The porosity and permeability of concrete result in the ingress of aggressive ions of liquids and gases into concrete leading to cracking and corrosion of reinforcing steel. Cathodic protection is an effective method of arresting corrosion. The paper presents results of an experimental investigation on sacrificial anode cathodic protection (SACP) conducted on 1.6m × 1.6m slabs with three grades of concrete namely M20, M30 and M40. The results show that SACP is effective in all three grades.