Sulfidation has been a frequently encountered high-temperature corrosion issue in petroleum refinery processes. Under sulfidation attack condition many carbon steel and low alloy steel components suffer large material wastage. To protect the ferritic steel components weld overlay has been extensively used as a long-term protection solution for many industries including refinery. Among the most commonly used weld overlay alloys current paper studied the sulfidation resistance of weld overlays of Type 309SS Type 312SS alloy 33 alloy 622 and alloy 72M along with Type 304SS wrought alloy as a reference in a highly reducing sulfidizing envrionment (i.e. low pO2 and high pS2 atmosphere). Tests were conducted for 2000 hours at 500? C (932? F) in the gas mixture consisting of N2-10% CO-5% CO2-2% H2O-0.12% H2S (vol. %). Results are presented in terms of weight changes metal loss data and corrosion scale analyses by optical microscopy and SEM/EDS and the characteristics of these alloys to resist sulfidation attack is analyzed and discussed.