In this paper, we present a simple method for scalable synthesis of uniform carbon nanoshell coated monodispersed iron oxide nanocrystals and report on the electrochemical performances of such nanocomposites. The structure and morphology of the resulting nanocomposites are investigated with X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). Cyclic voltammetry (CV) and cyclic test of the nanocomposites as an anode material for lithium ion batteries are also studied. The magnetite-C nanostructured material have a very high specific capacity of 859 mAh g−1 in the initial cycle and high capacity retention out to 50 cycles at a constant current density of 100mA/g, showing its potential as an anode material in lithium-ion batteries. The superior electrochemical characteristics are a result of the uniform distribution of magnetite nanoparticles, proper nanostructure, and good conductivity as well as the prevention of aggregation by the carbon nanoshell during cycling.