Polyclonal antibody (PoAb) and three monoclonal antibodies (MoAbs), 1C2, 1C9 and 1E2, against tobacco necrotic dwarf virus (TNDV), were produced and their serological characteristics were investigated. Results of antigen adsorption indirect ELISA (AAI-ELISA) by PoAb and MoAbs suggested that TNDV was serologically closely related to potato leafroll virus (PLRV), but far related to beet western yellow virus (BWYV). For detection of TNDV in crude saps, the clones, 1C2 and 1C9 were effective in indirect double antibody sandwich ELISA (IDAS-ELISA) and 1E2 was effective in double antibody sandwich ELISA (DAS-ELISA). These three MoAbs could differentiate PLRV from BWYV when anti-PLRV PoAb was used for trapping antibody in IDAS-ELISA and 1E2 also did in DAS-ELISA.