Accurate and timely assessment of steel reinforcement corrosion in reinforced concrete (RC) structures is important if the corrosion process is to be either mitigated or successfully stopped. It is therefore important that engineers are familiar with not only the different corrosion assessment techniques but also their reliability. Even though there are several commercial instruments available to assess corrosion in RC structures, they all rely on similar basic engineering fundamentals. It is important that engineers and contractors alike understand these fundamental basics so that a sound judgement, with respect to selection of the test method to use, can be made. This paper gives a general overview of the different test methods for corrosion in RC structures.