Using of magnetized water has shown several advantages including improvement quality of irrigation water and increase the productivity of vegetable crops. Therefore, the present work was carried out to study the response of growth, yield, water and nitrogen use efficiency of cowpea for irrigation with two types of irrigation water (magnetized and non-magnetized water) under two levels of nitrogen fertilizer (100 and 75 % of the recommended rate) during the summer seasons of 2018 and 2019. The results cleared that all yield parameters increased significantly when irrigation occurred using magnetic water, such as total yield which increased by about 26 and 31% in the first and second season, respectively. Concerning the effects of magnetized water, the results reflected that irrigation with magnetic water significantly increased the values of the water use efficiency from 0.40 and 0.42 kg/m3 to 0.52 and 0.54 kg/m3 with magnetic water in both growing seasons. The gradual increases of nitrogen fertilizer levels were accompanied with significant increases on vegetative growth and yield, as well as nitrogen uptake and nitrogen use efficiency. The interaction effects between types of irrigation water and different levels of nitrogen fertilizer significantly affected all treatments and reflected a positive impact. The results reflect the possibility of reducing the applied rate of nitrogen fertilizer when cowpea plants irrigated with magnetized water to a percentage 25% without affecting the different studied characters. As well as many benefits for cowpea plants such as enhancing vegetative growth, increasing yield, improving crop quality were achieved.