A panel of monoclonal antibodies (mAb) produced against peanut clump virus (PCV) was used to characterize five serotypes of the virus. Four different formats of enzyme-linked immunosorbent assays (ELISA) were compared to establish the most suitable one for diagnosis of infected plants and for serotype differentiation. Since most mAb retained their activity when used for coating microtitre plates, a dual mAb-type assay was found to be most suitable. The same mAb could be used in ELISA as coating and as biotinylated antibody. Because of the ability of mAb to recognize subtle conformational alterations in the viral antigen, it is important to carefully select the ELISA format used for comparing different viral isolates.