Incoloy alloy 909 is an Fe-Ni-Co based superalloy that is attractive for gas turbine engine applications. The absence of chromium, however, makes the alloy more susceptible to oxidation in high temperature. To improve the oxidation resistance aluminizing was performed by high activity low temperature pack cementation process. Aluminizing condition was examined with different times and temperatures. Optimum aluminizing conditions were at the temperature of $552^{circ}C$ for 20 hrs. In the optimized condition, the thickness of the aluminized layer was about $20{mu}m$. Also, the aluminized layer made the alloy to increase the resistance to the corrosion.