Approximately 5%-10% of all breast cancers are inherited as the result of germline mutations in the BRCA1 gene. Large genomic rearrangements (LGRs) in BRCA1 have not been well-researched in the Egyptian population. Using multiplex ligation-dependent probe amplification, we showed BRCA1 rearrangements in 4/22 cases (18.2%) of familial breast cancer. No influence of having multiple breast cancer cases within the family was observed in patients diagnosed at < or ≥ 45 years and having BRCA1-positive LGRs. However, focusing on cases with first-and second-degree relatives affected, we observed a significant difference between the percentage of patients with BRCA1-positive versus BRCA1-negative LGRs. Our results provide the first evidence that LGRs in BRCA1 exist in the Egyptian population. Screening for these alterations may be desirable when breast cancer patients are diagnosed at an early age, especially if these cases have first-and second-degree of relatives with breast cancer.