Two field experiments were carried out during to summer seasons (2007 and 2008) at the Experimental Farm of the Faculty of Agriculture, Assiut University, Assiut, to study the response of maize yield and its components for three irrigation intervals (12, 18 and 24 days), (Single cross Watania 4 and three way cross 310) and four spatial distribution of plants (40x50 cm, 35x60 cm, 30-70 cm and 25x80 cm).  Experimental design was split-split plot, where irrigation intervals were assigned to the main plots, genotypes were in the sub-plot and spatial distribution of plants were occupied the sub-sub-plots. According to research results, the maximum values of plant height, first ear height, ear length, ear diameter, No. of rows/ear, No. of grains/row, shelling percentage, 200-grain weight and grain yield/fed. were obtained when corn plants were irrigated at 12 day interval, or with genotype (Single cross Watania 4) or with spatial distribution of plants (30x70 cm) in both seasons. The first order interactions [irrigation x genotype, irrigation x spatial distribution of plants and genotype x spatial distribution of plants] for the all above studied traits gave the maximum values, for irrigation at 12 day interval x Single cross Watania (I₁ x G₁), irrigation at 12 day interval x spatial distribution of plants "30x70" (I₁ x Sd₃) and single cross Watania 4 x spatial distribution of plants "30x70" (G₁ x Sd₃), respectively, in both seasons.