A field strain of avian encephalomyelitis virus which was isolated from chicken flocks in Egypt was used to study the pathogenicity of the virus both in day-old-chicks and in chicken embryos. Infected chicks showed clinical signs and brain lesions charac teristic of the disease. Reioslation of the virus was successful at the 10th day post infection both from killed and dead birds. Muscular dystrophy, leg paralysis and embryo deaths appeared in 88.5% of the inoculated embryos. The study proved the exist ance and the wide spread nature of avian encephalomyelitis virus infection among poultry flocks in Egypt.