Two commercial austenitic steels, Esshete 1250 and NF709 and two experimental steels, based upon Esshete 1250, have been exposed to steam environments at 700 degreesC for times up to 3000 h. The commercial Esshete 1250 showed the poorest oxidation performance of the four materials, both in terms of scale growth rate and subsequent scale spallation. Commercial NF709 showed the best oxidation resistance whilst the two experimental steels showed intermediate behaviour. The chromia layer that formed on all four steels showed good adhesion when subjected to the Rockwell indentation test.