Ribosomal vaccines prepared from Salmonella typhimurium were effective immunogens in A/J inbred mice and C3H/HeTex, inbred mice. However, ribosomal vaccines were not protective in C57BL/6J inbred mice. A/J mice were protected against lethal challenge by attenuated S. typhimurium live-cell, ribosomal, phenol, and heat-killed vaccines. C3H/HeTex mice were protected by live-cell, ribosomal, and phenol vaccines but not the heat-killed vaccine. Only the live-cell vaccine gave significant protection in the C57BL/6J inbred mice. A comparison of the kinetics of infection in sham-immunized mice and mice immunized with ribosomes showed that ribosome preparations elicited protection against Salmonella infection in mice inherently sensitive and resistant to Salmonella.