Combining ability analysis of cultivars is important to exploit the relevant type of gene action for breeding program. A Half diallel crosses were made among eight parental lines, to produce 28 F₁hybrids.  These hybrids along with the check commercial cross SC 10 were planted at two locations (Sakha and Ismailia Agric. Res. Stns.) to estimate general (GCA) and specific (SCA) combining abilities, type of gene action, and their interactions with locations. The study would show the relative magnitudes of GCA for grain yield and yield component traits (YCTs) and determine the best yielding crosses which could be used in the maize breeding programs. A randomized complete blocks design with four replications was used at each location. General (GCA) and specific (SCA) combining ability variances were estimated for all studied traits according to Griffing^,s (1956) Method-4, Model-I. There were differences between the two locations (Loc) were significant in the performances of all studied traits, i.e., grain yield (GY), ear length (EL), ear diameter (ED), no of ears 100 plant^-1 (EP^-1), silking date (SD), plant height (PH), ear height (EH) and ear position% (Epos%) at both locations, indicating that these locations differed in their environmental conditions. Evaluation o GCA and SCA indicated that both additive and non additive gene actions were important in controlling all studied traits except for additive gene action for RE^-1 trait. In general, the additive gene action seemed to be more important than the non additive gene action in the expression of GY, ED, EP^-1, SD, PH and Epos%, while, the non additive gene action was more important in the inheritance of EL, RE^-1 and EH traits. The parental inbred lines P₁ and P₃ had the highest significant positive GCA effects (desirable) for GY, EL and EP^-1. The same lines had negative and significant GCA effects (desirable) for silking date toward earliness and ear position%. The inbred lines P₂ and P₅ had negative and significant GCA effects (desirable) for plant height toward shorter plants. Cross with high SCA effects usually comes from two parents possessing high GCA or from one with good GCA and other with poor GCA effects. Desirable SCA effects were obtained for GY between good and poor GCA parents in the crosses (P₁ x P₃), (P₁ x P₄), (P₁ x P₅), (P₂ x P₇), (P₃ x P₄), (P₃ x P₇) and (P₆ x P₈). Three crosses; P₁ x P₄ (35.64 ard/fed.), P₁ x P₅ (34.94 ard/ed.) and P₃ x P₇ (36.41 ard/fed.) were significantly superior than the check SC 10 (29.01 ard/fed) and the increasing percentage for grain yield relative to the check ranged from 20.44% to 25.51%.  These single crosses can be recommended in maize breeding and production program for release as new commercial hybrids.