Corrosion is one of the main factors which effect the life of reinforced concrete structures. The cross-sectional area of the rebar embedded in the concrete will be reduced during the process of corrosion which result in the degradation of structure. Reducing the w/c ratio, adding different pozzolanic materials and coating of rebars are the effective methods to prevent the corrosion of steel and also to improve the mechanical characteristics of the materials. In the present study, high strength concrete is developed for the w/c ratio’s 0.25,0.3 and 0.35. It is aimed to detect the corrosion potential, corrosion rate and electrical resistance of steel rebar embedded in the high strength concrete for different water-cement ratio cylinder samples by using half-cell potential and electrochemical impedance spectroscopy(EIS). The obtained results reveal the vital role of w/c ratio. With increase in w/c from 0.25 to 0.35 the corrosion rate, corrosion potential increased and electrical resistance decreased. © 2020 University of Manchester and the authors.