Cubic MnO with particle sizes of ∼200nm and ∼600nm was synthesized by decomposition of MnCO3. The corresponding MnO/C composite was obtained by thermal treatment of mixture of MnCO3 and sucrose. The structure and morphology of the products were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Electrochemical experiments showed that the as-prepared MnO/C exhibited promising electrochemical properties, and could potentially be used as anode material in lithium-ion batteries. MnO/C delivered a reversible capacity of about 470mAh/g after cycling 50 times, when testing at 75mA/g. The reversible capacity, when tested at 150, 375, 755mA/g, reached 440, 320, 235mAh/g, respectively. The good electrochemical performance was ascribed to the smaller particle size and the efficient carbon coating on MnO.