Polyaniline (PANI)-Ag nanocomposites were synthesized by in situ chemical polymerization approach using ammonium persulfate and silver nitrate as oxidant. Characterizations of nanocomposites were done by ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy, and transmission electron microscopy (TEM). UV-vis, XRD and FTIR analysis established the formation of PANI/Ag nanocomposites and face-centered-cubic phase of silver. PANInanofibers were of average diameter approximate to 30 nm and several micrometers in length. Morphological analysis showed that the spherical-shaped silver nanoparticles decorate the surface of PANI nanofibers. Silver nanoparticles of average diameter approximate to 5-10 nm were observed on the TEM images for the PANI-Ag nanocomposites. Such type of PANI-Ag nanocomposites can be used as bistable switches as well as memory devices. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013