Extracts of Ricinus communis leaves were tested for corrosion inhibitory effects towards mild steel in 100 ppm sodium chloride solution. The anticorrosion efficiency of plant extracts was studied by means of weight loss, electrochemical polarization and impedance measurements. It was found from weight loss measurements that the corrosion inhibition efficiency was about 84% in 300 ppm of the plant extract. Polarization measurements indicated that the plant extract acted as anodic inhibitor. Electrochemical impedance results also showed that the plant extract increased the corrosion resistance of mild steel and the formations of iron-organic complex reduced the corrosion of mild steel in neutral system.