In this study, uniformly dispersed MnO@C nanocomposite with an average MnO particle size of 10nm is synthesized via a simple wet-chemical/carbonization method. In the MnO@C nanocomposite, ultrasmall MnO nanoparticles are homogeneously coated with carbon layers. As an anode material for lithium ion batteries (LIBs), this nanocomposite shows significantly enhanced electrochemical performances compared with the non-carbon coated material due to the conductive carbon layer, which provides an ideal conductive matrix for electron/ion transfer and a buffer layer to accommodate the MnO expansion during lithiation process. As a result, the MnO@C nanocomposite exhibits a high reversible capacity of ∼750mAh/g over 600 cycles at a current density of 0.7A/g and a high-rate capability of ∼340mAh/g even at 2.1A/g, which are among the best reported electrochemical performances for MnO-based materials thus far, demonstrating its potential application in LIBs with long cycling life and high power density.