Effects of reactant gas flow rates and starvation on phosphoric acid fuel cell performance were studied. As the reactant gas flow rates increased, the cell performance increased and then the cell maintained constant performance. The optimum flow rates of hydrogen, oxygen and air under galvanostatic condition of 150 mA/cm$_{2}$ are found to be 5cc/min cm$_{2}$ 5cc/min cm$_{2}$ and 15cc/min cm$_{2}$ at room temperature and 1 atm, respectively. Also the open circuit voltage of single cell decreased with increasing oxygen flow rate due probably to the decreased probably to the decreased oxygen pressure in the cathode side. Hydrogen and oxygen starvation resulted in voltage loss of about 5mV and 0-2mV, respectively. The voltage loss was independent of starvation time. These results were discussed from point of view of electrochemical reaction of the cell. (author). 9 refs., 8 figs.