11 hybridoma cell lines secreting monoclonal antibodies (McAbs) against hemorrhagic fever with renal syndrome virus (HFRSV) were obtained in our laboratory by immunizing LOU/C rats with HFRSV Chen strain. These rat McAbs were characterized by radio-immunoprecipitation and western blotting methods, 2 directed against glycoprotein G2, 9 against nucleocapsid protein (NP) of HFRSV. The results of neutralization (NT) and hemagglutination inhibition(HI) test showed that most of the McAbs specific for NP had neither NT nor HI activities, but 2 had obvious NT and/or HI activities. It was suggested that there may be some neutralizing and hemagglutinating determinants on NP of HFRSV. Two McAbs to G2 had HI or/and NT activities. These date indicated that distinct neutralizing and hemagglutinating epitopes were located on the G2. Comparative antigenic analysis of 20 strains of HFRSV was carried out by immune horseradish peroxidase technique using 11 anti-HFRSV rat McAbs. It was found that these McAbs can be classified into group, subgroup, apodemus type and subtype specificity to HFRSV.