These studies were conducted to determine the effects of various concentrations of ammonium and nitrate on current generation using dual-cathode microbial fuel cells (MFCs). Current generation was not affected by ammonium up to 51.8±0.0 mg/l, whereas 103.5±0.0 mg/l ammonium chloride reduced the current slightly. On the other hand, when 60.0±0.0 and 123.3±0.1 mg/l nitrate were supplied, the current was decreased from 10.23±0.07 mA to 3.20±0.24 and 0.20±0.01 mA, respectively. Nitrate did not seem to serve as a fuel for current generation in these studies. At this time, COD and nitrate removal were increased except at 123±0.1 mg /l. These results show that proper management of ammonium and nitrate is very important for increasing the current in a microbial fuel cell.