The surface roughness of porous Ni-Zn-P electrodes was studied in 1 M NaOH using in situ electrochemical techniques: ratio of the polarization current densities, electrochemical impedance spectroscopy, cyclic voltammetry, coulometric oxidation of the surface, and a new technique of a CO molecular probe. The obtained surface roughness was about 5.5 x 10(3). Good agreement was observed between the results obtained by all these techniques.