Due to the shear number of papers currently published regarding MFCs we hope that omission of many articles will not cause offence to their authors. This review article will examine MFC’s currently in use, potential future applications and the limitations to implementing those applications. We suggest methods for improving the current output of a MFC. We also examine MFC applications in which microbes accept electrons from an electrode instead of donating them. This review will hopefully highlight some of the potential of and limitations to MFC technology implementation.