Food and beverage frequency questionnaires were administered to 215 white women with epithelial ovarian cancer and to 215 control women matched by age, race, and residence. Women with ovarian cancer favored foods higher in animal fats and consumed significantly greater amounts of animal fat and significantly less vegetable fat compared with control subjects. Adjusted for potential confounding due to differences between case and control subjects in weight and parity, there was a significant trend for increasing risk for ovarian cancer with increasing animal fat consumption. No major differences were noted between patients and control subjects in coffee, alcohol, and tobacco use. Dietary factors may partially explain variation in the international incidence of this disease and suggest a new pathway for its etiology.