We have developed a novel approach to obtain high metal sorption capacity utilizing a membrane containing chitosan and an immobilized reactive dye (i.e. Reactive Yellow-2). The composite membrane was characterized by SEM, FTIR, swelling test, and elemental analysis. The membrane has uniform small pores distribution and the pore dimensions are between 5 and 10 pm, and the HEMA:chitosan ratio was 50:1. The reactive dye immobilized composite membrane was used in the removal of heavy metal ions [i.e., Pb(II), Hg(II) and Cd(II)] from aqueous medium containing different amounts of these ions (5-600 mg 1(-1)) and at different pH values (2.0-7.0). The maximum adsorption capacities of heavy metal ions onto the composite membrane under non-competitive conditions were 64.3 mmol m(-2) for Pb(II), 52.7 mmol m(-2) for Hg(II), 39.6 mmol m(-2) for Cd(II) and the affinity order was Pb(II) > Hg(II)>Cd(II).