Steady state voltammetry for reduction of cadmium in dimethylsulphoxide (DMSO) with and without supporting electrolyte is studied at platinum microdisc electrodes. The ratio of limiting current in absence of supporting electrolyte I-lm to diffusive current I-ld in DMSO agrees well with theoretical predictions, while comparative measurements carried out in water, under the same condition of supporting electrolyte, show some discrepancies. A simple equation is also proposed for predicting the limiting current ratios for the reduction of labile complexes in the absence of supporting electrolyte.