The paper reports the novel application of plasma immersion ion implantation (PI3) technique for surface modification of ferritic stainless alloys. The results show that the implanted nitrogen ions can inhibit the emergence of persistent slip bands on the surfaces of ferritic Fe-19Cr-4Ni-2Al alloy during low cycle fatigue test. Consequently, the fatigue life is improved considerably at high strain amplitudes. Moreover, nitrogen PI3 implantation also leads to a slight improvement in the creep resistance of ferritic Fe-24Cr4Al stainless alloy. The extent of improvement in creep resistance brought by PI3 is rather small due to the creep failure is not initiated near the surface region.