A 200W-class stack consisting of twenty molten carbonate fuel cells has been fabricated and tested to establish the basic technology for an intemally mani- folded stack. Each cell in the stack had an effective electrode area of 100cm², and reactant gases were distributed in each cell in a co-flow configuration. The stack showed state-of-the-art performance; the stack voltage at a cu- rrent density of 150mA/cm² and gas utilization of 0.4 was 16.9V producing an output of more than 250W using an anode gas of 72%H₂/18%CO₂/10%H₂O and a cathode gas of 70%air/30%CO₂. Compared with the performance of the previously-tested stack, the voltage loss due to the internal resistance and the electrode polarization became lower and the distribution of cell voltages be- came more uniform indicating that some improvements were made incompo- nent fabrication and cell stacking technology. The voltage of the stack, how- ever, decayed during the continuous operation at 150mA/cm² and further works are required to enhance the life of the stack.