The electrochemical behavior of the iron(III)/iron(II) and the ferri/ferro-cyanide redox couples in aqueous media has been investigated at conductive diamond, to obtain information on the properties of this electrode material. The investigation has been carried out at as prepared and oxidized diamond surfaces, under conditions of different concentration and temperature. The electron transfer kinetics has been followed by cyclic voltammetry, quasi-steady polarization (low-Field conditions) and AC impedance, and the results have been interpreted on the basis of the Hush model, attempting its extension to the ferri/ferro-cyanide redox couple as well.