Graft copolymerization of methylmethacrylate (MMA) onto non-mulberry silk fibre Antheraea assama was carried out in aqueous medium using KMnO4-oxalic acid redox initiator. The rate of grafting (%) was evaluated as a function of initiator (oxalic acid) and H2SO4 acid concentrations, reaction temperature and time. The rate of grafting increased progressively with the increase of oxalic acid and H2SO4 concentrations up to 1.25x10(-2) and 16x10(-2) mol/L respectively. The extent of grafting (%) depends upon reaction time and temperature also. The grafted products were characterized with the help of infra-red (IR) spectroscopy, while the thermal decompositions of the ungrafted and grafted silk fibres were studied using TGA, DTG and DTA techniques at two heating rates 20degreesC and 30degreesC min(-1) in static air in the temperature range 30-800degreesC. The grafted products were found to be thermally more stable than the ungrafted ones. The water retention values (WRV) of the grafted fibres were in decreasing order with the increase in grafting (%).