Environmental pollution is one of the major problems facing the megacities. This study was carried out to investigate the effect of air pollution on the leaf morphological characters of 12 species commonly planted in the streets of Giza district, Cairo a highly polluted site and Smouha district, Alexandria as peri-urban non polluted site of Egypt. Both the Light (LM) and Scanning Electron Microscopes (SEM) were used to investigate the leaf characters. The thirty-one macro-and micro-morphological leaf characters were subjected to T-TEST to assess the influence of pollution on the leaf characters and to find out the significant variations among the species in the two sites (polluted and non-polluted), using SPSS software, in addition to, Bivariate correlation using Pearson correlation. The study results proved that leaf characters of the studied species exhibited significant reduction at polluted sites especially in leaf length, width, area, and number of lateral veins compared with non-polluted sites, and identified the most adapted species to the polluted sites.