Electrogenic bacteria are known for their ability to transfer electrons generated during metabolic processes to extracellular acceptors, including the surfaces of electrodes in systems specifically designed for this purpose. Research on these bacteria has contributed to the development of Microbial Fuel Cells (MFCs), which aim to harness the biological activity of microorganisms to generate electricity while simultaneously converting certain organic compounds. During metabolism, bacteria oxidize organic compounds and extract the energy required for their growth and activity. In some species, the resulting electrons can be transferred outside the cell through specialized proteins and mechanisms, or through chemical mediators under certain conditions. When this process is connected to an appropriate electrical circuit, electrons flow through the external circuit from the anode to the cathode, generating an electric current that can be measured and utilized within the limits of the system. Among the species studied in this field are Geobacter sulfurreducens and Shewanella oneidensis, which possess mechanisms that enable them to transfer electrons to minerals or extracellular surfaces. The precise mechanisms vary between species, while electron-transfer efficiency is influenced by the type of organic substrate, electrode design, and chemical conditions within the system. One of the most promising potential applications of microbial fuel cells is the treatment of certain types of wastewater. Microbial communities can break down some of the organic matter while recovering a portion of the energy in the form of electricity. Microbial systems may also be used to power certain low-energy environmental sensors, particularly in locations where conventional energy sources are difficult to access. Despite these possibilities, challenges remain concerning the power density produced, material costs, the stability of microbial communities, and scaling up from laboratory experiments to industrial applications. Therefore, this technology is not considered a comprehensive replacement for existing energy sources, but rather a research field that may contribute to developing solutions combining pollutant treatment with resource recovery. Electrogenic bacteria demonstrate how the natural metabolic activity of microorganisms can be harnessed in engineered systems, supporting research into bioenergy and sustainable environmental treatment. Al-Mustaqbal University – The First University in Iraq