Polyurethane (PU)-clay nanocomposite coatings were prepared by a sonication method. The stability and morphology of these coatings was characterized by turbidometry, X-ray diffraction, and transmission electron microscopy. The anticorrosive properties of these coatings were investigated by salt-spray and electrochemical impedance spectroscopy methods. According to the results, dispersed nanoclay layers in the matrix of the nanocomposite coating compositions led to superior anti-corrosive characteristics compared to those of pure PU coatings. The best results were obtained with coatings containing about 5 wt % clay. The resistance of the coating containing 5% clay was about 9.002 G Omega after 225 days of immersion in a 3.5 wt % NaCl solution, whereas it was only 97 k Omega for the pure PU coating. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 523-529, 2011