Abstract: Corrosion and electrochemical behaviour of reinforcing steel embedded in cement pastes with and without concrete admixtures used in Egypt to modify concrete properties have been studied. The influence of the admixtures on the corrosion resistance of the steel against chloride attack has been studied using impressed current and impressed voltage techniques. The results indicate that the type and concentration of the admixture used have an important effed on the extent of chloride induced corrosion of the steel. The mechanism of corrosion of steel due to chloride attack is discussed.