The corrosion of zinc in phosphoric acid containing hexamine has been studied at different acid concentrations, inhibitor concentration and temperatures. Corrosion increases with the concentration of acid and the temperature. The inhibition efficiency (IE) of hexamine increases with the concentration of inhibitor. The IE decreases with the increase in concentration of acid. As temperature increases, percentage of inhibition decreases. The plot of log (Θ/1-Θ) versus log C results in a straight line suggest that the inhibitors cover both the anodic and cathodic regions through general adsorption following Longmuir isotherm. Galvenostatic polarization curves show polarization of both anodes as well as cathodes.