The article presents the results of a study of the spectrum of mutations in the BRCA1 / 2 genes associated with the development of hereditary breast and ovarian cancer in patients of South Russia with malignant ovarian neoplasms.Mutations in the BRCA1 gene were determined by real-time PCR: 185delAG, 300T> C, 2080delA, 4153delA, 5382insC, 3819delGTAAA, 3875delGTCT; in the BRCA2 gene - 6174delT in 178 patients with a histologically verified diagnosis of ovarian cancer.The study included epithelial tumors (malignant) - 98.1%, and granulosa cell tumors - 1.9%. Of the epithelial tumors, the most common was high-grade serous carcinoma (78%). Based on the results of genotyping, the prevalence of germline mutations in the BRCA1 / 2 genes was revealed at 20.8%. The higher rate of genetic changes is obviously associated with hereditary history (40% of patients). Of the seven identified mutations, 5382insC (67.6%) was revealed more frequently. All patients confirmed the same mutation in the tumor. There were no cases of somatic changes in BRCA1/2. The prevalence of BRCA1 mutations was noted in the group of patients with low-grade serous carcinoma, in which all cases of mutations in the BRCA2 gene were identified.Thus, in patients with OC living in the south of Russia, the mutation frequency in the BRCA1 / 2 genes was 20.8%. The distribution of mutation types with predominance of 5382insC BRCA1 (67.6%) corresponds to the ratio of their occurrence in populations of European countries. BRCA1 / 2 mutations were recorded more frequently in the group of patients with high-grade serous carcinoma.