In this work, we report the facile synthesis of Fe3O4/reduced graphene oxide (RGO) nanocomposites and their improved lithium storage capability. Fe3O4/RGO composites synthesized by a facile co-precipitation method exhibited outstanding electrochemical performance with good cycling stability. As an anode material for lithium ion batteries (LIBs), the Fe3O4/RGO composites achieved a high reversible capacity of 1637 mA h g−1 (0.1 A g−1) at the 10th cycle, which still remained at 1397 mA h g−1 after 100 cycles. Moreover, the Fe3O4/RGO composites have excellent rate capability. Characterization results reveal that such a large reversible capacity is attributed to the synergistic effect between Fe3O4 and RGO, with the Fe3O4 nanoparticles (NPs) with surface step atoms offering abundant electrochemical active sites for lithium storage. In addition, RGO acts as a volume buffer and electron conductor, and more importantly preserves the electrochemically active surface and avoids the aggregation of the Fe3O4 NPs.