Purpose: Cadmium is a heavy metal and is an important part of Diesel Exhaust Particles (DEPs). Cd in high concentrations exhibited detrimental effects and cause also increase the allergenicity of pollen grains. The aim of the research was to study the effects of Cd on the proteins and allergenicity of Petunia hybrida pollens. Methods: Petunia planets were cultured in a greenhouse and treated with various concentrations of Cadmium Chloride (400, 800 & 1200 µmol/L). The pollen was daily collected from the flowers of both experimental and control plants. Pollen extracts were prepared in PBS from control and Cd-treated plants and changes in protein banding profiles were compared by SDS-PAGE. Mice were sensitized by treatment of pollen extracts and AlOH3, as an adjuvant, three times. The allergenicity of pollen extracts was evaluated by skin test and the amount of IgE in the experimental animals. Results: Gel electrophoretic studies revealed that in the Cd-treated pollen grains, two new protein bands, 46 and 51 kDa, were observed that may have allergenicity. Results of serological tests showed the mean of wheal diameter and IgE level in animals that were sensitized to Cadmium chloride-treated pollen grains are more than the control. Conclusion: In recent years pollinosis is increased in polluted areas, especially DEP-polluted areas; the reason may be that Cadmium, as an important part of DEP, acts as an effective agent in the induction of the formation of detoxifying proteins which can also act as new allergens.