Aphids cause serious damage to cereal crops worldwide leading to great economic loss. In this work, we addressed the correlation between the infestation rate of Rhopalosiphum maidis (Hemiptera: Aphididae) and the changes in some biochemical parameters after feeding on three cultivars of both sorghum (local, dorado, and sphinx) and maize (local, unique 6 and triple 310) plants cultivated at Assiut University farm in Egypt. Local variety of sorghum showed lower infestation rate by R. maidis than dorado and sphinx varieties, as well as it led to significant enhancement of total antioxidant, carbohydrates, and lipids, and activity of amylase and lipase. On the other hand, local strain of maize showed higher infestation rate by R. maidis than unique 6 and triple 310 varieties. The higher infestation rate to local variety of maize was associated with significant increase in total antioxidants, carbohydrate, and lipid content, and activity of amylase and lipase. This research suggests that there was no correlation between the infestation rate of R. maidis fed on different cultivars of sorghum and maize and the total content of antioxidants, carbohydrate and lipid content, as well as their catabolic pathways.