Cooling water systems are exposed to many types of corrosion and scale problems. Water-formed deposits result from naturally occurring minerals precipitating from water to form scale. Scales built up on surfaces can be extremely hard and difficult to remove. These phenomena have a great economic impact, since the first involves deterioration of metallic surfaces by the medium, and the second causes loss of capacity for thermal exchange. Scaling and corrosion are usually interdependent. When non -uniform formation of scale occurs, corrosion is often present particularly under the deposit. This book describes an experimental study on inhibition of these problems by organic inhibitors. The performance of the selected compounds as scale inhibitors was determined in terms of the amount of soluble calcium ions in solution. Also, the work was extended to study the corrosion inhibition effect of the selected compounds on carbon steel surface in contact with cooling water using both potentiodynamic polarization and electrochemical impedance spectroscopy techniques. It was found that the selected compound acts as a good scale and corrosion inhibitor.