The purpose of this study was to determine the frequencies of hereditary and familial breast cancers among Lower Silesian women. The questionnaires, dealing with cancer episodes in first-and second-degree relatives, were sent to 5,000 females, who were diagnosed with breast cancer between 1984 and 2005. Twenty-five percent of the questionnaires were completed and returned. Their analysis and further counseling revealed that 24.9% of the responders met the criteria for familial breast cancer (FBC), including 10.5% definitive cases. Mutations in BRCA1 were detected in 32.5% and 1.9% of patients with definitive and suspected FBC, respectively. They all represented three of the abnormalities of the BRCA1 gene: 300T/G, 4153delA and 5382insC. No mutations of BRCA2 were found in material studied. Although a fraction of FBCs identified in our study was similar to those described in other European countries and in the United States, the percentages of genetic mutations seen on routine tests were relatively low. Consequently, the standardized analysis of oncological pedigree seems to be a more valuable diagnostic tool if patients with familial aggregations of breast cancer are targeted in a prophylactic context only.