Hastelloy C-276 is a corrosion resistant nickel based solid solution hardened industrial alloy which has superior mechanical and corrosion properties. In this study, Hastelloy C-276 alloy was welded via the GTAW (Gas tungsten arc welding) method using ERNiCrMo-4 filler metal. Tensile, bending and notch impact tests were performed to determine the mechanical properties. The microstructure of the weld metal was investigated by light microscopy (LM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The impact toughness values of the heat affected zone (HAZ) showed a better performance than those of the weld metal. In addition, the corrosion properties of the weld metal and the base material were investigated by potentiodynamic polarization tests. Electrochemical potentiodynamic polarization parameters were determined according to corrosion behavior and microstructure properties. In particular, the corrosion rate of the weld metal increased because of the Mo-rich phases deposited in the weld metal microstructure.