The influence of the presence of a background electrolyte on the efficiency of the sonoelectrochemical (20 kHz ultrasound frequency) degradation of perchloroethylene (PCE) in aqueous solutions has been analyzed using sonoelectrolysis in batch mode. A significant enhancement of the efficiency of the sonoelectrochemical process is achieved when the process is carried out in the absence of the background electrolyte. The sonoelectrochemical degradation efficiency is found to be dependent on the ultrasonic power: about 100% degradation efficiency is achieved at a higher ultrasonic power level. The current efficiency is also enhanced (compared to the background-electrolyte-assisted sonoelectrochemical treatment. BEA-SECT) and a lower speciation in shorter times provides the total degradation of the pollutant into non-chlorinated compounds. (C) 2011 Elsevier B.V. All rights reserved.