Carbon nanotube (CNT) wired and oxygen-deficient MoO3−x /CNT structures are fabricated via a facile hydrothermal reaction followed by controlled reduction in Ar/H2. The MoO3−x /CNT, which consists of 63 mol% MoO3 and 37 mol% MoO2, exhibits a much improved Li-storage property compared with the original MoO3/CNT structure when evaluated as an anode in the 0.05–3.0 V region. It is able to retain a capacity of 421 mAh g−1 towards Li after 100 cycles at 200 mA g−1, and deliver 293 and 202 mAh g−1 at current densities of 2 and 4 A g−1, respectively. It is suggested that the formation and recovery of a metallic MoO2 phase over the conversion reaction may account for the enhanced performance.