Porous zinc electrodes were discharged galvanostatically in aqueous potassium hydroxide solutions. The morphology of the zinc oxide film formed was investigated with a scanning electron microscope. The current distribution in the porous electrode, and its dependence on current density, was determined by microslicing the electrode after discharge and chemical analysis. The oxide film had a porous, “carpet‐like” structure, consisting of long needle crystals with occasional sidearms. The formation of this type of film can be explained by a dissolution‐precipitation mechanism. The current distribution in the porous electrode, and its dependence on current density could also be explained, based on a model of oxide film consisitng of a thin, high resistance compact film, beneath the porous oxide.