In this study, ethyl cellulose (EC) micro and nanocapsules containing linseed oil for use in selfhealing coatings have been prepared by an emulsion-solvent evaporation method. The prepared micro and nanocapsules were individually embedded into the polyurethane coatings and the coatings were then applied on mild steel substrates using spray method. The corrosion resistance of the coatings was evaluated using linear polarisation and electrochemical impedance spectroscopy tests. Results obtained revealed that using EC nanocapsules compared to microcapsules significantly increased the corrosion resistance of the self-healing coating. In addition, the healing properties of the prepared nanocapsules containing coating would be greater than the microcapsules one.