The present paper discusses the operation of a low-temperature-type AMTEC cell. The cell consists of a sodium beta " -alumina solid electrolyte tube of 3 mm in outer diameter and capillary tubes of 50 mu m in inside. diameter. Experiments were conducted with porous molybdenum electrodes, and the measured maximum power density of the cell was 0.13 Wcm(-2) at 900 K. Electrochemical analysis with the A. C. impedance measurement was also performed under D. C. polarized conditions, and the internal resistances of the cell were examined. Based on these experimental results, the influence of the sodium vapor flow resistances in the cathode side for multi-tube type cells was evaluated. The parametric analysis shows that the low-temperature cell operating at 900 K has a predicted output power of 0.71 W per unit container base area. In this case, its performance is superior or equal to that of the high-temperature-type cells typically operating at 1, 100 K.