The corrosion of pure iron in is discussed in terms of the theory of mixed potentials and the theory is applied to inhibition by organic compounds. Corrosion rates with and without inhibition by aniline, several aniline derivatives, and alkylamines were determined by cathodic polarization measurements as well as by colorimetric analysis of the solution. It is shown that all compounds show a maximum inhibitor efficiency at a concentration of approximately 0.1 mole/1, that with one exception all are cathodic as well as anodic inhibitors, and that in most cases they are predominantly anodic inhibitors. An interpretation of the data on cathodic inhibition is suggested on the basis of the assumption of a uniform metal surface and uniform adsorption. The interpretation of anodic inhibition is found to be difficult due to a lack of satisfactory experimental data.