mites, grass and tree pollens). Eight out of these patients (16.3% of the group) were sensitized to moulds (Candida albicans, Alternaria alternata, Botrytis cinerea, Trichophyton mentagrophytes, Helminthosporium halodes, Aspergillus). In all cases sensitisation to moulds was accompanied by allergy to other common allergens. No isolated hypersensitivity to moulds was found. Although the frequency of self-reported symptoms was high, the prevalence of atopy and allergic diseases seems to be similar to that found in general population, but that statement must be confirmed by comparison of the control group.