Cigarette smoking may affect each of the currently proposed mechanisms of ovarian carcinogenesis. Whether cigarette smoking has any effect on the development of ovarian cancer has not been adequately evaluated. To study this issue, the authors examined data from the Cancer and Steroid Hormone Study, a multicenter, case-control study of gynecologic cancers conducted between December 1, 1980, and December 31, 1982, in eight geographic areas of the United States. This analysis utilized data on 494 women with newly diagnosed epithelial ovarian cancer and 4,238 population-based control women 20-54 years of age. There was no association of epithelial ovarian cancer with dose of cigarette smoking, age smoking started, time since smoking started, or time since smoking last occurred. Simultaneous adjustment for age, parity, history of oral contraceptive use, and other potentially confounding factors did not alter these results.