Multiwalled carbon nanotube (MWCNT) was modified through plasma polymerization of aniline by applying different radio frequency (radio frequency (RF): 13.56 MHz) powers. The modified MWCNTs were investigated in terms of morphology, chemical structure, and thermal behaviors, indicating the formation of composites based on the surface modification of MWCNT with polyaniline (PANI). These composites were then used in amperometric glucose biosensor, which was constructed by immobilizing glucose oxidase on premodified Pt electrode with PANI/MWCNT composites. The biosensor based on the composite obtained under RF power of 60 W exhibited the high sensitivity of 54.91 mu A mM(-1) cm(-2) to glucose.