The competitive removal of Pb2+, Cu2+, and Cd2+ ions from aqueous solutions by the copolymer of 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) and itaconic acid (IA), P(AMPS-co-IA), was investigated. Homopolymer of AMPS (PAMPS) was also used to remove these ions from their aqueous solution. In the preparation of AMPS-IA copolymer, the molar percentages of AMPS and IA were 80 and 20, respectively. In order to observe the changes in the structures of polymers due to metal adsorption, FTIR spectra by attenuated total reflectancetechnique and scanning electron microscopy (SEM) pictures of the polymers were taken both before and after adsorption experiments. Total metal ion removal capacities of PAMPS and P(AMPS-co-IA) were 1.685 and 1.722 mmol Me2+/g(polymer), respectively. Experimental data were evaluated to determine the kinetic characteristics of the adsorption process. Competitive adsorption of Pb2+, Cu2+, and Cd2+ ions onto both PAMPS and P(AMPS-co-IA) was found to fit pseudo-second-order type kinetics. In addition, the removal orders in the competitive adsorption of these metal ions onto PAMPS and P(AMPS-co-IA) were found to be Cd2+ >Pb2+ > Cu2+ and Pb2+ >Cd2+ > Cu2+, respectively. Copyright (C) 2008 John Wiley & Sons, Ltd.