An influence of the process condition on the grafting efficiency and molecular mass of the acrylic chains of graft copolymers of poly(methyl acrylate) with hydroxyethyl and carboxymethyl cellulose (HEC and CMC) has been studied. The kinetics of graft polymerization of methyl acrylate onto hydroxyethyl and carboxymethyl cellulose initiated by peroxydisulfate ion in the wide region of reagent concentrations has been investigated. The reaction order with respect to the monomer is about 1, to peroxydi sulfate ion and initial polymer is about zero for polymerization and grafting of methyl acrylate onto CMC and HEC. Effective activation energies are 102 and 110 kJ/mol for HEC and 78 and 80 kJ/mol for CMC in these reactions respectively. The kinetics of the peroxydisulfate ion decomposition and the change of molecular mass of HEC and CMC in their water solutions has been investigated. The reaction order with respect to peroxydisulfate is about 1 and with respect to cellulose derivatives changes from 0.3 to zero when the cellulose ether concentration increases in the reaction of peroxydisulfate decomposition. It has been showed that the process of polymer destruction and formation of cross-linked cellulose derivatives proceeds in their water solutions in the presence of peroxydisulfate.