In this work, some epidemiological aspects of childhood asthma were studied in El-Fayoum city among school children aged 6-12 years. The study revealed that asthma prevalence was 3.09% being higher in males than in females, the highest prevalence was at family size 3 and the least prevalence was at family size 7. The prevalence of episodes of asthma was more in winter season the most common allergen for asthma house dust mite, then infection, exercise and tobacco smoke.