The aim of our study was to estimate the prevalence of asthma and atopic diseases in schoolchildren aged 7-15 yrs who undergo mass health examination. The study was conducted during the scheduled screening clinical assessment from March 2003 through February 2004. The children were examined by experienced allergologists. Parents and children answered standardized ISAAC questionnaires. The frequency and characteristics of allergic contact dermatitis, food allergy and allergic reactions to drugs were evaluated as well. Of the 2147 children examined, 645 had a positive atopic history, with an estimated point prevalence of 28% in the reference population. The reported prevalence of doctor-diagnosed asthma was 2.8%; 1,8% for of atopic dermatitis and 6.5% for allergic rhinitis. The prevalence of allergic contact dermatitis (1.7%) was higher in girls (1.6%). 3% children showed symptoms of food allergy. The role of epidemiological population-screening by questionnaire is; essential to early detect allergic diseases, to manage and prevent them.