The association of environmental factors with atopic disease in children remains poorly understood. The aim of this study was to investigate the relationship between socio-environmental factors and symptoms of asthma and atopy in 6-7-yr-old children assessed as an adjunct to Phase I of the International Study of Asthma and Allergy in Childhood in Perth, Western Australia. Parental questionnaire responses were obtained for 2,193 children (73.6%) in 34 randomly selected primary schools in the Perth metropolitan area. Children born in Australia had a significantly increased risk of current asthma (odds ratio (OR) 237, p = 0.001). Having a mother born in Australia was the only factor independently associated with an increased risk of current hay fever (OR 1.56, p = 0.005). Increasing numbers of people living in the home were significantly associated with a multiplicative decrease in risk of current asthma (OR 0.88, p = 0.03) and eczema (OR 0.82, p = 0.01). Houses made of fibrocement (OR 2.40, p = 0.02) and the presence of mats on less than half of the floor area in the "main bedroom" (relative to wall-to-wall carpet) (OR 3.50, p = 0.003) were associated with an increased risk of current eczema. All reported associations were independent of socioeconomic status (categorized by school), age and sex. This study suggests that household and country-specific environmental factors are associated with asthma, hay fever and eczema risk in 6-7-yr-old schoolchildren, and may have substantially contributed to the increased prevalence of these diseases in Australia.