Of all the various anti-corrosion systems usEd. by offshore structures and ship-building industry to reduce the ravages of sea-water corrosion, cathodic protection is one of the most important. Impressed current cathodic protection (ICCP) is the principal means of corrosion control for submerged structures. The developments of offshore energy resources is rapidly moving into water depths greater than 300 metres. However changes in the sea water environment at greater depths have raised the concern that the cathodic protection design approaches for shallow water may not be adequate for deeper water. This paper discusses on environmental factors encountered in deep water and their effect on cathodic protection behaviour of steel. Further, current CP design approaches and deep water CP studies are also discussed. Finally, work being carried out in National Institute of Oceanography (NIO), Dona Paula, Goa, India on ICCP system for deep water structures is briefly described