Methyl methacrylate and other monomers were polymerized in systems involving cellulose completely or partially dissolved in complex solvents. Both the system [dimethylsulfoxide-sulfur dioxide] and the system [dimethylformamide-copper nitrate-cumene hydroperoxide] were found to be effective in initiating polymerization. In the presence of air, cellulose seemed to counteract the inhibiting effect of oxygen. All the reactions resulted in the formation of homopolymer only, and no graft co-polymers of cellulose were detected in the products.