Cathodic disbonding of the epoxy coatings on the mild steel was evaluated in 3.5% NaCl solution, where benzimidazole, benzothiazole and benzotriazole were used as additives in the coatings. Also, the electrochemical behavior of coatings delaminating in NaCl solution from a small artificial defect and the bare mild steel samples in the 3.5% NaCl solution containing the azole compounds was evaluated by electrochemical impedance spectroscopy at cathodic polarization condition. Results showed that the azole compounds were not immobilized in the coating as they could leach out and act as cathodic inhibitor at defect site and disbonding front.