In the present paper the results of an experimental analysis aimed to evaluate the ventilation rates in Italian classrooms are reported. Measurements were performed in 16 classrooms of 7 different public primary schools located in the Central Italy. Schools with a natural ventilation system were considered. Ventilation rates were evaluated through the pressurization method using a blower- door tool. Both pressurization and depressurization tests were performed. The study confirmed that the classrooms under investigation cannot be properly ventilated only relying on natural ventilation systems. In fact, an average natural air change rate equal to 0.12 h-1 was measured. This values is only the 5% of the minimum ventilation required by the European standards.