BACKGROUND: Adverse effects of urban air pollution on human health notably the paediatric age group is of great importance. Limited data exist from developing countries. This study investigates the hospitalization of children because of respiratory diseases and air pollution levels in Isfahan, the second large city in Iran. METHODS: Hospital admission data were collected retrospectively from 120 randomly selected respiratory patients in Pediatric wards from the main referral hospital in Isfahan from March 2005-2006, and simultaneous air pollution data were collected from two monitoring stations located in south and north parts of the city. RESULTS: The result of statistical modeling using generalized linear Poisson regression showed that PM(10) and sulfur dioxide (SO(2)) concentrations had statistically significant positive association with number of respiratory admissions of children. CONCLUSION: This study confirms the findings of previous studies about the association of air pollutants' levels with hospitalization because of respiratory diseases in young children. Air pollution continues to pose a threat to public health notably in the paediatric age group, and underscores the need to re-examine national environmental health policies and standards in developing countries.