This extension to a currently funded research project entitled “Are there interactions between the genetic make-up of an individual and specific factors in the environment that determine risk of ovarian cancer, and can this knowledge be used in prevention?” is to establish and co-ordinate an international collaboration of investigators carrying out genetic association studies in ovarian cancer. The aims of this collaboration are to create a resource of at least 4,000 cases of invasive ovarian cancer and 4,000 controls, and to organize a systematic approach to identifying and testing candidate genes for ovarian cancer.