The present study aimed to find out the relationship and correlation among biochemical constituents (total carbohydrates, total phenols and free amino acids) with defense enzymes (protease, alpha esterase and ascorbic acid oxidase) in seed and leaves of five corn varieties (Sc128  and Sc131 white varieties) and (Sc166, Sc176, Sc186 yellow varieties) that cultivated in summer corn season in 2014 at Experimental farm, Faculty of Agriculture, Benha University (Qalubiyah governorate) exposed to different infestation of Ostrinia nubilalis (Hubn.). Data demonstrated that corn variety of Sc 168 recorded the lowest mean of larvae number and stem bores, followed by variety of Sc 176 that recorded the lowest mean of infested ears and broken tassel. While, variety of Sc 128 recorded the highest increase in dry ears yield (13.70 Ardab/faddan) followed by variety of Sc 176 (12.18 Ardab/faddan). All the infestation symptoms by the insect were recorded in the field during the whole season. The data revealed that ascorbic acid oxidase in corn seed and leaves of tested varieties had negative correlation with all infestation symptoms of O. nubilalis. On the contrary, it caused positive correlation with weights of dry ears yield .On the other hand, alfa esterase enzyme in tested corn seed and leaves showed positive correlation with all infestation symptoms of O. nubilalis and negative correlation with dry ears yield. Current results demonstrated that biochemical constituents with defense enzyme as ascorbic acid oxidase plays an important role in seeds and continue in leaves for plants resistance against O. nubilalis infestation.