In an attempt to replace the traditional cyanide process of extracting gold, a new technology using ammoniacal solutions has been developed. In this study, the electrochemical behavior of gold in ammoniacal solutions at temperatures above 100 degrees C has been investigated. An electrochemical cell in an autoclave has been introduced to carry out this study. The system consists of a gold working electrode, a platinum counterelectrode, and an external saturated calomel electrode (SCE) which is connected to the autoclave system through a birch wood plug. Techniques used in this study included potentiodynamic polarization, galvanostatic polarization, cyclic voltammetry, and Tafel polarization. The electrochemical reaction mechanisms governing the dissolution process are presented.