5% of ovarian cancers occur in a hereditary predisposition context. Clinical syndromes are defined by 3 or more cases of breast or ovarian cancers, or cancers from the Lynch-type II spectrum (colon, endometrium...) in one family branch. When the diagnosis is established, genetic counselling is provided to the kindred, a molecular diagnosis is undertaken for BRCA1 and BRCA2 genes, screening for ovarian and other at risk cancers is proposed, or prophylactic oophorectomy is proposed for at least 35 years old women without children conception projects.