Liquid lithium, which is under consideration as blanket fluid of fusion reactors, is more corrosive against austenitic and martensitic-ferritic steels than liquid sodium. The results of corrosion studies in flowing lithium as well as of tests on the mechanical behaviour of the materials in stagnant lithium at 550°C are presented and discussed. The candidate materials are nearly insensitive against liquid metal embrittlement in lithium at 200 to 250°C. After precorrosion in lithium at 550°C, they show more or less brittle fracture behavior in lithium of 200 to 250°C.