The idea of using simple, genetically tractable host organisms to study the virulence mechanisms of pathogens dates back at least to the work of Darmon and Depraitère . They proposed using the predatory amoeba Dictyostelium discoideum as a model host, an approach that has proved to be valid in the case of the intracellular pathogen Legionella pneumophila . Research from the Ausubel laboratory has clearly established the nematode Caenorhabditis elegans as an attractive model host for the study of Pseudomonas aeruginosa pathogenesis . P. aeruginosa is a bacterium that is capable of infecting plants, insects and mammals. Other pathogens with a similarly broad host range have also been shown to infect C. elegans [3,4]. Nevertheless, the need to determine the universality of C. elegans as a model host, especially with regards pathogens that have a naturally restricted host specificity, has rightly been expressed . We report here that the enterobacterium Salmonella typhimurium, generally considered to be a highly adapted pathogen with a narrow range of target hosts , is capable of infecting and killing C. elegans. Furthermore, mutant strains that exhibit a reduced virulence in mammals were also attenuated for their virulence in C. elegans, showing that the nematode may constitute a useful model system for the study of this important human pathogen.