Copolymers of 2-(2-hydroxyethoxy)ethyl methacrylate and ethylene dimethacrylate in the form of homogeneous membrane sheets were modified by chelating groups of iminodiacetic acid (IDA) in a two step reaction. The obtained sorbents showed high chelating capacity for Ni(II), Cu(II) and Fe(III) ions (up to 1.3 mmol/g). The potential use of immobilized Ni(II)-IDA complexes for sorption of murine immunoglobulin G by the immobilized metal affinity (IMA) method was tested. The sorption behaviour was characterized by a Langmuir-Freundlich adsorption isotherm. It was shown that the chelating membranes could be used for the sorption of low amounts of protein.