To observe the difference of the susceptibility to Streptobacillus moniliformis (S.m.), we developed an experimental infection with Streptobacillus moniliformis in 6 strains of mice including KM, C57BL/6J, BALB/c,ICR, NIH and DBA. After peritoneal inoculation, only C57BL/6J and KM mice showed the typical clinic signs and pathologic changes. The mobility and mortality after infection with S.m., were 92% and 80% in KM mice, but in C57BL/6J were 80% and 12%. The KM mice showed the severe symptoms and the most of them died during the acute phase after infection. The NIH mice showed 8%, as well as the BALB/c and the DBA mice showed 4% of mobility but none of them died. ICR was not affected after the infection. For the pathological changes, there was a significant difference between KM and C57BL/6J mice. We observed that in Km mice, it is characterized by congestion, cyanosis and swelling in limb and tail, polyarthritis, diarrhea, and hindlimb paralysis. In C57LB/6J, however, abscesses in subcutaneous lymph nodes and the injection place, purulent polyarthritis were the main symptoms. The results demonstrate that not only the susceptibility to S.m. infection but also there climic signs and pathologic changes are different in the 6 strains of mice. Because of the high susceptibility to S.m. it is considered that as a sentinel animal, the KM mice can be used for routine monitoring of S.m. in rat.