Reduced size Dowex-50 (RDS-50) ion-exchanger was developed via a simple thermal treatment of commercial Dowex-50 in presence of L-methionine. Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and N-2 adsorption/desorption isotherms studies were performed to confirm functional groups, surface morphology, BET surface area and pore size of RDS-50 ion-exchanger. RDS-50 ion-exchanger was applied for the removal of Ni(II) and Cu(II) from aqueous solution under different experimental conditions such as contact time, solution pH, initial metal ion concentration and temperature. The equilibrium adsorption data were analyzed in detail using Langmuir, Freundlich and Temkin models. Adsorption kinetic study was conducted to fit the pseudo-first-order, pseudo-second-order and the intra-particle diffusion models. The adsorption isotherm experiments revealed that adsorption of Ni(II) and Cu(II) from aqueous solution onto RDS-50 ion-exchanger was fitted for Langmuir model. The maximum adsorption of Ni(II) and Cu(II) onto the RDS-50 ion-exchanger from aqueous solution was found to be 83.33 and 71.43 mg g(-1). The adsorption of Ni(II) and Cu(II) onto the RDS-50 ion-exchanger followed the pseudo second order kinetic model. The 87% Cu(II) and 93% Ni(II) were desorbed in 0.10 M HCl solution. (C) 2012 Elsevier B.V. All rights reserved.