This investigation was carried out during two successive seasons of 2014 and 2015 on 6 years old, Washington Navel orange trees (Citrus sinensis L.) budded on sour orange rootstock. Tree spaced at 5 x 5 meter and grown on sandy soil and irrigated with saline water (EC was 4 ds/m) under drip irrigation system in private orchard located at El-Behera Governorate, Egypt. The objection to study the impact of different levels of magnetized irrigation water and compost on growth, leaf mineral content and water use efficiency (WUE) of Washington Navel orange tree growing on sandy soil under drip irrigation saline water. Three levels of magnetized irrigation water 3658.5, 2743.8 and 1829 m3/fed. with and without compost at 4kg/tree along with control (non-magnetic water).  Results indicated that, the highest values of vegetative growth parameters i.e., shoot length, shoot thickness, number of leaves/shoot, leaf area/leaf, as well as chemical constituents of leaves (N, P, K, Ca, Mg)  obtained by trees irrigated with magnetized water levels combined with or without compost. Leaf Na content were increased under control treatment(non-magnetic water). The best results of both vegetative growth parameters and chemical constituents of leaves were recorded when trees irrigated with magnetized water at level 1(3658.5m3/fed/season) + 4kg compost followed by level 2(2743.8 m3/fed/season) + 4kg compost, while the highest yield efficiency (YE) and WUE obtained from irrigation treatment at level3(1829 m3/fed/season) + 4kg compost in both seasons .Therefore, magnetizing water at level 1+ 4kg compost or level 2+ 4kg compost treatment could be recommended for improving citrus trees performance under saline water conditions.