Diaphragm walls are built to exclude earth and water from an area so that work may be performed under reasonably dry conditions. The range of applications for diaphragm walls includes earth-retaining and load-bearing walls for a variety of constructs such as underpasses, deep basements, underground stations, tunnels docks, and pump houses. In traditional construction methods, the concrete diaphragm wall consists of separate panels, which are not formed as a continuous monolithic construction. Vertical joints are used to divide the wall into panels, and horizontal reinforcement is not continuous from one panel to the next. Recently, a diaphragm wall, believed to be one of the largest ever built, was successfully constructed in Egypt with a continuous horizontal reinforcement. This paper describes in detail a new construction method for a diaphragm wall system. In addition, the difficulties encountered during construction are highlighted. Movements of the wall during excavation are reported. A comparison between the new and traditional construction methods is carried out in terms of cost and schedule. Applying the method presented in this paper offers substantial opportunity for reducing the steel reinforcement requirement and eliminating the use of shoring systems or ground anchors.