An effort is underway to explore the potential of Fe-Cr-Mn austenitic alloys as substitutes for Fe-Cr-Ni alloys in fusion reactors. This substitution is desired to achieve a reduced level of long-term radioactivity and thereby reduce the cost and safety hazards associated with disposal of reactor components at their end of life. Neutron-induced swelling data to 50 dpa are now available at 520°C for three reduced activation alloy series and for lower exposures at 420 and 600°C. These three series cover simple binary and ternary alloys, solute-modified ternaries, and a variety of commercially available Fe-Cr-Mn alloys. The swelling of these alloys is initially similar to that of Fe-Cr-Ni alloys but then changes in response to phase instabilities that develop in the Fe-Cr-Mn system.