The present paper aims at to study the preparation of Polyaniline fibers and characterize them. Polyaniline fibers were synthesized by chemical oxidation polymerization where ammonium per sulfate [(NH4)2S2O8] was used as oxidant to oxidize Aniline to Polyaniline. The Polyaniline fibers were characterized by XRD, FTIR, TEM and UV-Visible Spectroscopy. The characteristic peaks in FTIR and UV-Visible spectra confirmed the expected structure of polymer as reported in the literature. Further, Transmission electron microscopy (TEM) confirmed the formation of Polyaniline fibers. The A.C. conductivity , dielectric constant (€’(w) ) and DielectricLoss (€’’(w) ) of Polyaniline fiber were measured using impedance analyzer. The antibacterial activity was examined for this Polyaniline nano fibers and it was observed that PANI could be used as an antibacterial agent.