The effect of power ultrasound in the modification of voltammetric processes is investigated and the role of surface activation by means of electrode erosion/roughening characterized. The potential benefits of sonovoltammetry are illustrated with two examples. First, the Flade potential for the passivation of nickel in air-saturated aqueous KOH solution is shown to be anodically shifted in the presence of ultrasound. Second, the voltammetric study of Cr(CO)(6) in acetonitrile solution is shown to be feasible without the passivation observed under silent conditions where the electrolysis results in surface-active species the,adsorption of which block further electron transfer.