The passivity of iron and nickel has been investigated in methanolic solutions of sulphuric acid with various water content. The stable oxide-hydroxide film can be formed on the metal surface only in the solutions with the molar ratio of acid to water lower than 1:4. In the solutions with higher ratio water molecules are bound in the hydratation shell of hydrogen ions. In such solutions the anodic behaviour of iron and nickel is similar to the behaviour of these metals in aqueous concentrated solutions of sulphuric acid. A thick unprotective anodic layer covers the nickel surface during anodic polarization whereas iron undergoes anodic dissolution without forming an anodic film.