In the recent past, a number of programs have focused on developing AMTEC technology associated with its fabrication and design. The performance level, however, achieved to-date is below the theoretical potential of this device. For improving performance characteristics we examined the sources of power loss and prl,posed some solution which are demonstrated with computer calculations. Two kind of losses that reduce efficiency are thermal (as a result of thermal conduction and radiation of materials) and electrical (Related to the ohmic resistance of material). Each of the losses can, in principle, be reduced separately by varying current in the load. To reduce the thermal losses, the current must be increased; to reduce the electrical losses, the current in the load must be decreased. In such inversely competitive situation, an optimum value must be sought which has been achieved by applying the optimization theory. Heat losses due to radiation are reduced by increasing the current density and by reducing the emissivity of electrodes and other surfaces. Changing of some of the materials used in the cell has proved to be helpful in improving the cell performance. As a result of this overall effort, we have been able to demonstrate the improvement in the efficiency of AMTEC cell by 77%. (C) 2000 Elsevier Science S.A. All rights reserved.