Recent advances in monoclonal antibody techniques have provided an opportunity to simplify the procedures of serological identification of microorganisms. Because monoclonal antibodies are raised against individual antigenic determinants (epitopes), they can be used to screen with great precision for antigenic relationships with taxonomic-phylogenetic implications. This approach has been shown to be useful in several groups of microorganisms including vertebrate viruses (Lee et al., 1981) and studies with baculoviruses (Roberts and Naser, 1982; Hohmann and Faulkner, 1983) indicate good potential. In the report, the authors describe the production and characterization of 12 anti-HzSNPV-polyhedrin monoclonal antibodies and the use of these monoclonal antibodies for serophylogenetic studies of a number of baculoviruses of both subgroup A and B.