The corrosion of zinc in sulphamic acid containing various isomer of toluidines has been studied. In plain sulphamic acid, the corrosion increases with the acid concentration and temperature. An increase in the concentration of the inhibitor increases the inhibition efficiency the order of inhibition efficiency in 0.1 M sulphamic acid containing 5 mM inhibitor being: o-toluidine (62%) < m-toluidine < p-toluidine (72%). Plot of log theta/(1-theta) versus log C results in a straight line suggesting that the inhibitors cover both the anodic as well as cathodic regions through general adsorption following Langmuir isotherm. Zinc shows a corrosion potential of -920, -880 and -875 mV versus Ag/ AgCl reference electrode in 0.1, 0.5, and 1.0 M sulphamic acid. Galvanostatic polarization curves show both anodic and cathodic polarization in the case of all inhibitors studied.