Objective: To evaluate the asthma prevalence in the Federal District of Brazil, using the questionnaire developed for the International Study of Asthma and Allergies in Childhood to look for correlations with socioeconomic levels. Methods: A total of 6437 children (3183 from six to seven years old and 3254 from thirteen to fourteen years old), attending public or private schools, were evaluated. The data were analyzed by gender and socioeconomic status (chi-square test). Results: The prevalence of asthma in the Federal District was 12.1% among the six- and seven-year-olds and 13.8% among the thirteen- and fourteen-year-olds (p < 0.04). In the six-to-seven age bracket, asthma prevalence was significantly greater, and asthma-related symptoms were more frequent, among males (p < 0.001). In contrast, asthma-related symptoms were more frequent among females in the thirteen-to-fourteen age bracket (p < 0.05). Children belonging to the lowest socioeconomic class, as determined by the responses given on the questionnaire completed by the parents, presented the highest prevalence of asthma, regardless of age bracket (p < 0.001). Among such children, asthma-related symptoms were also more frequent (p < 0.05). In the thirteen-to-fourteen age bracket, the prevalence of asthma was greater among those belonging to the highest socioeconomic class (p = 0.001). Conclusions: Overall, economically disadvantaged children more frequently presented asthma-related symptoms and experienced asthma attacks that were of greater severity. In addition, the prevalence of suspected asthma was higher than that of diagnosed asthma in this group, suggesting that asthma is underdiagnosed in children belonging to the lowest socioeconomic class.

Keywords: Asthma/epidemiology; Asthma/diagnosis; Socioeconomic factors; School health; Questionnaires