A 1 kW Phosphoric Acid Fuel Cell (PAFC) stack with an effective electrode area of 400 cm(2) was designed, fabricated, and assembled with "in-house" developed components at Energy Research Institute (ERI), King Abdulaziz City for Science and Technology (KACST). The stack was operated at 180 degrees C for 250 h without any degradation, using commercial H-2/CO2 gas and air at 1 bar. The electrical output power generated by the stack was 1 kW (20.5V x 50 A). Data such as individual cell voltages, stack voltage, stack current, stack temperatures, stack power, stack resistance and flow rates of hydrogen and carbondioxide gases, and air were recorded during the operation of the stack using a data acquisition and control system. The results of the stack operation show that the stack was stable and that the heat generated in the stack was sufficient to sustain its temperature of 180 degrees C without any external heating. Three cooling plates were used to cool the stack, and it was insulated to maintain a more uniform temperature. The water formed during stack operation was collected through the outlet of the hydrogen gas and air manifolds. Since the temperature at the centre of the stack was slightly higher than desired, it is recommended that two more cooling plates be added to achieve a more uniform temperature and better stack performance.