Being a green and sustainable technology, microbial fuel cells (MFCs) offer an integrated pathway to simultaneously produce bioelectricity and treat wastewater. However; their applications are limited due to their relatively low-output power density. The MFC's low-output power density is related to low electron-transfer rate at the anode and/or the cathode. The transfer of electrons is greatly influenced by the electrode materials' properties. Carbon-based materials are seen as promising candidates for electrodes in MFCs because of their favorable characteristics in terms of weight, microbial adhesion, stability, and cost. However, the use of plain carbon material led to weak biofilm formation and all the required properties for the oxygen reduction reaction in cathode could not be met. The MFC performance could be improved by modifying the carbon-based electrodes through nano- and/or polymeric materials. This chapter presents a review of the modified carbon-based polymer nanocomposites as they serve as electrodes for MFCs. © 2018 Elsevier Inc. All rights reserved.