The etiology of ovarian cancer is multifactorial. The aim of this literature review is to identify and quantify risk factors from their prevalence, relative risk and the etiological fraction. The most important endogenous risk factors are genetic disposition, parity and infertility. Women who have relatives with ovarian cancer and other adenocarcinomas have relative risks of ovarian cancer of 3 and 1.5 respectively. Nulliparity increases the risk by 100% compared to parous women and infertility implies a further 100-150% increased risk among nulliparae. Use of oral contraceptives in five years decreases the risk by 50% for at least 15 years.