The deposition of elemental sulfur is a major concern in the gas and oil industries. The effect of sulfur deposition on nickel-based alloy 825 under severe conditions is not well understood. This work investigates the impact of elemental sulfur deposition on Alloy 825 under two conditions using four-point bend test in accordance with NACE TM0316.The results show that alloy 825 samples were not affected by way of SSC, SCC, pitting or other corrosion damage mechanisms in temperature of 90° C, pressure of 75 bar, Chloride level of 1000 ppm, a partial pressure of H2S of 12 bara, and a partial pressure of CO2 of 55 bara with present of elemental sulfur. A further autoclave exposure test was performed in which alloy 825 samples were exposed in 20 bara H2S partial pressure and 57 bara CO2 partial pressure in 21,853 ppm chloride and =150gL-1 elemental sulfur at 190°C for 720 hours. Under this condition, alloy 825 shows environmentally assisted corrosion as well as SCC on all samples. As a conclusion, alloy 825 is not a robust material against elemental sulfur related degradation at high temperature and pressure with high H2S and CO2 environment. Hence, safety risk from elemental sulfur deposition at high temperature should be carefully considered and evaluated when using alloy 825. The limit tested in this paper could provide a reference for selecting alloy 825 in presence of sulfur.