Two field experiments in split -split plot design were carried out at the Agriculture Research Center, Shandweel Research Station, Sohag Governorate, during the summer seasons of 2010 and 2011 for 120 days to evaluate the effect of salicylic acid spraying (SA: 100 mg/L at 30 and 45 days from sowing) under three levels of nitrogen fertilizer (N: 0, 90, and 120 Kg N/feddan) on the vegetative growth and grain yield of two maize hybrids (Single cross Pioneer 30K09 and Three way cross-310). The results indicated that, there were gradual and significant increases in all growth parameters and grain yield resulted from foliar spray by SA and raising N-level from 0 to 90 and 120 kg N/fed. in both seasons. The S.C Pioneer 30K09 maize hybrid treated with 120 N/Fed. and sprayed by SA gave the maximum values of plant height, leaf area (LA), leaf area index (LAI), net assimilation rate (NAR), crop growth rate (CGR), total carbohydrates, proline and grain yield in both seasons. Photosynthetic rate (A), transpiration rate (E), stomatal conductivity (GS) and intracellular $CO_2$ concentration (Ci) were influenced by application of SA along with N. Generally, growing of S.C. Pioneer 30K09 fertilized with 90 or 120 N/fed. and applied 100 mg/L of SA recommended to get the maximum growth parameters and grain yield (ardab/feddan).