Background and Objective: Generally, abortion cause enormous economic losses in livestock animals. The most important pathogens involved in the abortion of ewes are Brucella melitensis, Campylobacter fetus, Salmonella abortus ovis, and Chlamidophilaabortus. Materials and Methods: In Assiut governorate, five flocks of mixed breed ewes showed unexplained high percentage of abortions (33.3%) and the etiology of abortions wasn't well understood. Therefore, the objective of the current study was to estimate the cause of late abortion in that flocks in Assiut governorate (Upper Egypt). A total number of 94 recently aborted ewes and 47 aborted fetuses with related placenta were examined and we correlated its possible association with Brucella melitensis, which is the most important abortive diseases in sheep. Serum samples were tested by Rose Bengal and ELISA for brucellosis. The infected tissues and serum were also used in polymerase chain reactions (PCR) for detection of DNA of Brucella spp. Results: the results revealed that serological tests were positive in (21.28%) of examined cases, while Brucella spp. DNA was detected in (34.04%) of serum samples and in (25.5%) of tissue samples. Conclusion: It concluded that there was an association between brucella infection and abortion in sheep in Assiut governorate, PCR could be accurate method for diagnosis of Brucellosis, thereby could control the infectious diseases in sheep and minimize reproductive losses.