Mite surveys were conducted in living rooms and bedrooms of 21 wooden houses in and around Nagoya City, from September 1983 to June 1984 at about 3-month intervals. Multiple regression analysis was applied to elucidate the influence of housing conditions on the prevalence of mites. The results revealed that the annual mean densities of Dermatophagoides farinae and the total mites were positively correlated with the number of rooms and type of flooring and inversely with family size. The estimated densities of these mites showed good agreement with the observed densities. While no significant factor was detected for the densities of D. pteronyssinus and Cheyletidae, major factors detected for the prevalence of Haplochthonius simplex and Tarsonemidae were the number of rooms, family size, and air conditioning; for the latter mites, type of bedding was also a factor. Major factors for Glycyphagidae were family size, working housewife, age of house and type of heater. Factors for Cosmochthonius reticulatus were the number of rooms, working housewife, age of house and house-cleaning frequency. For Acaridae, family size, working housewife and type of flooring were factors. The number of mite species had positive correlation with the number of rooms and working housewife, and negative correlation with house-cleaning frequency and type of flooring, whereas Simpson's indexes of diversity were negatively correlated with the number of rooms, house-cleaning frequency, and type of flooring. These results indicated that both the number of rooms and family size were the most important factors associated with the prevalence of domestic mites in wooden houses, followed by type of flooring, working housewife, house-cleaning frequency, etc. The difference in the prevalence was considered to be mostly due to the interrelationship between the biological characteristics of mites, especially their humidity requirements and the degree of dampness in houses largely influenced by household activities and dwelling spaces.