Bismuth (Bi) nanowires, prepared by mechanical pressure injection method followed with complete dissolution of the used anodic aluminum oxide (AAO) template, are milled with carbon black to form Bi/C nanocomposites. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy analyses have been used to reveal the continuous phases, crystal structure, and morphology of the Bi/C nanocomposites. When applied as an anode in Li-ion battery, Bi/C nanocomposites exhibit a high capacity of 905.9 mAh g-1 at a current density of 200 mA g-1. While, Bi/C nanocomposites are used as an anode in Na-ion battery, their electrochemical storage performance is lower than that in Li-ion battery. Ex-situ XRD measurements reveal that Bi follows an alloying mechanism with Li+ ions while an intercalation process for Na+ ions.