A total of 5149 small mammals belonging to 16 species were collected from the Lipetsk, Voronezh, and Belgorod regions (40 administrative districts) in 2003-2004 and examined by ELISA and IFA to detect hantavirus antigen and antibodies in the lung tissues. Hantavirus circulation was revealed in 13 species, the highest hantavirus activity being detected in field (Apodemus agrarius) and small wood (A. (S) uralensis) mice (Dobrava-Belgrad virus), bank (Clethrionomis glareolus) (Puumala virus) and common (Microtus arvalis) (Tula virus) voles. These species were frequently found to have their untypical hantaviruses, which was most commonly observed in small wood mice. It is suggested that the small wood mouse is likely to take a certain part in maintaining the circulation of Dobrava-Belgrad virus.