Abstract: In a monopolar electrolysis cell for chlor-alkali electrolysis by the diaphragm or membrane process, the cathodic and anodic electrode structures extend in the vertical direction, the anodic structure being surrounded by the cathodic electrode structure. In the area of the active electrode surfaces, an upward-directed flow of electrolyte-gas mixture is produced as a result of the gas bubbles generated electrolytically in the electrode gap, whereupon the electrolyte is then degassed. The degassed electrolyte, because of its higher specific gravity, then flows down through a flow channel inside the anodic electrode structure, this channel being formed by vertically oriented feed conductors and U-shaped flow guide plates.