The grafting reaction of ricinol-2-oxazoline methyl maleate onto molten low density polyethylene was investigated in a twin-screw extruder The influence of peroxide content, added ricinol-2-oxazoline methyl maleate and process variables such as residence time, screw speed and reaction temperature were considered. The rate and level of grafting were quantitatively measured by FTIR technique. Maximum level of grafting at constant peroxide content was obtained when concentration of ricinol-2-oxazoline methyl maleate reached 3 %, above which it declined. The rate of grafting increased with increasing peroxide content. However crosslinking of polyethylene was found to have taken place as parallel competitive reaction which was intensified with increasing peroxide content. It was demonstrated that it is possible to make an optimization of the grafting reaction on the basis of experimental results. The considerable grafting yield with acceptable melt flow rate for the samples was achieved when initial ricinol-2-oxazoline methyl maleate and peroxide concentrations were 2 to 3 % and 0.06 to 0.1%, respectively.