Nano-sized (nO-Co3O4, 387nm) and micron-sized (mO-Co3O4, 6.65μm) Co3O4 octahedra enclosed by {111} facets have been both synthesized through a wet chemical method followed by thermal treatment, and served as anode material of lithium ion batteries (LIBs). Electrochemical results demonstrate that the nO-Co3O4 shows excellent long cyclability and rate capability. The nO-Co3O4 can deliver a stable charge capacity as high as 955.5mAhg−1 up to 200 cycles without noticeable capacity fading at a charge/discharge current density of 0.1Ag−1 (ca. 0.11C). The excellent electrochemical performance is ascribed to the nano-size and the {111} facets that enclose the octahedra. While the mO-Co3O4 could only maintain 288.5mAhg−1 after 200 cycles, illustrating very poor cycling performance, which is ascribed to the large particle size that may cause huge volume change during repeated charging/discharging process. The results reveal that the Co3O4 nano-octahedra would be a promising anode material for the next-generation of LIBs.