Two field experiments were carried out at the Experimental Farm of Gemmeiza Agricultural Research Stations during 2007 and 2008 seasons to study the effect of row spacing, i.e. (60,70 and 80cm apart) and plant density, i.e. (20000, 25000 and 30000 plants/fed.) on growth, yield and yield components of two maize hybrids, i.e. (S.C125 and S.C162). A split-split plot design with four replicates was used in the two experiments. Results showed that increasing ridge spacing significantly recorded No. of days two 50% tassling and silking , plant and ear heights were in the same direction planting on 80 – cm ridge was associated with a significant increase in ear length , No. of kernels/row, 1000 kernels weight and grain yield (ard/fed). On the other side, plant density of 25000 plant/fed  was associated with the highest grain yield and its component as soon as it is considered of the optimum environmental. Single cross 125 was earlier than single cross 162 of days to 50% tassling and silking. S.C. 125 had the best effects of plant and ear height towards low ear position, 1000 kernels weight, S.C. 162 gave the highest values of No. of ear length kernels/row and grain yield. (Ridge spacing x plant density interaction was significant for No. of days to 50% tassling and silking, plant and ear heights, No. of kernels/row. Plant density x hybrid interaction  was significant for plant height, ear length, 1000 kernels weight (g) and grain yield ard./fed). This investigation showed that planting on 80- cm rows at plant density of 25000 plants/fed (25- cm between hills) in order to obtain the highest grain yield. This would also facilitate using the mechanization and saving costs, time, and effort.