The prevalence of Type I sensitization and its relationship to atopic dermatitis were assessed in a cohort of 1501 8th grade schoolchildren (aged 12-16) in Odense, Denmark. The protocol included a questionnaire, a clinical examination, IgE measurements and skin prick tests. A history of atopic dermatitis was found in 21.3%, allergic asthma in 6.9% and allergic rhinitis in 15.7% of the adolescents. One or more positive specific IgE measurements (CAP FEIA) were found in 29.6% of the schoolchildren (inhalant allergens 28.4%, food allergens 8.5%, pityrosporum ovale 1.5%) and a considerable proportion were sensitized without clinical relevance. The association between atopic dermatitis and Type I sensitization was related to concomitant inhalant allergy. A clear association with atopic dermatitis was indicated only for the allergen pityrosporum ovale.