Air pollution is one of the most important environmental problems in the last century which threatens human health. The main sources of urban air pollution are traffic, industrial activities and increasing consumption of fossil fuels. The effects of air pollution on human and environment have increased in recent years that the most important ones are the effect on the respiratory system and asthmatic and bronchial diseases. Isfahan is one of the biggest and the second industrial city in Iran which is considered as the second polluted city after Tehran. In this research, the air pollution maps of Isfahan were prepared using IDW and GIS for different months, seasons and whole year in 2009. Also, PSI interpolation maps were made to study the air pollution index in Isfahan. Air pollution monitoring data of the five air pollution measuring stations was taken from Isfahan environment protection office. One way ANOVA and Tukey tests were used to assess the mean different of pollutants concentration in different stations. The result showed that the mean difference of all the parameters, except SO 2 , was significant in most stations (P 0.05). Also the Pearson correlation coefficient indicated the significant linear correlation between NO and NO 2 (P 0.01) and SO 2 and PM10 ( P 0.05).NO, NO 2 , NOx and SO 2 concentrations in cold months and seasons were higher due to unsuitable photochemistry reactions condition and extreme usage of heating apparatus. The highest CO concentration was observed in times and areas in which there is more traffic. The highest O 3 concentration was in July when climate condition is appropriate for atmospheric reactions. There was no significant difference between mean of pollutant concentration during week days, except on Friday which the parameters concentrations were a bit lower. Interpolation maps showed that among all the regions, the amount of pollution was higher in some parts of districts 3 and 4 of municipality which were located in the center of city and have an intensive traffic. Generally, pollutants concentration was higher in eastern and north-eastern areas of Isfahan in comparison with south areas. PSI maps showed that the greatest amount of PSI in 1388 was in July and Ahmadabad station had the highest amount of PSI among all stations. Key word : Air pollution, Interpolation, IDW, GIS, Isfahan