BACKGROUND: Hantavirus are widely distributed in rodents populations even in geographical areas where hemorrhagic fever with renal syndrome (HFRS) has not been reported. Multiple species of Murid and Arvicolid rodents serve as the natural reservoirs of hantaviruses. Serologic diagnosis using hantaviral antigens indicates that hantaviruses are widely distributed in wild rodents. This study was designed to find the distribution of hantaviruses among wild rodents and small mammals in Korea, 1995-1996. METHODS: Rodents were trapped alive in selected areas. A total of 551 wild rodents from 7 species and 97 small mammals from 4 species were captured in Korea. Serologic evidence for hantavirus infection were tested using five hantavirus antigens by indirect immunofluorescent antibody technique (IFA). Among 162 Apodemus agrarius, 23 Apodemus peninsulae, 8 Clethrionomys regulus, 6 Microtus fortis, 1 Mus musculus, 283 Tamias sibiricus, 68 Sciurus vulgaris, 14 Crocidura laciura, 80 Lepus sinensis, 2 Capereolus capereolus and 1 Nyctereutes procyonoides. RESULTS: 29 A. agrarius, 2 A. peninsulae, 1 C. laciura, 2 C. regulus, 27 T. sibiricus and 7 S. vulgaris were seropositive against Hantaan virus and 7 L. sinensis were IF antibody positive against Seoul virus. Some of Tamias sibiricus were only seropositive against Puumala virus or prospect hill virus. CONCLUSION: This data suggests that new serotypes of hantavirus might distribute among rodents in Korea.