The reduction process of molybdenum in the presence of fulvic acids and phenanthroline was investigated by square-wave voltammetry (SWV), The mixed-ligand complex of molybdenum exhibits a pronounced tendency to adsorb onto the mercury electrode surface. The electrode reaction proceeds as a surface process in which both components of the redox couple are firmly confined to the electrode surface. The kinetics of the electrode reaction is studied utilizing the properties of "split SW peaks" and "quasireversible maximum". The kinetic parameters obtained with two different square-wave voltammetric methods are in good agreement. In 0.5 mol/L NaCl solution with pH 2.5 the kinetic parameters are: standard rate constant ks = 8 ± 2 s-1, cathodic electron transfer coefficient α = 0.41 ± 0.05, and number of exchanged electrons n =2. The SW kinetic measurements are confirmed by cyclic voltammetric method.