Studies of the histopathology of ovarian cancer arising in patients with germline mutations in BRCA1 or BRCA2 have shown inconsistent findings. We analyzed the large number of tumors from women enrolled in the Gilda Radner Familial Ovarian Cancer Registry for correlations between histopathology and BRCA mutation status. Histopathology slides and reports were reviewed for histology, grade, and stage for cancers of the ovary or peritoneum in 220 women from 126 Gilda Radner Familial Ovarian Cancer Registry families. At least one affected member of each family was analyzed for mutations in the BRCA1 and BRCA2 genes, and tumors from mutation-positive families were compared with those from mutation-negative families. Of 70 patients from 38 BRCA1-positive families, 69 had epithelial ovarian carcinoma and one had a dysgerminoma. Fifteen of 16 patients from nine BRCA2-positive families had epithelial ovarian cancer, and one had a primary peritoneal cancer. Of 134 patients from 79 BRCA-negative families, 118 had epithelial ovarian carcinoma, 11 had ovarian borderline tumors, three had nonepithelial tumors, and two had primary peritoneal carcinoma. There were fewer grade 1 (p < 0.001) and stage I (p = 0.005) cancers in patients from BRCA-positive families than in patients from BRCA-negative families. Neither mucinous nor borderline tumors were found in the BRCA-positive families. In conclusion, ovarian cancers arising in women from BRCA-positive families are more likely to be high-grade and have extraovarian spread than tumors arising in women from BRCA-negative families. Borderline and mucinous tumors do not appear to be part of the phenotype of families with germline mutations in the BRCA genes.