Rapid industrial development, increased population density and faster means of transportation have resulted in serious air pollution problems in cities worldwide affecting all the life forms. The effects of polluted air on morphological and bio-chemical parameters have been studied, while their effects on reproductive structure remained almost unattended. The present study is an attempt to investigate the effects of urban air on few ornamental tropical trees on their different floral characteristics. Delayed flowering and reduction in flower size, floral pigment and flower biomass was recorded. Fruits produced by these trees were small in size with reduced seed weight and numbers. The seed quality parameters like, density, soundness, viability and seed germination were also adversely affected.The study concludes that the reproductive behavior of trees growing along roadside have been altered. The known harmful effects of air pollutants on growth and metabolism had ultimately reflected in poor biomass and development of flower, fruit and seeds. The reproductive parts of Delonix regia and Cassia fistula were found more adversely affected than the others.