Mould exposure in indoor environments can cause various health effects: infections, allergies, toxic effects and irritations. We have lead environmental audits (n = 32), at physician's request, in suspected mould allergic patient homes. A deep home visit allows the detection of potential indoor fungal and humidity sources, afterwards, a sample strategy is determinate. Results show that indoor airborne spores concentrations vary from some units (CFU) to more than thousands per m3. In dust samples, the number of spores per gram ranges from hundred to millions. A statistical analysis shows that "mouldy dwellings" are more contaminated than "non mouldy" ones and than outdoor air. Mould species relative presence is specific in each contaminated home, depending on various factors (mouldy support nature, competition between species...).