The nomenclature of the genusSalmonellaand the biochemical reactions given by members of this genus are reviewed. It was concluded that the three-species system is the best solution to the problem of nomenclature within the genusSalmonella. Methods are outlined by which members of the three species ofSalmonella(Salmonella cholerae-suis,Salmonella typhi, andSalmonella enteritidis) can be differentiated from each other, définitions are given for each of the species, and recommendations are made as regards usage of the system of nomenclature.