The epidemiologic data collected to date have provided some important and provocative clues as to the etiology of ovarian cancer. The recognition of familial clustering of this disease has led to exciting advances in understanding the genetics involved. The contribution of endocrine factors has been well documented in the epidemiologic literature, leading to important insights into the process of carcinogenesis. Clearly, additional information is needed to further explain the interplay of genetic, physiologic, and life style factors, to lead to a better understanding of the disease, and ultimately to a means of prevention and control.