Microbial fuel cells present an emerging technology for utilizing the metabolism of microbes to fuel processes including biofuel, energy production, and the bioremediation of environments. The application and design of microbial fuel cells are of interest to a range of disciplines including engineering, material sciences, and microbiology. In addition, these devices present numerous opportunities to improve sustainable practices in different settings, ranging from industrial to domestic. Current research is continuing to further our understanding of how the engineering, design, and microbial aspects of microbial fuel cell systems impact upon their function. As a result, researchers are continuing to expand the range of processes microbial fuel cells can be used for, as well as the efficiency of those applications.