Electrospun carbon nanofibers (ECNs) have been explored as an electrocatalyst and low-cost alternative to platinum (Pt) for triiodide reduction in dye-sensitized solar cells (DSCs). The results of electrochemical impedance spectroscopy (EIS) and cyclic voltammetry measurements indicated that the ECN counter electrodes exhibited low charge-transfer resistance (R(ct)), large capacitance (C), and fast reaction rates for triiodide reduction. Although the efficiency (eta) of ECN-based cells was slightly lower than that of Pt-based cells, their short circuit current density (J(sc)) and open circuit voltage (V(oc)) were comparable. The ECN-based cells achieved an energy conversion efficiency (eta) of 5.5 % under the AM 1.5 illumination at 100 mW cm(-2). The reason for lower cell performance using the ECN electrode was because of its lower fill factor (FF) than that of Pt-based cells, probably caused by high total series resistance (R(Stot)) at similar to 15.5 Omega cm(2), which was larger than that of similar to 4.8 Omega cm(2) in the Pt-based devices. Simulated results showed that the fill factor (FF) and eta could be substantially improved by decreasing R(Stot), which might be achieved by using thinner and highly porous ECNs to reduce the thickness of the ECNs counter electrode.