Field and laboratory studies were carried out during two successive summer seasons in order to study the susceptibility of the different tested Maize cultivars namely (Giza (2), Single cross (10), and Treble cross (321) to infestation by Rhopalosphum maidis andRhopalosiphum padi. Field studies were carried out during the two consecutive growing seasons (2016 and 2017). There were significant differences in the susceptibility of Maize cultivars to infestation by these pests. Results showed that, G 2 and S.C (10) cultivars were the lowest infested ones by the two pests. On the other hand, T.C (321) variety was the highest infested cultivar. To give a spot light on the reason of the differences in the susceptibility of the tested Maize cultivars, chemical analysis of the dried leaves were carried out during growing season of 2017. Chemical analysis of infested leaves showed correlation between certain phytochemical components; potassium, total protein, carbohydrate, and phosphorous as well as Fiber , Vt B 6 and Vt B 1 content and population density of Rhopalosphum maidis  andRhopalosiphum padi.