By exerting sandblasting onto copper surfaces, we show that increasing the surface roughness can effectively promote CuO nanowire formation by significantly enhancing the nanowire growth density and length during the oxidation of copper. It is found that the enhanced nanowire nucleation and growth is associated with the increased thickness of the underlying CuO and Cu2O layers and decreased grain sizes of the two oxide layers. These results demonstrate that the increased surface roughness of the metal substrate results in finer grain structures in the layered oxide growth, thereby facilitating outward diffusional transport of Cu atoms along grain boundaries for enhanced CuO nanowire formation. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.102204jes] All rights reserved.