To investigate the impact of allergic airway diseases on the risk of attention deficit hyperactivity disorder (ADHD) in school-age children. Used stratified cluster sampling method, school-age children in first to sixth grade in primary schools in 9 randomly selected cities including Shanghai, Guangzhou, Xi'an, and Wuhan were enrolled in the study. Interview of parents with questionnaires, which included school-age individual and family social environment questionnaire (including history of diagnosed ADHD, allergic rhinitis, and bronchial asthma) and Children's Sleep Habits Questionnaire (CSHQ), were finished and collected during November to December in 2005.Diagnosed allergic rhinitis and asthma by specialist were independent variables and divided into following three categories as no allergic diseases (neither allergic rhinitis nor asthma), single allergic disease (allergic rhinitis or asthma), and combined allergic diseases (allergic rhinitis and asthma). Diagnosed ADHD as dependent variable, binary logistic regress model was used to analyze the risks of ADHD in school-age children. Totally 23 791 questionnaires were handed out, while 22 018 were collected. The children had an average age of (8.8±1.8) years, within which 10 869 were male, and 11 021 were female. The risk ratios of ADHD were 2.197 (95% 1.823-2.648) and 3.150 (95% 2.082-4.760) in children with single allergic disease and combined allergic diseases separately. There was no significant difference after adjusting for the factor of sleep habits, as the risk ratios were 2.055 (95%: 1.683-2.508) and 3.140 (95% 2.061-4.784) in children with single and combined allergic airway disease separately. Allergic rhinitis and bronchial asthma increased the risk of ADHD, not depending on sleep habits. Hence, allergic airway diseases could be independent risk factors of ADHD.