The purpose of this study was to evaluate the ability of a panel of eight antinucleocapsid monoclonal antibodies developed in Europe to assess rabies virus strains isolated from various animal species in geographically diverse areas of Mexico. Fifty-one rabies-positive brain tissue samples from animals and humans were examined. Material from these samples was used to infect mice, whose brain tissue was subsequently tested by indirect immunofluorescence using the monoclonal antibodies described above. The study did not turn up any strong evidence of Lyssavirus other than rabies virus, but did find four antigenic variants differing from the classic rabies virus serotype. Samples of these latter were sent to the Pasteur Institute in Paris for confirmation. Overall, the antibody panel was deemed useful for rapid typing of rabies virus in Mexico. It also appears possible that autochthonous antigenic variations are now appearing in strains of the virus found in Mexico, which could explain some of the failures observed with certain vaccines. These circumstances appear to create a need for producing antinucleocapsid monoclonal antibodies with strains of rabies virus indigenous to the area.