Effects of carbon on the hydrogen embrittlement behaviour of Fe3Al intermetallic compounds were observed by revealing its microstructure. In low-carbon content (0.05 wt.%) alloy embrittlement was found in the Fe3Al phase, in moderate level of carbon content (0.14-0.5 wt.%) there was no embrittlement in the alloy, whereas in high level of carbon content (1 wt.%) embrittlement was found in the interdendritic region. (C) 2003 Elsevier Ltd. All rights reserved.