The geometrical roughness factor, root mean square departure of the surface from flatness, the medium lateral correlation length and other parameters have been obtained for variously pre-treated Sb(1 1 1) and Sb(0 0 1) electrodes. Atomic resolution was achieved for cleaved at liquid nitrogen temperature Sb(1 1 1) surface using UHV-STM method. The surface pits with various depths and widths on the surface of electrochemically and chemically etched Sb(1 1 1) electrodes, and deep furrows on the surface of cleaved Sb(0 0 1) have been observed. Electrical double layer characteristics of variously pre-treated Sb(1 1 1) and Sb(0 0 1) electrodes were studied in terms of the Debye length dependent roughness theory (i.e., non-linear Poisson–Boltzmann theory), recently developed by Daikhin et al. [Phys, Rev. E 53 (1996) 6192; Electrochim. Acta 42 (1997) 2853 and J. Chem. Phys. 108 (1998) 1715]. According to the experimental data and results of theoretical calculation, the surface roughness increases in the order of Sb electrodes: cleaved at the temperature of liquid nitrogen Sb(1 1 1) < electrochemically polished single crystal Sb(1 1 1) < electrochemically etched Sb(1 1 1) < chemically etched Sb(1 1 1) < cleaved at temperature of liquid nitrogen Sb(0 0 1). This order of the electrode surface roughness is in agreement with the data obtained from STM, AFM and impedance measurements.