The graft copolymerization of methyl-methacrylate onto viscose fibers was studied under photoactive conditions with visible light using Ce4+/Ti3+ combination as redox initiator in a limited aqueous medium. Polymerization conducted in the presence of light at 30 +/- 1 degrees C produced significant grafting, compared with that conducted in the dark under the same conditions. The % grafting, % total conversion, and % grafting efficiency were studied by varying time, monomer concentration, initiator concentration, and pH of the medium. The mechanism of polymerization and graft copolymer formation have been discussed. Characterization of the grafted fibers was done by Fourier transform infrared spectroscopy and scanning electron microscopy. The effect of % grafting on thermal properties was studied by thermogravimetric analysis.