A new method to introduce iminodiacetic acid (IDA) onto polyethersulfone (PES) matrix through chlorosulfonation was described in this work, and the prepared PES-IDA was used as adsorbent for the removal of metal ions from aqueous solutions. Chlorosulfonic groups (-SO2Cl) were introduced onto PES first, then IDA was grafted onto PES by using the interactions between the chlorosulfonic group and the imino group of IDA. The grafted IDA was characterized by fourier transform infrared measurement, X-ray photoelectron spectroscopy analysis, and thermogravimetric analysis spectra. The adsorbed amounts by the PES-IDA for Cu2+ and Ag+ were 3.44 mg/g and 7.09 mg/g, respectively. The PES-IDA adsorbent may expand the usage of PES in purification fields and could make some potential contributions to the polymer-based adsorbents. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 345-350, 2011