Dietary data from a population-based case-control study of 172 epithelial ovarian cancer cases and 172 controls were analysed. A significant (P less than 0.01) dose-response relationship was found between intake of fat from animal sources and risk of ovarian cancer, but plant fat was not associated. Although the effect of animal fat was confounded by education, an adjusted odds ratio of 1.8 persisted for those in the upper quartile compared to the lower quartile of consumption (P for trend = 0.03). After adjustment for animal fat intake, calorific and protein intake had minimal effects on risk. Total vegetables were found to be somewhat protective, but the mechanism of action was unclear. Weight, height and relative weight (weight/height2) were not related to risk of ovarian cancer.