Calculations have been performed to assess the effects of fast-neutron-induced transmutation reactions in the blanket region surrounding the plasma in a Tokamak fusion reactor. The production of both stable and radioactive isotopes is considered in three structural materials suggested for CTRs; Type 316 stainless steel, niobium—1% zirconium, and vanadium—20% titanium. The results show that significant changes in the composition of the alloys will be produced along with the generation of large amounts of helium and radioactivity. Of the three alloys studied from the point of view of chemical changes, radioactivity, and afterheat, the vanadium—20% titanium alloy appears to be most favored followed by Type 316 stainless steel and niobium—1% zirconium.