Breast cancer is rare in men, and family history of the disease is a risk factor. The recently discovered BRCA2 gene on chromosome 13q is thought to account for some families with increased risk of breast cancer, including male breast cancer. We describe a family with multiple cases of male breast cancer but, interestingly, no increase in female breast cancer. Linkage to the BRCA2 region is demonstrated and all the affected men share the same haplotype for the BCRA2 markers and loss of the other alleles in their tumours.