The large number of corrosion problems in reinforced concrete structures worldwide has led to the durability of concrete structures exposed to aggressive environments becoming a problem of major importance. New results from research on chloride-induced corrosion of steel in concrete show that the corrosion mechanisms are quite complex. Normally, locally separated anodically and cathodically acting areas are formed on the steel surface. As the cathodically acting steel surface areas are not visible, the corrosion mechanisms can only be investigated indirectly using new electrochemical testing methods. In this paper the influence of temperature on the corrosion rate is discussed based on the theoretical background of chloride-induced macrocell corrosion of steel in concrete.