To investigate the response of maize hybrids to plant population and nitrogen fertilization rates. Two field experiments were conducted at the Experimental Farm, Faculty of Agriculture (Saba Basha), Alexandria University during 2018 and 2019 seasons. Factorial experiments (two factors) in randomized complete block design (RCBD). Whereas, the first factor was plant population (50000, 75000, 100000 plant/ha), while, the second factor was nitrogen fertilization rates (216, 288, 360, and 432 kg N/ha). The results revealed that ear length (cm), number of rows/ear, number of grains/row, number of grains/ear, 100-grains weight (g), grain yield (t/ha), straw yield, biological yield (t/ha), harvest index (%) and grain protein content (%) of maize hybrid were, significantly, affected by plant population and nitrogen fertilizer rates, where the highest grain yield was obtained by growing maize plant hybrid 3444 at a population of 75000 plant/ha under the application of 360 kg N/ha under the environmental conditions of Alexandria, Egypt.