The effect of pre-injection treatments on helium embrittlement of Fe-(25–40)Ni-Cr austenitic alloys with and without the addition of Ti and Nb was widely investigated using the helium injection method and a cyclotron. For the precipitation hardened alloys produced using γ′-Ni 3(Ti,Al) and γ″-Ni 3Nb, the total elongation of helium injected materials rapidly decreased with increase of tensile strength. By comparing the same alloy under various treatments at the same strength level, the pre-injection treatments, such as cold work and aging, were concluded to have a beneficial effect on the ductility. For the non-hardenable alloys, the degree of helium embrittlement is about the same order in 316 stainless steel and Fe-25Ni-15Cr alloys, but increasing Ni content to 35% caused a more severe reduction of total elongation for the solution treated condition. The ductility improving effect of cold work on the helium injected materials decreased with increase of Ni content.