Hot-dip aluminizing is a simple, cost-effective diffusion coating technique that can coat aluminum on diverse substrates with complicated shapes. It is carried out by dipping the substrate into molten Al bath for a certain period, and pulling out of the bath into the air. The employed substrates were mostly carbon steels, low alloyed steels, Fe-(Si, Cr) alloys. During hot-dipping, inter-diffusion between the steel substrate and molten Al occurs to produces the Al-rich topcoat, the outer FeAl₃ layer, and the inner Fe₂Al₅ layer. The property of these aluminized layers depends on various hot-dipping parameters such as bath composition, time, temperature, and substrate. In this study, hot-dipping was performed on Fe-Cr alloys, and the corrosion behavior of aluminized Fe-Cr alloys at high temperatures was studied. The corrosion tests were performed in air, SO₂-containing atmospheres, and H₂S-containing atmospheres. Hot-dip aluminizing was found as an effective coating technique, which could form protective α-Al₂O₃ scales not only in air but also in (SO₂, H₂S)-containing aggressive corrosive environments due to high thermodynamic stability of Al₂O₃. ACKNOWLEDGEMENT. This work was supported by the project “Development of the High-Efficiency Low-Emission Future Energy Production Technology (EO15580)” of National Research Council of Science & Technology (NST) grant by the Korea government (MSIP) (No. CRC-15-07-KIER).