A polysaccharide based bioplolymer, chitosan was grafted with polyaniline through a simple room temperature oxidative-radical copolymerization method employing CuSO4 as a polymerizing agent. The grafting conditions were optimized by varying different parameters. The optimized experimental findings have been discussed and proposed a probable mechanism for the graft copolymerization. The representative sample of chitosan-graft-polyaniline (CHIT-g-PANI) was characterized using UV-vis, FTIR, X-ray diffraction and Scanning electron microscopy techniques taking chitosan as reference material. The result revealed the formation of grafted composite. Which exhibited highly improved electrical conductivity , in the order of ~ 10 -6 times due to the grafting of PANI onto chitosan backbone. Further , composite was found responsive in nature for H+ ion , which will be a suitable properties for its use in fabrication of bio-sensor.