The effect of aging on mechanical properties of cold-worked Custom 465 stainless steel was studied.  Cold-worked Custom 465 stainless specimens were aged at temperatures, ranging from 900F to 1,025F.  Subsequently, they were subjected to microstructure examination, measurement of threshold stress intensity for stress corrosion cracking in 3.5% NaCl solution Kiscc, and tests of hardness, tension, fracture toughness and fatigue.  The results indicate that the aging-induced strengthening, indicated by UTS, YS and hardness, is peaked by 900F aging and reduced with increasing aging temperature.  However, the elongation and conditional fracture toughness Kq increased with increasing aging temperature.  It is noticeable that, by 950F aging, the mechanical properties become similar to those of AerMet 100 steel with better resistance to stress corrosion cracking.