Cyclic voltammetry and impedance have been employed for the quantitative study of D-ribose adsorption on the bismuth single crystal planes \0.05 M Na2SO4 aqueous solution interface. The adsorption of D-ribose on Bi planes is mainly limited by the diffusion step and thus the D-ribose adsorption in the region of zero charge potential E-sigma =0 is physical, The adsorption isotherms, Gibbs energy of adsorption, the maximal surface excess Gamma (max) and other adsorption parameters have been determined, The limiting Gibbs adsorption Gamma (max) of D-ribose decrease in the sequence of Bi planes (001) > (111) > (01 (1) over bar) as the reticular density of planes increases in the sequence (001) < (111) < (01 (1) over bar). The very low values of Gamma (max) and the limiting potential shift of zero charge, caused by the replacement of water monolayer by the monolayer of D-ribose, indicate that the D-ribose molecules probably have a flat orientation at Bi surface, The molecular interaction parameter a in the Frumkin isotherm decreases in the sequence of planes (111) > (001) > (01 (1) over bar). The negative values for Bi(001) and Bi(01 (1) over bar) planes indicate that there is a repulsive interaction between the adsorbed D-ribose molecules.