The research was conducted at the Maize Researches Department, General Commission for Scientific Agriculture Researches (G.C.S.A.R.) Damascus, Syria during the summer growing seasons of 2010, 2011 and 2012. Treatments were arranged in a Randomized Complete Blocks Design with three replications. The research aimed to evaluate genetic parameters for some traits like days to 50% silking, plant and ear height, ear length, ear diameter, number of rows per ear, number of kernels per row, 100 kernel weight and grain yield per plant using generations means analysis of two maize hybrids (IL.292-06 × IL.565-06, IL.459-06 × IL.362-06) to detect epistasis and estimates of mean effect [m], additive [d], dominance [h], additive × additive [i], additive × dominance [j] and dominance × dominance [l] parameters. Results showed that the additive - dominance model was adequate to demonstrate the genetic variation and its importance in the inheritance of most studied traits. Nonallelic gene interaction was operating in the control of genetic variation in most studied traits. The signs of [h] and [l] were opposite in most studied traits for the two crosses. Also, the inheritance of all studied traits was controlled by additive and non-additive genetic effects, but dominance gene effects play the major role in controlling the genetic variation of the most studied traits, suggesting that the improvement of those characters need intensive selection through later generations. The phenotypic variations were greater than genotypic variations for all studied traits in the two crosses, indicating greater influence of environment in the expression of these traits. Highly significant heterosis relative to mid and better parents, respectively was found for all characters, and this accompanied with inbreeding depression for all traits. Narrow sense heritability and genetic advance were low in most of the traits due to the dominance of non-additive gene action in controlling the genetic variation of the most studied traits and this predict low to medium values of genetic advance through selection process.