The work highlights a unique, one step protocol for room temperature immobilization of enzyme cata-lase onto epoxy functionalised cellulose matrix developed via gamma radiation induced simultaneousirradiation grafting of Glycidylmethacrylate (GMA). Effect of grafting parameters, such as radiation dose,monomer concentration and solvent composition on the grafting yield, was studied in order to opti-mize the radiation grafting process. Poly(GMA)-g-cellulose matrices were characterized by grafting yielddetermination, FTIR, SEM and TGA techniques. The epoxy functionalized poly(GMA)-g-cellulose matrixwas subsequently employed for covalent immobilization of an industrially relevant enzyme catalase. Thecatalytic activity of catalase-immobilized-poly(GMA)-g-cellulose was assayed by spectrophotometricallymonitoring the enzymatic degradation of H2O2at 240 nm. Catalase-immobilized-poly(GMA)-g-cellulosewas observed to be reusable for over 5 cycles within ten days. Catalase was observed to show improvedactivity at higher pH after immobilization. Thermal stability of Catalase-immobilized-poly(GMA)-g-cellulose was also enhanced in comparison to the free enzyme system.