The design of cathodic protection systems normally relies on a combination of experience, experimental data and heuristics. However, problems and failures of CP systems not only has an economic cost, it can also present a threat to life and the environment. This paper will describe the application of a software system designed to simulate the performance of cathodic protection systems and predict the impact of the design parameters and the environment on its performance. Two applications are presented. The first describes an approach to the global optimisation of a ship's Impressed Current Cathodic Protection (ICCP) system using the boundary element method coupled with "Simulated Annealing" (SA) algorithm and search methods. In the second the modelling and optimisation of a CP systems for storage tanks is described including the impact of coating holidays and stray currents.