Spin-polarized density functional theory is used to investigate the energetic stability and the electronic properties of oxygen impurity in SiC NWs. The results show that oxygen is more stable in a carbon site than in a silicon site. In addition, we observe a trend to the impurity migrates to the surface of the NW. The electronic band structure calculation shows that the oxygen impurity gives rise to electronic levels within the band gap of the NW. For the oxygen saturating the dangling bonds of the surface, the electronic properties present spin dependence, and a resulting magnetic moment can be observed. (C) 2013 Elsevier B.V. All rights reserved.