One-dimensional ordered LiNi0.5Mn1.5O4 nanorods have been fabricated and investigated for use as a high power cathode in rechargeable Li-ion batteries. These highly crystalline nanorods, with an ordered spinel structure and diameters and lengths around 130nm and 1.2μm, respectively, were synthesized in two steps by using a hydrothermal reaction to produce β-MnO2 nanorods followed by solid-state lithiation. Electrochemical analysis showed the superior performance of nanorods as a cathode in Li-ion half cells. The specific charge and discharge capacities were found to be 120 and 116mAhg−1 at a 0.5C rate, and 114 and 111mAhg−1 at a 1C rate between 3.5 and 5.0V vs. Li+/Li. Moreover, the nanorods exhibit high power capability, maintaining capacities of 103 and 95mAhg−1 at specific currents of 732.5 and 1465mAg−1 (5 and 10C rates), respectively.