Lysozyme adsorption onto Cibacron Blue F3GA attached and Cu(II) incorporated poly(2hydroxyethyl methacrylate±ethylene glycol dimethacrylate) [poly(HEMA-EGDMA)] microspheres was investigated. The microspheres were prepared by suspension polymerization. Various amounts of Cibacron Blue F3GA were attached covalently onto the microspheres by changing the initial concentration of dye in the reaction medium. The microspheres with a swelling ratio of 65%, and carrying different amounts of dye (between 1.4 and 22.5 mmol/g À1 ) were used in the lysozyme adsorption studies. Lysozyme adsorption on these microspheres from aqueous solutions containing different amounts of lysozyme at different pH values was investigated in batch reactors. The lysozyme adsorption capacity of the dye±metal chelated microspheres (238.2 mg g À1 ) was greater than that of the dye-attached microspheres (175.1 mg g À1 ). The maximum lyzozyme adsorption capacities (q m ) and the dissociation constant (k d ) values were found to be 204.9 mg g À1 and 0.0715 mg ml À1 with dye-attached and 270.7 mg g À1 and 0.0583 mg ml À1 with dye±metal chelated microspheres, respectively. More than 90% of the adsorbed lysozyme were desorbed in 60 min in the desorption medium containing 0.5 M KSCN at pH 8.0 or 25 mM EDTA at pH 4.9.