The study population included children aged 6-7 and 13-14 years from primary schools in Kraków (2302 and 2967 children respectively) and Poznań (3132 and 4069 children respectively). The prevalence was assessed using ISAAC questionnaire. In younger age group the number of children with diagnosed asthma and presenting asthma symptoms was significantly higher in Kraków than in Poznań. In older age group higher percentage was observed in Kraków in relation to wheeze ever and nocturnal cough during last year. Pupils from Kraków had symptoms of allergic rhinitis and were diagnosed as allergic rhinitis more frequently than from Poznań. Symptoms suggestive for skin allergy were more often observed in Kraków, but the differences were significant in relation to symptoms during last year in both age groups and in relation to symptoms ever in older age group. Our study revealed discrepancy between the prevalence of symptoms of asthma and allergic rhinitis and the prevalence of established diagnosis.