The phase equilibria of the Au-In-Ga system were investigated for the first time using Differential Thermal Analysis (DTA), X-Ray Diffractometry (XRD), Energy Dispersive Xray Spectroscopy (EDS) and Scanning Electron Microscopy (SEM). A new ternary phase (Au 2 InGa 2 ) with the hexagonal structure (P6 3 /mmc) was discovered which melts incongruently at 394 C. From the experimental results, several invariant reactions have been identified and discussed.