ABSTRACT Due to the drought and water scarcity, which is one of the obstacles to development in arid and semi-arid areas that depends on rain-fed agriculture and rain water only, wheat crop exposed to water shortage after the rain stopped, especially in the critical period during the formation and filling stage of the grain causing poor productivity, the yield is highly positively affected by using an additional irrigation source. So, this research was aimed to increasing wheat productivity by applying sprinkler supplemental irrigation for watering wheat in its critical period and maximizing the irrigation Water Use Efficiency (WUE) to raise the Water Use Productivity (WUP) in cultivated area as one of the tools for a climate changes challenges. The experiment was applied in North Sinai Governorate during winter season of 2021/2022. The study was conducted to determine the effect of optimum watering rates of the supplemental irrigation system on maximizing wheat productivity and water use efficiency under the drought and water scarcity conditions. Irrigation treatments was, (33% - 50% - 65%) of full daily irrigation rate compared to the traditional system without irrigation based on rain water only. Two seeding rates were used for cultivation: (48 and 60 kg.fed^-1). The results showed that treatment using supplemental irrigation at 65% of the actual water needs with seeding rate of 48 kg.fed^-1, achieved the highest values for crop productivity, (WUE) and (WUP) which reached to 1660 kg.fed^-1, 2.83kg.m^-3 and 11.90 kg.fed^-1.mm^-1 respectively, While T₂ (33% irrigation + 60 kg.fed-1 seeds for planting) and T₇ (Rain-fed condition) released the lowest values compared to other  treatments.