This case -control study, conducted in Zhejiang, China during 1999 -2000, investigated whether dietary factors have an aetiological association with ovarian cancer. Cases were 254 patients with histologically confirmed epithelial ovary cancer. The 652 controls comprised 340 hospital visitors, 261 non-neoplasm hospital outpatients without long-term diet modifications and 51 women recruited from the community. A validated food frequency questionnaire was used to measure the habitual diet of cases and controls. The risks of ovarian cancer for the dietary factors were assessed by adjusted odds ratios based on multivariate logistic regression analysis, accounting for potential confounding demographic, lifestyle, familial factors and hormonal status, family ovarian cancer history and total energy intake. The ovarian cancer risk declined with increasing consumption of vegetables and fruits but vice versa with high intakes of animal fat and salted vegetables. The adjusted upper quartile odds ratio compared to the lower quartile was 0.24 (0.1 -0.5) for vegetables, 0.36 (0.2 -0.7) for fruits, 4.6 (2.2 -9.3) for animal fat and 3.4 (2.0 -5.8) for preserved (salted) vegetables with significant dose-response relationship. The risk of ovarian cancer also appeared to increase for those women preferring fat, fried, cured and smoked food. British Journal of Cancer (2002) Ovarian cancer is the seventh most common cancer in women and the leading cause of death among gynecological cancers (Kristensen and Trope, 1997). However, little is known of its aetiological factors (World Cancer Research Fund, 1997). Dietary factors, especially vegetables, fruits and fat intake, have been suggested to influence ovarian cancer risk (Snowdon, 1985;La Vecchia et al, 1987;Shu et al, 1989;Tzonou et al, 1993;Risch et al, 1994;Kushi et al, 1999;Parazzini et al, 2000). Shu et al (1989) found a significant positive dose-response relationship between intake of fat from animal sources and ovarian cancer, and a somewhat protective effect from vegetables, in a case -control study in China. The aim of this case -control study is to further assess the association between dietary factors and epithelial ovarian cancer, which accounts for more than 90% of all ovarian malignancies (Cotran et al, 1999). MATERIALS AND METHODS Study design and participantsA case -control study was conducted in Hangzhou, China, between July 1999 and June 2000. Two hundred and fifty-five hospital patients with epithelial carcinoma of the ovary were identified. To ensure complete ascertainment of cases, all medical records and laboratory pathology reports were reviewed during the period of the study. Pathological diagnoses were based on the International Histological Classification of Ovarian Tumours (Cotran et al, 1999;Underwood, 2000). A total of 254 patients (non-response rate 0.04%) participated in the study. Inclusion criteria for cases were defined to be women under 75 years of age, who were residents (at least 10 years residence in Zhejiang province) and who had been histopatho...