Silver nanowires were synthesized by glycerol mediated process with the assistance of polyvinyl pyrrolidone. The grown nanowires have preferential orientation of [111]. Purified silver nanowires showed the absorptions at 400 and 352nm in UV–vis-NIR spectrum. The average width and length of the purified silver nanowires were measured as 60nm and 7μm, respectively, using the scanning electron microscopy. The ammonia vapor sensitivity of the dispersed silver nanowires coated on cladding removed polymethyl methacrylate fiber was calculated to be 0.17 counts/ppm at room temperature. The response and recovery times were found to be 70 and 80min, respectively, for 500ppm ammonia vapor concentration in the absence of carrier gas.