The natural history of hereditary and BRCA1- and BRCA2-associated epithelial ovarian cancer may differ from that of sporadic disease. The purpose of this study was to compare the clinical characteristics of BRCA1- and BRCA2-associated hereditary ovarian cancer, hereditary ovarian cancer with no identified BRCA1/2 mutation, and ovarian cancer in population-based controls. BRCA1 and BRCA2 mutation testing was carried out on index cases from 119 families with site-specific epithelial ovarian cancer or breast-ovarian cancer. We estimated overall survival in 151 patients from 57 BRCA1 and BRCA2 mutation families and compared it with that in 119 patients from 62 families in which a BRCA1/2 mutation was not identified. We compared clinical outcome and data on tumor histopathology, grade, and stage. We also compared survival in familial epithelial ovarian cancer, whether or not a mutation was identified, with that of an age-matched set of population control cases. Overall survival at 5 years was 21% (95% confidence interval, 14-28) in cases from BRCA1 mutation families, 25% (8-42) in BRCA2 mutation families, and 19% (12-26) in families with no identified mutation (P = 0.91). Survival in familial ovarian cancer cases as a whole was significantly worse than for population controls (P = 0.005). In the familial cases, we found no differences in histopathological type, grade, or stage according to mutation status. Compared to population control cases, mucinous tumors occurred less frequently in the familial cases (2 versus 12%, P<0.001), and a greater proportion of the familial cases presented with advanced disease (83% stage III/IV versus 56%; P = 0.001). We have shown that survival in familial ovarian cancer cases is worse than that in sporadic cases, whether or not a BRCA1/2 mutation was identified, perhaps reflecting a difference in biology analogous to that observed in breast cancer.