The reduction of oxygen has been examined in 1 M NaOH at 25°C with a fluidized bed electrode of solid silver spheres and of silver coated glass spheres of different diameter.The realizing feasibility of the fluidized bed electrode also depends on the applied current. The current at which the overpotential is minimum slightly depends on bed expansion; this occurs at a bed expansion of 20 and 24% for respectively 1·00 mm and 0·61 mm diameter of spheres. The relation between overpotential and current is linear over a large region of overpotential. The maximum current which is attainable with a fluidized bed electrode strongly depends on bed expansion. The results suggest that a fluidized bed electrode behaves analogously to the suspension electrode.