The present study reports just 4 cases of cancer of the ovary which occurred in 3 families with a history of cancer of the ovary. The authors reviewing the literature of the last 15 years have tried to indicate the present status of knowledge of the features of ovarian familial cancer. At present, as there are no specific enzymatic, immunological, reliable genetic markers nor screening tests, the only prophylaxis that is available is bilateral oophorectomy. As the epithelium of the ovary and of the peritoneum are embryologically derived from the same sources, this prophylactic procedure cannot completely abolish the risk of the development of cancer of the peritoneum in these families.