Institute of Nuclear Chemistry and Technology, Pulp and Paper Research Institute and Institute of Chemical Fibres carry out a joint research project in order to develop the radiation methods for modification of cellulose pulp to produce useful cellulose derivatives such as cellulose carbamate, carboxymethyl cellulose and methylcellulose. It is expected that radiation treatment should yield a final product with average degree of polymerization in the range 250 - 350 limiting the amount of chemicals activators used in classic methods and providing environmental benefits. In this paper the effect of 10 MeV electron beam on degree of polymerization of various cellulose pulps has been studied. The role of free radicals in degradation process is also discussed.