The proper agronomical practices should be carefully chosen for optimizing grain sorghum productivity, particularly under limited-resources environments. Therefore, two field experiments were carried out in the Desert Research Center, Agriculture Experimental Station at El-Kharga Oasis, New Valley Governorate, during 2010 and 2011 growing seasons, to evaluate the effect of irrigation rate (5, 6 and 7 mm/fed/day); nitrogen fertilization rate (60, 80 and 100 kg N/fed) and plant density (17500, 23333 and 35000 plant/fed) on grain sorghum. Results showed that irrigation by 7 mm/fed/day was the potent treatment for increasing plant height, head length, head weight, weight of grains per head, seed index, grain yield, straw yield and biological yield compared to irrigation by 6 and 5 mm/fed/day. On the contrary, water use efficiency (WUE) and protein percentage were significantly decreased with increasing irrigation levels in both seasons. Adding 100 kg N/fed gave the maximum values of yield, yield components, water use efficiency and protein percentage compared to 80 and 60 kg N/fed in both seasons. Increasing plant density from 17500 to 35000 plant/fed caused significant increases in yield, yield attributes, water use efficiency and protein percentage, except for head weight, weight of grains per head and seed index in both seasons. Plots irrigated by 7 mm/fed and fertilized with 100 kg N/fed achieved the maximum values of grain, straw and biological yield/fed, when sorghum plants grown at high density (35000 plant/fed).