Precipitation hardening (PH) stainless steels are high chromium, high nickel and low carbon stainless steels which were mainly developed to provide high strength and fracture toughness while maintaining good corrosion resistance. Precipitation hardening treatment involves solution annealing treatment followed by aging treatment which is applied on these steel to impart high hardness, fracture toughness and strength. The PH stainless steels develop high strength and toughness through additions of copper, aluminum, titanium, niobium, vanadium, and/or nitrogen, which form precipitates during aging heat treatment. In this work effect of severe plastic deformation (SPD) on aging kinetics of pH 17–4 stainless steel was investigated. Severe plastic deformation was applied on the surface of pH stainless steel specimens by shot-peening process. For comparison, aging of specimens with shot-peening and without shot-peening were done. After aging specimens were characterized by microhardness testing, optical and electron microscopy. The results showed considerably high hardness in the range of 617–649 HV for pH 17–4 stainless steel after aging on severely deformed specimens which is nearly 29% higher than the specimens which were aged without SPD.