Major sources of allergy from plants are seeds and pollens. A large number of protein antigens have been identified to be causative agents of allergy and possible biochemical and structural attributes of these molecules have been explored. The studies so far have not been able to provide clear mechanistic details that could be generalized. The reason for this could be that the studies have not been systematically explored. The structural proteomics approaches adopted in our laboratory is an attempt in this direction to establish the structural basis of allergenicity. Known crystallographic structures of proteins from plant pollens have been analyzed in this context.