Six yellow inbred lines of maize, were setup in a half diallel crosses mating design, to produce 15 F₁ hybrids. All genotypes with the three commercial checks : SC 155, SC 162 and SC 170 were evaluated using the two nitrogen levels : 80 and 120 kg N/fed during the 2007 growing season at Sakha Agriculture Research station Kafr El- Sheikh. The aim of this study was to estimate the phenotypic and genotypic correlations, GCA, SCA and their interactions with the two nitrogen levels. The results would also identify the superior genotypes for yielding performances. The studied traits were : grain yield (Ard./fed)., ear length (cm), ear diameter (cm), number of rows / ear and weight of 100 kernels(g).  The results indicated the presence of significant differences among  genotypes for most studied traits .This finding was expected due to the different origin of  the parental inbred lines. General combining ability (GCA) and specific combining ability (SCA) mean squares were significant or highly significant for most studied traits under both nitrogen levels. The interactions between GCA and SCA with nitrogen levels were not significant for all studied traits except for SCA x N which was significant for weight of 100 kernels(g). The values of SCA mean squares were higher than those of GCA mean squares for grain yield (Ard./fed.), No. of rows / ear and weight of 100 kernels(g) traits.   All means were higher under the high nitrogen level than the low nitrogen level for all studied traits. The  best general combiners for grain yield (Ard./fed.) were the  inbred lines: Sk 5001/50 and Sk 7070/62. The  single  hybrids  Sk5001/50  x  Sk  5005/ 12, Sk  5002/9 x Sk 5005/16,    Sk 5001/50 x Sk5005/16 and Sk 5002/9 x Sk 5001/5 showed positive significant SCA under the two nitrogen levels for grain yield Ard./fed. The phenotypic and genotypic correlations among the five studied traits were positive for all studied traits.