Crosslinked acrylonitrile/acrylamidoxime/2-acrylamido-2-methylpropane sulfonic acid (AN/AAx/AMPS)-based hydrogels were prepared by free radical crosslinking solution polymerization technique. The chemical structures of the hydrogels were characterized by FTIR analysis. The morphology of the dry hydrogel sample was examined by scanning electron microscope (SEM). These hydrogels were used for the removal of Cd(II), Cu(II), and Fe(III) ions from their aqueous solutions. The influence of the uptake conditions such as pH, time and initial feed concentration on the metal ion binding capacity of hydrogel was also tested. The selectivity of the hydrogel towards the different metal ions tested was arranged in the order of Cd(II) > Fe(III) > Cu(II). It was observed that the specific interaction between metal ions and ionic comonomer in the hydrogel affected the metal binding capacity of the hydrogel. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 999-1011, 2011