Microbial fuel cells (MFCs) are an emerging technology that has gained considerable attention in the recent years because they provide new opportunities for sustainable production of energy from a wide range of soluble complex organic wastes and renewable biomass. The driving force for research in this field has been the apprehension over the energy climate crisis and environment pollution. MFCs are bioreactors that can convert the chemical energy present in organic compounds into electrical energy. Presently, the literature shows that current and power yields are relatively low, but improvements in the technology can enhance these parameters as well as the efficiency of these cells. Sediment MFCs in powering low-powered electronic monitoring devices is one of the practical uses of MFCs. Additionally, MFCs can be used in implantable medical devices and wastewater treatment plants. This review discusses the factors governing the performance of these cells and the maximum power density that can be obtained using various combinations of substrates and microorganisms.