Graft polymerization of ethyl methacrylate (EMA) onto acacia gum (AG) has been studied. The grafting was found to be optimal under the following reaction conditions: gum 0.4 g/dL, monomer 0.066 mol/dL, H2SO4 0.037 mol/dL, ceric ammonium sulphate 0.0009 mol/dL, temperature 50 degrees C and time 3.5 h. FTIR spectroscopy was used for the confirmation of grafting. Thermal, physical and biodegradation properties of the copolymer were studied. A probable mechanism of polymerization has been suggested based on reaction kinetics.