This paper describes the efficiency of the microbial fuel cells in wastewater treatment and power generation. Throughout the experiment, the single chamber -MFCs (SC-MFCs) can treat the wastewater up to 60%. With using the municipal or domestic wastewater as a substrate, the optimum power generation produce is 0.031V. To further improve the efficiency of the wastewater treatment using the MFCs, a better understanding in wastewater and MFCs itself is crucial. For example, understand and examine the microorganisms in the wastewater. Besides that, the setup of the MFCs also needs understanding and knowledge. The results indicated that MFCs is efficient in treat the wastewater and produce power generation. From the research, it is concluded that further improvements on MFCs is required for further development of the MFCs.