Although growing numbers of tubal carcinomas in carriers of BRCA1 and BRCA2 germline mutations have been reported, very little is known about the nature and frequency of their possible precursor lesions. The aim of this study is to investigate the occurrence of atypical proliferative tubal lesions in grossly normal fallopian tubes from 26 women with BRCA1 and BRCA2 germline mutations who underwent prophylactic salpingo-oophorectomy and whose ovaries were histologically negative for carcinoma. Fallopian tubes from 49 women who had undergone hysterectomy with salpingo-oophorectomy for uterine leiomyoma served as controls. In the 22 BRCA1-mutated women, there were two in situ carcinomas and two atypical hyperplasias of the tubal epithelium. The tubes of the BRCA2-mutated women and of the 49 control women did not show any atypical proliferation. The frequency of proliferative lesions of the tubal epithelium, including in situ carcinoma, appears to be increased in BRCA1 mutation carriers. Removal and thorough examination of the fallopian tubes at the time of surgical prophylaxis for ovarian cancer is therefore recommended.