CuO nanorods have been successfully prepared from a solution of copper nitric acid, urea, citric acid, and cetyltrimethyl ammonium bromide by the hydrothermal method at 105C for 48h and characterized by means of X-ray diffraction, scanning electron microscopy, and IR spectra. The CuO nanorods are 40-60nm in diameter and up to 150-250nm in length, and a possible formation mechanism of their formation is proposed.