In the present study, a novel application of microbial osmotic fuel cell (MOFC) for simultaneous treatment of real wastewater, bioenergy generation and desalination of real oilfield produced water is investigated. A three-chambered MOFC provided with forward osmosis (FO) membrane and cation exchange membrane (CEM) was inoculated with activated sludge and fueled with actual domestic wastewater. Real oil produced water having initial total dissolved solids (TDS) concentration of 49,200 mg/L was used as a draw solution for the desalination mid chamber. Results revealed that maximum removal efficiency of COD from real wastewater, TDS removal efficiency from actual produced water, power density, current density, and power yield were 92%, 80%, 48.52 mW/m(2), 136.30 mA/m(2), and 7.46 W/kg CODR, respectively. A mathematical model was developed to predict the performance of MOFC. it was found that the predicted results were in a good agreement with experimental results with a correlation coefficient up to 0.989, indicating the validity of the suggested model for this bioelectrochemical-osmotic system within the selected range of operating conditions. (C) 2015 Elsevier B.V. All rights reserved.