Purpose: The aims of this study were to determine the incidence of BRCA mutations among Ashkenazi Jewish patients with fallopian tube carcinoma (FTC) or primary peritoneal carcinoma (PPC), to study the clinicopathologic features of these cancers, and to estimate the risks of these cancers in association with a BRCA mutation. Patients and Methods: A retrospective review at two institutions identified 29 Jewish patients with FTC and 22 Jewish patients with PPC. These patients were genotyped for the three Ashkenazi Jewish BRCA founder mutations (185delAG and 5382insC in BRCA1 and 6174delT in BRCA2). Surgical and pathologic information, family history, and survival data were obtained from hospital records. All statistical tests were two sided. Results: Germline BRCA mutations were identified in five of 29 patients with FTC (17%) and nine of 22 patients with PPC (41%). Mutation carriers had a younger mean age at diagnosis than patients without a mutation (60 v 70 years; P = .002). The overall median survival was 148 months for mutation carriers and 41 months for patients without a mutation (P = .04). For BRCA mutation carriers, the lifetime risks of FTC and PPC were 0.6% and 1.3%, respectively. Conclusion: Substantial proportions of Ashkenazi Jewish patients with FTC or PPC are BRCA mutation carriers. Patients with BRCA-associated FTC or PPC are younger at diagnosis and have improved survival compared with patients without a BRCA mutation. Although the lifetime risks of FTC or PPC for patients with BRCA heterozygotes are greater than those for the general population, the absolute risks seem relatively low.