This paper deals with the numerical determination of potential and current distribution along the reinforcement when using patch repair applied to reinforced concrete elements. Numerical finite element models of the electrochemical phenomena demonstrate the useful contribution of Sacrificial Anode in improving the Cathodic Protection of the reinforcement by testing several configurations. The main result is that the Sacrificial Anode should be embedded in the substrate concrete area rather than in the patch area. Moreover, the influence of the resistivity of the repairing concrete is evaluated.