Catalytic reduction of N2O was carried out with atomic hydrogen permeating through a palladized Pd sheet electrode. N-2 was solely produced in the reduction of N2O. Current efficiency for the reduction of N2O at current densities from 10 to 50 mA cm(-2) exceeded 90%. A palladized Pd sheet electrode was found to work not only as a source of atomic hydrogen supply, but also as a catalyst with high activity for the reduction of N2O.