Biodegradable sheath-core structured nanofibers, with chitosan as the sheath material and polylactide (PLA) at the core, were developed for the removal of metal ions. For the electrospinning of sheath-core nanofibers, predetermined weight percentages of chitosan were first dissolved in trifluoroacetic acid (TFA) with sonication for 30 minutes, and then mixed by a magnetic stirrer for 12 hours. The same procedure was conducted with polylactide (PLA). The chitosan and polylactide solutions were then fed into two different capillary tubes with needles of small diameter, respectively, for co-axial electrospinning. The delivery rates of the solutions were controlled by two independent pumps for the sheath chitosan solutions and the core PLA solution. The morphology of the electrospun nanofibers was examined by a scanning electron microscope (SEM). The average diameter of the electrospun nanofibers was found to range from 234 nm to 562 nm. The influence of various process conditions on the metal removal was also investigated. The removal efficiency of the sheath-core chitosan/PLA nanofibers was measured and compared with the efficiency of blended chitosan/PLA nanofibers. The experimental results suggested that the electrospun sheath-core nanofibers exhibited superior metal ion removal efficiency compared to the blended nanofibers. The removal efficiency of the nanofibrous membranes increased with the initial metal ion concentrations and the pH value and decreased with the temperature of the solutions.