This paper firstly reports that cupric oxide nanowires (CNWs) were synthesized by thermal oxidation of copper coated carbon fibers (Cu/CFs). The results of transmission electron microscope images indicate that the nanowires are about 50 nm in diameter and several microns in length. The optimum growth conditions of the nanowires are found when the film of Cu/CFs is annealed at 400 degrees C for 4 h in air. The results show that the reflectivity of cupric oxide-nanowire-covered carbon fibers (1-1.3 mm in thickness) is less than -4 dB over the range of 8.6-18 GHz. Furthermore, the possible growth mechanism of CNWs is discussed. (C) 2009 Elsevier B. V. All rights reserved.