RESUMEN
The 86 strains of field rodents captured in Chollanamdo were analyzed its infection rates of Orientia tsutsugamushi by nested PCR. The detection rate of O. tsutsugamushi was 14.3 % in A. agrarius whereas O. tsutsugamushi could not be detected in C. lasiura. In locality, the rodents captured in the mountainous area showed higher detection rate than suburban area. In the case of detection rate by organs, the spleen was most appropriate specimen, but in two cases, O. tsutsugamushi could be detected in only kidney specimens. The major serotype of detected O. tsutsugamushi was serotype Karp, but four cases were serotype Boryong. These serotypes were confirmed by nucleotide sequence determination of amplified PCR products. In conclusion, the serotype Karp was the major O. tsutsugamushi in Chollanamdo.