The purpose of the study is to evaluate the expression of TNF-α and IFN-gamma (IFN-γ) in the lung and liver tissues of aborted sheep fetuses using immunohistochemical methods and determine, which type of cells specifically secrete TNF-α and IFN-γ. Moreover, the roles of these cytokines in the immune response and inflammatory reaction associated with the disease were evaluated. The materials used in the study consisted of abomasum contents and lung and liver tissue samples from 114 aborted sheep fetuses. Of the 114 fetuses brought to the Microbiology and Pathology Department, Faculty of Veterinary Medicine for routine histopathological and microbiological diagnoses. As a result of cultural and phenotypic analysis, Brucella spp. were isolated from 100 (87.71%) of 114 fetal tissue samples and all of them were identified as B. melitensis. These isolates identified as B. melitensis were also confirmed by the Bruce-ladder PCR in the presence of relevant amplified products representing specific gene regions. Bronchopneumonia and hepatitis were the most important pathological lesions. TNF-α and IFN-γ immunoreactivities were significantly increased in the brucellosis group compared to the control group. In conclusion, it is supported by the data obtained from this study that cytokines such as TNF-α and IFN-γ were highly effective in the cellular immune response (Th1) developed against ovine brucellosis.