In this study, the removal of Cu2+ and Pb2+ ions by precipitation from aqueous solutions by using six fly ashes with different compositions was achieved. The effect of four parameters on the removal of Cu2+ and Pb2+, which are contact time, fly ash composition, pH of the solution and fly ash concentration, were investigated. The fly ash concentrations required to achieve maximum Cu2+ and Pb2+ removal were found to vary between 0.2-10 and 0.075-3.5 g/l, respectively. It was also observed that both the Cu2+ and Pb 2+ removal capacities of the fly ashes depend strongly on their CaO content. © 2004 Elsevier Ltd. All rights reserved.