Six cases of apparent vaccination failures in rural dogs given modified live virus, chicken embryo origin, low egg passage, Flury-type vaccine, were investigated. Four cases were dumb rabies while two were furious forms of rabies. Human exposure (six people) was attributed to the furious form only. Four brain smears from dogs which died of dumb rabies were positive for Negri bodies while two brain smears obtained from dogs which died of the furious form of rabies were negative. All the brain samples were positive when subjected to a mouse inoculation test. Contact with other dogs was eliminated. Furthermore, the time lapse between vaccination and development of clinical signs (incubation period) varied from 4 to 14 days. The 'break' in vaccination was therefore linked with the vaccine used. Dumb rabies was observed more than the furious form of rabies in this study, with considerable potential health hazards.