The present study reported field outbreaks of bovine ephemeral fever virus infection in Assiut governorate, Egypt, during the period of 2000. A total number of 585 cattle of both sexes belonging to Bani Morr and Abnoub Holstein Friezian Dairy Stations, Assiut governorate were used in this study. Clinical signs were evident in 267 animals (45.64%). The rate of deaths and emergency-slaughtered animals reached 9.36%. A total of 25 dead cattle were subjected for thorough postmortem examination. Tissue samples from recently dead cattle were obtained for application of avidin biotin immunoperoxidase and indirect immunofluorescent techniques for the diagnosis of bovine ephemeral fever (BEF). These techniques demonstrated that BEF viral antigen was present in the reticuloendothelial cells in the lungs, spleen and lymph nodes as well as in the epithelium lining the alveoli and bronchioles, the hepatocytes and kupffer cells in the liver, the lymphocytic population in the spleen and lymph nodes, the myocardial muscles in the heart and in the endothelial lining the blood vessels. So, all these sites could be considered as sites of BEF viral distribution. The current study also indicated that using of immunoperoxidase and immunoflu- orescent techniques are rapid and confirmatory methods for the diagnosis of the BEF outbreaks.