The synthesis of the single-crystal Co 3 O 4 nanorods by molten salt approach was reported for the first time. The products were characterized by Transmission electron microscopy (TEM), X-ray diffraction (XRD), High-resolution transmission electron microscopy (HRTEM) and Selected-area electron diffraction (SAED). TEM results indicate that these nanorods have diameters of about 150 nm and lengths of about 2 μm. According to the analysis of the SAED and HRTEM results, we drew the conclusion that these nanorods grew along an unusual [−1,−1,15] direction by Ostwald ripening mechanism.