Synthesis of graft copolymer under the influence of microwave radiation is a rapid, efficient, clean, cheap, convenient, energy-saving, and green method. Grafting of methylmethacrylate (MMA) + acrylamide (AAm), MMA + acrylonitrile (AN), and MMA + acrylic acid (AA) binary mixtures onto acetylated Saccharum spontaneum L was carried out under the influence of microwave radiation (MWR), and maximum graft yield 94.5% was found with MMA + AAm binary mixture. Synthesized graft copolymers were characterized with FT-IR, scanning electron microscopy, TGA/DTA/DTG, and X-ray diffraction techniques. Thermal stability of Ss-g-poly(MMA + AAm) was found to be more than that of acetylated S. spontaneum fiber and other graft copolymers. Although on grafting, percentage crystallinity and crystallinity index decreased but graft copolymers were found to exhibit more moisture, chemical, and thermal resistance. (C) 2011 Wiley Periodicals, Inc. Adv Polym Techn 30: 122-137, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20209