The eae (Escherichia coli attaching and effacing) gene from enteropathogenic Escherichia coli (EPEC) was previously shown to be essential for production of the 'attaching and effacing' histopathology characteristic of EPEC infections (Jerse et al., 1990). We have now cloned the eae gene from enterohaemorrhagic E. coli (EHEC) which, in addition to producing Shiga-like cytotoxins, also produces the attaching and effacing effect. The sequence homology between the EPEC and EHEC sequences was 86% and 83% at the nucleotide and amino acid levels, respectively. The predicted amino acid sequence of the EHEC eae gene shared 31% identity and 51% similarity with invasin of Yersinia pseudotuberculosis. Alignment of the EPEC and EHEC Eae proteins and the Y. pseudotuberculosis and Y. enterocolitica invasins shows striking regions of identity with the greatest divergence at the C-terminal end, the putative receptor-binding portion of invasin.