Anode modification is an effective method for enhancing extracellular electron transportation and improving the power density of microbial fuel cells (MFCs). In this study, a new conductive polymer called poly (3,4-ethylenedioxythiophene) (PEDOT) is electrochemically polymerized to modify the anode. The surface of the electrochemically polymerized PEDOT layer has a widespread porous structure. Both the anode electrochemical discharge experiment and MFC discharge test demonstrate the improved performance of the PEDOT-modified anode compared with a plain anode. Cyclic voltammetry and electrochemical impedance spectroscopy analyses show that the PEDOT modification increases the availability of redox active sites and reduces the interfacial electron transfer resistance of the anode. Compared with the unmodified anode, the PEDOT anodic modification improves the power density by 43%-140 mW m(-2). Possible mechanisms are proposed to help understand the function of the PEDOT-modified anodic layer. (C) 2014 Elsevier B.V. All rights reserved.