The electrochemical behaviour of non-labile metallic complexes under square wave voltammetry (SWV) conditions is analysed theoretically, considering the influence of ligand adsorption-desorption processes as well as the ligand concentration on the quasi-reversible redox reaction mechanism. The dependence of current and peak potentials on the transfer reaction rate and on complex stoichiometry is considered. Voltammetric responses for processes in which the ligand is desorbed or remains adsorbed after the electroreduction process are compared. Diagnosis criteria for the selection of optimum SWV parameters in view of analytical applications are presented for each case.