Brenner’s tumor is a rare fibroepithelial ovarian neoplasia, histologically characterized by an epithelial component similar to the transitional epithelium of the urinary tract. The histogenesis of neoplasm, which only rarely secretes estrogens, is still controversial. The Authors describe the clinical and anatomopathological features of six cases come to their observation. Only one of these was malignant; the woman died 18 months after diagnosis. There is no strict correlation between histological picture and biological behaviour. Only this one can give assurance on the benign or malignant nature of Brenner’s tumor.