Next generation engies and turbines will continue to push the turbine inlet temperature higher to attain greater efficiency. Hot corrosion can become a significant factor obstructing rapid progress in developing these turbines. In this study, the short and long term hot corrosion behavior of some gas turbine superalloys (IN738LC, IN939, CMSX-4, CM247LC, MAR-M002, X-45) was comparatively evaluated. It was found that superalloys (IN739LC and IN939) with sufficient Cr show excellent hot corrosion resistance due to the formation of a protective Cr2O3 scale, while superalloys with lower Cr suffered severe hot corrosion attack. The catastrophic attacks to these alloys are caused by acidic fluxing due to the presence of high refractory elements of W and/or Mo. Scale spalling occurred at all test temperatures predominantly due to the coalescence of pores and the formation of cracks underneath the oxide scale.