A program is currently underway to use ion implantation to improve the tribological and corrosion characteristics of load bearing surfaces in both rolling element bearings and gears used in aircraft propulsion systems. This paper describes that aspect of the program concerned with the use of ion implantation for surface alloying of bearing components in order to alleviate the problem of corrosion in costly M50 steel mainshaft aircraft engine bearings. Results to data indicate that implantation of selected ion species can significantly improve resistance to both generalized and localized (pitting) corrosion without adversely affecting bearing performance or fatigue endurance life.