In this study the direct effects of urban green space dispersal and density on quality of the environment of the regions of Tehran have been investigated and evaluated. In order to do so, the area and green space per capita and vegetation cover density of the regions of Tehran have been measured as ecological indices for evaluating their environmental quality. The measurements have been done by means of land use layers in GIS, satellite images of vegetation cover dispersal and density and calculating the normalized difference vegetation index (NDVI). High levels of population density and carbon monoxide concentration in each city region have been considered as human indices for low quality of urban environments. Comparison of these indices, and analysis of the correlation level between them, indicates that the regions which have the least green space area per capita and vegetation cover density are also the most polluted and populated areas. The results of this study would introduce planning priorities for urban green space development in Tehran.