This paper present synthesis of Polyaniline-Zinc Oxide Composites and their usage as Ammonia Gas Sensor. The authors adopted a novel chemical route for the synthesis of polyaniline composites via chemical method. These samples were prepared by oxidation of aniline via rapid mixing method. Aniline solution is prepared in sulphuric acid with addition of fixed wt % of zinc oxide. PANI-ZnO composites were synthesized by rapid mixing of ammonium persulphate to aniline solution in an ice bath. The synthesized samples were characterized using X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) techniques. The morphology of synthesized samples exhibited fibrous and spherical structures. The thick films were prepared salt deposited on alumina substrate for gas sensing application. These sensors exhibited excellent response and recovery time, when exposed to different concentration of ammonia gas at room temperature.