This study evaluated the concentration of Der p 1, Der f 1 and Blo t 5 in the fur and households of 20 dogs with atopic dermatitis (AD) and 20 healthy dogs. The diagnosis of AD was clinical based on Favrot's criteria. Dust samples were collected with a domestic vacuum cleaner. For each site, 1m(2)was vacuumed for 2 min. The samples were collected in separate filters, transferred into plastic containers, sealed and kept frozen until ELISA analysis. In the fur of atopic dogs the average concentration of Der p 1 was 0.25 mu g/g compared to 0.03 mu g/g in healthy dogs. In households with atopic dogs the highest concentrations of Der p 1 were found in carpets (2.18 mu g/g), followed by couches (1.53 mu g/g), beds (1.14 mu g/g), dogs' bed linen (0.64 mu g/g) and floors (0.14 mu g/g). The concentrations of Der p 1 on carpets, couches and beds were significantly higher than in atopic dogs' fur (p0.05). The concentrations of Der p 1, Der f 1 and Blo t 5 were equivalent in atopic and non-atopic dog's households. Among the allergens studied, Der p 1 was the most commonly found, predominantly in carpets and couches.