Background & objectives: Air pollutants as one of the societies problems have different adverse effects on human health. Deleterious effects of gaseous air pollutants especially ozone justify investigation of its concentrations and the health effects. In this study the effects of ozone on health of the residents of Mashhad, Tabriz, Shiraz, Isfahan and Arak metropolises were investigated in 2011. Methods: The required data were obtained from environmental protection agencies of studied cities in 2011. The data were validated according to the WHO criteria and entered to the AirQ software after preparation by Excel software. Results: Annual average concentration of O3 in Shiraz was higher than the others cities and its concentrations in most of the studied cities were higher in summer than the cold seasons. The highest cumulative number of death 294 and 148 cases, were in Isfahan and Mashhad, respectively. The minimum cumulative number of death was in Arak with 55 cases. Conclusion: The high concentration of O3 in Shiraz requires investigation of O3 precursors, climate and geographic conditions, and location. Consequently one can say that the use of AirQ software and WHO recommendations is a reliable, useful, and simple method to assess the health effects of O3 on human health.