A total number of 450, 300, 220 and 180 blood samples from ewes, rams, does and bucks respectively were collected in Assiut province and another 426, 210, 105 and 70 samples from the same species respectively were collected in Sohag province. The collected blood samples were screened for detection of brucella antibodies using Rose Bengal plate antigen test (RBPT), buffered acidified plate antigen tests (BAPAT), tube agglutination test (TAT) and Rivanol Tube test (RTT). 1.26% and 9.30% of animals were found to be the positive percentage in Assiut and Sohag provinces respectively. B.A.P.T. showed the highest number of positive reactor animals. No gross lesions could be detected in pregnant and non-pregnant uteri of ewes and goats. Microscopically, the non-gravid uterus of ewes revealed necrobiotic changes of the endometrial glands and diffuse aggregations of plasma cells and lymphocytes in the lamina propria. In chronic cases, atrophy of the endometrial glands was observed. The uterus of non-pregnant goat revealed presence of multiple endometrial granulomas composed of a necrotic center surrounded by proliferated fibrous connective tissue and mononuclear cells. In pregnant ewes and goats, the uterus revealed presence of large granulomas and the glandular epithelium of the endometrial glands was extensively atrophied. The placenta in these cases showed necrosis and desquamation of the chorionic epithelium and the lamina propria revealed few to moderate mononuclear cell infiltrations and fibrous connective tissue proliferations. The udder of sero-positive ewes and goats showed focal and inter-acinar inflammatory cell infiltrations, which is mostly composed of lymphocytes and plasma cells with necrobiotic changes in the acinar epithelium. The supramammary and retropharyngeal lymph nodes of sero-positive cases in sheep and goats were enlarged. Microscopically in ewes showed presence of pyogranuloma, while in goats the lymph nodes showed moderate changes represented by sinus macrophagal reactions in both cortex and medulla. The liver revealed presence of pyogranulomas 384 Assiut Vet. Med. J. Vol. 52 No. 109 April 2006 composed of aggregated neutrophils surrounded by a layer of proliferated connective tissue and lymphocytic infiltration in-between hepatic cords. No changes could be detected grossly in testes of rams and bucks and the microscopic lesions were nearly similar in sheep and goats. The testes showed fibrous periorchitis and the parenchyma revealed necrosis of seminiphrous tubules and mononuclear cell infiltrations. Finally, it was concluded that, diagnosis of brucella infected animals is based on the evaluations of history as well as screening of serum samples and correlating gross and microscopic lesions.