Cathodic Protection (CP) is a technique used to control the corrosion of a metal surface by making it the cathodic side of an electrochemical cell. The simplest method to apply CP is by connecting the metal to be protected with another more easily corroded metal to act as the anode of the electrochemical cell.

Cathodic protection can, in principle, be applied to any metallic structure in contact with a bulk electrolyte although in practice its main use is to protect steel structures buried in soil or immersed in water.