The prevalence of atopic dermatitis (AD) has increased during the last decades. Whether the prevalence is still increasing or has reached a stable level during the 1990s is still not certain. The purpose of this study was to compare the prevalence of AD in two different random samples of Danish children studied in 1986 and 2001 and to examine the associations between AD and other atopic outcomes. Two samples of children and adolescents living in urban Copenhagen were drawn at random from the civil registration list in 1986 and 2001. A total of 527 and 480 subjects participated in 1986 and 2001, respectively. Subjects were classified as AD cases when responding affirmatively to the question "Do you have, or have you ever had, significant and recurrent episodes of eczema in the folds of your elbows or knees?" Immunoglobulin E (IgE) measurements, skin-prick tests, and airway responsiveness tests were performed. The prevalence of AD increased from 17.3% in 1986 to 27.3% in 2001. For male subjects, the prevalence of AD was 16.4% in 1986 compared with 25.7% in 2001. For female subjects, the prevalence of AD was 18.1% in 1986 compared with 28.7% in 2001. Elevated levels of IgE, airway hyperresponsiveness (AHR), and rhinitis were statistically significant predictors of AD. The prevalence of AD has increased significantly from 1986 to 2001 in urban Copenhagen, Denmark. In addition, we found that AD was significantly associated with AHR, rhinitis, and elevated levels of IgE, supporting the idea of the atopic triad.