This study included 20 selected female patients with breast cancer, 30 of their female relatives (sisters and daughters), and 10 healthy females as a control group. Genomic DNA was extracted from peripheral blood lymphocytes of all the subjects, and the polymerase chain reaction was carried out using specific primers for BRCA1 (exons 2 and 8) and BRCA2 (exons 9, 11, and 21). The mutations were detected using a single-strand conformation polymorphism assay and heteroduplex analysis. Finally, the sample variants and their controls were sequenced. Mutations were detected in 44% of the study population, with 18% found in the BRCA1 gene and 26% attributed to BRCA2. Five sequence variants were identified, including two frameshift mutations, one nonsense mutation, and two missense mutations. Therefore, we conclude that germline mutations in two major genes, BRCA1 and BRCA2, may have an important influence on the predisposition and development of familial breast cancer.