The interest in the use of electroactive microorganisms for different applications by means of bioelectrochemical systems (BES) has been constantly increasing since the last decade. The main application of BES among others, which has received a widespread attention and researched extensively, is the microbial fuel cell (MFC) technology that relies on the electrogenic nature of certain bacteria to simultaneously treat different wastewaters and produce electric power. Various types of wastewaters have been examined as substrates for feeding bacteria in MFCs. The number and complexity of wastewaters have increased rapidly over the last few years thus necessitating the need for documenting this data further. This review provides a comprehensive and the state-of-the-art information on various wastewater substrates that have been used in MFCs. The performance of different types (designs) of MFCs in terms of electric current and power outputs together with the wastewater treatment efficiency in terms of chemical oxygen demand (COD) removal and columbic efficiency (CE) is presented. Some of the challenges and future perspectives with regard to the energy recovery from wastewaters using MFCs are briefly discussed.