During the testing of the alkali metal thermal to electric converter (AMTEC) in laboratory, maximum power output of the AMTEC was found to be decreasing from 2.48 to 1.27W after 18,000h of operation with the hot side temperature of 1023K and the condenser side temperature of 600K. Electrode is one of the components in AMTEC which has effective lifetime. In this study, the role of the electrode on the overall power degradation has been investigated and reasons of the degradation are established qualitatively and quantitatively. The electrode is found 17% on average responsible for the overall degradation of power output.