Information on hay fever, eczema, urticaria, respiratory symptoms, smoking habits and occupational dust or gas exposure was obtained by a self-administered questionnaire from a random sample of 4992 subjects of the general population aged 15-70 years of the Hordaland county, Norway. The response rate was 90% of the sample. The lifetime prevalences of hay fever, eczema and urticaria were 10%, 25% and 9% of the respondents, respectively. Eczema and urticaria were more often reported by women than by men. The lifetime prevalence of hay fever decreased substantially by age in both sexes. A history of hay fever was inversely related to cigarette smoking. The lifetime prevalences of eczema and urticaria were associated with occupational dust or gas exposure after adjusting for sex, age, smoking habits and area of residence. Adjusted odds ratios of respiratory symptoms in subjects with hay fever were almost 2.0 compared with those without.