Development of vaccines against enterobacterial species responsible for enteric infections sounds like an unrealistic project. On the other hand, based on our growing understanding of the pathogenesis of infections caused by the major species (i.e. Salmonella typhi, Shigella flexneri and Shigella dysenteriae 1, Enterotoxigenic Escherichia coli) and on our better characterization of the immunological parameters of mucosal protection, it is likely that a limited number of vaccines controlling diseases such as typhoid fever, bacillary dysentery and cholera-like E. coli infections will become available. There are three major problems that still need to be solved: the variety of antigens and antigenic specificities, the nature of protective antigens and, provided that these prerequisites are fulfilled, the presentation of the vaccine and the immunization route. With the exception of typhoid fever, which has a systemic phase that probably makes immunization attempts by purified Vi antigen successful, experimental strategies rely very much on induction of a mucosal immunity. Either subunit vaccines, or genetically manipulated strains which attenuated virulence are currently considered.