Hantavirus is a genus of the Bunyaviridae family causing two serious diseases, hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). Puumala virus is a member of hantavirus originally found in Europe, and its natural reservoir is Clethrionomys glareolus. It is also associated with the human disease nephropathia epidemica, a milder form of HFRS. To identify the hantaviruses in bats, bats were collected from Jeong-Sun, Won-Joo, Chung-Ju and Hwa-Cheon area in Korea, and nested RT-PCR was performed with serotype specific primer from M segment. Interestingly, Puumala virus was detected in bats (Rhinolophus ferrum-equinum) only from Won-Joo. The 327 bp nested RT-PCR product, was sequenced. The sequence database search indicates that the sequence is homologous to the published sequence of Puumala viruses. The sequence similarities were ranged from 71% to 97%. The highest sequence similarity was 97% with Puumala virus Vranicam strain, and the lowest was 71% with Puumala virus K27 isolate. Puumala virus Vranicam strain was isolated from a bank vole (Clethrionomys glareolus) in Bosnia-Hercegovina. Puumala virus K27 was isolated from human in Russia. This analysis confirms that bats (Rhinolophus ferrum-equinum) in Korea are natural reservoir of Puumala virus.