The current state of research in petroleum acid corrosion of metals is surveyed. It is shown that the corrosion of refinery equipment caused by petroleum naphthenic acids is a multifactor process. The general characteristics of the acid content in crude oils and the acid number give quite a rough evaluation of the corrosive power of oils, and the determining factors useful for evaluation are the type, structure, and functionality of petroleum acids. Effective ways of preventing petroleum acid corrosion of metals are comprised of the demineralization and careful alkali treatment of crude oil, the use of organic corrosion inhibitors, and improvement in the metal quality by alloying with anticorrosive additives. Methods for simulation of the metal corrosion processes caused by petroleum acids are becoming of substantial importance.