Batch and column tests were conducted to compare the efficiencies of three Fenton-like systems in the degradation of chlorobenzene. In the investigated systems, iron powder was the source of Fe2+ ions, and either Fe3+ or Cu2+ were added in order to enhance the degradation process. Optimum pH and concentrations of Fe3+, Cu2+ and hydrogen peroxide were assessed by treating synthetic chlorobenzene solutions both in batch and in column mode, thus achieving the minimum residual concentration of chlorobenzene. Optimum conditions assessed by means of column tests were then applied to column treatment of real chlorobenzene-contaminated groundwater. Results showed that, when the TOC content of water was above 12 mg L(-1), the performance of the Fe0/H2O2 system was enhanced by the addition of Fe3+, leading to 10-20 microg L(-1) of residual chlorobenzene.