Between 70 and 75% of ovarian carcinomas are not discovered until they have reached an advanced stage III or later. Efforts should therefore be concentrated on earlier diagnosis. Ovarian cancer is not an entirely silent disease. Today, it is known that there are key symptoms which, depending on their frequency and intensity, can serve as warning signs to clinicians and patients. Mass screening for ovarian cancer is not currently possible because of a lack of specific markers for use in biological and imaging techniques, although new markers are now being developed. Screening every six or twelve months with the CA 125 blood test plus a transvaginal ultrasound is restricted to women at risk. Certain teams have proposed preventive bilateral adnexectomy for such women. The ovary is a complex organ subjected to a hormonal environment and affected by immune system dysfunctions. There now appears to be consensus on the influence of hormones in ovarian cancer, namely the beneficial role of pregnancy, breast feeding and in particular oral contraception, as well as the deleterious role of hormone replacement therapy (HRT). However, the two main arguments put forward, incessant ovulation and exposure to gonadotropins, do not explain all the epidemiological data. It is through a better understanding of the etiology of ovarian cancer that new therapies can be developed. The theory of cancer immune surveillance, whereby lymphocytes have a sentinel role of recognizing and constantly suppressing malignant cells, provided a starting point for research into antitumoral immunotherapy. The first trials of vaccination by direct injection of tumor antigens or „loaded“ dendritic cells today offer considerable hope for patients.